A geochemical approach on reconstructing Upper Pleistocene environmental conditions from wadi...

A geochemical approach on reconstructing Upper Pleistocene environmental conditions from wadi deposits ndash an example from the Wadi

Sabra (Jordan)

Manuel Bertrams Jens Protze Eileen Eckmeier and Frank Lehmkuhl

with 8 figures and 3 tables

Abstract Stratified Upper Pleistocene sediment sequences have been geochemically investigated in the arid environment of the Wadi Sabra (Southern Jordan) The wadi fills are associated to archaeological finds of Upper Palaeolithic to Epipalaeolithic age and intended for a reconstruction of palaeoenvironmental condi-tions during and after the time of the initial human occupation As the mineralogical and sedimentological composition of the sediments is highly influenced by the nature of the local source rock the significance of provenance analysis and depositional processes is limited Therefore geochemical characteristics were consulted as indicators for secondary alteration and weathering processes

A combined approach of CNS analysis carbonate fractionation electrical conductivity and colour spectrophotometry supported by selective XRF scanning and chemical iron extraction was used to elaborate the nature and characteristics of various fine grained calcrete horizons Although a detailed palaeoenviron-mental interpretation of these deposits was complicated by an inhomogeneous distribution of precipitated solutes a diversity of source materials and potential sedimentation gaps the results indicate that most of the fine grained deposits represent fossil and relict palaeosol horizons Consequently the study area might have experienced repeated phases of landscape stability and initial soil development during the latest phase of the Upper Pleistocene before a change in hydrological conditions initiated a distinctive erosional period that prevailed during most of the Holocene until modern times

Key words spectroscopy geoarchaeology calcretes palaeosols iron oxides Jordan

1 Introduction

In arid environments the availability of water from springs or torrential streams often provides exploitable areas for human settlements Wadis generally act as sediment traps or sediment basins and the investigation of these terrestrial deposits close to archaeological sites provides contiguous information on palaeoenvironmental conditions for ancient periods of human occupation which can be superior to more distal climate proxies such as lacustrine records lake level variations or speleothems Many fluvial and torrential wadi deposits do not account for detailed investigations due to their homogeneous character or discordances in the sediment record (RoumlgneR amp Smykatz-kloSS 1991) However phases of landscape stability and non-deposition often induce second-ary changes of geochemical characteristics which are preserved as significant palaeosol horizons (yaalon 1990 WRight 2007)

In Southern Jordan the Wadi Sabra valley system has preserved various remnants of stratified wadi deposits which are connected to archaeological sites ranging from Initial Upper Palaeolithic to Epipalaeolithic (~50 ndash18 ka) in age (gebel 1983 1988 Schyle amp UeRpmann 1988) These sites are currently under investigation by the Collaborative Research Centre 806 ldquoOur Way to Europerdquo

copy 2013 Gebruumlder Borntraeger Verlagsbuchhandlung Stuttgart Germany wwwborntraeger-cramerdeDOI 1011270372-88542013S-00156 0372-885413S-00156 $ 750

Zeitschrift fuumlr Geomorphologie Vol 58 (2014) Suppl 1 051ndash080 ArticlePublished online November 2013B

52 Manuel Bertrams et al

(RichteR et al 2012) Due to a relatively small catchment area dominated by sandstone geology most of the Upper Pleistocene wadi fills in the study area are of homogeneous character which complicates detailed provenance analysis or separation of depositional processes (beRtRamS et al 2012a) In addition OSL dating emerged to be complicated due to low luminescence sensitivity and inhomogeneous radiation characteristics of the quartz grains

In some geomorphological positions however fine grained calcretic horizons are intercalated or appear as surface crusts covering the fragile sandy material and increasing the preservation po-tential (naSh amp mclaRen 2007) Comparable deposits from semiarid and arid environments have often been described but the palaeoenvironmental evidence and attribution to certain depositional environments is ambiguous (eg lattman 1973 RoumlgneR amp Smykatz-kloSS 1991 moUmani et al 2003 Retallack amp hUang 2010 mclaRen et al 2012) The nature and origin of these calcretic deposits therefore represents the main issue of this paper Next to field studies pedological meth-ods like colorimetry and chemical iron extraction were applied to obtain additional information on the intensity of past weathering processes and the attribution of iron oxide bearing sands to different geological bedrocks The combination of both approaches is used to identify and evalu-ate the potential to reconstruct the geomorphologic history and palaeoenvironmental conditions conveyed from these ancient deposits

2 Study area and investigated sections

The Wadi Sabra valley system is a highly dynamic geomorphological environment situated in the eastern escarpment of the Dead Sea Transform It originates 5 km southwest of Wadi Musa and the ancient Nabataean capital of Petra (Fig 1) Draining the Jordanian plateau in south-western direc-tion the wadi has a catchment of ~ 90 km2 with elevations ranging from ~ 1720 ndash 210 m asl The geology is dominated by Palaeozoic sandstones of the Ram formation (bendeR 1974) mainly the reddish fluvial Umm Ishrin Sandstone of Cambrian age which forms a distinctive belt along the western slope of the highland area that faces the Wadi Araba (makhloUf amp abed 1991 baRjoUS 2003) Additionally local outcrops of light coloured fluvial sandstones (Ordovician Disi formation discordantly overlain by the Early Cretaceous Kurnub formation) and Mesozoic marine limestones (Early Cretaceous NaprimeUr formation) influence the mineralogical and geochemical composition of the wadi fills Under the modern climatic conditions the largest part of the Wadi Sabra is affected by arid conditions with an annual precipitation of lt 100 mm subsequently decreasing to lt 50 mm towards the Wadi Araba which forms a wide geomorphic depression from the southern Dead Sea basin in the North towards the gulf of AqabaEilat in the South Consequently the catchment area is mostly dominated by riparian Irano-Turanian steppe and desert scrub vegetation (al-eiSaWi 1996 McLaren et al 2012) However the catchment also comprises some higher elevated areas along the western edge of the eastern plateau region around the cities of Wadi Musa and Taibeh that experience higher precipitation around 150 ndash170 mma (Royal joRdanian geogRaphic cen-tRe 2007 joRdan meteoRological depaRtment 2013) These areas receive higher amounts of rainfall particularly during the winter months thus providing higher runoff and a narrow strip with a more developed area of Mediterranean vegetation (beRtRamS et al 2012b) Soil formation is mostly inhibited under the modern climatic conditions (khReSat 2001 koUki 2006 mclaRen et al 2012) except for some local surface crust formation

53A geochemical approach on reconstructing Upper Pleistocene

The abundant wadi fill sequences in the study area (Fig 2A) are predominantly of fluvial origin and slightly inclinated downstream (2 ndash 5deg) Particularly in the Upper Wadi Sabra these sediments are covered by a thick calcareous duricrust up to 100 cm in thickness (Fig 2B) resulting from a long-term surface exposure and contiguous weathering processes (eitel 1994) This crust inhibits rainwater percolation which infers that the geochemical characteristics in the protected underlying sediments may provide evidence for past climatic fluctuations

During three field campaigns in Jordan from 2009 to 2011 the sediment stratigraphy of the Wadi Sabra was investigated in different composite sections (cf Fig 8) A particular emphasis was given to the nature of calcretic layers and surface crusts In the northern part of the study area (Sabra 3 North) a sediment stratigraphy of 7 m thickness was exposed near to a side channel of the main wadi Due to the steepness of the slope the locality was investigated in two composite sec-tions SBR2009_9 and SBR2009_10 (Fig 2C) Below the surface crust (unit I) and a dark coloured archaeological horizon (unit II) unit IIIndashV in the upper section (SBR 2009_9) and unit VI and VII in the lower section (SBR 2009_10) feature interstratifications of decalcified reddish to yel-lowish coloured fluvial and fluvio-aeolian sands and concrete calcretic horizons The lowermost sedimentary unit (VIII) finally features 3 m of homogeneous fluvial sands with a horizontal layer-ing being stabilized by a minor content of calcium carbonate (Fig 3) A detailed description of the sedimentological and archaeological features of this locality has already been published (beRtRamS et al 2012a) From its sedimentological characteristics unit VIII was interpreted as representing a continuous phase of fluvial aggradation while the fine grained intercalations in the overlying sands were hypothesized to present phases of landscape stability under near surface weathering conditions Due to the high degree of stratification it was not possible to obtain any OSL data from the sections but the Early Epipalaeolithic stone artefacts (Qualkhan and KebaranNebekian inventories) from above and below the surface crust clearly point to a Marine Isotopic Stage (MIS) 2 age shortly after the Last Glacial Maximum (LGM) at least for the upper section (Fig 2B)

Fig 1 Digital elevation model ( jaRviS et al 2008 ASTER GDEM 2010) showing the location of the study area the catchment of the Wadi Sabra (dashed line) and investigated sites


An additional section (SBR2009_15) was investigated in a lower geomorphological position of the main wadi channel situated a few hundred meters north of the Sabra 3 locality (Fig 2A+D) Below a thin layer of surface sands enriched with silts and carbonate this 33 m thick section also features both homogeneous reddish (unit II and IV) and yellowish (unit III) sand units and an abundant platy structured silt layer (unit V) 25 cm in thickness appearing in more discordant bed-ding thus probably indicating a depositional hiatus In contrast the lowermost sedimentary unit (VI) comprises light coloured sands with fine indurated silt laminations and parallel iron band-ings (Fig 2D) Whether these sediments derive from a different provenance or testify different environmental conditions for iron oxide weathering and leaching had to be verified by laboratory investigations

Fig 2 A) Pleistocene wadi fill sequences in the Upper Wadi Sabra B) Highly stratified sediment section below the massive surface crust (unit I) at Sabra 3 North C) Investigated sediment stratigraphy at the site of Sabra 3 North D) Stratified section with characteristic fine grained layers and iron bands in the Upper Wadi Sabra E) Pleistocene wadi deposits around the Ahmarian site of Al-Ansab in the Lower Wadi Sabra F) Surface soil under desert pavement north of Al-Ansab


In the southern part of the study area the archaeological site of Al-Ansab is situated on top of a 20 m thick remnant of fluvial deposits near to a converging tributary wadi being protected from erosion by an uplifted limestone ridge (Fig 2E) At the base of the recent wadi channel the local stratigraphy again contains various calcretic deposits However due to a lack of age control by radiometric and archaeological dating from these deposits our focus in this paper will be constrained to small surface sections of homogeneous sands (ANS 2009_3 + 6 ANS 2010_2 + 4) which were investigated in context of the archaeological excavation The site is archaeologically dated to the Ahmarian industry (~ 32 ndash 42 ka BP) and associated OSL samples provided age es-timates of ~ 28 ndash 38 ka (including 1 σ errors) which also point towards a late MIS 3 age of the sediments on top of the remnant (klaSen et al 2011) The surface trenches were sampled in dif-ferent parts of the valley to investigate pedogenic processes at the recent surface Furthermore 14 surface samples (GOE 1-15) were taken over the entire catchment area at those points where spectroscopic data from ASTER satellite images showed an abundant Fe3+ signal which was inter-preted as advanced surface weathering of the sediments in relation to the local bedrock (loumlhReR et al 2013) For methodological calibrations supplementary material was investigated from local bedrock formations and recent channel deposits in the study area as well as from surface calcretes dune sands and lake sediments (gypsum precipitate) from adjacent wadis (Fig 1)

3 Wadi fills as archives of palaeoenvironmental conditions

The sedimentological and mineralogical composition of wadi fills is primarily determined by the parent lithology It also reflects the processes of recycling transport and deposition (Weltje amp von eynatten 2004) The identification of pedogenic horizons in stratigraphies of fluvio-aeolian environments provides evidence for a significant hiatus in the depositional record (haRRiSon amp yaiR 1998) and a longer phase of landscape stability and near surface weathering conditions (WRight 2007 zielhofeR et al 2009) Palaeosols can be identified by horizons or horizontal laminations enriched with salts dust sized particles or other solutes (dan 1983 yaalon 1990) As most pedogenic processes are inhibited in arid environments due to deficient moisture and organic matter accumulation modern surface soils as well as palaeosols are generally not fully developed but remain in an initial state of formation (Retallack 1990) Common features are surface crusts or calcretic layers resulting from a secondary relocation of carbonates or salts either induced by evaporation or by infiltrating rainwater and subsequent erosional exposure (eg bachman amp ma-chette 1977 mack amp jameS 1992 naSh amp mclaRen 2007 WRight 2007)

Although studies on geochemical characteristics of wadi deposits are rare (coRdova et al 2005 mclaRen et al 2012) some methods established in aeolian environments can also be suit-able for wadi fills particularly in sandstone environments which provide a high permeability and an oxidizing environment (eg gaRdneR 1981 toRRent et al 1980 felix-henningSen 2000 baRRett 2002) According to beSleR (2008) the salinity and rubification of quartz sands are the best suitable indicators to attain information on past humid periods in recent drylands In a further state iron oxide weathering may initiate in horizons from which carbonates have been washed out inducing a significant change in soil colour which is related to the amount of available water and the associated formation and release of iron oxides In floodplain environments iron oxide weath-ering can additionally be influenced by fluctuating groundwater controlling redox conditions


31 Carbonates and surface crusts

In the arid regions of the Levant water migration is the dominant soil formation factor induc-ing variations in soil chemical properties (hattaR et al 2010) As a result horizontal calcretic horizons with irregular boundaries and locally varying thickness can be found in the Wadi Sabra over hundreds of meters (Fig 2) The carbonates might either be derived from outcrops of up-lifted limestone formations within the catchment or from the deposition of silt sized aeolian dust originating from deflation areas like dune surfaces in the Wadi Araba or exposed areas of fine grained lacustrine deposits in the Dead Sea depression (khReSat et al 1998) The deposition of pedogenic carbonate can generally be related to two different processes (SchleSingeR 1985 eitel 1994) The formation of thin surface crusts (Fig 2F) is usually the result of evaporation of water from the soil profile inducing an upward (ascendent) dilution of soluble chemical compounds like carbonates and salts Covering of the soil inhibits further percolation of rainwater and subsequent evaporation and thus elevates the surface runoff A vertical growth of the crust layer is thus in-hibited or remains restricted to smaller depressions on the surface where water can accumulate temporarily In contrast the formation of discrete calcic horizons in subsurface areas first requires a fluctuating CO2-pressure in the pore space which is usually found in flooded soils or induced by respiration of roots or microbial activity (loeppeRt amp SUaRez 1996 amit et al 2006) Additionally relatively high amounts of rainfall over a longer period and a high permeability of the soil material are necessary An elevated CO2-pressure may mobilize carbonate solutions and enable a descend-ing dissolution of soluble phases resulting in a supersaturation and precipitation of carbonates at greater depth (mclaRen 2007) The thickness of surface crusts and depth of pedogenic carbonate horizons are often used as indicators for palaeoprecipitation (dan 1983 RoyeR 1999 khReSat 2001) However these estimates require a complete preservation of soils without phases of erosion or colluviation and should therefore be supported by other geochemical proxies (RoyeR 1999)

Some calcretes have also been described as non-pedogenic features eg in the zone of capil-lary rising ground water in dune systems (SemeniUk amp meagheR 1981) or as channel calcretes in arid wadi systems (lattman 1973 mclaRen et al 2004) In the former systems plants may use phreatic water thus releasing high contents of carbonates and salts in solution In the latter case carbonate saturated river- and ground-waters induce an inorganic cementation of coarse grained alluvium Furthermore lacustrine or palustrine evaporites are often misinterpreted as pedogenic calcretes (eg RoumlgneR amp Smykatz-kloSS 1991 veRRecchia 2007) thus demonstrating that the complex nature of carbonate precipitates deserves a detailed investigation of sedimentological and geochemical characteristics

32 Soil salinity in arid environments

Salinity generally refers to the presence of major dissolved inorganic solutes in aqueous samples or solutions In soil science it represents the soluble and readily dissolvable fraction of salts in an aqueous extract of the soil sample (RhoadeS 1996) which is influenced by climate groundwater and soil properties (yaalon 1961 Smettan amp blUme 1987) Variations in soil salinity can either be attributed to primary evaporation from closed ponds or secondary accumulation by pedogenic processes (haRRiSon amp yaiR 1998) If not present in local bedrock material dissolved salts may


originate from aeolian dust which was deflated from dry lake deposits (sample Qa2) or surface crusts (Table 2) During arid phases the water reaches only shallow depths in the soil profile and salts get evaporated a few cm above the water table due to capillary action (paRiente 2001) This process leads to the development of thin salt crusts near to the surface a common feature in arid soils (Fig 2F) However during phases with higher precipitation the water may quickly reach a depth from where evaporation is no more effective thus enabling a relocation of dissolved salts to greater depth Consequently a higher salinity in subsurface horizons might indicate former pre-cipitation events or even phases with increased rainfall However in alluvial environments these processes can be altered by a high groundwater table The separation of relocation processes can be achieved by lateral investigation of different trenches and by using variations in solubility induced by different ionic conductivities of salts (SchalleR 2000) In soils from arid environments gyp-sum (CaSO42H2O) is the predominant calcium sulphate mineral It is usually of pedogenic origin and often appears as white surface crust resulting from dissolution of near surface water (loep-peRt amp SUaRez 1996) Under the more soluble salts NaCl has the highest abundance but CaCl2 or KCl might be common as well (Smettan amp blUme 1987 maRion et al 2008 zhU amp yang 2010) Both gypsum and chlorides have higher solubilities in water than carbonates (NaCl 359 glndash1 gt CaSO42H2O 24 glndash1 gt CaCO3 0014 glndash1) so the vertical distribution of horizons enriched with different solutes (eg saline Bz-horizon gypsic By-horizon calcic Bk-horizon fao 2006) can be useful for the interpretation of evaporate dynamics (cf gile et al 1966 goUdie 1972 maRion et al 2008 Retallack amp hUang 2010 amit et al 2010)

The salinity of sands can provide evidence of more humid periods in the past and may even allow for drawing conclusions on the former rainfall pattern and amount (beSleR 2008) Calcretes are generally related to wetter climate conditions while a high salinity or gypsification is a process of hyperarid conditions (goUdie 1972) In the Levant amit et al (2006 2007) were the first who connected diagnostic soil horizons to specific rainfall regimes They investigated soils on alluvial material in the Negev desert (Israel) and found that arid to hyperarid regions (lt 80 mma precipitation) are exclusively characterized by gypsic and salic soils while in semiarid regions (80 ndash 250 mma) a transition to more saline-calcic to calcic soils occurs Calcic and non-calcic soils without any contents of gypsum or salts can only be found in areas with an annual precipitation of gt 250 mm In general agreement with these findings the research on soils from four different cli-matic regions in Israel by paRiente (2011) defined an abiotic threshold around the 200 mm isohyet

Table 1 Broad classification of saline sediments according to their electrical conductivity and related sedi-mentary processes (modified according to RoWell 1994 beSleR 2008 bUbenzeR amp beSleR 2010)

Electrical conductivity

Classification Sedimentary environment processes

lt 01 mScm non saline Sediments and soils from humid regions

gt 01 mScm saline Sediments and soils from semiarid regionsgt 1 mScm strongly saline Fluvial sandstones or saline soils from arid regions

evaporation and infiltration over longer periodsgt 10 mScm extremely saline Sediments deposited by sea water or terrestrial lakes

pedogenic salt crusts


above which soluble salts are depleted from soils A downward leaching of solutes requires at least a precipitation of 50 ndash100 mma (Smettan amp blUme 1987) creating a common vertical succession of solutes in sandy desert soils (Nitrates amp Chlorides gt Sulphates gt Carbonates) Palaeoclimatic interpretations however require the consideration of ephemeral flooding and groundwater influ-ences (amit et al 2006)

33 Rubification of quartz sands

The colour of soils is generally influenced by moisture organic matter and iron content (Sanchez-maRantildeoacuten et al 1997) Areas with hot and dry climates are particularly favourable to form red sedimentary beds because iron oxides are the predominant colouring agents (WalkeR 1974 folk 1976) while the two other factors play only a minor role In Pleistocene wadi fills the red colour of quartz grains is commonly attributed to two different sources On the one side red sandstones may appear as local bedrock formation providing an allothigenic detrital component of iron ox-ide bearing source material of relocated fluvial or aeolian sediments On the other side it can be induced by rubification a secondary change in soil colour due to intense weathering of iron bear-ing minerals resulting in an in situ alteration and release of iron oxides as thin coatings on quartz grains (coRdova et al 2005 lekach et al 1998 RoSkin et al 2011) This process of reddening usually appears in warm climates with alternating humid and dry seasons but is also found in floodplain environments with alternating redox conditions (gaRdneR amp pye 1981) Iron is mainly released from less stable minerals in the form of ferrihydrite [(Fe3+)2O3 ∙ 05H2O] and subsequently transformed into more stable Fe3+-forms like hematite [Fe2O3] or goethite [FeO(OH)] by internal dehydration and aggregation under oxidizing conditions (SchWeRtmann 1966 1969 gaRdneR 1981 SchWeRtmann amp coRnell 2000) The intensity of hydrolysis is controlled by the nature and amount of leaching solutions and therefore enables a linkage to moisture conditions (Retallack 1997) Only a minimum of moisture is required to initiate alteration from original iron minerals to hydroxides but with increasing moisture rubification is reinforced over longer time periods as long as periodical dehydration occurs during intermittent dry periods (folk 1976) However minor amounts of iron oxides can also be introduced by fluctuating ground-water or the deposition of aeolian dust so these factors should be considered as well (gaRdneR amp pye 1981)

Fluvial sandy soils are commonly characterized by low amounts of total iron (lt 5 ) and a low quantity of amorphous oxides or hydroxides illustrating weak soil formation (venegaS et al 1994) Hematite is the most abundant iron oxide in arid environments as its formation requires high temperatures and temporary drying In contrast goethite is the dominant iron oxide under rather humid conditions although it is abundant in desert soils as well (lafon et al 2004) It appears as advanced state of iron weathering under the presence of water and oxygen but may also result from oxidation of carbonate rich materials with a high abundance of CO3-ions (SchWeRtmann 1959)

For a qualitative description of soil colour the classic cylindrical Munsell notification (mUn-Sell coloR company 1975) and the tristimulus CIE-LAB system (commiSSion inteRnationale de l eclaiRage 1978) are the most frequently used systems in geoscientific research (toRRent et al 1983 toRRent amp baRRoacuten 1993 mathieU et al 1998) These systems also provide the potential for a reliable identification of different iron oxides in the soils (ScheinoSt amp SchWeRtmann 1999) Goethite dominated soils usually have yellowish-brown colours with a munsell hue of 5 YR ndash


25 Y whereas hematite rich materials are more reddish with hues lt 5 YR (SchWeRtmann amp lentze 1966 SchWeRtmann amp coRnell 2000 coRnell amp SchWeRtmann 2003) Due to electron transitions in the visible spectrum free iron oxides hold significant spectral signatures which make them easily distinguishable Goethite generally shows an absorption feature around 485 nm and hematite at 535 nm (Fig 7A+B) In contrast quartz as the dominant mineral in sands has no significant spectral characteristics in the VIS range and therefore does not affect the reflectance (SheRman amp Waite 1985 gRove et al 1992 ScheinoSt et al 1998 ben-doR et al 2006)

In addition diverse numerical indices can be used to relate the qualitative colour data to the intensity of colouring and rubification eg in context of weathering intensities (toRRent et al 1983 mathieU et al 1998 ben-doR et al 2002) These spectroscopic indices often appear in posi-tive correlation to laboratory measurements of total iron or hematite content (toRRent et al 2007) As calculated amounts depend on a linear regression from different materials and source areas the prediction of hematite content from colour should always be based on a calibration which was obtained from materials which are similar to the ones being studied (toRRent et al 1983)

Many studies have investigated palaeoclimatic inferences in connection to reddening of fossil sediments and soils (eg folk 1976 felix-henningSen et al 1989 RoSkin et al 2011) but some authors also provided critical views concerning the palaeoclimatic evidence of iron oxide weather-ing as soil colour is influenced by diverse sedimentological and geochemical factors (WalkeR 1974 folk 1976 gaRdneR amp pye 1981) Consequently the texture and composition of investigated sediments should be relatively homogeneous and other sediment characteristics like depositional indicators or the occurrence of evaporate minerals and faunal or floral remains should also be ac-counted for in order to facilitate the interpretation

4 Methods

41 Geochemical analysis

The electrical conductivity (EC) of an extract is a variable that is proportional to salt concentration and can therefore be used to calculate the content of total soluble salts (TSS) in sediments The amount of salts that can be leached from a sediment or soil is directly related to the amount of water and the solubility of the present salts Easy soluble salts like NaCl CaCl2 or KCl can already be leached by 11 or 125 soilwater extractions Less soluble salts like gypsum can only be deter-mined by using larger amounts of water (Schlichting et al 1995) Accordingly different soil-water extracts (15 125) were used for different fractions of water soluble salts (goUdie 1972 RhoadeS 1996) In a first step all samples were air dried homogenized and sieved to lt 2 mm Sample ali-quots of 5 ndash10 g were agitated in the respective amount of distilled water All extracts were shaken for one hour and conductivity was measured after an intercepting hour in the clear suspension with a microprocessor conductivity meter (WTW LF196) All EC values were calculated in mScm and normalized to temperature (25 degC) and to saturation extracts (soilwater 11) The conductivity of the 15 extract was used to calculate Total Soluble Salt (TSS) concentrations (Schlichting et al 1995 SchalleR 2000) while Easily Soluble Salts (ESS) were calculated from the 125 extract (according to RUck amp StahR 1987 felix-henningSen 2000) The difference of both fractions represents the less soluble salt fraction XRF analysis (mcaliSteR amp Smith 2007 Shackley 2010)


was supportively applied for selected samples from SBR2009_9 on an energy dispersive Spectro Xepos device Due to high amounts of quartz masking other elemental distributions the analysis was performed in powdered mode on the fine fraction (lt 63 microm) thus enabling a qualitative geo-chemical identification of elemental compounds and solutions

For further geochemical characterization of the sediments the total concentrations of car-bon (C) and sulphur (S) were determined using a CHNS elemental analyzer (HECAtech Eu-roEA3000) Additionally the content of CaCO3 was determined by dissolving the sample material in 10 HCl and calculating the amount of produced CO2 using a gas-volumetric procedure (Schei-bler method SchalleR 2000) so that the content of organic carbon (Corg) could be quantified by difference between total C and carbonate C (nieUWenhUize et al 1994 felix-henningSen et al 2008) The total values for sulphur were then used to calculate the content of gypsum by molar mass under the assumption that the latter is by far the most dominant calcium sulfate mineral in the investigated soils (loeppeRt amp SUaRez 1996 poRta 1998) In addition the presence of gypsum was constrained for selected samples by treating the supernatant of the salinity measurements with acetone (C3H6O RichaRdS 1954) In support of the geochemical analysis sedimentological characteristics were determined by laser diffraction (Beckmann Coulter LS13320) after sample pre-treatment with H2O2 and Na4P2O7 to elaborate the influence of particle sizes on permeability and transport of solutes For the granulometric analysis grain size classes were calculated accord-ing to FAO (2006)

42 Colour Spectrophotometry

Soil colour was measured on dried and homogenized sediment and soil samples using a spectro-photometer (Konica Minolta CM-5) Colour spectra were obtained by detecting the diffused re-flected light under standardized observation conditions (2deg standard observer illuminant C) in the range of visible light (360 ndash740 nm) in 10 nm increments In this range the spectral curves usually have a positive slope and differ from soil to soil as the colour is mostly influenced by the absorp-tion characteristics of dominant minerals or oxidic colouring agents like hematite and goethite (mathieU et al 1998) The spectral reflectance data was converted into the Munsell colour system (mUnSell coloUR company 1975) and the CIELAB colour space (commiSSion inteRnationale de l eclaiRage 1978) by using the software SpectraMagic NX (Konica Minolta) The CIE Lab system expresses the extinction of light as luminance on a scale from L 0 (absolute black) to L 100 (absolute white) and colour as chromacity coordinates on red-green (a) and blue-yellow (b) scales We used a bivariate plot of the CIE a- and b-values (according to nagano et al 1994) to illustrate the relation of samples and background materials in the colour space on iron oxide weathering paths from the instable ferrihydrite to the stable forms of hematite (along the a-axis) and goethite (along the b-axis)

Different redness indices developed for colour spectroscopy and remote sensing were ob-tained for a calculation of hematite contents (toRRent et al 1983 baRRon amp toRRent 1986 toRRent amp baRRon 1993) These indices provide an established alternative to chemical extraction techniques and enable a reliable estimation of the abundance of this iron oxide on a large number of samples The Redness Rating [RRMun = (10-H)CV] according to toRRent et al (1980) is probably the most established one in colorimetric studies as it is linearly correlated to hematite


contents up to 4 Due to this quantitative limitation baRRon amp toRRent (1986) proposed an-other redness index based on the CIE colour system [RLab = a(a2+b2)051010bL6] Both indices were calculated based on a linear regression obtained from European soil material (toRRent et al 1983) and showed a strong correlation to indices commonly applied for remote sensing applica-tions (eg CITM and RITM according to mathieU et al 1998 RTM according to bUllaRd amp White 2002) Consequently the RLab and RRMun data were used for further calculation of quantitative hematite contents Only those samples that showed significant variations for both indices were additionally investigated for iron extraction with ammonium oxalate (Feo) and Na-dithionite (Fed) (SchWeRtmann 1959 mehRa amp jackSon 1960) As high carbonate contents mask the redness of sandy palaeosols samples with gt 5 CaCO3 were excluded from quantitative calculations

In addition to the spectral reflectance plots the continuum removed absorption analysis was applied to the spectral reflection curves of selected samples This method enhances characteristic absorption features by normalizing monotonous reflectance spectra to a unity reflectance value and subsequently dividing the reflectance at each wavelength by the level of a continuum line created by a segmented upper hull curve (claRk et al 1987 ben-doR et al 2006 noomen et al 2006) For a calibration of significant spectral characteristics (Fig 7A+B) data for synthetic iron oxides were obtained from the ASTER spectral library (gRove et al 1992 baldRidge et al 2009)

5 Results

51 Evaporite dynamics

Despite of their fluvial origin the local bedrocks in the study area contain low amounts of CaCO3 so that local outcrops of limestone and aeolian input have to be considered as primary carbon-ate source to the alluvial sediments Lithogenic components of salts and gypsum were found in some samples from the local reddish Umm Ishrin and white Disi sandstone formations so these compounds should at least partially derive from within the catchment (Table 2) As a result of dust input and evaporation processes surface sections may be enriched with silt sized particles and carbonates (beSleR 2008 hattaR et al 2010) Section ANS2009_7 in the Lower Wadi Sabra illustrates these processes This 50 cm thick section features thin light coloured and fine grained laminations covering homogeneous sandy wadi fills located directly below the desert pavement at the recent surface (Fig 2F) These laminations are selectively enriched with carbonate (335 ) gypsum (12 ) and salts (45 ) and appear as a common feature in different parts of the study area However comparable laminations could not be found in other near surface sections around Al-Ansab which only comprise homogeneous sands stabilized by contiguous but low carbonate contents lt 5 (beRtRamS et al 2012a)

In the ancient sediment deposits at Sabra 3 North (Fig 3) the massive silt dominated layers have significantly higher carbonate concentrations in the range of 10-30 (CaMg ratio 77ndash198) and abundant amounts of clay (lt 20 ) and organic matter the latter evidenced by dark greyish colours and organic carbon concentrations up to 09 (SBR 2009_10 unit VII) In contrast the fluvial sands and sandy sub-units generally contain low amounts of CaCO3 (lt 5 ) and some lay-ers particularly in the upper section of Sabra 3 North are even decalcified to values lt 05 This suggests that these horizons were affected by a secondary leaching of carbonates which resulted in


the formation of massive calcretisized horizons appearing in concordant bedding within the sur-rounding sands As organic particles are included in minor amounts these processes should have occurred in a surface or near-surface environment (hattaR et al 2010)

Elevated contents of gypsum (up to 33 ) could only be detected in sub-unit IVa (130 cm) and IVc (180 cm) of this locality Other fine grained horizons like the massive surface crust or unit VII contain low amounts of gypsum so that a positive correlation of Ca and S remains constricted to this part of the section Moreover the discordant transition between unit III and unit IV is indica-tive for a sedimentation gap The nature of sub-unit IIIb (90 cm) is specified by the fact that this is the only calcretic horizon without an elevated amount of organic matter In addition the adjacent sandy sub-units IIIa and IIIc are completely decalcified (Fig 3)

High amounts of easy soluble salts were found at the base of the surface crust (40 cm) and in the calcretic unit VII in the lower part of the stratigraphy XRF analysis showed a strong correla-tion of Na and Cl (r = 086 n = 24) with highest contingents at the base of the surface crust (unit I) being coincident with the highest values for Easy soluble salts (ESS = 987 ) in this section This shows that ESS should be derived from halite (SchleSingeR 1985) Comparable salt contents were also detected in unit IV and V However higher amounts of less soluble salts indicate the presence of gypsum in these units (felix-henningSen et al 1989) Overall the ubiquitous character of salts complicates a reconstruction of genetic processes and a detailed pedogenic classification for most palaeosol horizons

Fig 3 Sedimentology geochemistry and colour indices of the Sabra 3 North stratigraphy in the Upper Wadi Sabra Designation of sediments cS = coarse sand mS = medium sand fS = fine sand Si = silt C = clay stratigraphic units are described in the text


Tabl

e 2

Sed

imen

tolo

gica

l ge

oche

mic

al a

nd c

olor

imet

ric c

hara

cter

istic

s of

inve

stig

ated

bac

kgro

und

sam

ples

fro

m g

eolo

gic

bedr

ocks

(Qx1

ndashQx6

) de

posi-

tiona

l cal

ibra

tion

sam

ples

(Qa1

ndash 2)

rece

nt d

une

field

s an

d to

psoi

l cal

cret

es

Due

to a

mas

sive c

hara

cter o

f raw

mat

eria

l so

me sa

mple

s did

not

prov

ide s

uffic

ient a

moun

ts of

subs

trate

in p

owde

red m

ode

Sam

ple

Cla

ssifi

catio

nLo

catio

nSa

nd

()

Silt

()

Cla

y (

)C

aCO

3 (

)G

ypsu

m

()

TSS

(

)M

unse

ll C

olou

r (H

VC

)R

RM

unH

em

()

Qx1

A

bu K

hush

ayba

San

dsto

neW

adi S

abra

709

523

12

593

00

00

002

73 9

40

YR

759

393

03

016

Qx2

D

isi S

ands

tone

Wad

i Sab

ra77

21

198

82

91 0

10

003

008

99

0Y

R7

793

110

00

05

Qx3

Um

m Is

hrin

San

dsto

neW

adi S

abra

893

0 8

73

197

00

41

831

98 4

20

YR

533

397

43

170

Qx4

U

mm

Ishr

in S

ands

tone

Wad

i Sab

ra77

06

191

83

76 0

17

002

010

24

0Y

R5

373

665

22

03Q

x6

Kur

nub

Sand

ston

eW

adi S

abra

630

432

08

488

20

20

000

3310

00

YR

822

159

00

004

Qa1

Rece

nt c

hann

el d

epos

itW

adi S

abra

902

0 7

16

264

35

60

000

62 4

90

YR

564

348

31

125

Qa2

La

cust

rine

gyps

um la

yer

Wad

i Gar

anda

l ndash

massi

vendash

149

87

775

55 ndash

ndashndash

ndashndash

ndash

Dun

e1D

une

field

Wad

i Ara

ba96

30

23

81

32 7

22

000

040

80

0Y

R6

233

871

20

52D

une2

Dun

e fie

ldW

adi A

raba

933

2 4

30

238

85

10

020

56 7

80

YR

630

408

14

059

Dun

e3D

une

field

Wad

i Sad

r93

59

42

42

17 3

77

000

042

73

0Y

R5

933

881

80

72

Cal

cret

e1Re

cent

tops

oil c

alcr

ete

(10

cm)

Wad

i Mus

andash

massi

vendash

910

30

000

73 ndash

ndashndash

ndashndash

ndashC

alcr

ete2

Rece

nt to

psoi

l cal

cret

e (3

0 cm

)W

adi M

usa

ndashma

ssive

ndash87

99

000

034

ndashndash

ndashndash

ndashndash

Cal

cret

e3Re

cent

tops

oil c

alcr

ete

(50

cm)

Wad

i Mus

andash

massi

vendash

664

30

005

64 8

90

YR

695

336

05

024


Section SBR2009_15 (Fig 4) also contains different types of massive silt units that deserve for a geochemical characterization A thin laminated layer at the recent surface (unit I) is significantly enriched with silt particles CaCO3 (gt 40 ) and minor amounts of salts and organic matter The alluvial sands of unit IIndashIV are completely decalcified except from a fine concordant layer at 90 cm depth (unit IIIb) which also contains carbonate and organic matter (06 ) thus being similar to unit I In contrast unit V (180 ndash 200 cm) represents a platy structured discordant and dark col-oured silt layer composed of fine laminations of different colour and consistency This deposit is partly enriched in carbonate (17 ) and highly soluble salts (up to 8 ) while also containing minor amounts of gypsum and organic matter Additionally the highest abundance of clay within the study area (22 ) was detected in this unit Two additional silt laminations at 260 cm (Unit VIb) and 290 cm depth (Unit VId) are also indurated and characterized by similar grain size distribu-tions amounts of gypsum and TSS However these deposits are completely free of CaCO3 and the layer morphology is quite inhomogeneous and not horizontally bedded which indicates a different formation process

In an adjacent region on the Eastern Plateau a few km north of Wadi Musa a calcretisized coarse grained channel deposit in geomorphological topsoil position was sampled in order to cor-relate geochemical characteristics to deposits from the Wadi Sabra catchment Different peak con-centrations of solutes with depth were also found here but total values for CaCO3 attest for a pure carbonate matrix (Table 2) thus prohibiting a direct comparison and illustrating the high diversity and complicated nature of calcrete deposits (WRight 2007)

52 Iron oxide weathering

In the study area the reddish Umm Ishrin Sandstone formation appears as the dominant bedrock material and light coloured sandstones metamorphic rocks and limestones appear in minor con-tingents so that different colours of sands may be induced by different source materials (Table 2) Local outcrops of Mesozoic limestones provide minor contents of carbonates to the sands thus

Fig 4 Sedimentology geochemistry and colour indices of the SBR2009_15 stratigraphy in the Upper Wadi Sabra Designation of sediments cS = coarse sand mS = medium sand fS = fine sand Si = silt C = clay stratigraphic units are described in the text


increasing the luminance (CIE L) and lowering the separability of reddish colouring components (Sanchez-maRantildeoacuten et al 1997) An evaluation of secondary weathering dynamics thus requires a distinct provenance analysis for the alluvial sediments as different source materials have to be excluded The applied methodology shows that colorimetry can be used as a reliable tool for delin-eating different sandstone sources

Fig 5 shows a bivariate plot of the CIE a and b values for all sandy wadi deposits and se-lected background samples from different parts of the study area The plot provides a good dis-crimination of the progress of iron weathering for the different stratigraphic units The dominant reddish colour of sands is inherited from the local Palaeozoic Ummprime Ishrin sandstone formation (black dots) The surface material is closely related to the bedrock although a change in iron oxide mineralogy was evident from remote sensing analysis (loumlhReR et al 2013) Evidence for secondary alteration is only provided by a decrease of a values This could be related to a leaching of hematite which seems to be a dominant process in the initial stage of weathering in this arid environment The b-values were not affected by these processes so that the position of the sample data in the plot does not indicate the dominance of a specific iron oxide (Fig 5A)

The surface sections around the site of Al-Ansab in the lower part of the study area also do not bear a distinct evidence for iron oxide alteration (Fig 5B) Similar to the individual surface samples most of the values are arranged in parallel direction to the hematite pathway and even plot on a larger distance of decreasing redness in relation to the bedrock No progression or depth dependence of changes in b-values could be detected and therefore a dominant influence of he-matite on the colouring of the Al-Ansab sediments still has to be suggested

Fig 5 Bivariate plot of the CIE a and b values (according to nagano et al 1994) for investigated surface samples stratified sand units and selected bedrock samples from different parts of the study area


In contrast the amount of goethite increases from the base of the wadi towards the recent surface in the Sabra 3 sections (Fig 5C) The samples from the base section (SBR2009_10) plot in the same range as the surface samples showing a close relation to the bedrock material Proceeding towards the top (section SBR2009_9) a slight increase of the b values in unit IV provides first evidence for initial goethite formation due to chemical weathering The yellowish colour in this unit still appears in particular relation to vertical root marks The sand units directly below the surface crust have the highest b values (up to 292) of the section which indicates an increased influence of goethite This assumption is confirmed by the spectral curves (Fig 6) and the applica-tion of the continuum removal approach (Fig 7) Unit II and III are characterized by a high varia-tion in total reflectance with both the shallowest and steepest gradient (Fig 6B) while the spectral curves of all other units at Sabra 3 show minor variations (Fig 6C) Furthermore the continuum removed absorption spectra testify that the lower section (unit VIII) is dominated by a mixture of hematite and goethite while the overlying sands show a dominance of goethite particularly in unit III and unit VI as indicated by a distinct minimum at 485 nm (Fig 7C) In unit IIIc this goethite dominance is coincident with a slight shift towards finer grain sizes (Fig 3) which might indicate a temporary input of aeolian sands or dust (bUllaRd amp livingStone 2002)

Colouring intensities and hematite contents show only minor fluctuations between 1 and 2 over the whole stratigraphy The hematite content decreases at the base of unit III in the upper sec-tion which facilitates a dominance of yellowish colours (Fig 3) The fluctuation of Redness Rating values indicates an intense weathering dynamic in this part of the stratigraphy The highest values for Redness Rating (RRMun = 52) and respectively hematite content (203 ) were detected in the local Umm Ishrin Sandstone (Table 2) suggesting that hematite in the sandy wadi fills is generally depleted after deposition The dark archaeological horizon at Sabra 3 (unit II) yielded a very high value in the RLab-index (153) which was not detected by the RRMun Additional results from XRF measurements and chemical iron extraction showed that the archaeological horizon is significantly

Fig 6 Visible reflectance spectra of all sand samples from near surface sections at the site of Al-Ansab (A) sections SBR 2009_9 + 10 (B+C) and section SBR2009_15 (D)


enriched in iron in relation to the surrounding sediments Low amounts of NH4-oxalate extract-able iron from the same sample however indicate a weak pedogenic activity (FeoFed = 013 ndash 016) in this layer Moreover XRF analysis revealed a high abundance of Manganese (Mn) restricted to this horizon which could also induce the dark colouring (Table 3)

In section SBR2009_15 the bivariate colour plots clearly show a bisection of the samples in relation to their stratigraphic position (Fig 5D) The upper units (IIndashIV) are similar to the proxi-mate Sabra 3 stratigraphy Again the initial reddish colour of the sediments contains the same signature like the Umm Ishrin Sandstone which is altered by a secondary formation of Fe3+ In contrast the lowermost sedimentary unit VI is characterized by lower a and higher b values Sample Q130 at 270 cm depth has by far the highest b value (394) of all investigated samples On the one side this plot shows that these samples are closely related to a different source rock material (Disi Sandstone grey dot) which is presently exposed near to the recent valley bottom in different parts of the valley (Fig 5) On the other hand horizontal yellowish-reddish iron bands are found directly below the fine laminated silt layers at 260 cm and 290 cm depth The redness indices also reveal a clear discordance in this section as the hematite contents in the upper part of the section are comparable to the ones from the Sabra 3 sections and the background samples In contrast hematite suddenly decreases in unit VI to values below 02 which should be related to the different source rock and is not the result of a complete bleaching as the a and b values show no relation to the Umm Ishrin Sandstone The thin iron bands are represented by minor peaks of a-values and one significant peak of b at 260 cm depth indicating an upward leaching of goethite towards the fine grained unit VIb that inhibits further relocation (Fig 4) The spectral data and continuum removed reflectance curves thus reveal a comprehensive dominance of goethite in this lower part of the section (Figs 6D +7D) A comparable but constricted spectral signature was also derived from the Disi Sandstone

Fig 7 Visible reflectance spectra (R) and continuum removed spectra (RH) of synthetic iron oxides (A+B) and selected samples from sections SBR2009_9 + 10 (C) and section SBR2009_15 (D) data for synthetic samples of hematite (Ondash1 A) and goethite (OHndash 2 A) according to Grove et al (1992) and BaldridGe et al (2009)


Age control for section SBR2009_15 can only be derived from stratigraphic investigations as radiometric ages and archaeological finds are lacking Due to its lower geomorphological position in the main wadi channel (Fig 8) and its relation to local bedrock outcrops which are presently exposed at the valley bottom a younger and potentially Holocene age of this section has to be estimated

6 Discussion

61 Palaeosol horizons in ancient wadi fill sequences

Pedogenesis in arid environments is usually a polygenetic procedure If the sediment material is permeable and rainfall is abundant carbonates can be leached to greater depth forming calcic horizons over time (Retallack 1997) In the leached pedogenic units rubification then releases larger amounts of iron oxides which crystallize as fine dispersed red coloured hematite upon dry-ing (bReSSon 1974 Ubeid 2011) If supportive conditions prevail pedogenesis proceeds with a secondary alteration of present iron oxides and a subsequent formation of more clayey vertisols In the study area little evidence is found for this latter stage so palaeosol horizons still have to be classified as initial stages of soil formation

Except for some fine grained laminations most investigated surface sections from the study area show only weak pedogenic overprinting and an absence of horizontation This indicates that under the recent arid conditions periodic rainfall events are insufficient to leach evaporates to greater depth (RoumlgneR et al 1999 mclaRen et al 2012) and thus further chemical weathering redoximorphic processes and the secondary alteration of iron oxides are also inhibited The sur-face sands around the site of Al-Ansab (ANS2009_3 + 6 ANS2010_2 + 4) are stabilized by minor contents of CaCO3 and thin topsoil layers enriched with carbonate gypsum and salts under re-cent desert pavement (ANS2009_7) result from an upward moving of solutes with capillary water (SchleSingeR 1985) This process is characteristic for high evaporation and limited leaching and therefore restricted to climatic conditions with high temperatures and low precipitation (dan amp yaalon 1982 Retallack 1990 paRiente 2001)

In contrast the stratified wadi fill sequences in the Upper Wadi Sabra cover various fine grained sedimentary units either indicating a high variability of depositional environments or a secondary postdepositional alteration of the sediments under stable landscape conditions (Fig 3) Inhomogeneous grain sizes and vertical distribution of solutes calcretisized root fragments with related root traces in the rubified sands and layer morphologies with sharp upper and diffuse lower boundaries argue for the occurrence of bioturbation and a pedogenic origin of these sedi-ment layers (Retallack 1990 RoumlgneR et al 1999) Elevated clay contents should be related to secondary relocation as the quartzic bedrock does not provide minerals for a neo-formation of clay particles Moreover a sandy matrix admixed with different amounts of fines is indicative for an alluvial origin of the fine grained sediments which were secondarily enriched with fines and geochemical solutes In most calcic soil horizons the stage of cementation qualifies for stages IIIndashV of palaeosol development (gile et al 1966 bachman amp machette 1977) which is triggered by the high permeability of the sands In contrast marine limestones or terrestrial deposits of fines like paludal or lake sediments generally contain lower amounts of coarse grained clasts but are


rather dominated by silt and clay sized particles (beSleR 2008) and often contain shells or other freshwater fauna (chivaS 2007) which were not detected in the Wadi Sabra Temporary phases of landscape stability could have caused superimposing by different pedogenic processes A general palaeoenvironmental interpretation is complicated by the fact that a complete preservation of the sediment record cannot be proved Consequently a detailed geochemical characterization of spe-cific units is required

The lowermost part of the Sabra 3 North stratigraphy (Unit VIII 400 ndash700 cm) is character-ized by homogeneous sands with moderate carbonate values (2 ndash 6 ) thus representing a continu-ous fluvial aggradation without longer phases of surface exposure where sediments could be de-calcified by rainwater infiltration A coincident geochemical fingerprint was detected in a sample from the recent wadi channel (Table 2) The overlying sediments (Units IndashVII 0 ndash 400 cm) contain various interstratifications of calcretic horizons and decalcified sand units (lt 05 CaCO3) The vertical distribution of solutes is irregular but appears well related to their chemical solubility Elevated salt contents are widely distributed over the whole section The interstratified sand units contain a saline phase (lt 5 mScm) while the fine grained soil horizons contain significantly high-er amounts (gt 10 mScm) with maximum values of 24 mScm which qualifies for a classification as extremely saline (Table 1) Comparable salt concentrations in sandy desert soils were described by Smettan amp blUme (1987) from studies in Egypt or by haRRiSon amp yaiR (1998) from the Negev desert in Israel In contrast high amounts of gypsum remain constricted to unit IV (130 ndash 220 cm) and carbonates appear in fine peak concentrations in unit IIndashIV according to their low solubility while occurring in massive bedding in unit I V and VII coincident with a complete absence of gypsum

The boundary morphology of the fine-grained layers can be explained by the temporary suc-cession of deposition and pedogenesis Indistinct boundaries between sand units and palaeosols can be interpreted as a phase where pedogenesis exceeds the rate of sediment accumulation while sharp boundaries result from sudden changes to higher sedimentation rates resulting in a burial

Table 3 Laboratory results from chemical iron extraction and XRF analysis on selected sedimentary units of the Sabra 3 North stratigraphy

Iron extraction (lt 2 mm) XRF Analysis (lt 63 microm)Unit Depth (cm) Fed (ppm) Feo (ppm) FeoFed Fe (ppm) Mn (ppm)

II 60 8151 1019 013 73510 3778

IIIa 80 1674 146 009 17730 143IIIc 100 1456 97 007 18430 118IIIc 120 2620 97 004 30130 74

IVa 140 5749 2038 035 31000 215IVb 170 2863 873 031 27410 141

IVc 180 6331 1261 020 48300 225

IVd 190 4027 679 017 50130 204IVd 210 3615 388 011 46020 343

V 250 5482 873 016 42600 246


of palaeosols (Ubeid 2011) Unit IV with its sharp upper boundary and minor thickness of fine grained sub-units suggests an ascending relocation of solutes by evaporation This part of the sec-tion is thus indicative for near surface weathering under arid climatic conditions (dan amp yaalon 1982 amit et al 2007) as the thin dark coloured laminations enriched with salts particularly gypsum are similar to the ones found in recent surface soils (Fig 2F) The absence of gypsum and salts in unit III could in turn indicate a climatic shift to more humid conditions (lekach et al 1998) In unit I and unit V the maximum content of salts is located a few cm beneath the carbon-ate maximum suggesting a descending migration of both compounds in relation to their solubil-ity which is supported by the abundant thickness of these horizons A groundwater influence is unlikely for this vertical distribution (felix-henningSen et al 2008 zhU amp yang 2010) These massive units rather formed during phases with higher precipitation where CaSO4-compounds have been washed out However salts are still enriched in these units and elevated amounts of Corg can generally not be related to secondary relocation but rather to a subsequent surface exposure (StevenSon 1969 felix-henningSen et al 2008) The palaeosol horizons at this locality are there-fore probably not the result of one single phase of pedogenesis but rather suggest a multigenetic formation history with various phases of initial leaching of solutes followed by a surface exposure due to erosional capping of the overlying sediments

As similar palaeosol horizons are also found in section SBR2009_15 (Fig 4) the pedogenic features are not a local phenomenon restricted to specific geomorphological positions but rather a general feature of fluctuating moisture conditions in this arid environment (goUdie 1972 hattaR et al 2010) The enrichment of silt and solutes at the recent surface (unit I) is a common feature in the study area and probably the result of evaporative processes or input of aeolian dust A tempo-rary swamp like paludal sedimentation might be alternatively suggested considering the fine lami-nated nature and high contents of clay and Corg in unit V (goRing-moRRiS amp goldbeRg 1990 veR-Recchia 2007) but no desiccation cracks or burrows are found in support of this hypothesis The horizontal laminations in unit VI potentially inhibited rainwater infiltration during ancient times so that leaching and precipitation of solutes might have been influenced by groundwater fluctua-tions In this case the obtained proxies for iron oxide weathering provide useful indicators for identifying the influence of fluctuating water tables in the secondary weathering of these deposits

62 Weathering dynamics in sandy wadi fills

Even in arid climatic phases the weathering dynamics in the Wadi Sabra support a minor altera-tion of dominant iron oxides As the local Umm Ishrin sandstones provide hematite rich sedi-ments the neo-formation of goethite in related deposits can be taken as an indirect proxy for palaeohumidity (felix-henningSen et al 1989) Most investigated samples from the wadi fills contain mixtures of hematite and goethite The CIE Lab colour plots indicate that the progress of iron oxide weathering in the study area is related to geomorphological processes and landscape development In a first step weathered sediments from local bedrocks get relocated by fluvial andor aeolian processes Due to the influence of water the reddish colour component (CIE a) decreases after deposition which is indicative for a selective dissolution of hematite that induces a bleaching of the sediments (loumlhReR et al 2013) Whether a decrease of red colouring already proceeds in the stage of relocation or initiates after the sediments have been redeposited is not


detectable However the investigated surface trenches from the study area clearly indicate that the progress of iron oxide weathering is inhibited under the recent climatic conditions An advanced stage of weathering is only documented in ancient sediments particularly in the Sabra 3 sections where the colour plots still show a relation to the bedrock but a decrease of a-values was progres-sively followed by a significant increase of b-values which shows that the influence of goethite in colouring of these samples increases This process is well documented by the continuum removed absorption spectra showing two characteristic minima which are correlated to the ones found in synthetic goethites (Fig 7)

In concordance to the geochemical results the colour values from all surface samples and sections around Al-Ansab testify that processes of intensive rubification do not appear under recent climatic conditions (Fig 6A) During humid seasons weathering of iron bearing minerals forms hydrates of iron oxide whilst in the arid season the iron minerals are usually dehydrated which results in an improvement of their crystalline structure (beSleR 2008) In moister periods hydrolysis and dissolution of iron oxides may induce a bleaching of the sediment column Intensive reddening and alteration from the initial sediment colour derived from the bedrock material were however suggested to require distinctly alternating moisture conditions and repeated pedogenesis (WagneR et al 2011)

The sediment from the active channel has similar characteristics as the local bedrock material indicating fluvial redeposition in an active geomorphological environment without in situ weath-ering Only on floodplains or in inactive areas of wide migrating channels soil formation may in-duce a leaching of exchangeable bases and a secondary alteration of iron oxides (amit et al 2007) Hematite generally dominates the colour of natural samples with hematite-goethite mixtures if present in specific amounts (SchWeRtmann amp lentze 1966) An increase in yellowish colouring by the presence of goethite either indicates selective leaching of hematite or local input of goethite-rich aeolian material from a different source region Due to the homogeneous sedimentological composition of the sands an aeolian influence was considered to be of minor importance and restricted to the sediment sources within the wadi catchment (beRtRamS et al 2012a) The close relation of colour values to local sandstone formations and the different sedimentological and geochemical composition of investigated dune sands from adjacent regions (Table 2) improve this evidence Consequently the diversity of colours in the ancient wadi deposits rather reflects in situ rubification and neoformation of Fe3+ in relation to the local source rock

At Sabra 3 North all sandy deposits are closely related to the Umm Ishrin Sandstone (Fig 5) Unit VIII displays an initial weathering stage with a dominance of hematite as colouring agent which supports the idea of a continuous fluvial relocation of weathered bedrock sediments An increase of rubification intensities in unit VI and IV is illustrated by higher values for RRMun and particularly RLab thus indicating a secondary alteration of hematite under oxidizing conditions primarily along root tracks In unit III rubification intensities and hematite contents decrease and goethite has a higher influence on the sediment colour as supported by the CR-plots of associated samples (Fig 7C) Comparable weathering dynamics can be suggested for the upper units of section SBR2009_15 In contrast unit VI at this locality is clearly derived from a different source material therefore a direct comparison to the other sands is not possible Moreover the aforementioned possibility of fluctuating groundwater conditions is supported by laminated iron bandings and a complete leaching of the surrounding sediments with low iron contents and insignificant spectral


signatures (Fig 7D) respectively As a comparably significant colorimetric signature is lacking at other localities the influence of groundwater by ephemeral flooding should have been restricted to this lower geomorphological position while higher elevated areas probably experienced an earlier phase of pedogenesis under terrestrial conditions induced by rainfall variations (Fig 8)

Overall colorimetric investigations are a sensitive method for an investigation of weathering dynamics in ancient wadi fills The CIE and Munsell colour values discriminate the progress of iron oxide weathering and facilitate an approximate provenance analysis of the sands in relation to derivative bedrocks The applied continuum removal algorithm supports this information by defining specific spectral characteristics of iron oxides and the RRMun and RLab indices (according to toRRent et al 1980 baRRon amp toRRent 1986) provide the opportunity for a quantification of hematite contents by linear regression analysis The RLab seems to be the more sensitive weathering index in this arid environment but overestimates the hematite contents in dark coloured samples because the calculation of this index is highly dependent of the lightness (L value) This became evident for the archaeological horizon at Sabra 3 North (unit II) for which the RRMun and CIE a and b values indicate a minor influence of hematite and the CR-analysis even testifies a high influence of goethite (Fig 7C) Moreover a high abundance of Mn was revealed by XRF analysis This element generally has a higher solubility in relation to Fe and is therefore more easily relo-cated in the sediment profile eg under fluctuating ground water conditions (felix-henningSen et al 1989) Due to the clearly defined nature of this sediment unit and small remains of charcoal and dispersed organic particles the influence of fire or other anthropogenic activities is also con-siderable as a cause for the enrichment of Fe and Mn in this archaeological context (demeyeR et al 2001) The fact that both high contents of Mn and an increase of organic particles were detected in this horizon complicates the interpretation concerning to a possible anthropogenic influence or fluctuating groundwater This issue thus deserves further research

Fig 8 Conclusive sketch through the upper part of the study area illustrating the geomorphological position of investigated sediment sections in relation to depositional environments and potential ground water influ-ence The vertical axis is superelevated to illustrate stratigraphic relations


63 Palaeoenvironmental implications

In the Wadi Sabra highly stratified wadi deposits are the result of diverse transitional phases of sedimentation and landscape stability indicating climatic fluctuations over longer time periods which have also been reported from other geoscientific studies in the Levant (eg goRing-moRRiS amp goldbeRg 1990 RoumlgneR et al 1999 baRtov et al 2002 baR-mattheWS et al 2003 RobinSon et al 2006 vakS et al 2006 gRUneRt et al 2007 liSkeR et al 2010 fRUmkin et al 2011) In this context a secondary precipitation of carbonates elevated organic matter and root penetrated ho-rizons are generally related to phases with higher moisture availability (Retallack 1990 khReSat 2001) A dense vegetation cover is locally inferred by root tracks and rhizoconcretions but not a general feature of all palaeosol horizons Consequently semiarid conditions are considerable as salts and gypsum would have been leached from the sediments under conditions with even higher rainfall The fine grained deposits in the Upper Pleistocene sediment stratigraphies should there-fore be related to rather short phases of slightly moister climatic conditions up to a maximum of 200 ndash 250 mma (felix-henningSen 2000 paRiente 2001 amit et al 2006 2007) However the reconstruction of specific moisture regimes is quite complicated as calcic horizons in semiarid or sub-humid regions are connected to dryer climatic conditions while they represent more humid conditions in drylands (goldbeRg 1986)

Furthermore it has to be noted that the age control on the sediment sequences is relatively inaccurate to date as radiometric dating could not be applied successfully and relative age estimates derive from archaeological finds of the Final Upper Palaeolithic to Epipalaeolithic which are em-bedded in the sediments mostly in near surface positions This suggests that the formation of the fine grained deposits occurred prior to the LGM which is in general agreement with other pal-aeoenvironmental studies in this region (henRy 1986 moUmani et al 2003 mclaRen et al 2004 RobinSon et al 2006 WineR et al 2006) Particularly in the Negev and Sinai region archaeological sites of different periods were reported in comparable geomorphological positions and at least two calcic palaeosols with sharp erosional upper boundaries mark the transition of Upper Palaeolithic to Epipalaeolithic times (goldbeRg 1986 goodfRiend amp magaRitz 1987) The Epipalaeolithic is often associated to palaeosols indicating phases of landscape stability and pedogenesis which lasted until the onset of the Younger Dryas (~ 13 ka) The Holocene is then marked by large scale erosion and narrow entrenchment of the wadi channel until modern times The modern climate in the study area is characterized by arid conditions with high annual temperatures and periodically occurring heavy torrential rainfall events inducing fast runoff and incising erosion

Although the Wadi Sabra is located in the same geographic latitude as the Southern Negev which is reported to have been continuously arid during the last glacial-interglacial cycle (eg amit et al 2006 fRUmkin et al 2011) its catchment potentially received higher amounts of moisture due to the higher topographic elevation During higher intensities of west winds bringing more moisture into the southern Levant during winter this moisture could have reached the highlands on the eastern plateau region as there are not so many topographic barriers within the southern Negev However even an increase of rainstorms during the last glacial period might have had rela-tively low effects on Jordan as the coastline of Israel was located further to the west and the rains mainly affected the highlands of Israel while Jordan was still located in the eastern rain shadow (eg amit et al 2006 enzel et al 2008) A more homogeneous distribution of annual rainfall is


thus rather assumable to have caused alluvial deposition and the formation of palaeosols in the Wadi Sabra

7 Conclusion

The present research provides a general methodological approach on the investigation of alluvial wadi fills in palaeoenvironmental research and is not primarily intended for a detailed contribution to the palaeoclimatic history of the Levant In summary the combination of various palaeoenvi-ronmental indicators provides arguments for alternating and temporary moister climatic condi-tions in the Wadi Sabra at the end of the Pleistocene

1 The secondary relocation of carbonates and salts like gypsum and chlorides in the ancient wadi fill sequences testified by geochemical analysis

2 The advanced pedogenic alteration of decalcified sediments and soil horizons by iron oxide weathering (rubification) in relation to derivative bedrocks and recent surface sands as sup-ported by colorimetry

3 The additional evidence for biogenic activity derived from root casts rhizoconcretions and faunal remains in the investigated palaeosol horizons (cf beRtRamS et al 2012b)

4 The additional evidence for human occupation of the area derived from various archaeologi-cal find layers and surface sites (cf beRtRamS et al 2012a loumlhReR et al 2013)These factors support the hypothesis of environmental conditions which allowed for a contin-

uous human occupation in this environment during Upper Palaeolithic and Epipalaeolithic times However a detailed evidence for specific moisture conditions or annual distribution of rainfall can only roughly be estimated due to the limited evidence from the sediments and the low number of studies available from comparable environments Moreover it remains not completely distinguish-able whether the formation of initial palaeosols at the highest morphologic positions was partly influenced by fluctuating ground water conditions thus preceding the main incision phase of the wadi or occurred independently from the influence of ground water dynamics

Acknowledgments

This study is funded by the German Research Foundation (DFG) in context of the multidiscipli-nary Collaborative Research Centre 806 ldquoOur Way to Europerdquo eileen eckmeieR is funded by the DFG-project EC 4011-1 Archaeological excavations were accomplished by juumlRgen RichteR and daniel Schyle (University of Cologne Institute for Prehistoric Archaeology) Supportive OSL dating was conducted by nicole klaSen and alexandRa hilgeRS at the Department of Geog-raphy (University of Cologne) Additional thanks go to Rene loumlhReR for cartographic support in Fig 1 maRianne dohmS for analytical guidance in the laboratory as well as michael baaleS and michael lemke for providing photographs for Fig 2 Field work from 2009 to 2011 took place in close cooperation with the Department of Antiquities (DOA) of Jordan for whom we are greatly indebted for the continuous support of the project Finally the authors would like to thank olaf bUbenzeR peteR felix-henningSen joumlRg gRUneRt SUe mclaRen and affiliated members of the AK ldquoDesert Margin Research ndash Wuumlstenrandforschungrdquo for providing supportive information on the evaluation and interpretation of arid sedimentary archives


References

al-eiSaWi D (1996) Vegetation of Jordan ndash Regional Office for Science and Technology for the Arab StatesUNESCO Cairo Office Cairo 284 pp

amit R enzel Y amp ShaRon D (2006) Permanent Quaternary hyperaridity in the Negev Israel resulting from regional tectonics blocking Mediterranean frontal systems ndash Geology 34 509 ndash 512

amit R lekach J ayalon A poRat N amp gRodek T (2007) New insight into pedogenic processes in extremely arid environments and their paleoclimatic implications ndash the Negev Desert Israel ndash Quatern Int 162 ndash163 61ndash75

amit R enzel y gRodek t cRoUvi o poRat n amp ayalon a (2010) The role of rainstorms in the formation of calcic soil horizons on alluvial surfaces in extreme deserts ndash Quatern Res 74 177ndash187

bachman G O amp machette M N (1977) Calcic soils and calcretes in the southwestern United States ndash United States Department of the Interior Geological Survey ndash Open-File Report 77-794 163 pp

baldRidge A M hook S J gRove C I amp RiveRa G (2009) The ASTER Spectral Library Version 20 ndash Rem Sens Environ 113 711ndash715

baR-mattheWS M ayalon A gilmoUR M mattheWS A amp haWkeSWoRth C J (2003) Sea-land oxy-gen isotopic relationships from planktonic foraminifera and speleothems in the Eastern Mediterranean region and their implication for paleorainfall during interglacial intervals ndash Geochimica et Cosmo-chimica Acta 6717 3181ndash 3199

baRjoUS M O (2003) The Geology of Petra and Wadi al Lahyana area map sheets No 3050-I and 3050-IV ndash The Hashemite Kingdom of Jordan Natural Resources Authority Geology Directorate Geological Mapping Division Amman Bull 56 96 pp

baRRett L R (2002) Spectrophotometric color measurement in situ in well drained sandy soils ndash Geo-derma 108 49 ndash77

baRRon V amp toRRent J (1986) Use of the Kubelka-Munk theory to study the influence of iron oxides on soil colour ndash J Soil Sci 37 499 ndash 510

baRtov Y Stein M enzel Y agnon A amp RecheS Z (2002) Lake levels and sequence stratigraphy of Lake Lisan the Late Pleistocene precursor of the Dead Sea ndash Quatern Res 57 9 ndash 21

ben-doR E levin N SingeR A kaRnieli A amp bRaUn O (2002) Quantitative mapping of the soil rubification process on sand dunes using field and airborne sensors ndash AVIRIS Airborne Geoscience Workshop Proceedings 2002 ndash Available from httpavirisjplnasagovproceedings2002_tochtml (accessed 02102012)

ben-doR E levin N SingeR A kaRnieli A bRaUn O amp kidRon G J (2006) Quantitative mapping of the soil rubification process on sand dunes using an airborne hyperspectral sensor ndash Geoderma 131 1ndash 21

bendeR F (1974) Geology of Jordan ndash Borntraeger Berlin 196 ppbeRtRamS M pRotze J loumlhReR R Schyle D RichteR J hilgeRS A klaSen N Schmidt C amp

lehmkUhl F (2012a) Multiple environmental change at the time of the Modern Human passage through the Middle East First results from geoarcheological investigations on Upper Pleistocene sedi-ments in the Wadi Sabra ( Jordan) ndash Quatern Int 274 55 ndash72

beRtRamS M pRotze J Schyle D klaSen N amp lehmkUhl F (2012b) A preliminary model of Up-per Pleistocene landscape evolution in the Wadi Sabra ( Jordan) based on geoarchaeological investiga-tions ndash In bebeRmeieR W hebenStReit R kaiSeR E amp kRaUSe J (eds) Landscape Archaeology Proceedings of the International Conference held in Berlin 6thndash 8th June 2012 eTopoi ndash J anc Stud spec vol 3 229 ndash 236

beSleR H (2008) The Great sand Sea in Egypt Formation dynamics and environmental change ndash A sediment-analytical approach ndash Developm Sedimentol 59 250 pp Elsevier Amsterdam

bReSSon L M (1974) A study of integrated microscopy rubefication under wet temperature climate in comparison with Mediterranean rubefication ndash In RUtheRfoRd G K (ed) Soil microscopy 526 ndash 541 Limestone Press Kingston (Ontario)

bUbenzeR O amp beSleR H (2010) Sands as Archives of Environmental Change Examples from Egypt Sudan and Namibia ndash In moumlhlig W J G bUbenzeR O amp menz G (eds) Towards Interdisciplinar-ity ndash Experiences of the Long-term ACACIA Project ndash Topics in Interdisciplinary African Studies 15 23 ndash 48 Cologne


bUllaRd J E amp livingStone I (2002) Interactions between aeolian and fluvial systems in dryland envi-ronments ndash Area 34 8 ndash16

bUllaRd J E amp White K (2002) Quantifying iron oxide coatings on dune sands using spectrometric measurements An example from the Simpson-Strzelecki Desert Australia ndash J Geophys Res 107 51ndash 511

chivaS A R (2007) Terrestrial evaporites ndash In naSh D J amp mclaRen S J (eds) Geochemical sediments amp landscapes 330 ndash 364 Blackwell Malden (MA USA)

claRk R N king T V V amp goRelick N S (1987) Automatic continuum analysis of reflectance spectra ndash Proc Third AIS Workshop 2 ndash 4 June 1987 JPL Publ 8730 138 ndash142 JPL Pasadena

commiSSion inteRnationale de lrsquoeclaiRage CIE (1978) Recommendations on Uniform Color Spaces Color-difference Equations Psychometric Color Terms ndash Suppl 2 of publ CIE No 15 (E-131) 21 pp Bureau Central de la CIE Paris

coRdova C E foley C noWell A amp biSSon M (2005) Landforms sediments soil development and prehistoric site settings on the Madaba-Dhiban plateau Jordan ndash Geoarchaeology 201 29 ndash 56

coRnell R M amp SchWeRtmann U (2003) The Iron Oxides ndash Structure Properties Reactions Occur-rences and Uses ndash Wiley-VCH Weinheim 703 pp

dan J amp yaalon D H (1982) Automorphic saline soils in Israel ndash Catena 13 59 ndash79dan J (1983) Soil chronosequences in Israel ndash Catena 10 287ndash 319demeyeR A voUndi nkana J amp veRloo M (2001) Characteristics of wood ash and influence on soil

properties and nutrient uptake an overview ndash Bioresource Technology 773 287ndash 295eitel B (1994) Kalkreiche Decksedimente und Kalkkrustengenerationen in Namibia Zur Frage der

Herkunft und Mobilisierung des Calciumcarbonats ndash Stuttg Geograph Stud 123 193 pp Stuttgartenzel Y amit R dayan U cRoUvi O kahana R ziv B amp ShaRon D (2008) The climatic and

physiographic controls of the eastern Mediterranean over the late Pleistocene climates in the southern Levant and its neighbouring deserts ndash Glob Planet Change 60 165 ndash192

FAO (2006) Guidelines for soil description ndash FAO (Food and Agriculture Organization of the United Na-tions) Rome 97 pp

felix-henningSen P zakoSek H amp liang-WU L (1989) Distribution and genesis of red and yellow soils in the central subtropics of Southeast-China ndash Catena 16 73 ndash 89

felix-henningSen P (2000) Paleosols on Pleistocene dunes as indicators of paleo-monsoon events in the Sahara of East Niger ndash Catena 41 43 ndash 60

felix-henningSen p RUmmel b amp blUme h p (2008) Soil processes and salt dynamics in dune soils ndash In bReckle S W yaiR A amp veSte M (eds) Arid dune ecosystems The Nizzana sands in the Negev desert ndash Ecol Stud 200 225 ndash 238 Springer Berlin

folk R L (1976) Reddening of desert sands Simpson Desert N T Australia ndash J Sediment Petrol 463 604 ndash 615

fRUmkin A baR-yoSef O amp SchWaRcz H P (2011) Possible paleohydrologic and paleoclimatic effects on hominin migration and occupation of the Levantine Middle Paleolithic ndash J Human Evol 604 437ndash 451

gaRdneR R A M (1981) Reddening of dune sands ndash evidence from southeast India ndash Earth Surf Proc Landf 6 459 ndash 468

gaRdneR R A M amp pye K (1981) Nature origin and palaeoenvironmental significance of red coastal and desert dune sands ndash Progr Phys Geogr 19815 514 ndash 534

gebel H G (1983) Sabra 1 und die Wadisysteme um PetraWadi Musa ndash Arch Orientforsch 2930 282 ndash 284

gebel H G (1988) Late Epipalaeolithic ndash Aceramic Neolithic sites in the Petra-Area ndash In gaRRaRd A N amp gebel H G (eds) The prehistory of Jordan The state of research in 1986 ndash Brit Archaeol Rep Int Ser 396 i 67ndash100 Archaeopress Oxford

gile L H peteRSon F F amp gRoSSman J B (1966) Morphological and genetic sequences of carbonate accumulation in desert soils ndash Soil Sci 101 347ndash 360

goldbeRg P (1986) Late Quaternary environmental history of the Southern Levant ndash Geoarchaeology 13 225 ndash 244


goodfRiend G A amp magaRitz M (1987) Carbon and oxygen isotope composition of shell carbonate of desert land snails ndash Earth Planet Sci Lett 86 377ndash 388

goRing-moRRiS A N amp goldbeRg P (1990) Late quaternary dune incursions in the Southern Levant Archaeology chronology and palaeoenvironments ndash Quatern Int 5 115 ndash137

goUdie A (1972) The Chemistry of World Calcrete Deposits ndash J Geol 804 449 ndash 463gRove C I hook S J amp payloR E D (1992) Laboratory Reflectance Spectra of 160 Minerals 04 to 25

Micrometers ndash JPL Publ 922 394 pp Jet Propulsion Laboratory PasadenagRUneRt J W voumllkel J amp leopold M (2007) Reconstruction of changes in fluvial regime using sedi-

ments from Wadi Morikh South Sinai (Egypt) first results ndash In tooth S amp WoodWaRd J C (eds) 4th International Palaeoflood Workshop 24ndash 30062007 36 CreteGreece

haRRiSon J B J amp yaiR A (1998) Late Pleistocene aeolian and fuvial interactions in the development of the Nizzana dune field Negev Desert Israel ndash Sedimentology 45 507ndash 518

hattaR B I taimeh A Y amp ziadat F M (2010) Variation in soil chemical properties along topose-quences in an arid region of the Levant ndash Catena 83 34 ndash 45

henRy D O (1986) The Prehistory and palaeoenvironments of Jordan An overview ndash Paleacuteorient 122 5 ndash 26

jaRviS A ReUteR H I nelSon A amp gUevaRa E (2008) Hole-filled seamless SRTM data V4 ndash Inter-national Centre for Tropical Agriculture (CIAT) ndash Available from httpsrtmcsicgiarorg (accessed 141112)

joRdan meteoRological depaRtment (2013) Climate data from local rain stations ndash Available from httpmetjometeogovjoacc_rain (accessed 22032012)

khReSat S A RaWajfih Z amp mohammad M (1998) Morphological physical and chemical properties of selected soils in the arid and semi-arid region in north-western Jordan ndash J Arid Environ 40 15 ndash 25

khReSat S A (2001) Calcic horizon distribution and soil classification in selected soils of north-western Jordan ndash J Arid Environ 47 145 ndash152

klaSen N Schmidt C hilgeRS A beRtRamS M Schyle D lehmkUhl F RichteR J amp Radtke U (2011) Optical dating of sediments in Wadi Sabra (SW Jordan) ndash 13th International Conference on Luminescence and Electron Spin Resonance Dating 10 ndash14 July 2011 Torun Poland Book of Abstracts

koUki P (2006) Environmental change and human history in the Jabal Harucircn area Jordan ndash Dissertation 201 pp Department of Cultural Studies Archaeology University of Helsinki

lafon S Rajot J L alfaRo S C amp gaUdichet A (2004) Quantification of iron oxides in desert aerosol ndash Atmosph Environ 38 1211ndash1218

lattman L H (1973) Calcium Carbonate Cementation of Alluvial Fans in Southern Nevada ndash Geol Soc Amer Bull 84 3013 ndash 3028

lekach J amit R gRodek T amp Schick A P (1998) Fluvio-pedogenic processes in an ephemeral stream channel Nahal Yael Southern Negev Israel ndash Geomorphology 23 353 ndash 369

liSkeR S vakS A baR-mattheWS M poRat R amp fRUmkin A (2010) Late Pleistocene palaeoclimatic and palaeoenvironmental reconstruction of the Dead Sea area (Israel) based on speleothems and cave stromatolites ndash Quatern Sci Rev 29 1201ndash1211

loumlhReR R beRtRamS M eckmeieR E pRotze J amp lehmkUhl F (2013) Mapping the distribution of weathered Pleistocene wadi deposits in Southern Jordan using ASTER SPOT-5 data and laboratory spectroscopic analysis ndash Catena (in press) httpdxdoiorg101016jcatena201302003

loeppeRt R H amp SUaRez D L (1996) Carbonate and Gypsum ndash In SpaRkS D L (ed) Methods of Soil Analysis Part 3 Chemical Methods SSSA Book Ser 5 437ndash 474 Madison (WIUSA)

mack G H amp jameS W C (1992) Calcic paleosols of the Plio-Pleistocene Camp Rice and Palomas Forma-tions southern Rio Grande rift USA ndash Sediment Geol 77 89 ndash109

makhloUf I M amp abed A M (1991) Depositional facies and environments in the Umm Ishrin Sandstone Formation Dead Sea area Jordan ndash Sediment Geol 71 177ndash187

maRion G M veRbURg P S J mcdonald E V amp aRnone J A (2008) Modeling salt movement through a Mojave Desert soil ndash J Arid Environ 72 1012 ndash1033

mathieU R poUget M ceRvelle B amp eScadafal R (1998) Relationships between satellite-based radio-metric indices simulated using laboratory reflectance data and typic soil colour of an arid environment ndash Rem Sens Environ 66 17ndash 28


mcaliSteR J amp Smith B J (2007) Analytical techniques for investigating terrestrial geochemical sedi-ments ndash In naSh D J amp mclaRen S J (eds) Geochemical sediments amp landscapes 409 ndash 442 Black-well Malden (MA USA)

mclaRen S J gilbeRtSon D D gRattan J P hUnt C O dUlleR G A T amp baRkeR G A (2004) Quaternary palaeogeomorphologic evolution of the Wadi Faynan area southern Jordan ndash Palaeogeogr Palaeoclimatol Palaeoecol 205 131ndash154

mclaRen S J (2007) Aeolianite ndash In naSh D J amp mclaRen S J (eds) Geochemical sediments amp land-scapes 144 ndash172 Blackwell Malden (MA USA)

mclaRen S J leng M J knoWleS T amp bRadley A V (2012) Evidence of past environmental condi-tions during the evolution of a calcretised Wadi System in Southern Jordan using stable isotopes ndash Pal-aeogeogr Palaeoclimatol Palaeoecol 348 ndash 349 1ndash12

mehRa O P amp jackSon m l (1960) Iron oxide removal from soils and clays by a dithionite-citrate system buffered with sodium bicarbonate ndash Clays and Clay Minerals 7 317ndash 327

moUmani K alexandeR J amp bateman M D (2003) Sedimentology of the Late Quaternary Wadi Hasa Marl Formation of Central Jordan a record of climate variability ndash Palaeogeogr Palaeoclimatol Pal-aeoecol 191 221ndash 242

mUnSell coloR company inc (1975) A Color Notation An illustrated system defining all colors and their relations by measured scales of Hue Value and Chroma ndash Gould Library Baltimore 74 pp

nagano T nakaShima S nakayama S amp Senoo M (1994) The use of color to quantify the effects of pH and temperature on the crystallization kinetics of goethite under highly alkaline conditions ndash Clays and Clay Minerals 42 226 ndash 234

naSh D J amp mclaRen S J (2007) Introduction Geochemical sediments in landscapes ndash In naSh D J amp mclaRen S J (eds) Geochemical sediments amp landscapes 1ndash 9 Blackwell Malden (MA USA)

nieUWenhUize J maaS Y E M amp middelbURg J J (1994) Rapid analysis of organic carbon and nitrogen in particulate materials ndash Marine Chemistry 45 217ndash 224

noomen M F SkidmoRe A K van deR meeR F D amp pRinS H H T (2006) Continuum removed band depth analysis for detecting the effects of natural gas methane and ethane on maize reflectance ndash Rem Sens Environ 105 262 ndash 270

paRiente S (2001) Soluble salts dynamics in the soil under different climatic conditions ndash Catena 43 307ndash 321

poRta J (1998) Methodologies for the analysis and characterization of gypsum in soils ndash Geoderma 87 31ndash 46

Retallack G J (1990) Soils of the past ndash An introduction to Paleopedology ndash Unwin Hyman Boston 512 pp

Retallack G J (1997) A Colour Guide to Paleosols ndash Wiley Chichester 175 ppRetallack G J amp hUang C M (2010) Depth to gypsic horizon as a proxy for paleoprecipitation in paleo-

sols of sedimentary environments ndash Geology 38 403 ndash 406RhoadeS J D (1996) Salinity Electrical conductivity and total dissolved solids ndash In SpaRkS D L (ed)

Methods of Soil Analysis Part 3 Chemical Methods SSSA Book Ser 5 417ndash 436 Madison (WI USA)RichaRdS L A (ed) (1954) Diagnosis and Improvement of Saline and Alkali Soils ndash United States Depart-

ment of Agriculture (USDA) Agriculture Handbook 60 166 ppRichteR J melleS M amp Schaumlbitz F (eds) (2012) Temporal and spatial corridors of Homo sapiens sapiens

population dynamics during the late Pleistocene and early Holocene ndash Quatern Int 274 272 ppRobinSon S A black S SellWood B W amp valdeS P J (2006) A review of palaeoclimates and pal-

aeoenvironments in the Levant and Eastern Mediterranean from 25000 to 5000 years BP setting the environmental background for the evolution of human civilization ndash Quatern Sci Rev 25 1517ndash1541

RoumlgneR K amp Smykatz-kloSS W (1991) The deposition of eolian sediments in lacustrine and fluvial envi-ronments of Central Sinai (Egypt) ndash Catena Suppl 20 75 ndash 91

RoumlgneR K Smykatz-kloSS W amp zoumllleR L (1999) Oberpleistozaumlne palaumloklimatische Veraumlnderungen im Zentral-Sinai (Aumlgypten) ndash Erdkunde 53 220 ndash 230

RoSkin J blUmbeRg D G poRat N tSoaR H amp RozenStein O (2011) Do dune sands redden with age The case of the northwestern Negev dunefield Israel ndash Aeolian Res 5 63 ndash75

RoWell D L (1994) Soil science Methods and Applications ndash Longman Prentice Hall London 350 pp


Royal joRdanian geogRaphic centRe (2007) Atlas of Jordan and the World 2007 128 ppRoyeR D L (1999) Depth to pedogenic carbonate horizon as a paleoprecipitation indicator ndash Geology 27

1123 ndash1126RUck A amp StahR K (1987) Wasser-und Salzhaushalt aus der Leitfaumlhigkeit verschiedener Boden-zu-Was-

ser-Extrakte ndash Mitt Dtsch Bodenkdl Ges 55 233 ndash 238Saacutenchez-maRantildeoacuten M delgado G melgoSa M hita E amp delgado R (1997) Cielab color param-

eters and their relationship to soil characteristics in Mediterranean red soils ndash Soil Sci 16211 833 ndash 842SchalleR K (2000) Praktikum zur Bodenkunde und Pflanzenernaumlhrung ndash Geisenheimer Ber 2 592 pp

Forschungsanstalt GeisenheimScheinoSt A C chaveRnaS A baRRoacuten V amp toRRent J (1998) Use and limitations of second-derivative

diffuse reflectance spectroscopy in the visible to near-infrared range to identify and quantify Fe oxide minerals in soils ndash Clays and Clay Minerals 46 528 ndash 536

ScheinoSt A C amp SchWeRtmann U (1999) Color Identification of Iron Oxides and Hydroxysulfates Use and Limitations ndash Soil Sci Soc Amer J 63 1463 ndash1471

SchleSingeR W H (1985) The formation of caliche in soils of the Mojave Desert California ndash Geochimica et Cosmochimica Acta 49 57ndash 66

Schlichting E blUme H P amp StahR K (1995) Bodenkundliches Praktikum ndash Eine Einfuumlhrung in ped-ologisches Arbeiten fuumlr Oumlkologen insbesondere Land- und Forstwirte und fuumlr Geowissenschaftler ndash Blackwell Berlin 297 pp

SchWeRtmann U (1959) Die fraktionierte Extraktion der freien Eisenoxyde in Boumlden ihre mineralogis-chen Formen und ihre Entstehungsweisen ndash Z Pflanzenernaumlhrung Duumlngung und Bodenkunde 84 194 ndash 204

SchWeRtmann U amp lentze W (1966) Bodenfarbe und Eisenoxidform ndash J Plant Nutrition and Soil Sci 115 209 ndash 214

SchWeRtmann U (1966) Inhibitory effect of soil organic matter on the crystallization of amorphous hy-droxide to goethite ndash Nature 212 645 ndash 646

SchWeRtmann U (1969) Der Einfluss einfacher organischer Anionen auf die Bildung von Goethit und Haumlmatit aus amorphem Fe(III)-Hydroxid ndash Geoderma 3 207ndash 214

SchWeRtmann U amp coRnell R M (2000) Iron Oxides in the Laboratory ndash Preparation and Characteriza-tion ndash Wiley-VCH Weinheim 204 pp

Schyle D amp UeRpmann H-P (1988) Paleolithic sites in the Petra Area ndash In gaRRaRd A N amp gebel H G (eds) The Prehistory of Jordan The State of Research in 1986 39 ndash 65 ndash Brit Archaeol Rep Int Ser 396 i 67ndash100 Archaeopress Oxford

SemeniUk V amp meagheR T D (1981) Calcrete in quaternary coastal dunes in Southwestern Australia ndash A capillary rise phenomenon associated with plants ndash J Sediment Petrol 51 47ndash 68

Shackley S M (2010) X-Ray Fluorescence Spectrometry (XRF) in Geoarchaeology ndash Springer New York 231 pp

SheRman D M amp Waite T D (1985) Electronic spectra of Fe3+oxides and oxide hydroxides in the near IR to near UV ndash Amer Mineralogist 70 1262 ndash1269

Smettan U amp blUme H P (1987) Salts in sandy desert soils Southwestern Egypt ndash Catena 14 333 ndash 343StevenSon F J (1969) Pedohumus accumulation and diagenesis during the Quaternary ndash Soil Sci 107

470 ndash 479toRRent J SchWeRtmann U amp SchUlze D G (1980) Iron Oxide Mineralogy of some soils of two river

terrace sequences in Spain ndash Geoderma 23 191ndash 208toRRent J SchWeRtmann U fechteR H amp alfeRez F (1983) Quantitative relationships between soil

colour and hematite content ndash Soil Sci 1366 354 ndash 358toRRent J amp baRRoacuten V (1993) Laboratory measurement of soil colour Theory and practice ndash Soil Sci

Soc Amer J Spec Publ 31 21ndash 33toRRent J liU Q bloemendal J amp baRRoacuten V (2007) Magnetic enhancement and iron oxides in the Up-

per Luochuan loess-paleosol sequence Chinese Loess Plateau ndash Soil Sci Soc Amer J 71 1570 ndash1578Ubeid K F (2011) The nature of the Pleistocene-Holocene palaeosols in the Gaza Strip Palestine ndash Ge-

ologos 173 163 ndash173


vakS A baR-mattheWS M ayalon A mattheWS A fRUmkin A dayan U Halicz L almogi-labin A amp Schilman B (2006) Palaeoclimate and location of border between Mediterranean climate region and the Saharo-Arabian Desert as revealed by speleothems from the northern Negev Desert Israel ndash Earth Planet Sci Lett 249 384 ndash 399

venegaS R labenSki de kanteR F acebal S gRaSSi R RUeda E H agUiRRe M E amp SaRagovi C (1994) Analysis of iron state in some Argentinian soils by dissolution methods and Moumlssbauer spec-troscopy ndash Hyperfine Interactions 83 443 ndash 450

veRRecchia E P (2007) Lacustrine and palustrine geochemical sediments ndash In naSh D J amp mclaRen S J (eds) Geochemical sediments amp landscapes 298 ndash 329 Blackwell Malden (MA USA)

WagneR S SkoWRonek A eckmeieR E amp gUnSteR N (2011) Reddening as a climatic indicator In-vestigations on Quaternary soils and soil sediments of the Balearic Islands ndash Conference contribution presented at the XVIII annual INQUA congress Bern Switzerland

WalkeR T R (1974) Formation of red beds in moist tropical climates A hypothesis ndash Geol Soc Amer Bull 8 633 ndash 638

Weltje G J amp von eynatten H (2004) Quantitative provenance analysis of sediments review and out-look ndash Sediment Geol 171 1ndash11

WineR E Rech J A amp coinman N R (2006) Late Quaternary wetland deposits in Wadi Hasa Jordan and their implications for paleoenvironmental reconstruction ndash Geol Soc Amer (GSA) Philadelphia Annual Meeting Abstracts with Programs 387 314

WRight V P (2007) Calcrete ndash In naSh D J amp mclaRen S J (eds) Geochemical sediments amp land-scapes 10 ndash 45 Blackwell Malden (MA USA)

yaalon d h (1961) On the origin and accumulation of salts in groundwater and in soils of Israel Depart-ment of Geology ndash Publ 255 The Hebrew University of Jerusalem

yaalon d h (1990) The relevance of soils and paleosols in interpreting past and ongoing climatic changes ndash Palaeogeogr Palaeoclimatol Palaeoecol (Glob Planet Change Sect) 82 63 ndash 64

zhU B amp yang X (2010) The origin and distribution of soluble salts in the sand seas of northern China ndash Geomorphology 123 232 ndash 242

zielhofeR C eSpejo J M R gRanadoS M A N amp faUSt D (2009) Durations of soil formation and soil development indices in a Holocene Mediterranean floodplain ndash Quatern Int 209 44 ndash 65

Addresses of the authorsManuel Bertrams (corresponding author) Jens Protze and Prof Frank Lehmkuhl Department of Geogra-phy RWTH Aachen University Wuumlllnerstraszlige 5 b D-52056 Aachen Germany phone+49-241-8096461 e-mail mbertramsgeorwth-aachendeDr Eileen Eckmeier Institute of Crop Science and Resource Conservation (INRES) Soil Science and Soil Ecology University of Bonn Nuszligallee 13 D-53115 Bonn Germany


(RichteR et al 2012) Due to a relatively small catchment area dominated by sandstone geology most of the Upper Pleistocene wadi fills in the study area are of homogeneous character which complicates detailed provenance analysis or separation of depositional processes (beRtRamS et al 2012a) In addition OSL dating emerged to be complicated due to low luminescence sensitivity and inhomogeneous radiation characteristics of the quartz grains

In some geomorphological positions however fine grained calcretic horizons are intercalated or appear as surface crusts covering the fragile sandy material and increasing the preservation po-tential (naSh amp mclaRen 2007) Comparable deposits from semiarid and arid environments have often been described but the palaeoenvironmental evidence and attribution to certain depositional environments is ambiguous (eg lattman 1973 RoumlgneR amp Smykatz-kloSS 1991 moUmani et al 2003 Retallack amp hUang 2010 mclaRen et al 2012) The nature and origin of these calcretic deposits therefore represents the main issue of this paper Next to field studies pedological meth-ods like colorimetry and chemical iron extraction were applied to obtain additional information on the intensity of past weathering processes and the attribution of iron oxide bearing sands to different geological bedrocks The combination of both approaches is used to identify and evalu-ate the potential to reconstruct the geomorphologic history and palaeoenvironmental conditions conveyed from these ancient deposits

2 Study area and investigated sections

The Wadi Sabra valley system is a highly dynamic geomorphological environment situated in the eastern escarpment of the Dead Sea Transform It originates 5 km southwest of Wadi Musa and the ancient Nabataean capital of Petra (Fig 1) Draining the Jordanian plateau in south-western direc-tion the wadi has a catchment of ~ 90 km2 with elevations ranging from ~ 1720 ndash 210 m asl The geology is dominated by Palaeozoic sandstones of the Ram formation (bendeR 1974) mainly the reddish fluvial Umm Ishrin Sandstone of Cambrian age which forms a distinctive belt along the western slope of the highland area that faces the Wadi Araba (makhloUf amp abed 1991 baRjoUS 2003) Additionally local outcrops of light coloured fluvial sandstones (Ordovician Disi formation discordantly overlain by the Early Cretaceous Kurnub formation) and Mesozoic marine limestones (Early Cretaceous NaprimeUr formation) influence the mineralogical and geochemical composition of the wadi fills Under the modern climatic conditions the largest part of the Wadi Sabra is affected by arid conditions with an annual precipitation of lt 100 mm subsequently decreasing to lt 50 mm towards the Wadi Araba which forms a wide geomorphic depression from the southern Dead Sea basin in the North towards the gulf of AqabaEilat in the South Consequently the catchment area is mostly dominated by riparian Irano-Turanian steppe and desert scrub vegetation (al-eiSaWi 1996 McLaren et al 2012) However the catchment also comprises some higher elevated areas along the western edge of the eastern plateau region around the cities of Wadi Musa and Taibeh that experience higher precipitation around 150 ndash170 mma (Royal joRdanian geogRaphic cen-tRe 2007 joRdan meteoRological depaRtment 2013) These areas receive higher amounts of rainfall particularly during the winter months thus providing higher runoff and a narrow strip with a more developed area of Mediterranean vegetation (beRtRamS et al 2012b) Soil formation is mostly inhibited under the modern climatic conditions (khReSat 2001 koUki 2006 mclaRen et al 2012) except for some local surface crust formation







































4 Methods












5 Results










Tabl

e 2

Sed

imen

tolo

gica

l ge

oche

mic

al a

nd c

olor

imet

ric c

hara

cter

istic

s of

inve

stig

ated

bac

kgro

und

sam

ples

fro

m g

eolo

gic

bedr

ocks

(Qx1

ndashQx6

) de

posi-

tiona

l cal

ibra

tion

sam

ples

(Qa1

ndash 2)

rece

nt d

une

field

s an

d to

psoi

l cal

cret

es

Due

to a

mas

sive c

hara

cter o

f raw

mat

eria

l so

me sa

mple

s did

not

prov

ide s

uffic

ient a

moun

ts of

subs

trate

in p

owde

red m

ode

Sam

ple

Cla

ssifi

catio

nLo

catio

nSa

nd

()

Silt

()

Cla

y (

)C

aCO

3 (

)G

ypsu

m

()

TSS

(

)M

unse

ll C

olou

r (H

VC

)R

RM

unH

em

()

Qx1

A

bu K

hush

ayba

San

dsto

neW

adi S

abra

709

523

12

593

00

00

002

73 9

40

YR

759

393

03

016

Qx2

D

isi S

ands

tone

Wad

i Sab

ra77

21

198

82

91 0

10

003

008

99

0Y

R7

793

110

00

05

Qx3

Um

m Is

hrin

San

dsto

neW

adi S

abra

893

0 8

73

197

00

41

831

98 4

20

YR

533

397

43

170

Qx4

U

mm

Ishr

in S

ands

tone

Wad

i Sab

ra77

06

191

83

76 0

17

002

010

24

0Y

R5

373

665

22

03Q

x6

Kur

nub

Sand

ston

eW

adi S

abra

630

432

08

488

20

20

000

3310

00

YR

822

159

00

004

Qa1

Rece

nt c

hann

el d

epos

itW

adi S

abra

902

0 7

16

264

35

60

000

62 4

90

YR

564

348

31

125

Qa2

La

cust

rine

gyps

um la

yer

Wad

i Gar

anda

l ndash

massi

vendash

149

87

775

55 ndash

ndashndash

ndashndash

ndash

Dun

e1D

une

field

Wad

i Ara

ba96

30

23

81

32 7

22

000

040

80

0Y

R6

233

871

20

52D

une2

Dun

e fie

ldW

adi A

raba

933

2 4

30

238

85

10

020

56 7

80

YR

630

408

14

059

Dun

e3D

une

field

Wad

i Sad

r93

59

42

42

17 3

77

000

042

73

0Y

R5

933

881

80

72

Cal

cret

e1Re

cent

tops

oil c

alcr

ete

(10

cm)

Wad

i Mus

andash

massi

vendash

910

30

000

73 ndash

ndashndash

ndashndash

ndashC

alcr

ete2

Rece

nt to

psoi

l cal

cret

e (3

0 cm

)W

adi M

usa

ndashma

ssive

ndash87

99

000

034

ndashndash

ndashndash

ndashndash

Cal

cret

e3Re

cent

tops

oil c

alcr

ete

(50

cm)

Wad

i Mus

andash

massi

vendash

664

30

005

64 8

90

YR

695

336

05

024






















6 Discussion











II 60 8151 1019 013 73510 3778

IIIa 80 1674 146 009 17730 143IIIc 100 1456 97 007 18430 118IIIc 120 2620 97 004 30130 74

IVa 140 5749 2038 035 31000 215IVb 170 2863 873 031 27410 141

IVc 180 6331 1261 020 48300 225

IVd 190 4027 679 017 50130 204IVd 210 3615 388 011 46020 343

V 250 5482 873 016 42600 246






















7 Conclusion







Acknowledgments



References












































































































































































4 Methods












5 Results










Tabl

e 2

Sed

imen

tolo

gica

l ge

oche

mic

al a

nd c

olor

imet

ric c

hara

cter

istic

s of

inve

stig

ated

bac

kgro

und

sam

ples

fro

m g

eolo

gic

bedr

ocks

(Qx1

ndashQx6

) de

posi-

tiona

l cal

ibra

tion

sam

ples

(Qa1

ndash 2)

rece

nt d

une

field

s an

d to

psoi

l cal

cret

es

Due

to a

mas

sive c

hara

cter o

f raw

mat

eria

l so

me sa

mple

s did

not

prov

ide s

uffic

ient a

moun

ts of

subs

trate

in p

owde

red m

ode

Sam

ple

Cla

ssifi

catio

nLo

catio

nSa

nd

()

Silt

()

Cla

y (

)C

aCO

3 (

)G

ypsu

m

()

TSS

(

)M

unse

ll C

olou

r (H

VC

)R

RM

unH

em

()

Qx1

A

bu K

hush

ayba

San

dsto

neW

adi S

abra

709

523

12

593

00

00

002

73 9

40

YR

759

393

03

016

Qx2

D

isi S

ands

tone

Wad

i Sab

ra77

21

198

82

91 0

10

003

008

99

0Y

R7

793

110

00

05

Qx3

Um

m Is

hrin

San

dsto

neW

adi S

abra

893

0 8

73

197

00

41

831

98 4

20

YR

533

397

43

170

Qx4

U

mm

Ishr

in S

ands

tone

Wad

i Sab

ra77

06

191

83

76 0

17

002

010

24

0Y

R5

373

665

22

03Q

x6

Kur

nub

Sand

ston

eW

adi S

abra

630

432

08

488

20

20

000

3310

00

YR

822

159

00

004

Qa1

Rece

nt c

hann

el d

epos

itW

adi S

abra

902

0 7

16

264

35

60

000

62 4

90

YR

564

348

31

125

Qa2

La

cust

rine

gyps

um la

yer

Wad

i Gar

anda

l ndash

massi

vendash

149

87

775

55 ndash

ndashndash

ndashndash

ndash

Dun

e1D

une

field

Wad

i Ara

ba96

30

23

81

32 7

22

000

040

80

0Y

R6

233

871

20

52D

une2

Dun

e fie

ldW

adi A

raba

933

2 4

30

238

85

10

020

56 7

80

YR

630

408

14

059

Dun

e3D

une

field

Wad

i Sad

r93

59

42

42

17 3

77

000

042

73

0Y

R5

933

881

80

72

Cal

cret

e1Re

cent

tops

oil c

alcr

ete

(10

cm)

Wad

i Mus

andash

massi

vendash

910

30

000

73 ndash

ndashndash

ndashndash

ndashC

alcr

ete2

Rece

nt to

psoi

l cal

cret

e (3

0 cm

)W

adi M

usa

ndashma

ssive

ndash87

99

000

034

ndashndash

ndashndash

ndashndash

Cal

cret

e3Re

cent

tops

oil c

alcr

ete

(50

cm)

Wad

i Mus

andash

massi

vendash

664

30

005

64 8

90

YR

695

336

05

024






















6 Discussion











II 60 8151 1019 013 73510 3778

IIIa 80 1674 146 009 17730 143IIIc 100 1456 97 007 18430 118IIIc 120 2620 97 004 30130 74

IVa 140 5749 2038 035 31000 215IVb 170 2863 873 031 27410 141

IVc 180 6331 1261 020 48300 225

IVd 190 4027 679 017 50130 204IVd 210 3615 388 011 46020 343

V 250 5482 873 016 42600 246






















7 Conclusion







Acknowledgments



References















































































































































5 Results










Tabl

e 2

Sed

imen

tolo

gica

l ge

oche

mic

al a

nd c

olor

imet

ric c

hara

cter

istic

s of

inve

stig

ated

bac

kgro

und

sam

ples

fro

m g

eolo

gic

bedr

ocks

(Qx1

ndashQx6

) de

posi-

tiona

l cal

ibra

tion

sam

ples

(Qa1

ndash 2)

rece

nt d

une

field

s an

d to

psoi

l cal

cret

es

Due

to a

mas

sive c

hara

cter o

f raw

mat

eria

l so

me sa

mple

s did

not

prov

ide s

uffic

ient a

moun

ts of

subs

trate

in p

owde

red m

ode

Sam

ple

Cla

ssifi

catio

nLo

catio

nSa

nd

()

Silt

()

Cla

y (

)C

aCO

3 (

)G

ypsu

m

()

TSS

(

)M

unse

ll C

olou

r (H

VC

)R

RM

unH

em

()

Qx1

A

bu K

hush

ayba

San

dsto

neW

adi S

abra

709

523

12

593

00

00

002

73 9

40

YR

759

393

03

016

Qx2

D

isi S

ands

tone

Wad

i Sab

ra77

21

198

82

91 0

10

003

008

99

0Y

R7

793

110

00

05

Qx3

Um

m Is

hrin

San

dsto

neW

adi S

abra

893

0 8

73

197

00

41

831

98 4

20

YR

533

397

43

170

Qx4

U

mm

Ishr

in S

ands

tone

Wad

i Sab

ra77

06

191

83

76 0

17

002

010

24

0Y

R5

373

665

22

03Q

x6

Kur

nub

Sand

ston

eW

adi S

abra

630

432

08

488

20

20

000

3310

00

YR

822

159

00

004

Qa1

Rece

nt c

hann

el d

epos

itW

adi S

abra

902

0 7

16

264

35

60

000

62 4

90

YR

564

348

31

125

Qa2

La

cust

rine

gyps

um la

yer

Wad

i Gar

anda

l ndash

massi

vendash

149

87

775

55 ndash

ndashndash

ndashndash

ndash

Dun

e1D

une

field

Wad

i Ara

ba96

30

23

81

32 7

22

000

040

80

0Y

R6

233

871

20

52D

une2

Dun

e fie

ldW

adi A

raba

933

2 4

30

238

85

10

020

56 7

80

YR

630

408

14

059

Dun

e3D

une

field

Wad

i Sad

r93

59

42

42

17 3

77

000

042

73

0Y

R5

933

881

80

72

Cal

cret

e1Re

cent

tops

oil c

alcr

ete

(10

cm)

Wad

i Mus

andash

massi

vendash

910

30

000

73 ndash

ndashndash

ndashndash

ndashC

alcr

ete2

Rece

nt to

psoi

l cal

cret

e (3

0 cm

)W

adi M

usa

ndashma

ssive

ndash87

99

000

034

ndashndash

ndashndash

ndashndash

Cal

cret

e3Re

cent

tops

oil c

alcr

ete

(50

cm)

Wad

i Mus

andash

massi

vendash

664

30

005

64 8

90

YR

695

336

05

024






















6 Discussion











II 60 8151 1019 013 73510 3778

IIIa 80 1674 146 009 17730 143IIIc 100 1456 97 007 18430 118IIIc 120 2620 97 004 30130 74

IVa 140 5749 2038 035 31000 215IVb 170 2863 873 031 27410 141

IVc 180 6331 1261 020 48300 225

IVd 190 4027 679 017 50130 204IVd 210 3615 388 011 46020 343

V 250 5482 873 016 42600 246






















7 Conclusion







Acknowledgments



References












































































































































Tabl

e 2

Sed

imen

tolo

gica

l ge

oche

mic

al a

nd c

olor

imet

ric c

hara

cter

istic

s of

inve

stig

ated

bac

kgro

und

sam

ples

fro

m g

eolo

gic

bedr

ocks

(Qx1

ndashQx6

) de

posi-

tiona

l cal

ibra

tion

sam

ples

(Qa1

ndash 2)

rece

nt d

une

field

s an

d to

psoi

l cal

cret

es

Due

to a

mas

sive c

hara

cter o

f raw

mat

eria

l so

me sa

mple

s did

not

prov

ide s

uffic

ient a

moun

ts of

subs

trate

in p

owde

red m

ode

Sam

ple

Cla

ssifi

catio

nLo

catio

nSa

nd

()

Silt

()

Cla

y (

)C

aCO

3 (

)G

ypsu

m

()

TSS

(

)M

unse

ll C

olou

r (H

VC

)R

RM

unH

em

()

Qx1

A

bu K

hush

ayba

San

dsto

neW

adi S

abra

709

523

12

593

00

00

002

73 9

40

YR

759

393

03

016

Qx2

D

isi S

ands

tone

Wad

i Sab

ra77

21

198

82

91 0

10

003

008

99

0Y

R7

793

110

00

05

Qx3

Um

m Is

hrin

San

dsto

neW

adi S

abra

893

0 8

73

197

00

41

831

98 4

20

YR

533

397

43

170

Qx4

U

mm

Ishr

in S

ands

tone

Wad

i Sab

ra77

06

191

83

76 0

17

002

010

24

0Y

R5

373

665

22

03Q

x6

Kur

nub

Sand

ston

eW

adi S

abra

630

432

08

488

20

20

000

3310

00

YR

822

159

00

004

Qa1

Rece

nt c

hann

el d

epos

itW

adi S

abra

902

0 7

16

264

35

60

000

62 4

90

YR

564

348

31

125

Qa2

La

cust

rine

gyps

um la

yer

Wad

i Gar

anda

l ndash

massi

vendash

149

87

775

55 ndash

ndashndash

ndashndash

ndash

Dun

e1D

une

field

Wad

i Ara

ba96

30

23

81

32 7

22

000

040

80

0Y

R6

233

871

20

52D

une2

Dun

e fie

ldW

adi A

raba

933

2 4

30

238

85

10

020

56 7

80

YR

630

408

14

059

Dun

e3D

une

field

Wad

i Sad

r93

59

42

42

17 3

77

000

042

73

0Y

R5

933

881

80

72

Cal

cret

e1Re

cent

tops

oil c

alcr

ete

(10

cm)

Wad

i Mus

andash

massi

vendash

910

30

000

73 ndash

ndashndash

ndashndash

ndashC

alcr

ete2

Rece

nt to

psoi

l cal

cret

e (3

0 cm

)W

adi M

usa

ndashma

ssive

ndash87

99

000

034

ndashndash

ndashndash

ndashndash

Cal

cret

e3Re

cent

tops

oil c

alcr

ete

(50

cm)

Wad

i Mus

andash

massi

vendash

664

30

005

64 8

90

YR

695

336

05

024






















6 Discussion











II 60 8151 1019 013 73510 3778

IIIa 80 1674 146 009 17730 143IIIc 100 1456 97 007 18430 118IIIc 120 2620 97 004 30130 74

IVa 140 5749 2038 035 31000 215IVb 170 2863 873 031 27410 141

IVc 180 6331 1261 020 48300 225

IVd 190 4027 679 017 50130 204IVd 210 3615 388 011 46020 343

V 250 5482 873 016 42600 246






















7 Conclusion







Acknowledgments



References



























































































































































6 Discussion











II 60 8151 1019 013 73510 3778

IIIa 80 1674 146 009 17730 143IIIc 100 1456 97 007 18430 118IIIc 120 2620 97 004 30130 74

IVa 140 5749 2038 035 31000 215IVb 170 2863 873 031 27410 141

IVc 180 6331 1261 020 48300 225

IVd 190 4027 679 017 50130 204IVd 210 3615 388 011 46020 343

V 250 5482 873 016 42600 246






















7 Conclusion







Acknowledgments



References












































































































































II 60 8151 1019 013 73510 3778

IIIa 80 1674 146 009 17730 143IIIc 100 1456 97 007 18430 118IIIc 120 2620 97 004 30130 74

IVa 140 5749 2038 035 31000 215IVb 170 2863 873 031 27410 141

IVc 180 6331 1261 020 48300 225

IVd 190 4027 679 017 50130 204IVd 210 3615 388 011 46020 343

V 250 5482 873 016 42600 246






















7 Conclusion







Acknowledgments



References



























































































































































7 Conclusion







Acknowledgments



References







































































































































References






































































































































A geochemical approach on reconstructing Upper Pleistocene environmental conditions from wadi...

Documents

Transcript of A geochemical approach on reconstructing Upper Pleistocene environmental conditions from wadi...