Chapter 18

A Thin BAsis The soil Landscape of Ebla and Tell Tuqan

A. Arnoldus-Huyzendveld

1. IntroductIon

Generally, soil sustains the growth and renewal of vegetation and, therefore, the production of food and fiber for the human community. Production capacity depends on its intrinsic characteristics, on climate, and on human actions. Through the interaction of inorganic and living elements, soils are as resilient to changes from the outside as organisms: in other words, soil features and functions are rather stable over time unless they degrade under a catastrophic or continuous outside pressure (natural or anthropic). Soil characteristics are not isolated from other environmental components, like geological substrate, geomorphology, drainage pattern, vegetation, and land use. The complex of these elements forms the evolving soil landscape system, which can be analyzed through an integrated framework that includes data from other disciplines.

This study focuses on the soil landscape of the areas surrounding Tell Mardikh and Tell Tuqan.1 My fieldwork was guided by two main questions: first, is there a clear difference between the environmental conditions of the two tells, considering that the economy of Ebla was mainly based on cattle herding (besides commerce) and the economy of Tell Tuqan on cultivation? Second, do the local soil characteristics offer any indication of ongoing or past environmental degradation? In what follows I will present my answers to both questions, even though the second one is only a working hypothesis at the

moment (see also Cantelli, Martina and Picotti, in this volume).

2. GeoloGIcal context

The city of Ebla is located on a low hill at an altitude of just over 400 m asl within a rolling landscape, on the divide between two minor wadis running northward. Regarding the original morphology of the city of Ebla, before the artificial creation of the tell, one may presume the existence of a very low ridge oriented more or less from north to south. This is shown by the similar altitudes of the geological formations in the excavation area and in the area south of the walls (415 m asl).

More broadly, the area belongs to the Syrian upland, which forms a closed watershed surrounded by the Euphrates basin, the internal basin of Palmyra, and the Mediterranean coastal basins flowing out into the Orontes River. The western boundary of the watershed is formed by the Jebel ez-Zawiye mountain chain, and the eastern boundary by a slightly uplifted area along the axis Aleppo–Palmyra (Wirth 1971, 41–67; Ente Nazionale Idrocarburi 1978). The foot slopes of the Taurus in Turkey and the mountain chains extending between Damascus and Palmyra also enclose the area. This closed watershed originated in the Miocene2 as a consequence of the uplift along the axis Aleppo–Palmyra, which gave rise to a number of vast lakes between the uplifted area and the coastal chains. Over time, drainage

“Ebla and its Landscape, Early State Formation in the Ancient Near East”, editors Paolo Matthiae & Nicola Marchetti, Left Coast Press Inc. 2013, pp. 324-333.

2 A. Arnoldus-Huyzendveld

links between the various basins were created, though not an outflow to the coast.

The available geological maps are on a scale of 1:1,000,000 (Technoexport 1964a), 1:500,000 (Technoexport 1964b), and 1:200,000 (Syrian Arab Republic 1963). According to the more detailed maps, the formations outcropping near Ebla and Tell Tuqan are of Tertiary and Quaternary origin, and of Secondary origin (Cretaceous) in the nearby mountains to the southwest. The oldest outcropping formations (see Figure 1, code P) are Middle Eocene chalky and nummulitic limestone, directly overlying the marls and limestone of the Paleocene–Lower Eocene. The major outcropping formation of the area is composed of Middle Miocene (Helvetian) organogenic limestone (S). The lakes formed in the Upper Miocene (Tortonian) received continental deposits (marls, clays, sandstones, and conglomerates); they are located amongst others to the west of Idlib (8 km ca west of Ebla), and the geological maps show a small relict around Ebla (Figure 1, code R). The great basaltic lava flows (B) were deposited during this period and later on. During the Pliocene, under the influence of the still rather humid climate, the drainage network was outlined, with the formation of a great number of watercourses. During the Quaternary, the alluvial—partly terraced—sediments were laid out (A), mainly within the limits of the former internal basins, which still today form low-lying and marshy zones.

Some field observations focused on the geological formations. Indeed, it became evident that the substrate on and near Tell Mardikh is different from the dominant surrounding substrate: it is a white soft calcareous stone, locally called “ràchu” (codes R, r on Figure 1). The upper part (60–70 cm) tends to indurate, and it is directly overlain by a thin (2–3 cm) lamellar calcareous crust. The maximum thickness of the formation observed at Ebla was about 6 m, but overall it could well be in the order of tens of meters. Karst cavities were absent from the formation in the road to the west of Tell Mardikh. Near Idlib the stone is the same, but slightly marlier. Field observations showed

that the extension of this formation is somewhat larger than indicated on the detailed geological map, since at least in one site to the north of Tell Mardikh it is present with a thickness of a few meters over the underlying formation (Figure 1, code r/s). The Middle Miocene formation (S), not outcropping at Tell Mardikh, is of a different nature. It is a hard calcareous stone with large fossil shells, which was observed amongst others near Saraqeb. According to the information collected locally, the same stone is present in a quarry south of Tell Mardikh. Modest karstic phenomena could be observed in this rock in the road cuts near Saraqeb. Together with basalt, these hard calcareous stones were used as building blocks for the walls of the city of Ebla. The soft calcareous formation of Tell Mardikh can be considered suitable for the creation of artificial underground cavities, not only because it is relatively easy to excavate, but also because the indurated superficial layer can sustain a cavity’s roof. Considering also its low tendency to form karstic phenomena, it is highly probable that all cavities below the town of Ebla are artificial in origin.

De Maigret (1981, 16) states that in the area of Ebla the groundwater generally flows from west to east and from south to north. According to information collected in the field, in the area of Tell Mardikh the groundwater table (in the wells) stands at a depth of 150–200 m. Based upon these data, the surface of the groundwater table was reconstructed as sloping towards the north (Figure 1). It is possible that here the middle aquifer mentioned by De Maigret (1981, 16) is intercepted, located in the permeable Eocene nummulitic limestone (P). Arguments for this interpretation are the gradual rising of the groundwater surface in correspondence with the rising of the Eocene formation to the east starting from Tell Mardikh, and the presence (well visible on aerial photographs in at least four points between Tell Tuqan and Cheikh Idris) of valley heads incised in correspondence to outcrops of the Eocene formation (P) below the Middle Miocene formation (S). Normally such a morphology would mean outflow of springs. But no water outflow was visible after the first rains

3A Thin Basis: The Soil Landscape of Ebla and Tell Tuqan

in the only spot that was observed in the field (Cheick Idris), so these forms could well be fossil (Pliocene or younger).

In the city of Ebla there is a well with a depth of 60 m. This is much shallower than indicated by the subsurface water data from the surroundings. A possible explanation is the presence of the upper aquifer mentioned by de Maigret (1981, 16), located in the Middle Miocene marls (R?). In this context it is interesting to consider the difference between the areas of Tell Mardikh and Tell Tuqan. Near the former the groundwater depth is 150–200 m, whereas near the latter it is much shallower: 35–40 m to the north-north-east of the tell and 15 m in the surrounding plain. This is a remarkable difference, also in view of the agro–zootechnical potential of the two areas (see below). These subsurface waters were probably an important resource in antiquity (see de Maigret 1981, 25 for Ebla, and Mathys 2001, 128 for the Jazeerah region).

3. SoIl characterIStIc

Many soil characteristics are related to climate, and therefore we shall address this aspect first. According to the Köppen classification, this area is a hot semiarid Mediterranean steppe (code BSh; Strahler 1975, 243). The average annual rainfall in Saraqeb, located 7 km to the north of Tell Mardikh, is 350 mm, reaching a peak during the months of December/January3 The average temperature data from the nearest weather station, Aleppo, are: July/August, minimum 22.3°C, maximum 37.7°C; December/January, minimum – 2.6°C, maximum 11°C (Odenthal 1987, 330). The soil moisture regime is “xeric” (Ilaiwa 1983, 36) and the thermal regime is “thermic” (Soil Survey Staff 2010, 28). The “Length of Growing Period” (LGP), a parameter expressing the climatic potential for agriculture based on precipitation and temperature data, is about 150 days, with a dry period that goes on average from April, 10 to November, 12 (FAO 1982; data averaged between Aleppo and Hama). In practice, the start of the dry period should be even earlier, because of the (partially)

low Available Water Capacity (AWC) of the soils, estimated between 30 and 150 mm.

The Syrian soils are generally characterized by low humus content, high to excessive Ca and Mg carbonate content, and by montmorillonitic (swelling) clay minerals (Van Liere 1965, 9). Several soil maps are available for Syria, on different scales and with different soil classifications (Ilaiwa 2001, 227). It should be noted that inhomogeneity in the naming of soil types is generally related to the relatively late development of a worldwide soil classification, which started only with the realization of the Soil Map of the World (FAO/UNESCO 1974). This classification, at first only used as a map legend, has grown into a soil mapping tool that can be used on any scale with the creation, in 1998, of the World Reference Base for Soil Resources (WRBSR), further refined in a second edition in 2006 (FAO 2006). A sensible change for our purposes has been the elimination in 2006 of the Xerosols and their replacement with the Calcisols. Other worldwide applied classifications are the Soil Taxonomy (Soil Survey Staff 2010) and the classification used in the USSR (Bridges and Davidson 1982, 79).

The available soil maps of the area (ordered from a general to a more detailed scale) are: 1) FAO/ISRIC, 1974, Soil Map of the World, sheet VII-1, scale 1:5,00,000;4 2) Ilaiwa, M., 1985, Soil Map of Syria & Lebanon, sheet Aleppo, scale 1:1.000.000;5 3) Cherkess R., 1954 (1964?), Soil Map of Syria, scale 1:500.000; 4) two soil maps at scale 1:200,000 of the zones around Aleppo and Hama (reported in Subramanian 1981).6 Contrasts between the several maps can largely be reduced to scale and classification differences. We report here the regional data according to the most detailed soil map presently available7 (1:500.000). Soils are classified according to the Russian system, for which the corresponding names according to FAO (2006) are indicated in parentheses. The western part of our area is characterized by two alternating units: unit 16, soils on limestone plateaus, red grumusols (=Vertisols) and cinnamonic (=Calcisols) overlying calcareous crust, undulating and

4 A. Arnoldus-Huyzendveld

shallow; and unit 26, alluvials, outwash and other formations, with red grumusols (=Vertisols) and cinnamonic (=Calcisols), deep and level. In the eastern part there is almost exclusively unit 26. Further east there is unit 32, characterizing the Matkh depression, with brown groundwater soils. So basically we can see, moving from west to east, a transition from shallow cinnamonic soils on limestone and shallow red grumusols to deeper red grumusols and cinnamonic soils, up to the groundwater soils in the Matkh depression.

In 1988 two soil maps were compiled of the areas directly around Tell Mardikh and Tell Tuqan, on a 1:50,000 scale (see Plate 1–2). The classification, originally FAO/ISRIC (1974), has now been converted into FAO (2006). Calcisols and Vertisols are the dominant soil types. In Calcisols there is a substantial secondary accumulation of lime. They are common in highly calcareous parent materials and widespread in arid and semiarid environments. Vertisols are churning, heavy clay soils with a high proportion of swelling clays. These soils form deep, wide cracks from the surface downward when they dry out, which happens in most years. In the mapped areas, calcic horizons, more or less pronounced, are present in all shallow and moderately deep soils and in some deep ones. The soil complex corresponds perfectly to unit 41 as described by Ilaiwa (1983, 194): “Dominance of soils with a (lamellar) petrocalcic horizon on the plateaus and Vertisols in the lower parts”. The soil types encountered are listed in Table 1.

In the Tell Mardikh area (Plate 2) the landscape is gently undulating, with slopes averaging 1–3 percent, and rarely exceeding 5 percent (Plate 3). The distinction between valleys and ridges is scarcely marked; therefore, it is not always possible to establish the direction of the surface drainage. The shallow depressions (Figure 2) are characterized by Vertisols with a calcic horizon at moderate depth (50–100 cm; unit V), locally at greater depth (W). Along the sides of the depressions and upon the ridges there are shallow (< 50 cm) Calcisols on hard (B) or chalky limestone (C), generally with a lamellar petrocalcic horizon. On the limestone plateaus there are Vertisols of moderate depth (U). Artificial soils (A), partly composed of decayed mud bricks and shards, are found near the archaeological areas.

The landscape around Tell Tuqan (Plate 2) has a more pronounced morphology, with deeper incised valleys and slopes up to 8 percent. The tell is located at the edge of the Matkh depression, swampy in this region. The latter area has been reclaimed through three main canals that divide the winter floodwater of the wadi Queik (Van Liere 1965, 92). The general drainage direction of the mapped area is clearly towards this depression. The position of the various types of red soils within the landscape is the same as in the Tell Mardikh area, though chalky limestone is absent. In the Matkh depression we find deep gray-brown Vertisols (unit Y).

The soils around Tell Mardikh and Tell Tuqan form a pedogenetic continuum. They have several characteristics in common, among which the

a: artificial soils – Urbic Technosols (calcaric, clayic).B: shallow red Calcisols on hard limestone - Leptic Petric Calcisols (clayic, chromic).

c: shallow red Calcisols on chalky limestone - Leptic Petric Calcisols (clayic, chromic).u: moderately deep red Vertisols on the limestone plateaus - Endoleptic Calcic Vertisols (chromic).V: moderately deep red Vertisols in the valleys - Calcic Vertisols (chromic).W: deep red Vertisols in the valleys - Haplic Vertisols (calcaric, chromic).Y: deep gray–brown Vertisols in the valleys - Haplic Vertisols (calcaric).

Table 1. Soil types of Ebla and Tell Mardikh, classification FAO 2006.

5A Thin Basis: The Soil Landscape of Ebla and Tell Tuqan

Depth

cmph

Salinity

ec (1:1) mS/cm

cacO3

%

O r g a n i c carbOn

%

clay

%lOam

%SanD

%

0 - 13 8.2 0.26 24.2 0.50 70.8 23.5 5.713 - 32 8.2 0.21 25.1 0.32 72.9 21.7 5.532 - 65 8.3 0.24 24.4 0.26 72.4 21.4 6.265 - 110 8.6 0.32 29.5 0.30 70.7 22.7 6.6110 - 140 8.7 0.41 30.0 0.21 71.0 32.6 5.5

Table 2. Soil analyses of a deep red Vertisol near Taftanaz.

dominant red color (hence the terms also used of “chestnut” or “cinnamonic” soils), the overall clayey texture dominated by swelling clays, and the presence of a calcium carbonate concentration at variable depth and with variable degrees of development. Soils are calcareous throughout, with a pH of 7½–8; Munsell soil colors are 5YR 6/5 dry and 5YR 5/6 wet. Soil colors in the Matkh depression are less red (7.5YR 6/2 dry, 7.5YR 5/2.5 wet), a phenomenon undoubtedly due to the generally wetter (less oxidizing) conditions of the soil with respect to the plateau and its incisions. The artificial soils are less plastic and have a lighter and browner color (5YR 7/4 dry, 5YR 5/5 wet).

In the Calcisols on the plateaus the carbonate concentration has taken the form of a 2–3 cm thick lamellar crust (petrocalcic) directly overlying the limestone substrate (Figures 3 and 4), which in case of a chalky substrate has an indurated upper part; in the Vertisols on the plateaus the carbonate tends to form a dense accumulation of more or less hardened nodules (Plate 4). In the Vertisols of the valleys the carbonate concentrations occur at greater depth and are less developed or even absent. In the dry season all soils of the area exhibit fissures caused by the swelling clays, but only in the Vertisols they reach a depth of more than 50 cm and a width of 3–4 cm; the cracks fill in gradually with surface material (Figure 5).

The following profile analysis draws on data available from ICARDA in Aleppo and related to Taftanaz, 20 km north of Ebla (Table 2). It refers

to a typical deep red Vertisol, thus comparable to the “W” type of the detailed maps. One may observe the clayey texture and the gradual increase towards the bottom of the percentage and pH of calcium carbonate; also worth noting are the low content in organic carbon and the complete absence of salinity.

A few words on the pedogenesis of these soils. Van Liere (1965, 139) considers the “reddish brown chestnut soils” to be seldom autochthonous, but, at least in the red upper part, to be made of sedimentary (colluvial) layers; the reddish colors would have been inherited from the warmer Pleistocene period. The formation of a calcic horizon or crust in calcareous sediments or rocks involves the weathering and rearrangement of the inherited carbonate (Birkeland 1999, 129). In these soils, when the crust or substrate form a barrier to percolation, the water starts flowing horizontally, forming a laminated top (Retallack 1990, 265) like the ones that were observed in the field.

4. SoIl QualItIeS and lImItatIonS

Our area is located in the so-called wheat belt of Syria. The cropping system usually applied is a three-year rotation, with cereals (wheat and barley), spring crops (chick peas and lentils), and fallow. Watermelons are sometimes grown in the fallow year. In some areas grapes and figs are grown. Cotton is the most frequent irrigated culture (Van Liere 1965, 12). Van Liere considers the current land use in the Aleppo-Idlib region balanced, since the best soils are reserved for field

6 A. Arnoldus-Huyzendveld

crops and the poor soils for grapes, figs, olives, and pistachios. But to his opinion, too much wheat intended for dry farming has been planted on the reddish brown soils, and these should have been reserved for barley instead (ibidem, 100). A list of soil qualities and of the limitations of Syrian soils is given in Ilaiwa (2001, 231). Among the limitations are the presence of carbonate concentrations and crusts and the low organic matter content. The soils of the Upper Orontes plain, just south of Hama, mentioned in a special study by Van Liere (1965, 135), are probably similar to ours, and soil depth is indeed an important limiting factor in agricultural production.

Presently near Tell Mardikh there is rain-fed cultivation of wheat and irrigated farming of corn and cotton. Tree crops can be found, especially in the lower-lying zones: olives, figs, pomegranates, apricots, and almonds. Livestock is limited to sheep. In the plain of Tell Tuqan there is mainly irrigated agriculture. As for agricultural potential, the red soils of Tell Mardikh and Tell Tuqan are potentially moderately to highly productive soils for dry farming.9 The main limitations seem to be the climate, the low nutrient and organic matter content, and, in part, the lack of soil depth over the calcic or petrocalcic horizon. The gray-brown soils of the Matkh depression can be considered excellent for dry or irrigated farming (see Rossi, Ventura, and Vignudelli, in this volume).

As a comparison, in an area not dissimilar to ours, the second-class wheat land of the Jazeerah, the production is on average 1,200 kg per year per hectare (Van Liere 1965, 34). Van Liere states that, contrary to general opinion, good management improves in particular the steppe soils, since the virgin steppe soil is hard to work and has poor structure, and often gives very low yields. In the course of a number of years, the structure improves by proper management and yields may increase. Soil improvement is difficult anyhow in the Mediterranean savanna, as Van Liere (1965, 32) notes: “Building up the humus content of the topsoil is a difficult task, and probably too expensive for steppe soils. The summer is too long and too hot, soil temperature

rises too high and its control is too difficult to prevent yearly excessive oxidation of organic matter. Leguminous crops, often recommended to improve the soil, have a doubtful value in the steppe. Agriculture in Syria is not poor in legumes, but they seem to contribute little to soil fertility”. And moreover: “Afforestation is often proposed for certain parts of the Wheat Belt, but as this zone was originally Pistachio–to–quercetum savanna, growth is very slow and regeneration almost impossible. Thus afforestation on a commercial basis is not possible in this zone.”

5. SoIl and land deGradatIon

Major land degradation processes in Syria are salinization in irrigated areas, water erosion in mountain regions, and wind erosion in the steppe area. Salinization of irrigated land only started in the 1940s, when large-scale irrigation became possible by using diesel pumps. It became critical from the 1950s on, when cotton was introduced as a summer cash crop, with a rise in groundwater level because of the absence of any drainage system and misuse of irrigation water. Water erosion mainly occurs in the mountains in the subhumid western part of the country. Wind erosion is presently affecting about a quarter of the arid steppe areas, and has intensified significantly in recent decades following the large increase in rain-fed agriculture (barley) from some 36,000 ha in 1982 to more than 550,000 ha in 1990 (Ibrahim 2002).

In 1991 the second edition of the World Map of the Status of Human-Induced Soil Degradation on a scale of 1:10,000,000 was published (GLASOD, ISRIC–UNEP 1991). The whole belt from Hama to the Jazeera footslopes is marked with the red code Cn 2.5/Wt2.1 a. This indicates a very strong chemical degradation caused by agricultural activity, in the form of a moderate loss of nutrients/organic matter on 100 percent of the surface and a moderate loss of topsoil by water erosion on 0–5 percent of it. In this case “moderate” means that the terrain has greatly reduced agricultural productivity but is still suitable for use in local farming systems (ibidem, 14). Supposing that water erosion in

7A Thin Basis: The Soil Landscape of Ebla and Tell Tuqan

this map unit is limited to the steeper slopes near the mountains, degradation of our area would consist mainly in chemical degradation in the form of an overall moderate depletion of nutrients and organic matter.

Van Liere (1965, 29) mentions the absence of soil erosion in the Jazeera footslopes, an area quite similar to ours. This is confirmed by Edwards-Jones (2003, 10), who states that the plateaus and the plains are actually not suffering much from water erosion, as they are flat and the soils tend to have good structural stability even where rainfall is relatively high.10 Vaezi et al. (2011), working in Iran, noted that most soils located in the semiarid regions have a high structure stability and low erodibility due to their high carbonate content, and that therefore their erodibility is much lower than would result from the models generally used to estimate this factor. Indeed I did not observe traces of water erosion in the field nor on the aerial photographs, although it is known that this process can happen also on weak slopes, starting from 2 percent on (Soil Survey Division Staff 1962, 260). Cracking clays, so typical of our area, could well be quite resistant to the impact of the first rains, since the water filtrates into the fissures and the structural elements are initially brick-hard and impermeable. In fact, during a comparative experiment in Spain with various soil types, the subsurface cracking of the vertisol induced a high infiltration rate and a low soil loss in both dry and wet infiltration runs (Duiker, Flanagan, and Lal 2001). These data seem to contradict the strong regional soil erosion suggested by de Maigret (1981, 23).

6. concluSIonS

To answer the first question raised in the introduction, there is indeed a marked difference between the surroundings of the two sites. The Tell Mardikh area has medium and good soils for dry farming and cattle herding, with no serious risks of degradation other than the loss of organic matter and possibly some erosion; by contrast, Tell Tuqan, apart from the soils mentioned, is located near a wide depression with good soils for both dry and irrigated farming, though with

a potential risk of salinization. The groundwater water level is also different in the two areas, being closer to the surface in the Tell Tuqan area.

The second question is more difficult to deal with. We can start from the known characteristics of a certain soil type and its recent history, and then go back in time. In my opinion there are two arguments sustaining the thesis that our soils have not degraded much over the past thousand years, the first being the absence of degradation under the recent pressure, and the second the presence of a well-developed, and therefore probably “old,” calcic horizon.

As stated before, the soils of the Mediterranean savanna belt have nowadays a good structural stability and a low erodibility. Their main degradation under recent agricultural use has consisted in a moderate depletion of nutrients and organic matter. The intrinsic characteristics and the proven resistance to modern degradation of the soils in the Tell Mardikh and Tell Tuqan areas indicate that probably these are still the same soils as a few thousands years ago, originally a bit richer in organic matter and nutrients and, due to a modest erosion, somewhat deeper on the plateaus and shallower in the valleys. Although I am not an expert on historical climate changes, I tend to think that those mutations might eventually have affected agricultural production, but not necessarily the above-mentioned characteristics.

Soils are normally conservative and resilient and their profiles register environmental changes cumulatively. Some features develop continuously with time, more or less quickly, and eventually reach a steady state. In most cases a precise chronological reference scale is lacking, but Retallack (1990, 263) indicates a time lapse for the calcic horizon in the order of 10,000 years and more, though this estimate doesn’t seem to take into account climatic variability. Robbin and Stipp (1979) radiocarbon-dated various sections of a laminated carbonate crust in Florida, and found that laminae groups ranged uniformly in age from 5,680 years B.P. at the bottom to 400 years B.P. at the top, indicating that the crust formed during the last 5,000 to 6,000

8 A. Arnoldus-Huyzendveld

years. Several distinct stages of development of the calcic horizon have been recognized in the literature. According to the descriptions given in Birkeland (1999, 357), our Calcisols are in stage IV (a plugged calcic horizon with a weakly expressed laminar top), and the calcic horizons of the red Vertisols in stage III (many carbonate nodules). These features may indicate a persistence of the local soil characteristics, at least over the archaeological time scale of thousands of years. An open question is if this presumed soil stability is valid only for the time span following one of the attested deforestation phases (see Valsecchi 2007).

The hypothesis of a discrete stability of the soil landscape since historical times in the areas around the tells, as testified by the calcic horizons, can be a starting point for further comparisons with the other available data.

noteS

1 This contribution is based on a study originally car-ried out in 1988 for the University of Rome “La Sa-pienza,”, at the invitation of Professor Paolo Matthiae. Bibliographic data were collected in Rome (FAO, University “La Sapienza”) and in Syria (International Center for Agricultural Research in the Dry Areas, ICARDA, Aleppo). The original report was delivered in November 1988. The following text is an updated and revised version of that report within the ERC Ebla Chora project.

2 The later Tertiary period is divided in Miocene, from 23 to 5.3 millions of years ago, and Pliocene, from 5.3 to 1.8 millions of years ago. The Quaternary period is divided in Pleistocene, from 1.8 million to 11,000 years ago, and Holocene, from 11,000 years ago to the present.

3 Data from ICARDA for the period 1960–1985.

4 This map is probably based upon the 1:500,000 soil maps by Cherkess. The dominant unit in our area is Lc 69-3a: fine textured Chromic Luvisols, level/undu-lating, with associated Calcic Luvisols and included Lithosols. Both Tell Mardikh and Tell Tuqan are on the limit of the unit Xk27-2a/b: Calcic Xerosols, me-dium texture, level/gently undulating to rolling/hilly, with associated Luvic Xerosols and included Calcaric Regosols and Lithosols.

5 The classification applied originally was the Soil Tax-onomy, first edition (Ilaiwi 2001, 228). The domi-nant unit in our area is 41: Petrocalcic Xerochrepts, medium and fine/Calcixerollic Xerochrepts, level and sloping. Tell Mardik is located on the limit of units 40 (Lithic Xerochrepts/Calcixerollic Xerochrepts/Lithic Xerorthents/Petrocalcic Xerochrepts, fine and sloping) and 34 (Calcixerollic Xerochrepts, fine/Vertic Xerochrepts, level to sloping, on basalts).

6 These maps are not available to me anymore. The map of the Hama area may refer to the work of Van Liere (1986, 135) in the Upper Orontes plain.

7 According to the indications of ISRIC (http://library.wur.nl/WebQuery/isric/24696), this map was reduced later to a scale of 1:100,000 prepared by Van Liere in 1953.

8 Unfortunately none of the analyzed profiles reported in the appendix of Ilaiwa (1983) refers directly to one of the local map units (40, 41).

9 On Map 5 in Wirth (1971, 116), our area is indeed indicated as favorable for agriculture from the view-point of soil quality and groundwater availability.

10 It would be useful to recover some measures of local soil erosion available at ICARDA (Aleppo), as men-tioned in my original report.

9A Thin Basis: The Soil Landscape of Ebla and Tell Tuqan

Figure 1. Geological map of the larger zone of Tell Mardikh and Tell Tuqan

10 A. Arnoldus-Huyzendveld

Figure 2. Typical landscape of the moderately deep red Vertisols of the valleys (unit V), north of Ebla.

Figure 3. Soil profile visible in a hole for tree planting, West of Ebla: shallow Calcisol (25 centimeters) on soft Upper Miocene limestone (unit C); visible is the wavy lamellar calcareous crust on top of the geological formation.

Figure 4. Plowed shallow Calcisol on soft Upper Miocene limestone (unit C), north of Ebla; visible are the rock fragments with the secondary calcareous crusts still attached.

Figure 5 Partially filled in cracks on the surface of a moderately deep red Vertisol (unit V), valley east of Ebla.

6 Plate

Plate 1. Soil Landscape around Ebla (slightly undulating, slopes 1-3%).

Ch18_Arnoldus

Plate 2. Soil Landscape around Tell Tuqan (undulating, slopes 1-8%).

7Plate

Plate 3. Typical landscape of the shallow Calcisols (unit C), north-east of Ebla.

Plate 4. Nodular calcic horizon in the profile of a moderately deep red Vertisol (unit V), valley West of Tell Tuqan.

Ch18_Arnoldus