Lourinha stratigraphy Lusitanian Basin GeolJournal_2013 Taylor etal

Stratigraphical correlation of the Late Jurassic Lourinhã Formation in theConsolação Sub-basin (Lusitanian Basin), Portugal

ANDREW M. TAYLOR 1*, STUART GOWLAND 1, SIMON LEARY 2, KEVIN J. KEOGH 3 andALLARD W. MARTINIUS 3

1Ichron Limited, Century House, Gadbrook Business Centre, Northwich, Cheshire, CW9 7TL, UK2Statoil Gulf Services LLC, Houston, TX 77042, USA

3Statoil Canada, Calgary, AB T2P 0H7, Canada

The c. 700m thick succession of continental–brackish-marine deposits forming the Lourinhã Formation, cropping out along the coast of westernPortugal between Baleal and Santa Cruz, has been correlated using laterally persistent shelly marker beds. Three shelly units record the episodicestablishment of relatively short-lived, brackish-marine embayments, transgressing from the southwest, onto a low-lying coastal plain. Thesuccession displays systematic changes in facies types and stacking patterns reflecting differences in fluvial style, bedload character andpalaeontological content. Based on these observations, four new members for the Lourinhã Formation are proposed: the Sáo Bernardino, Portode Barças, Areia Branca and Ferrel members. New biostratigraphical data indicate that the Lourinhã Formation is Late Kimmeridgian to earliestEarly Tithonian in age. This age has also been obtained from the underlying mixed carbonate and clastic deposits of the Abadia Formation atConsolação. As a result, these latter sediments are now re-assigned to the Alcobaça Formation, a lithostratigraphical term currently in use in otherareas of the Lusitanian Basin. Improved regional mapping of the Lourinhã Formation has established a new sub-basin within the western parts ofthe Lusitanian Basin. This sub-basin, now named the Consolação Sub-basin, is bounded to the east by the Lourinhã–Caldas de Rainha (L–C)fault zone and to the west by the Berlengas Horst. Copyright © 2013 John Wiley & Sons, Ltd.

Received 13 July 2012; accepted 7 March 2013

KEY WORDS Lourinhã Formation; Lusitanian Basin; brackish-marine bays; Late Jurassic; lithostratigraphy; biostratigraphy

1. INTRODUCTION

The stratigraphical correlation of thick, rapidly deposited conti-nental deposits has always been a challenge, principally due tothe lack of biostratigraphical resolution and the near absence ofreliable marker beds. Sequence stratigraphic modelling hasattempted to resolve this problem by providing a frameworkto interpret bedding stacking patterns (including channel-based deposits) and palaeosol frequency, primarily in terms ofrelative sea-level change (Shanley and McCabe, 1994; Wrightand Marriott, 1993; Olsen et al., 1995; Muto and Steel, 1997;Posamentier and Allen, 1999; Miall, 2006). Clearly, the factorsinfluencing the development of rivers and their associatedfloodplains are numerous and are not all directly linked to sea-level fluctuations. The prevailing climatic conditions, basintopography, catchment area, bedrock characteristics, bedload,variations in runoff and type of vegetation cover are some of

the main factors (e.g. Miall, 1992; Collinson, 1996; Knighton,1998). In order to unravel the relative effect of these controls,and then to test anymodel of deposition, it is important to estab-lish reliable correlation points, so that meaningful comparisonscan be made along the course of the ancient fluvial system.

The study area, located in the west-central part of theLusitanian Basin (Fig. 1), comprises two near-continuouscoastal outcrops of the Lourinhã Formation close to thetown of Peniche (Fig. 2). These outcrops are approximately7 km apart. Firstly, a 3 km long SW–NE orientated sectionbetween Baleal and Ferrel displays inclined strata, with adip of some 10� towards the east (Fig. 3). The basal partof the Lourinhã Formation in this section is faulted out nearBaleal to the west (Fig. 3C) and the top passes into the flat-lying Early Cretaceous-aged Torres Vedras Formation tothe east. A c. 700m thick, continuous vertical stratigraphi-cal section of almost the entire Lourinhã Formation can beseen here. Secondly, a 17 km long N–S orientated sectionfrom São Bernardino to Porto Novo displays the LourinhãFormation in a series of shallow anticlines and synclines(Fig. 4). Whilst this structural overprinting, combined with

*Correspondence to: A.M. Taylor, Ichron Limited, Century House,Gadbrook Business Centre, Northwich, Cheshire, CW9 7TL, UK.E-mail: [email protected]

Copyright © 2013 John Wiley & Sons, Ltd.

GEOLOGICAL JOURNALGeol. J. (2013)Published online in Wiley Online Library(wileyonlinelibrary.com). DOI: 10.1002/gj.2505

the relatively low height of the cliff sections, restricts theability to observe thick continuous vertical successions, itdoes demonstrate lateral facies changes within the fluvialdepositional system. The presence of distinctive shell-rich bedshas provided a framework for further correlation of thefluvially-dominated deposits. This has been supplemented bynew biostratigraphical data, resulting in a revision of the stratig-raphy in the study area. This stratigraphical re-appraisal hasalso helped define a new sub-basin of the Lusitanian Basin,the Consolação Sub-basin, named after the coastal village ofthe same name (Fig. 2). This paper discusses the new strati-graphical framework for the Lourinhã Formation. Other publi-cations have focussed upon aspects of the fluvial channelarchitecture, tidal modulation of fluvial flow and tidal bores(e.g. Martinius and Gowland, 2011).

2. GEOLOGICAL SETTING

The Lusitanian Basin is the largest of Portugal’s six sedimen-tary basins with an areal extent of approximately 22 000 km2

(Alves et al., 2003a) and a sedimentary pile up to 6 km thick(Fig. 1) (Wilson et al., 1989). This basin formed during theopening of the North Atlantic Ocean. The fill of the basin re-cords one major phase of sea-floor spreading and four riftingepisodes, which spanned the Late Triassic to Cretaceous(Wilson et al., 1989; GPEP, 1993; Alves et al., 2003a, b,2006; DGGE, 2007), the last of which was responsible forthe current separation of Western Iberia from Canada.The main structural controls on the development

of the Lusitanian Basin follow the pre-existing NNEand NW Variscan trends. The presence of halite (latestTriassic–Hettangian age, Dagorda Formation) at depth,limited and modified the propagation of basement faults intothe post-salt overburden. This contributed to the developmentof salt pillows and extensionally-forced folds during theJurassic extensional phases (Alves et al., 2003b) and resultedin development of complex fault- and diapir-bound sub-basins (Fig. 2). During the Late Cretaceous, rifting in the Bayof Biscay triggered rotation of the Iberian Peninsula. A strike-slip fault system became established, producing NNW-trending faults and the reactivation of the Nazare Fault (Alveset al., 2003a). Compression during the Miocene, associatedwith sea-floor spreading in the Alboran Sea (to the south ofSpain), generated a strong transpressional regime, whichfollowed pre-defined Variscan lineaments. This was responsi-ble for tectonic inversion within the Mesozoic sedimentarybasins, culminating during the Burdigalian and Tortonianstages (Pinheiro et al., 1996; Antunes et al., 1999). Recentseismic acquisition and processing by TGS Nopec (reportedby Alves, 2002; Alves et al., 2006) off the coast of Portugalhas recognized new sedimentary basins, such as the PenicheBasin and the Sagres Basin, as well as re-defining the sizeand shape of the existing basins (Fig. 1). In the western parts ofthe Lusitanian Basin, faults and diapirs demark a series of sub-basins (Arruda, Turcifal and Bombarral–Alcobaça: Fig. 2), thefills of which record a history starting with Middle Oxfordian-aged platform carbonates (Montejunto Formation), followedby a mixed clastic and carbonate basin/shelf (Abadia Forma-tion) that shallows rapidly into the terrigenous, largelycontinental deposits of the Lourinhã Formation (Leinfelderand Wilson, 1989; Leinfelder, 1993) (Fig. 5). The LourinhãFormation, deposited during the third phase of basin riftingand subsequent thermal subsidence during the Late Oxfordianto Tithonian, is the subject of this study.Plate reconstructions for the third phase of rifting show that

sea-floor spreading between Africa and North America hadstarted whilst Iberia was still attached to the North Americanplate (Withmarsh et al., 2001; Russell and Withmarsh,2003). Mateus (2006) argued that similarities in the dinosaurcommunity, flora and other faunas between the Lourinhã For-mation and the North American Morrison Formation indicatethese landmasses were still linked in Late Jurassic times. TheGrand Banksmicroplate also remained attached to Iberia, hence

PORTO

?

ALENTEJOBASIN

8oW

0

0

25 50 Km

25 miles

SAGRESBASIN

SPAIN

N

PORTUGAL

LISBOA

Study Area

PORTOBASIN

SHALLOWBASEMENT

38oN

39oN

40oN

41oN

42oN

10oW

37oN

Spain

Por

tuga

l

FrancePORTO/GALICIABASIN

PENICHEBASIN

LUSITANIANBASIN

FARO

ALGARVE BASIN

Figure 1. Sedimentary basins of Portugal with the study area marked. Thisfigure is available in colour online at wileyonlinelibrary.com/journal/gj

A. M. TAYLOR ET AL.

Copyright © 2013 John Wiley & Sons, Ltd. Geol. J. (2013)DOI: 10.1002/gj

the similarities of the oil-prone Jeanne d’Arc Basin in New-foundland, Canada and the Lusitanian Basin (Driscoll et al.,1995). During deposition of the Lourinhã Formation, the Lusi-tanian Basin was situated in the northern hemisphere at latitudes30–35�, within the Tethyan realm (Stampfli and Borel, 2002).The palaeoclimate was considered to have been warm, allowingabundant herbaceous and arborescent plants to flourish in closeproximity to water sources, with winter-wet, summer-dryseasons (Rees et al., 2004; Martinius and Gowland, 2011).

3. HISTORICAL LITHOSTRATIGRAPHY

The Lourinhã Formation is the widely adopted term for theclastic continental succession of Kimmeridgian- to earlyBerriasian-aged sediments that occurs throughout theLusitanian Basin, ranging in thickness from 200m to

1100m (Leinfelder and Wilson, 1989; Wilson et al.,1989; GPEP, 1993; Rocha et al., 1996; Pena Dos Reis etal., 1996). It has replaced the Grés Superiores division usedin the older, Portuguese Geological Survey memoirs andmaps (e.g. Camarate Franca et al., 1960) and the lesswidely adopted Bombarrel Formation (Leinfelder, 1986).The older part of the Lourinhã Formation passes south-wards into carbonate shelf deposits assigned to the FartaPão Formation (Fig. 5). The ‘Pteroceriano Beds’ is anotherlithostratigraphical term for these widespread bioclasticlimestones that interdigitate with the Lourinhã Formation(Leinfelder, 1987; Rocha et al., 1996; Pena dos Reiset al., 1996, 2000).

The base of the laterally extensive Lourinhã Formation,within the Lusitanian Basin, is traditionally taken as thefirst significant and sustained development of continentaldeposits above either shallow marine to estuarine sandstones

Figure 2. Map showing the structural setting of the sub-basins in the western and central Lusitanian Basin. This delineates the new Consolaçao Sub-basin andindicates the area studied in detail. The structural data used in this reconstruction has been obtained from Wilson (1979), Alves (2002), Alves et al. (2003a, b),Roche et al. (1996) and DGGE (2007), together with regional survey maps (GPEP, 1993; Manuppella, 1996; Carmarate et al., 1960). This figure is available in

colour online at wileyonlinelibrary.com/journal/gj

LOURINHÃ FORMATION STRATIGRAPHY


(Sobral Formation), oolitic limestones (Amaral Formation),shelfal carbonates (Alcobaça Formation) or shelf to deep-water clastics (Abadia Formation). These different formationsare all considered to be Late Oxfordian to Kimmeridgian inage (Leinfelder, 1993; Leinfelder and Wilson, 1998, Fig. 5).Another bioclastic unit, the Lima psuedoalternicosta Beds,has also been used to mark the top of the Abadia Formation(Choffat, 1901; Mouterde et al., 1972; Wilson, 1979; Rochaet al., 1996; Pena Dos Reis et al., 1996).

The top of the Lourinhã Formation is difficult to define, asit is gradational with the overlying Early Cretaceous-agedTorres Vedras Formation, which also comprises clastic conti-nental sediments (Fig. 5). One of the most intensely studiedaspects of this stratigraphy has been the palaeogeographicalcomplexity of the Late Kimmeridgian interval (Wilson, 1979;Ellis et al., 1990; Leinfelder, 1994). For example, the growthof diapiric highs at this time affected the architecture of shallowmarine carbonate ramps (e.g. the Caldos–Bolhos carbonate).

These elevated (salt-cored) areas of deposition are thought tohave acted as ‘stratigraphical fences’, separating dominantlycontinental deposition in the north, from southern areasexhibiting extensive variable salinity lagoons, with adjacentalluvial fans. Basin margin highs such as at Ota and MonteGordo continued to experience carbonate deposition away fromthe major fluvial systems (Wilson, 1979; Leinfelder, 1993).A number of previously published lithostratigraphic schemes

have attempted to sub-divide the Lourinhã Formation into bedsand members. The Praia Azul Member, proposed by Fürsich(Fürsich, 1981), is the most widely cited and is a thin, bioclasticand carbonate-rich interval recorded south of Santa Cruz. TheArranhó and Freixial members are thin carbonate intervalsrecorded by Leinfelder (Leinfelder, 1993) further south still(near Assenta), in the Turcifal and Arruda sub-basins. Bothcarbonate units are published as being early Tithonian in ageand have been tentatively correlated (Leinfelder, 1987, fig. 3).Manuppella (1998) suggested that the Lourinhã Formation

Figure 3. Geological maps of the study area with (A) simplified Geological Survey map (Manuppella, 1996), (B and C) the Lourinhã Formation base maps made in thisstudy with themembers, shelly units, faults, structural dips, anticlines and synclines indicated. This figure is available in colour online at wileyonlinelibrary.com/journal/gj.

A. M. TAYLOR ET AL.


interbeds with Alcobaça Formation carbonates, whereasLeinfelder (1993) considered the mixed carbonate and clasticdeposits of the Arranhó and Praia Azul members and theAmaral and Sobral formations to be coeval. Hill (1989),working on outcrops at Porto Novo, divided the LourinhãFormation into five members (Fig. 5), correlating the PraiaAzul Member with carbonates of the same name first recog-nized by Fürsich (1981). The five members of Hill (1989) havealso been informally linked to the nine depositional sequencesof Bernardes (1992) in the section at Baleal (Sousa, 1998).Unfortunately, these members have not been defined in detailor mapped extensively.

4. BIOSTRATIGRAPHY

Since no ammonites have been recovered from marineintervals in the Lourinhã Formation it has previously provendifficult to date reliably. The formation is consideredto range in age from Middle Kimmeridgian to Tithonian(Dodekova, 1969; Wilson, 1979, 1988; Leinfelder, 1986,

1987, 1994; Hill, 1989; Manuppella et al., 1999;Mateus, 2006). The source of this age is derived fromthe micropalaeontological zonation schemes of Ramalho(1971, 1981), Wightman (1990) and the palynological zona-tion of Riding and Thomas (1988), plus William and Bujak(1980). This is summarized in Pena dos Reis et al. (1996).

The key biozonal markers are agglutinating foraminifers:Alveosepta jaccardi Schrödt (Middle Oxfordian to LateKimmeridgian range) and Kurnubia palastiniensis Henson(Oxfordian to ?Early Tithonian range), plus the dasycladaceanalgaClypeina jurassica Favre (Late Kimmeridgian). The pres-ence of the agglutinating foraminifers Anchispirocyclinalusitanica (Egger) (Tithonian to Berriasian range) is taken toindicate base Tithonian (Figs. 6 and 7). A problem oftenrelated to these specific taxa is that misidentification with othermorphologically similar species can lead to incorrect agedating (e.g. Anchispirocyclina praelustianica (Maync)),which ranges into the Kimmeridgian (Septfontaine, 1981)).Another useful zone fossil is the ostracod Cetacella armataMartin (Late Kimmeridgian to Early Tithonian range), whichhas been recorded from both the Praia Azul Member at Alto

Figure 4. Stratigraphical correlation of the Lourinhã Formation seen in cliff sections between Baleal and Santa Cruz. The main faults, anticlines and synclinesare indicated. This figure is available in colour online at wileyonlinelibrary.com/journal/gj



Vela and the Abadia Formation at Consolação (Fürsich, 1981;Werner, 1986).

The shellymacrofauna has beenwell documented (e.g.Wilson,1979; Fürsich, 1981; Fürsich and Werner, 1986; Werner,1986), with distinctive bivalves such as Isognomon lusitanicumSolander, Trigonia lusitanica Sharpe, Myophorella lusitanica(Sharpe), Acromytilus morrisi (Dunker), Myopholasmulticostata (Agassiz), Praeexogyra pustulosa (Sharpe) andNanogyra nana (Sowerby) (Fig. 8). Corals, sponges, brachio-pods and echinoids (Psuedocidaris lustanica de Loriol) havealso been identified from the shell beds at Praia Azul, PaiMogo and Consolação (e.g. Leinfelder et al., 2004). AnOxfordian to Tithonian age range is reported for this fauna.

As part of this study, a total of 142 new samples (91 paly-nology and 51 micropalaeontology) were analysed. The re-sults of these analyses are summarized here. Samplesyielding the greatest recovery came frommudrocks associatedwith the shell beds, with diagnostic dinoflagellate cysts andostracods being recovered. Floodplain muds associated withmature palaeosols, although yielding useful sporomorph andpollen assemblages, lacked any age-diagnostic flora. Fluvialchannel sandstones generally lacked recovery, although localmud-drapes did yield a rich spore and pollen flora. In additionexamples of log-jams at the bases of some fluvial channelswere sampled and their flora evaluated (Martinius andGowland, 2011). In total, 98 spore and pollen taxa, 27

Figure 5. Stratigraphical summary of the Late Jurassic to Early Cretaceous interval in the central part of the Lusitanian Basin. The sequence data is derivedfrom Pena Dos Reis et al. (1996) (1), Leinfelder and Wilson (1998) (2), Pena Dos Reis et al. (2000) (3) and Alves et al. (2003a) (4). The time scale adopted

is from Gradstein et al. (2004). This figure is available in colour online at wileyonlinelibrary.com/journal/gj

A. M. TAYLOR ET AL.


dinocyst taxa, 7 acritarch taxa, 2 algae, 11 foraminiferid taxa,27 ostracod taxa and 4 charophyte spores were identified.From this diverse faunal and floral assemblage, the keymarkers for dating appeared to be the ostracods Schulerideatriebeli (Steghaus) and Cytherelloidea weberi Steghaus,the agglutinating foraminifers Alveosepta jaccardi andPseudocyclamina parvula Hotinger, the charophytePorochara kimmeridgensis (Mädler) and the dinoflagellatecysts Dichadogonyaulax pannea Norris, D. brenneriPoulsen, Gochteodinia mutabilis Riley, Cribroperidiniumgranuligerum (Klement) ‘complex’ and Subtilisphaerapaeminosa Drugg (Fig. 7). Perhaps the most useful

miospores are Cicatricosisporites sp., Foraminisporis sp.and Pilosisporites trichopapillosus (Thiergart), which areknown Kimmeridgian markers (Herngren et al., 1980;Van Erve et al., 1988; Van Erve and Mohr, 1988; Mohrand Schmidt, 1988). It is interesting to note that S. triebeli,D. pannea, C. granuligerum and P. kimmeridgensis, alongwith the calcareous foraminifer Guttulina sp., were foundthroughout the Lourinhã Formation and in the underlyingshell-rich Abadia Formation sampled at Consolação (Fig. 7).

The age ranges of these marker taxa derived from publishedoccurrences in Portugal, Britain, France, Denmark andPoland, are illustrated in Figure 6 (Dodekova, 1969; Kilenyi,

hybonotum

durangites

microcanthum

ponti/peroni

fallauxi

semiformedarwini

AGE/STAGE

AMMONITEZONE

(TETHYAN REALM)

KEY MARKER TAXAMICROBIO-

ZONE FORAMS OSTRACODS CHARO-PHYTES DINOCYSTS MIOSPORES

154.6

159.6

150.8

145.5

EA

RLY

LAT

ELA

TE

LAT

EM

IDD

LEM

IDD

LEE

Anc

hisp

irocy

clin

alu

sitâ

nica

Alv

eose

pta

jacc

ardi

Alv

eose

pta

jacc

ardi

Pse

udoc

ycla

min

a pa

rvul

a

Kur

nubi

a pa

last

inie

nsis

Sch

uler

idea

trie

beli

Cyt

here

lloid

ea w

eber

i

Por

ocha

ra k

imm

erid

gens

is

Am

phor

ula

met

aelli

ptic

a

Sys

tem

atop

hora

pen

icill

ata

Dic

hado

gony

aula

x pa

nnea

Goc

hteo

dini

a m

utab

ilis

Cic

atric

osis

porit

es s

p.

Pilo

sisp

orite

s tr

icho

papi

llosu

s

Dic

hado

gony

aula

x br

enne

ri

Sub

tilis

phae

ra p

aem

inos

a

Crib

rope

ridin

ium

gra

nulig

erum

‘com

plex

’

OX

FO

RD

IAN

KIM

ME

RID

GIA

N

LAT

E J

UR

AS

SIC

TIT

HO

NIA

N

beckeri

eudoxusacanthicum

divisum

hypselocyclum

platynota

planula

bimammatum

bifurcatus

transversarium

plicatilis

Figure 6. Biostratigraphical range chart for key marker taxa. The micropalaeontological biozones are those of Ramalho (1981). The time scale is adopted fromGradstein et al. (2004). The overlap of occurrences of all the key taxa is marked by the grey shading and this corresponds to the Tethyan beckeri and hybonotum

ammonite subzones and the Boreal elegans and autissiodor ammonite subzones.



Figure 7. Some of the key biostratigraphical taxa used to date the Lourinhã Formation in the study area. They are: (1) Subtilisphaera paeminosa Drugg, Shelly Unit 1,Porto Dinheiro. (2) Dichadogonyaulax pannea Norris, Alcobaça Formation, Consolação. (3) Amphorula metaelliptica Dodekova, Alcobaça Formation, Consolação.(4) Gochteodinia mutabilis Riley, Shelly Unit 1, Porto Dinheiro. (5) Dichadogonyaulax brenneri Poulsen, Shelly Unit 1, Porto de Barças. (6) Gicatrichosisporites sp.,Areia Branca Member, Baleal. (7) Pilosisporites trichopapillosus (Thiergart), Shelly Unit 2, Praia de Caniçal. (8) Corollina torosus (Reissinger), Areia Branca Member,Baleal. (9) Couperisporites jurassicus Pocock, Shelly Unit 2, Praia de Caniçal. (10) Chomotriletes sp., Areia Branca Member, Baleal. (11) Pseudocyclammina parvulaHotinger, Shelly Unit 1, Porto Dinheiro. (12) Alveosepta jaccardi Schrödt, Shelly Unit 1, Porto de Barças. (13) Ammobaculites sp., Shelly Unit 1, Porto Dinheiro.(14) Guttulina sp., Shelly Unit 2, Porto Dinheiro. (15) Porochara kimmeridgensis (Mädler), São Bernardino Member, Baleal. (16) Gyrogonites sp., São BernardinoMember, Baleal. (17) Cytherelloidea weberi Steghaus, Shelly Unit 1, Porto Dinheiro. (18) Schuleridea triebeli (Steghaus), Shelly Unit 1, Porto Dinheiro.(19) Mandelstamia sp., Shelly Unit 2, Praia de Caniçal. (20) Timiriasevia sp., Shelly Unit 3, Praia da Areia Branca. This figure is available in colour online at

wileyonlinelibrary.com/journal/gj.

A. M. TAYLOR ET AL.


1978; Dépêche, 1985; Poulsen, 1996; Pereira et al., 2003;Azerêdo and Cabral, 2004). It is apparent that the age spanrecorded is Oxfordian to Tithonian. The point of overlap,and therefore the mostly likely age of the Lourinhã Formationin the study area, is latest Late Kimmeridgian to earliest EarlyTithonian. In fact the key marker, the dinocyst S. paeminosahas a relatively very narrow known range (Tethyan ammonitesubzones hypselocyclum to hybonotum and Boreal ammonitesubzones mutabilis to elegans). The two principal difficultiesin dating the Lourinhã Formation are the presence of relativelylong-ranging fauna and flora such as the ostracods, agglutinat-ing foraminifers and dasycladacean algae, plus the lack of evo-lutionary events in what is a very diverse spore and pollen flora.The tendency to call the Lourinhã Formation Tithonian in ageappears to be based on long-ranging foraminifers, which canrange from Oxfordian to Berriasian. It may be more applicableto use the shorter-ranging dinocysts, which are relatively abun-dant and have well-established age distributions and taxon-omies (Fig. 6).

5. LITHOSTRATIGRAPHICAL REVISION

The thickness of the Lourinhã Formation in the study areaexceeds 700m. It is not possible to give a more accuratethickness, as the base of the Lourinhã Formation is only vis-ible in one location (Praia de São Bernardino), on the N–S

trending outcrop, where true vertical thickness is more diffi-cult to ascertain due to the gently folded strata. The base ofthe section, which crops out to the east of Baleal is faulted-out, with the Lourinhã Formation juxtaposed against theMiddle Jurassic carbonates of the Candeeiros Formation.The top of the Lourinhã Formation is only seen at PedrasRuivas and at Praia de Santa Cruz where the PortugueseGeological Survey has mapped the contact with theCretaceous-aged Torres Vedras Formation (Manuppella,1996). This is difficult to validate as the fluvial facies styledoes not change significantly and there is no definitivebiostratigraphical evidence to support this boundary.Within the Lourinhã Formation it has been possible tomap and correlate a succession of shelly units, fluvialchannel styles and palaeosol character. Four mappableunits are given member status, named after the coastaltowns located close to the type sections (Figs. 9 to 13).The characteristics of these members are described belowin chronological order.

5.1. Sáo Bernardino Member

The Sáo Bernardino Member is developed to a thicknessof around 340 m (Fig. 9). The percentage of sand in anygiven logged vertical section varies from 34 to 44%. At SáoBernardino, the base of the member is marked by the transitionfrom brackish-water embayment facies (Alcobaça Formation),

Figure 8. Common bivalves recorded in the shelly units of the Porto de Barcas Member (scale bar is 1 cm). (1) Isognomon lusitanicum Solander from ShellyUnit 2, Porto de Barças. (2) Isognomon lusitanicum Solander from Shelly Unit 1, Porto de Barças. (3) Eomiodon securiformis (Sharpe) from Shelly Unit 1,Porto de Barças. (4) Jurassicorbula edwardi (Sharpe) from Shelly Unit 3, Praia da Areia Branca. (5) Placunopsis suprajurensis (Buvignier) from Shelly Unit1, Porto de Barças. (6) Myophorella lusitanica (Sharpe) from Shelly Unit 1, Porto Novo. (7) Praeexogyra pustulosa (Liostea sp.) from Shelly Unit 1, Peralta.

(8) Unio sp. from São Bernardino Member, Porto Dinheiro. This figure is available in colour online at wileyonlinelibrary.com/journal/gj.



into deposits dominated by fluvial channels and mature, red-brown palaeosols (Fig. 10). The top of the member is takenat the first shelly unit of the overlying Porto de Barças Member.This interval as a whole comprises fluvial channel sands andcalcrete-bearing floodplain muds (Fig. 11). Channel-fills showthe influence of a dominant granitic source, especially at thebase of the member, where granule- to pebble-size graniticclasts occur. The floodplain muds commonly show evidenceof soft-sediment deformation, and locally display deep fissures.Crevasse splay deposits are rare. The trace fossils Taenidiumbarretti (Bradshaw) and Planolites montanus Richter arelocally abundant (Fig. 14); T. barretti is most prominent in thechannel-fill sandstones, whereas P. montanus occurs both inchannels-fills and laminated floodplain muds. Channels areinterpreted to be mainly of meandering habit, with well-defined point-bar deposits commonly preserved. However, asubordinate proportion of the channel-fills suggest straightergeometries, with in-channel bars generated by downstreamaccretion. Biostratigraphical recovery is moderate to good,with abundant spores and pollen recovered from floodplainmuds. There is a distinctive abundance peak of Cyathiditesminor Couper and the long-ranging spore Corollina torosus(Reissinger) exhibits a marked reduction in abundancehere. Dinocyst influxes are recorded at the base, with C.granuligerum, Batiacasphaera sp., Tehamidinium sp. andDichadogonyaulax ‘minor’ recognized. There is one thin sandylimestone bed, rich in high-spired gastropods (Nerinea sp.),ostracods (Timiriasevia sp.), foraminifers (Psuedocyclamina

parvula), charophytes (Porochara kimmeridgensis) and dinocysts(C. granuligerum) exposed at Baleal (Fig. 7).

5.2. Porto de Barças Member

The thickness of the Porto de Barças Member is estimated tobe 110–123m. The percentage sand values within this mem-ber are consistently low, ranging from 12 to 25%. The baseof this member is defined by the initial transgressive surfaceand overlying first shelly unit (Figs. 12 and 13). The upperboundary of the member is picked on the top of the thirdand final shelly unit. In the absence of shell beds, to the eastof Baleal, the base corresponds to the change to a noticeablylower net sand interval which, in practice, is taken at the base ofthe first thick package of mature palaeosol deposits. The topsurface is defined by the transition into the significantly higherpercentage sand deposits of the overlying Areia Branca Mem-ber. The Porto de Barças Member interval is characterized bythe presence of three, laterally traceable shelly units, whichare developed in thick successions of floodplain muddeposits. Fluvial channels, where present, are meanderingand commonly contain abundant carbonaceous material.Thin (1–2m) sheet-sands attributed to minor mouth-barsand sandy bay shorelines are recognized locally, whilsttidally-influenced meander-belt deposits are noted towardsthe base of the member at Porto de Barças (Martinius andGowland, 2011). Palaeosols are dominantly calcrete-bearing, with organic rootlets locally preserved. Bioturbation

Figure 9. Summary of the lithostratigraphical divisions of the Lourinhã Formation in the Consolação Sub-basin. This figure is available in colour online atwileyonlinelibrary.com/journal/gj.

A. M. TAYLOR ET AL.


Figure 10. Stratigraphical summary for the Lourinhã Formation. This illustrates the change in stacking patterns and location of the shell beds used to define themembers of the Lourinhã Formation. This figure is available in colour online at wileyonlinelibrary.com/journal/gj.



Figure 11. Examples of the type of continental deposits typical of each member of the Lourinhá Formation. (1). Braided channel deposits in the Ferrel Memberat Pedras Ruivas. (2). Stacked fluvial channels with tidal modulation at the top of the Porto de Barças Member (B), which are overlain by fluvial channels of theAreia Branca Member (A) at Areia Branca. (3). Meandering channels in the Porto de Barças Member at Praia de Barças. (4). Meandering channels in the Sáo

Bernadino Member at Praia de Sáo Bernardino. This figure is available in colour online at wileyonlinelibrary.com/journal/gj.

Figure 12. Examples of the three Shelly Units in the Porto de Barças Member. The arrowsmark the tops and bases of these shelly units. (1). Shelly Unit 1 at Praia deBarças. (2). Shelly Unit 2 at Praia de Pai Mogo. (3). Shelly Unit 3 at Peralta. This figure is available in colour online at wileyonlinelibrary.com/journal/gj.

A. M. TAYLOR ET AL.


is common, with T. barretti and P. montanus throughout.The shell-rich units often form a number of individual bedsand are very distinctive, comprising sandy bioclastic lime-stones, micritic limestones and organic-rich, laminated mud-stones. The shelly biota is dominated by Isognomonlusitanicum Solander, Liostrea sp. (?Praeexogyra pustulosa),Eomiodon securiformis (Sharpe), Nanogyra nana (Sowerby),Myophorella lusitanica (Sharpe), Jurassicorbula edwardi(Sharpe) and Placunopsis suprajurensis (Buvignier) (Fig. 8).The trace fossil community closely associated with these shellbeds is diverse, consisting of Thalassinoides suevicus Rieth,Rhizocorallium jenense Zenker, Teichichnus rectus Seilacher,Planolites beverlyensis (Billings), Diplocraterion parallelumTorell, Skolithos linearis (Haldeman), Cylindrichnus sp.and Arenicolites statheri Bather (Fig. 14). Echinoid spines,serpulids, algal material and rare terebratulid brachiopodsare also noted.

There is good biostratigraphical recovery throughoutthis interval, with the most diverse assemblages recorded fromthe shelly units. Miospores are dominant with a high abundancepeak of Varirugosisporites sp. recorded. The most distinctiveaspect of the samples is the abundance and diversity ofthe dinocysts (S. paeminosa, D. brenneri, G. mutablis,Systematophora penicillata (Ehrenberg), C. granuligerum,Amphorula metaelliptica Dodekova, Batiacasphaerasp.), spores (e.g. Couperisporites jurassicus Pocock), algae(Chomotriletes sp., Tasmanites sp., Caddasphaerahalosa (Filatoff)), ostracods (S. triebeli, C. weberi, Cytherellasp., Candona sp., Eucytherura sp., Schuleridea sp.,Mandelstamina sp., Galliaecytheridea sp., Klieana sp.,Darwinulina sp., Sinocythere sp., Iliocypris sp., Timiriaseviasp.), foraminifers (A. jaccardi, P. parvula, Ammobaculitessp., Reophax sp., Guttulina sp.) and charophytes (Gyrogonites,P. kimmeridgensis, Porochara raskye) (Fig. 7).

Figure 13. Outcrop sedimentary logs of the Porto de Barças Member to illustrate the changes in the three shelly units across the study area. The base of ShellyUnit 1 is a regional transgressive surface. Given that Shelly Unit 1 also displays the most diverse ichnology and shelly biota it is also the best candidate for themaxiumum flooding surface. Regression terminates Shelly Unit 3 and fluvial/alluvial deposition dominates for the rest of the Lourinhá Formation. This figure is

available in colour online at wileyonlinelibrary.com/journal/gj.



5.3. Areia Branca Member

The overall thickness of the Areia Branca Member isaround 123–167m thick with percentage sand values of55 to 57%. The base of this member is picked at thetop of the youngest shelly unit (Fig. 11). In the absenceof shell markers, the base is picked at the base of the firstsignificantly thick fluvial channel or mouth-bar depositmarking the vertical transition into higher net sand de-posits. The top of the member is marked by a transitionin to significantly coarser grained and more sand-prone,fluvial channel deposits (percentage sand values of 71to 74%). This member comprises mainly subaerial coastalplain deposits, with numerous fluvial channel sandstonesand calcrete-bearing floodplain muds. Crevasse splay de-posits and lacustrine muds are rare. The channel-fills arecommonly multi-storey, and represent a predominantlymeandering river system. Tidally modulated fluvialchannel-fills are locally recognized (Martinius andGowland, 2011). At the base of the member, accommo-dation space created by the final phase of bay develop-ment in the underlying Porto de Barças Member wasfilled locally by sandy mouth-bar deposits. Large Uniosp. bivalves (Fig. 8) can be found along with T. barrettiand P. montanus (Fig. 14). Although this member lacksrecovery of ostracods and foraminifers, there are a num-ber of minor dinocyst influxes marked by A. metaelliptica

and C. granuligerum. Miospores dominate the palynoflora,with an abundance peak of Krauselisporites cf. linearis seen.

5.4. Ferrel Member

The Ferrel Member is developed to a thickness of at least 75 mbut unmeasured sections suggest this may be as high as 200 m(Fig. 10). Percentage sand ratios of 71 to 75% are noted. Thebase of the member is marked by the onset of significantlycoarser grained sediments, which commonly display a darkred-brown colouration, contrasting with the light grey-brown colour of the underlying Areia Branca Member.The top of the Ferrel Member corresponds to the top ofthe Lourinhã Formation and the contact with theCretaceous-aged Torres Vedras Formation. The FerrelMember comprises dark red-brown, sharp-based and rela-tively flat-topped fluvial channel-fills within a backgroundof palaeosol facies. Grain-sizes are generally coarser thanin the underlying members, comprising coarse sand andgravel arranged into in-channel bar forms (Fig. 11). Therivers were probably subject to a flashy discharge regime.Channel-fills have an overall sheet-like geometry and areconsidered to reflect braided channel development. Theencasing floodplain muds are locally calcrete-bearing.Bioturbation levels are low with T. barretti and P.montanusnoted. Locally, the fills of more sinuous channels are seen.

Figure 14. Common trace fossils recorded in the Lourinhá Formation. (Scale bar is 1 cm.) (1) Arenicolites statheri Bather from Shelly Unit 1 at Porto deBarças. (2) Cylindrichnus isp. from the Porto de Barças Member at Porto de Barças. (3) Diplocraterion paralellum Torell from Shelly Unit 2 at Praia de SantaRita. (4) Rhizocorallium jenense Zenker from Shelly Unit 1 at Porto de Barças. (5) Taenidium barretti (Bradshaw) (T) and Planolites montanus Richter (P) fromthe São Bernardino Member at Praia do Sáo Bernadino. (6) Taenidium barretti from the São Bernardino Member at Pai Mogo. (7) Teichichnus rectus Seilacherfrom Shelly Unit 1 at Porto de Barças. (8) Thalassinoides suevicus Reith from the base of Shelly Unit 1 at Porto de Barças. This figure is available in colour

online at wileyonlinelibrary.com/journal/gj.

A. M. TAYLOR ET AL.


This interval has yielded very little biostratigraphical infor-mation; a low diversity miospore assemblage is present withForaminisporites wonthaggiensis (Cookson and Dettmann)locally abundant and some Chomotriletes sp. (acritarch)noted (Fig. 7). No ostracods or forams were recovered fromthis interval.

6. CORRELATION

The excellent exposure along the coast from Consolaçãosouthwards to Santa Cruz allows the key shelly units to betraced some 17 km (Fig. 4). The carbonate content of thesebeds means that they weather proudly in the cliff-face andcan be traced round the main headlands where access isdifficult (Fig. 12). High-resolution photographs were takenfrom a boat over the entire section and the shelly unitshave been logged at the outcrop and referenced to the out-crop photographs.The laterally extensive (km-scale) shelly units contain a

suite of discrete shell beds, each of which may persist overdistances of several hundred metres. However, the shellyunits change in character across the study area with an overallnorthward thinning recorded for all three units. The pinch-outpoint for the lowermost shelly unit is in the north around PaiMogo (Fig. 13). Here, before the bed terminates laterally, itis represented only by a centimetre-scale shelly lag deposit.Further south, this unit thickens into a series of in situ shellbanks exhibiting community succession, plus crustacean-colonized firmgrounds bioturbated by Thalassinoides andRhizocorallium (Fig. 14). Each of the three shelly units inthe Porto de Barças Member yields a slightly different biotaand trace fossil community, which means it can be easily iden-tified in the field. The most diverse community is seen in thelowermost shelly unit, which shows prominent Eomiodonsecuriformis, whilst the middle shelly unit is marked by thepresence of Nanogyra nana, and the upper by abundantJurassicorbula edwardi. Isognomon lusitanicum is recordedin all three units (Fig. 8). The ostracod content of the shellyintervals also shows slight variations, with C. weberi,Cytherella sp. and Schuleridea sp. common in the lowest unit,Mandelstamina sp. and Galliaecytheridea sp. in the middleunit and Klieana sp., Darwinulina sp., Sinuocythere sp.,Iliocypris sp. and Timiriasevia sp. recorded in the uppermostunit. The most significant biostratigraphical markers wererecovered from the shelly successions. For example, theforaminiferid A. jaccardi has only been recorded in the lower-most shelly unit. The dinocysts S. paeminosa, D. brenneri, G.mutablis and the ostracod C. weberi were only found in thelower two shelly units (Fig. 7). In the section east of Baleal,no shelly units are recorded, as they appear to have died outto the south, in the vicinity of Pai Mogo. Consequently, thecorrelation in the northern outcrops relies on a combination

of facies stacking patterns, fluvial channel styles andpalaeosol character to resolve the different members. Forexample, the interval containing the three shelly units (Portode Barças Member) has few fluvial channel sandstones,with the percentage sand content remaining consistentlylow in all sections measured (12–25%); thick palaeosolsdominate. This contrasts markedly with both the underlyingSáo Bernardino Member (34–44% sand) and the overlyingAreia Branca Member (55–57%). The contrasting styles offluvial channel architecture towards the top of the LourinhãFormation indicate a clear shift from dominantly meander-ing (Areia Branca Member) to dominantly braided systems(Ferrel Member). In addition, changes in colour, bedloadand sediment source correspond to the boundary betweenthe two members.

7. CONSOLAÇÃO SUB-BASIN

As a direct result of mapping the four new members of theLourinhã Formation, it is possible to define a new sub-basinin the western part of the Lusitanian Basin. We have namedthis the Consolação Sub-basin after the coastal town aroundwhich it is located (Fig. 2). There is a continuity of faciesand thicknesses within the members extending from the Balealarea in the north to Praia de Santa Rita in the south. However,facies and stratigraphical thicknesses appear to change on thesouthern side of the Santa Cruz diapir (L–C strike slip faultzone) that marks the boundary with the Turcifal Sub-basin.The sections described by Fürsich (1981) at Praia Azuland Ellwood (1987) at Santa Cruz all belong in the TurcifalSub-basin, whereas, Hill’s (1989) work at Porto Novo was inthe Consolação Sub-basin.

Regional sections published for the study area show themajor NE–SW orientated fault zone (L–C fault), whichcontrolled the development of the Caldas de Rainha, Bolhosand Santa Cruz diapirs (Alves, 2002; Alves et al., 2003b).This fault zone defines the eastern edge of the ConsolaçãoSub-basin. The western margin has a similar inferred orienta-tion and is marked by the Berlengas Horst Block (Fig. 2).Wilson (1979, fig 7) was the first to recognise the differentialfill of the basin across the Santa Cruz diapir. The cross-section of Ravnås et al. (1997, fig 3) illustrated the fill of thissub-basin, and noted a thinning onto the Berlengas High.The Consolação Sub-basin was not differentiated from theTurcifal Sub-basin by Ravnås (op. cit.), however, the westernmargin can be clearly seen to have a different fill history toboth the eastern part of Turcifal Sub-basin and the ArrudaSub-basin. Alves (2002) and Alves et al. (2003b) also illus-trated a major change in basin-fill history across the L–C faultzone that was consistent with the definition of a new sub-basin,separated from both the Bombarral–Alcobaça and Turcifalsub-basins. In the Turcifal Sub-basin, the Lourinhã Formation



bedding stacking patterns are noticeably different; the coastalsection exposed from Praia Azul to Assenta records anincreased frequency and thickness of bioclastic limestones inwhat appear to be progressively younger Lourinhã Formationdeposits. Leinfelder et al. (2004) reported the occurrence atFoz of corals and oysters in a stratigraphically younger sectionthan the Praia Azul Member. The Arranhó Member outcrop-ping at Praia de Assenta is younger still, and the top of theLourinhã Formation is not seen. The base of the LourinhãFormation is exposed at Praia de Formosa (Ellwood, 1987),where a shallowing profile is seen, comprising shelf,shoreface, brackish bay and, eventually, continental deposits.Here, the boundary between the marine Abadia Formationand the largely continental Lourinhã Formation is difficult todefine. If the new member stratigraphy were to be applied tothe coastal exposures of the Lourinhã Formation in theTurcifal Sub-basin, the São Bernardino Member would be c.300 m thick and comparable to the Consolação Sub-basin,whereas the Porto de Barças Member would be in excess of400 m thick and containing many more shelly units than areseen in the Consolação Sub-basin. This is likely to reflect acombination of different subsidence patterns at this time, plusclear proximity to the palaeo-coastline in the more southerlyTurcifal Sub-basin.

8. DISCUSSION

Like other similar successions, dating of the marine-influenced Lourinhã Formation is made somewhat diffi-cult by the absence of ammonites. As previously stated,the known ranges of most of the taxa recorded fromthese sediments span the Oxfordian to Berriasian. Themajority of published interpretations of the Lourinhã For-mation suggest that it is Tithonian in age. Compelling ev-idence supporting this interpretation does not appear inthe public domain. In this study there are a number ofbiostratigraphic markers that do range into the Tithonian,but nothing that is exclusively Tithonian in age, such asthe foraminifer Anchispirocyclina lusitanica. However,the key marker that supports a definitive latest LateKimmeridgian to earliest Early Tithonian age, thedinocyst Subtilisphaera paeminosa, is only recorded fromthe Porto de Barças Member. This does raise the possi-bility that the Areia Branca and Ferrel Members couldbe Tithonian in age.

The Abadia Formation, which crops out on the coast atConsolação, has been dated as Late Kimmeridgian in age. Thisformation directly underlies the Lourinhã Formation andcomprises interbedded bioclastic sandy limestones, micrites,sandstones and mudstones. The depositional interpretation isthat of a muddy marine shelf contracting into brackish watercoastal bays (c.f. Werner, 1986; Leinfelder et al., 2004; Yin

et al., 1995). Abadia Formation sediments have a similarbiostratigraphical signature to the Porto de Barças Memberand both contain shell beds with abundant Isognomonlusitanicum, Praeexogyra pustulosa and Nanogyra nana.Both the Abadia Formation and the Porto de Barças Memberare biostratigraphically dated as Late Kimmeridgian. As such,this stratigraphical interval may be broadly coeval with theLourinhã Formation in the wider context of the LusitanianBasin. For these reasons it is suggested that the sedimentsof the Abadia Formation be re-assigned to the previouslydesignated Alcobaça Formation (sensu Manuppella, 1998).We would suggest that the term ‘Abadia Formation’ shouldbe reserved for mudrock-dominated shelfal successions ofEarly to Late Kimmeridigian age.The persistence of distinctive shelly horizons has been

recognized previously in the Lourinhã Formation of theLusitanian Basin (Wilson, 1979; Rocha et al., 1996;Leinfelder, 1987; Fürsich, 1981). These intervals have a num-ber of lithostratigraphical names, but due to the lack of detailedbiostratigraphy and mapping, correlation remains uncertain.For example, the Lima psuedoalternicosta beds refer to theLate Kimmeridgian, Isognomon-bearing carbonates mappedas part of a brackish-water interdistributary bay by Wilson(1979). These beds would appear to be the same as the lower-most shelly unit in the Porto de Barças Member and similar toa number of horizons in the Alcobaça Formation exposed atConsolação. The ‘Pteroceriano Beds’ are considered to be abase Tithonian marker event (Rocha et al., 1996). It is alsothe same Isognomon-bearing shelly interval that Leinfelder(1987) recorded in this study area and it corresponds tothe lowermost shelly unit within the Porto de BarçasMember. Careful mapping of the Porto de Barças Memberhas shown that it equates, in part, to the Praia Azul Memberof Fürsich (1981) and is of the same age. The ArranhóMember is stratigraphically younger than the Praia AzulMember and could conceivably equate to the Porto deBarças Member (Fig. 5)The Lourinhã Formation is dominated by continental

deposits, indicating the development of well-vegetated flood-plains, traversed by sandy fluvial channels flowing broadlysouth-westwards. The presence of calcrete-rich palaeosolssuggests a generally warm climate, whilst combined sedimen-tological and ichnological attributes of the fluvial channelsindicate perennial, though fluctuating flow. Distinct growthring variations in fossil conifer wood samples also point toa seasonal climate (Martinius and Gowland, 2011). Thesporomorph community is dominated by a mixture of lowlanddry flora and lowland marsh flora, with subordinate river-fringing Lycopodiales and coastal flora (e.g. Callialasporites,Corollina) also seen. In summary, a warm, seasonal (winterwet) climate is favoured, with temperatures high enough to al-low vegetation growth throughout the year, provided enoughwater was present. The presence of marine intercalations in

A. M. TAYLOR ET AL.


the form of brackish-marine bays suggest that the LourinhãFormation developed as part of a low-lying coastal plain,fringing a shallow tropical sea (supporting corals) to thesouthwest. The changes in fluvial architecture and the occur-rence of marine horizons could reflect a combination oftectonic events (reactivation of Hercynian lineaments), relativechanges in sea level and climatic cyclicity affecting run-offand water table levels.The Lourinhã Formation has been compared to the Late

Kimmeridgian Morrison Formation in the Western Interior,USA by Mateus (2006). Both formations have similarpalaeolatitudes (30–35 degrees), comparable palaeoclimates(wet–dry) and comprise coastal plain facies with marineincursions. Mateus (2006) compared the flora and fauna ofthe formations suggesting that the dinosaur communitieswere very similar and concluded that a land bridge must havelinked Iberia and North America at this time. AlthoughMateus (2006) believed that this land bridge existed throughboth the Kimmeridgian and Tithonian stages, the MorrisonFormation is dated as Late Kimmeridgian in age (Kowalliset al., 1988). The conclusion of this study is that the LourinhãFormation is predominately Late Kimmeridgian in ageand so the comparison is valid, but the ‘isthmus’ thatmay have linked these areas may have started to disappearin the Tithonian.The Consolação Sub-basin is the name proposed herein for

part of the western margin of the Lusitanian Basin. There areno seismic lines across this area to confirm the subsurfacegeology and image the fault-bounded margin in the west. Therelationship to the Turcifal, Arruda and Bombarral–Alcobaçasub-basins is derived from outcrop data, particularly themapped changes in the Lourinhã Formation and regionalcross-sections published by Ravnås et al. (1997) and Alveset al. (2003b). Conclusions from this study differ from previ-ously published accounts and question the age dating andstratigraphical correlation of the Late Jurassic reefal carbon-ates mapped on the diapirs at Caldos de Rainha, Bolhos andVimeiro (Wilson, 1979; Wilson et al., 1989; Ellis et al.,1990; Manuppella et al., 1999). Previous work considersthese carbonate reefs to be coeval with the Lourinhã Forma-tion, recording the presence of a shallow water carbonateramp growing in response to salt migration along the L–Cfault zone. Previously this fault zone was believed to haveacted as a ‘stratigraphical fence’ separating clastic fromcarbonate deposition during the Kimmeridgian (Leinfelder,1987, 1994; Hill, 1989; Wilson et al., 1989). However,published palaeogeographical reconstructions of the regionare often contradictory, displaying a fully marine shelfdeveloping on a submarine high well within the basin,and surrounded by clastic continental deposition. Alterna-tively, the carbonates could be slightly older (?MiddleKimmeridgian) and therefore might be more appropriatelyassigned to the Alcobaça Formation.

9. CONCLUSIONS

(1) The Lourinhã Formation in the studied area appears to belatest Late Kimmeridgian to earliest Early Tithonian in age,based on the occurrence of the dinocyst Subtilisphaerapaeminosa. The same age is also recognized for the mixedcarbonate and clastic deposits exposed at Consolação, whichwere previously assigned to the Abadia Formation, but arenow re-assigned to the Alcobaça Formation. This islogical given that these sediments represent shallow marineshelf and bay environments linked to the more continentalLourinhã Formation.(2) The key biozonal markers for the Lourinhã Formation arelong-ranging species spanning the Middle Oxfordian to theEarly Tithonian. They include Alveosepta jaccardi, Kurnubiapalastiniensis, Clypeina Jurassica, Cetacella armata andAnchispirocyclina lusitanica. In this study, the recognition ofthe ostracods Schuleridea triebeli and Cytherelloidea weberi,the agglutinating foraminifer Pseudocyclammina parvula, thecharophyte Porochara kimmeridgensis and the dinoflagellatecysts Dichadogonyaulax pannea, D. brenneri, Gochteodiniamutalbilis and Cribroperidinium granuligerum ‘complex’ sug-gest a Middle Kimmeridgian to Early Tithonian age. Perhapsthe most useful floral taxon is Cicatricosisporites sp., which in-dicates a Kimmeridgian age. However, the presence of the short-ranging dinocyst Subtilisphaera paeminosa confirms the mostlikely age of the Lourinhã Formation to be Late Kimmeridgian.(3) Four new members: the Sáo Bernardino, Porto de Barças,Areia Branca and Ferrel are proposed for the LourinhãFormation. These are mappable units that are defined on thebasis of lateral extent, facies types and stacking patterns, andpalaeontological content (shelly macrofaunas and ichnotaxa).(4) The Porto de Barças Member contains three distinc-tive shelly units that can be mapped from their pinch-out point in the north at Pai Mogo to a southern limitaround Foz. These form the framework for correlationof the continental sediments. The bivalve communitiesare dominated by Isognomon lusitanicum, Liostrea sp.(?Praeexogyra pustulosa), Eomiodon securiformis, Nanogyranana, Jurassicorbula edwardi, Myophorella lusitanica andPlacunopsis suprajurensis. The associated trace fossil coloniza-tions comprise Thalassinoides suevicus,Rhizocorallium jenense,Teichichnus rectus, Planolites beverlyensis, Diplocraterionparallelum, Skolithos linearis, Cylindrichnus sp. andArenicolites statheri. These shelly units represent periodicmarine incursions onto a low-lying coastal plain in the formof brackish-marine bays.(5.) When the biostratigraphical data is examined in detail,Kimmeridgian taxa range throughout the stratigraphical inter-val. However, the key marker S. paeminosa is only recoveredfrom the Porto de Barças Member. This raises the possibilitythat the Areia Branca and Ferrel members may be LateKimmeridgian or Early Tithonian in age. No specific Early



Tithonian marker is recorded here, but the age range of anumber of taxa does not wholly exclude this either.(6) A combination of regional mapping and stratigraphicalcorrelation of the Lourinhã Formation indicate that the L–Cfault zone, with its associated diapirs (Caldas de Rainha,Bolhos and Santa Cruz) is a significant lineation boundingthe eastern margin of the newly defined Consolação Sub-basin of the Lusitanian Basin. The western margin of thenew sub-basin is defined by the Berlengas Horst. There is acontinuity of deposition seen for the Lourinhã Formationthat differs from that seen in the Turcifal, Arruda andBombarral–Alcobaça sub-basins. The structural settingillustrated by Alves et al. (2003b) and Ravnås et al. (1997)supports this view.

ACKNOWLEDGEMENTS

This project benefited from the biostratigraphical skills ofMike Ayress (micropalaeonotology) and Salih Mahdi(palynology). Many thanks to Statoil employees who helpedwith data capture and discussions in Portugal, particularlyHjørdis Nese, Silje Berg, Carsten Elfenbein (now at DetNorske Oljeselskap), Scott Bullimore, Eirik Larsen (now atRocksource), Pål Trygve Sandbakken, Kjetil Nordahl,Erik Hammer (now at Lundin Petroleum), Eirik Vik, AnnaStrömbäck, Carlo Messina and Thomas Gorm Theting. Theresearch area was brought to our attention whilst working(AMT/SG) with the Direcçao Geral de Geologia é Energia(DGGE) on the Petroleum Geology of Portugal. We areindebted to José Miguel Martins and Terasinha Abecasisfor all their help. The financial support of Statoil and Ichronis gratefully acknowledged. Finally Rob Raine (Ichron)suggested significant improvements to the original manuscript.

REFERENCES

Alves, T.M. 2002. Salt vs fault tectonics on the Western Iberian Margin,Portugal: controls on Meso-Cenozoic depositional systems. PhDThesis, University of Manchester, 1–386.

Alves, T.M., Gawthorpe, R.L., Hunt, D.W., Monteiro, J.H. 2003a. Post-Jurassic tectono-sedimentary evolution of the Northern Lusitanian Basin(western Iberian margin). Basin Research 15, 227–249. DOI: 10.1046/j.1365-2117.2003.00202.x.

Alves, T.M., Manuppella, G., Gawthorpe, R.L., Hunt, D.W., Monteiro,J.H. 2003b. The depositional evolution of diapir- and fault-bounded riftbasins: Examples from the Lusitanian Basin (Offshore Portugal). Marineand Petroleum Geology, 19, 727–754. DOI: 10.1016/S0264-8172(02)00036-3.

Alves, T.M.,Moita, C., Sandnes, F.,Cunha, T.,Monteiro, J.H.,Pinheiro, L.M.2006. Mesozoic–Cenozoic evolution of North Atlantic continental-slope basins: The Peniche Basin, western Iberian margin. AAPG Bulletin90, 31–60. DOI: 10.1306/08110504138.

Antunes, M.T., Elderfield, H., Legoinha, P., Nascimento, A., Pais, J. 1999.A stratigraphic framework for the Miocene from the Lower Tagus Basin(Lisbon, Setubal Peninsula, Portugal). Depositional sequences, biostratigra-phy and isotopic ages. Revista Sociedad Geológica de España 12, 3–15.

Azerêdo, A.C., Cabral, M-C. 2004. Bio-sedimentary signatures of high-frequency salinity/subaerial exposure changes: Examples from theOxfordian of Portugal (Cabaços Formation). Rivista Italiana diPaleontologia e Stratigrafia 110, 231–238.

Bernardes, C. 1992. A sedimentação durante o Jurássico Superior entre oCabo Mondego e o Baleal (Bacia Lusitana): Modelos deposiciuonais earquitectura sequencial. PhD Thesis, University Averio, 1–261.

Camarate Franca, J., Zbyszewski, G., Moitinho de Almeida, F. 1960. Cartageológica de Portugal 1/50000. Folha 26-C, Peniche. Departamento deGeologico e Mineriro.

Choffat, P. 1901. Notice préliminaire sur la limite entre le Jurassique et leCrétacique en Portugal. Bulletin de la Société Belge de GéologiePaléontologie Hydrologie XV, 11–140.

Collinson, J.D. 1996. Alluvial sediments. In: Sedimentary Environments:Processes, Facies and Stratigraphy, Reading, H.E (ed.), BlackwellScience Ltd, Oxford, 37–82.

Dépêche, F. 1985. Lias supérieur, Dogger, Malm. In: Atlas des Ostracodesde France (Paléozoïque-Actuel), Oertli, H.J. (ed.),. Bulletin de centres derecherches Exploration-Production Elf-Aquitaine, Mémoir 9, 119–145.

Dodekova, L. 1969. Dinoflagellates et acritaches du Tithonique aux envi-rons de Pleven, Bulgaria Central du Nord. Bulgarian Academy ofSciences, Committee of Geology, Bulletin of Geological Institute, SeriesPaleontology 18, 13–24.

Direcção Geral de Geologia e Energie (DGGE) 2007. Archives (seewww.dgge.pt).

Driscoll, N.W., Hogg, J.R., Christie-Blick, N., Kraner, G.D. 1995.Extensional tectonics in the Jeanne d’Arc Basin, offshore Newfoundland:implications for the timing of break-up between Grand Banks and Iberia.In: The tectonics, sedimentation and palaeooceanography of the NorthAtlantic region, Scrutton, R.A., Stoker, M.S., Shimmield, G.B.,Tudhope, A.W. (eds), Geological Society London Special Publication90, 1–28.

Ellis, P.M.,Wilson, R.C.L.,Leinfelder, R.R. 1990. Controls on Upper Jurassiccarbonate buildup development in the Lusitanian Basin, Portugal. In:Carbon-ate Platforms, Facies, Sequences and Evolution, Tucker, M.E., Wilson, J.L.,Crevello, P.D., Sarg, J.R., Read, J.F. (eds) International Association ofSedimentologists, Special Publication 9, 169–202.

Ellwood, P.M. 1987. Sedimentology of the Upper Jurassic AbadiaFormation and its equivalents, Lusitanian Basin, Portugal. Ph.D thesis,The Open University.

Fürsich, F.T. 1981. Salinity-controlled benthic associations from the UpperJurassic of Portugal. Lethaia 14, 203–223. DOI: 10.1111/j.1502-3931.1981.tb01690.x.

Fürsich, F.T,Werner,W. 1986. Benthic associations and their environmentalsignificance in the Lusitanian basin (Upper Jurassic, Portugal). NeuesJahrbuch für Geologie und Paläontologie, Abhandlungen 172, 271–329.

Gabinete Para a Pesquisa e Exploração (GPEP), 1993. The PetroleumPotential of Portugal. Data package. Instituto Geológico e Mineiro,Portugal.

Gradstein, F., Ogg, J., Smith, J. 2004. A Geologic Time Scale. CambridgeUniversity Press, Cambridge. 1–589.

Kowallis, B.J., Christiansen, E.H., Deino, A.L., Peterson, F., Turner, C.E.,Kunk, M.J., Obradovich, J.D. 1988. The age of the Morrison Formation.Modern Geology 22, 235–260.

Herngren, G.F.W., Van Hoeken-Klinkenberg, P.M.J., De Boer, K.F.1980. Some remarks on selected palynomorphs near the Jurassic–Cretaceousboundary in the Netherland. Proceedings of the Fourth International Palyno-logical Conference, Lucknow (1976–77) 2, 357–376.

Hill, G. 1989. Distal alluvial fan sediments from the Upper Jurassic ofPortugal: Controls on their cyclicity and channel formation. Journalof the Geological Society, London 146, 539–555. DOI: 10.1144/gsjgs.146.3.0539.

Kilenyi, T. 1978. The Jurassic Part III Callovian–Portlandian. In: AStratigraphical Index of British Ostracoda, Bate, R., Robinson, E.(eds). Geological Journal Special Issue 8, 259–298.

Knighton, D. 1998, Fluvial Forms and Processes: A New Perspective.Arnold, London & New York, 1–383.

Leinfelder, R.R. 1986. Facies, stratigraphy and paleogeographic anal-ysis of the Upper Kimmeridgian to Upper Portlandian sediments inthe environs of Arruda dos Vinhos, Estremadura, Portugal.

A. M. TAYLOR ET AL.


http://www.dgge.pt

Münchner Geowissenschaftliche Abhandlungen, Reihe A: Geologieund Paläontologie 7, 1–215.

Leinfelder, R.R. 1987. Multifactorial control of sedimentation patterns inan ocean marginal basin: The Lusitanian Basin (Portugal) during theKimmeridgian and Tithonian. Geologische Rundschau 76, 599–631.DOI: 10.1007/BF01821094.

Leinfelder, R.R. 1993. A sequence stratigraphic approach to the UpperJurassic mixed carbonate–siliciclastic succession of the central LusitanianBasin, Portugal. Profil 5, 119–140.

Leinfelder, R.R. 1994. Karbonatplattformen und Korallenriffe innerhalbsiliziklastischer sedimentationsbereiche (Oberjura Lusitanisches Becken,Portugal). Profil 6, 1–207.

Leinfelder, R.R., Wilson, R.C.L. 1989. Seismic and sedimentologicfeatures of Oxfordian–Kimmeridgian syn-rift sediments on the easternmargin of the Lusitanian Basin. Geologische Rundschau 78, 81–104.DOI: 10.1007/BF01988355.

Leinfelder, R.R., Wilson, R.C. 1998. Third-order sequences in an UpperJurassic rift-related second-order sequence, Central Lusitanian Basin,Portugal. In: de Graciansky, P-C, Hardenbol, J., Jacquin, T., Vail, P.R. (eds) Mesozoic and Cenozoic Sequence Stratigraphy of EuropeanBasins, SEPM Special Publication 60, 507–525. DOI: 10.2110/pec.98.02.0507.

Leinfelder, R.R., Nose, M., Schmid, D., Werner, W. 2004. Reefs andcarbonate platforms in a mixed carbonate–siliciclastic setting: examplesfrom the Upper Jurassic (Kimmeridgian to Tithonian) of west-centralPortugal. . In: Duarte, L.V., Henriques, M.H. (eds), Carboniferous andJurassic Carbonate Platforms of Iberia. 23rd IAS Meeting of Sedimentology,Coimbra, 2004, Field Trip Guidebook 1, 95–123.

Manuppella, G. 1996. Carta geológica de Portugal 1/50000. Folha 30-A,Lourinhã. Departamento de Geologico e Mineriro (map).

Manuppella, G. 1998. Geological data about the ‘Camadas de Alcobaça’(Upper Jurassic) North of Lourinhã and facies variation. Memórias deaAcademia de Ciências de Lisboa 37, 17–24.

Manuppella, G., Antunes, M.T., Pais, J., Ramalho, M.M., Rey, J.1999. Carta Geologigica de Portgal na escala de 1/50,000. Noticiaexplicativa da folha 30-A Lourinhã. Departamento de Geologico eMineriro, Lisboa, 1–83.

Martinius, A., Gowland, S. 2011. Tide-influenced fluvial bedformsand tidal bore deposits (Late Jurassic Lourinhã Formation, LusitanianBasin, western Portugal). Sedimentology 58, 285–324. DOI: 10.1111/j.1365-3091.2010.01185.x.

Mateus, O. 2006. Late Jurassic Dinosaurs from the Morrison Forma-tion (USA), the Lourinhã and Alcobaça Formations (Portugal), andthe Tendaguru Beds (Tanzania): A comparison. In: Paleontologyand Geology of the Upper Jurassic Morrison Formation, Forster,J.R., Licas, S.G.R.M. (eds). New Mexico Museum of NaturalHistory and Science Bulletin 36, 1–9.

Miall, A.D. 1992. Alluvial deposits. In: Walker, R.G., James, N. (eds)Facies Models: Response to Sea Level Change. Geological Society ofCanada, St. Johns Newfoundland, 119–142.

Miall, A.D. 2006. Reconstructing the architecture and sequence stratigra-phy of the preserved fluvial record as a tool for reservoir development:A reality check. AAPG Bulletin 90, 989–1002. DOI: 10.1306/02220605065.

Mohr, B.A.R., Schmidt, D. 1988. The Oxfordian/Kimmeridgian bound-ary in the region of Poto de Mos (Central Portugal): Stratigraphy, faciesand palynology. Neues Jahrbuch für Geologie und Paläontologie,Abhandlungen 176, 245–267.

Mouterde, R., Ramalho, M., Rocha, R.B., Ruget, C., Tintant, H. 1972.Le Jurassique du Portugal: Esquisse stratigraphique et zonale. Boletimda Sociedade Geológica de Portugal 18, 73–104.

Muto, T., Steel, R.J. 1997. Principles of regression and transgression:The nature of the interplay between accomodation and sediment supply.Journal of Sedimentary Research 67, 994–1000.

Olsen, T., Steel, R.J., Høgseth, K., Skar, T., Roe, S. 1995. Sequentialarchitecture in a fluvial succession: Sequence stratigraphy in the UpperCretaceous Mesaverde Group, Price Canyon, Utah: Journal of Sedimen-tary Research B62, 265–278.

Pena Dos Reis, R.P.B., Trincão, P.R., Proenca Cunha, P., Dinis, J.L.1996. Estratigrafia sequencial e biostratigrafia do Jurássico superior

da Bacis Lusitânica. Basin Analysis Group Study (BAGS) unpublishedreport, Insitituto Pedro Nunes, Coimbra, 1–186.

Pena Dos Reis, R.P.B., Proenca Cunha, P., Dinis, J.L., Trincao, P.R.2000. Geological evolution of the Lusitanian Basin (Portugal) duringthe Late Jurassic. GeoResearch Forum 6, 345–356.

Pereira, R., Feist, M., Azeredo, A.C. 2003. New Charophytes fromthe Upper Jurassic of the Lusitanian Basin (Portugal). Journal ofMicropalaeontology 22, 113–126.

Pinheiro, L.M.,Wilson,R.C.L.,PenaDosReis, R.B.,Ribeiro, A. 1996. 1. TheWestern Iberia Margin: A geophysical and geological overview. In:Whitmarsh, R.B., Sawyer, D.S., Klaus, A., Masson, D.G. (eds). Proceedingsof the Ocean Drilling Program, Scientific Results 149, 3–23.

Posamentier, H.W., Allen, G.P. 1999. Siliciclastic sequence stratigraphy— Concepts and applications. SEPM Concepts in Sedimentology andPaleontology Series 7, 1–204. DOI: 10.2110/csp.99.07.

Poulsen, N.E. 1996. Dinoflagellate cysts from marine jurassic deposits ofDenmark and Poland. American Association of Stratigraphic Palynolo-gists, Contribution Series 31, 1–227.

Ramalho, M.M. 1971. Contribuition à l´étude micropaléontologiqueet stratigraphique du Jurassique supérieur et du Crétacé inférieurdes environs de Lisbonne (Portugal). Servicos Geologicos de Portu-gal, Memoria 19, 1–212.

Ramalho, M.M. 1981. Note préliminaire sur le microfoacies duJurassique Supérieur Portugais. Communicações Serviços Geológicosde Portugal 67, 41–45.

Ravnås, R., Windelstad, J., Mellere, D., Nøttveldt, A., Stuhr Sjøblom,T., Steel, R.J., Wilson, R.C.L. 1997. A marine Late Jurassic syn-riftsuccession in the Lusitanian Basin, Western Portugal: Tectonic signifi-cance of stratigraphic signature. Sedimentary Geology 114, 237–266.DOI: 10.1016/S0037-0738(97)00068-7.

Rees, P.M., Noto, C.R., Parrish, J.M., Parrish, J.T. 2004. Late Jurassicclimates, vegetation and dinosaurs distributions: Journal of Geology112, 643–653. DOI: 10.1086/424577.

Riding, J.B., Thomas, J.E. 1988. Dinoflagellate cyst stratigraphy of theKimmeridge Clay (Upper Jurassic) from the Dorset coast, southernEngland, UK. Palynology 12, 65–88.

Rocha, R.B.,Marques, B.L.,Kullberg, J.C.,Caetano, P.C.,Lopes, C.,Soares,A.F.,Duarte, L.V.,Marques, F.J.,Gomes, C.R. 1996. The First and SecondRifting Phases of the Lusitanian Basin: Stratigraphy, Sequence Analysis andSedimentary Evolution. Final report CEC Project Milupobas, Lisboa.

Russell, S.M., Withmarsh, R.B. 2003. Magmatism at the west Iberia non-volcanic rifted continental margin: Evidence from analyses of magneticanomalies. Geophysical Journal International 154, 706–730.DOI: 10.1046/j.1365-246X.2003.01999.x.

Septfontaine, M. 1981. Les foraminifére imperforés des milieux de plate-forme au Mésozoique détermination, partique interpretation et utilisationbiostratigraphique. Revue de Micropaléontologie 23, 169–203.

Shanley, K.W., McCabe, P.J. 1994. Perspectives on the sequence stratig-raphy of continental strata: AAPG Bulletin 78, 544–568.

Sousa, L. 1998. Upper Jurassic (Upper Oxfordian–Tithonian)palynostratigraphy from the Lusitanian Basin (Portugal). MemóriasAcademia Ciências Lisboa 37, 49–78.

Stampfli, G.M., Borel, G.D. 2002. A plate tectonic model for the Paleozoicand Mesozoic constrained by dynamic plate boundaries and restoredsynthetic oceanic isochrones. Earth and Planetary Science Letters196, 17–33. DOI: 10.1016/S0012-821X(01)00588-X.

Van Erve, A.W., Besems, R.E., Love, C.F. 1988. Palynological investiga-tion of some Lower Kimmeridgian deposits from Spain. Journal ofMicropalaeontology 1, 217–232.

Van Erve, A.W., Mohr, B.A.R. 1988. A palynological investigation ofthe Late Jurassic microflora from the vertebrate locality Guimarota coalmine (Leiria, Central Portugal). Neues Jahrbuch für Geologie undPaläontologie, Monatshefte. 4, 246–262.

Werner, W. 1986. Palökolgische und biofazielle analyse des Kimmeridge(Oberjura) von Consolação, Mittelportugal. Zitteliana 13, 1–109.

William, G.L., Bujak, J.P. 1980. Dinoflagellate cyst zonation of theEnglish Jurassic. Institute of Geological Sciences, Report 83/2, 1–41.

Wightman, W. 1990. Micropalaeontology of Portugal: Correlation ofammonite, ostracod and dinoflagellate zones of Upper Jurassic andCretaceous age. Unpublished UPPL report, Utrecht 1–24.



Wilson, R.C.L. 1979. A reconnaissance study of Upper Jurassic sedimentsof the Lusitanian Basin. Ciências da Terra 5, 53–84.

Wilson, R.C.L. 1988. Mesozoic development of the Lusitanian Basin,Portugal. Revista Sociedad Geológica de España 1, 393–406.

Wilson, R.C.L., Hiscott, R.N., Willis, M.G., Gradstein, F.M. 1989.The Lusitanian Basin of west central Portugal: Mesozoic and Tertiarytectonics, stratigraphy and subsidence history. In: Extensional Tectonics andStratigraphy of the North Atlantic Margins, Tankard, A.L., Balkwill, H.R.(eds). AAPG Memoir 46, 341–361.

Withmarsh, R.B., Minshull, T.A., Russel, S.M., Dean, S.M., Louden,K.E., Chan, D. 2001. The role of syn-rift magnetism in the rift to drift

evolution of the west Iberia continental margin: Geophysical observa-tions. In: Non-volcanic rifting of continental margins: a comparison ofevidence from land and sea, Wilson, R.C.L., Withmarsh, R.B., Taylor,B., Frontzheim, N. (eds). Geological Society Special Publication187, 107–124.

Wright, P.V., Marriott, S.B. 1993. The sequence stratigraphy of fluvialdepositional systems: The role of floodplain sediment storage. SedimentaryGeology 86, 203–210.

Yin, J., Fürsich, F.T., Werner, W. 1995. Reconstruction of paleosalinityusing carbon isotopes and benthic associations: A comparison.Geologische Rundschau 84, 223–236. DOI: 10.1007/s005310050001.

Scientific editing by Alastair Ruffell

A. M. TAYLOR ET AL.


Lourinha stratigraphy Lusitanian Basin GeolJournal_2013 Taylor etal

Documents

Transcript of Lourinha stratigraphy Lusitanian Basin GeolJournal_2013 Taylor etal