Geochemical, δ13C and Eustatic curves as means for reconstructing and characterising deep marine...

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Geochemical, δ13C and Eustatic curves as meansfor reconstructing and characterising deep marine carbonatestratigraphic sequences (Upper Cretaceous, Tunisia)

Amina Mabrouk El Asmi

Received: 24 September 2013 /Accepted: 11 December 2013# Saudi Society for Geosciences 2014

Abstract A geochemical study of a thick chalk Tunisianonshore section of the Campanian–early Maastrichtian AbiodFormation was undertaken in order to assess the previouslyproposed linkages between chemostratigraphy, sequence stra-tigraphy and eustatic variations. An up-to-date correlation ofthe Abiod Formation δ13C curve at Le Kef to other Tethyan,Boreal and NW Pacific Ocean sections adds important data toimprove and revise previous correlations. Fourteen correlationsequences including earlier published tie points are proposed,two of which are considered to be major isotopic events. TheCaCO3, Al2O3, MnO, SiO2, TiO2 and Zr contents of Le Kefsection were determined in order to assess the vertical elemen-tal variations of such elements in pelagic sediments in re-sponse to eustatic fluctuations. For that, a correlation ofδ13C, CaCO3, Mn, Ti/Al, Zr/Al and Si/Al of the Campa-nian–early Maastrichtian sediments with published regionaland global sea-level curves is proposed and overall infers that:(1) δ13C can be used for estimating eustatic sea-level cyclesand have subsequently permitted to allocate the Abiod For-mation, at Le Kef, to five third order cycles (UZA) corre-sponding to five stratigraphic sequences; (2) sequence bound-aries are mainly characterised by minima inMn–CaCO3 and alow Ti/Al ratio (or Si/Al, Zr/Al); (3) transgressive systemtracts are characterised by increasing δ13C, Mn, CaCO3 andTi/Al ratio; (4) maximum flooding surfaces correspond to arise in carbonate, manganese and Ti/Al or (Si/Al, Zr/Al); (5)and highstand system tracts show a Ti/Al ratio (or Si/Al, Zr/Al) decrease, a carbonate increase, a manganese rise and aδ13C reaching high levels. These conclusions fairly agree withthe idealised relationship between chemostratigraphy,

depositional sequences and sea-level curves proposed byJarvis et al. (J Geol Soc Lond 158:685–696, 2001). Further-more, the Abiod Formation is a proven reservoir in many oilfields in Tunisia, and we believe that the present sequencestratigraphic characterization, via geochemical signatures, canbe of great future usefulness to better identify and correlatesimilar pelagic and hemi-pelagic horizons.

Keywords Campanian . Carbonates . δ13C . Sea level .

Sequence stratigraphy . Bulk rock geochemistry .MFS

Introduction

Studies of North Sea fields such as Ekofisk, West Ekofisk, Tor,Albuskjell, Dan and others have shown that, although thereservoir properties of chalk are generally poor, excellent pro-duction can be attained with sufficient fracturing and a suffi-ciently thick pay section. Yet, during 30 years of exploration inTunisia, the Campanian–Maastrichtian Abiod Formation car-bonates have been underestimated as a potential reservoir. Thisis despite numerous hydrocarbon shows in several wells, suchas those of Dougga-1, Magroun-1, Alouan-1, Yasmin-1; theproduction of gas/condensate in Tazerka-1, Miskar-3 andMiskar-4; and the production of oil and gas in Sidi el Itayem.However, since 1989, discovery of oil in Maamoura, Sidi elKilani and Zinnia, the Abiod Formation carbonates have be-come the focus of considerable exploration interest as well asof multidisciplinary studies in northern and central Tunisia.

In addition and worldwide, chalk is a sedimentary rock,which was not seen as a major target for oil and gas explora-tion until the last 30–40 years. Chalk is a soft friable, micriticlimestone, generally very pure, consisting almost entirely oforganically derived low-Mg calcite particles, mainlycoccoliths, rhabdoliths and calcispheres, all the remains ofplanktonic organisms, and mostly 5 μm or less in size.

A. Mabrouk El Asmi (*)UR: Géochimie et Géologie de l’Environnement,Département de Géologie, Faculté des Sciences de Tunis,Université Tunis-El Manar, Tunis 2092, Tunisiae-mail: [email protected]

Arab J GeosciDOI 10.1007/s12517-013-1243-4

Foraminifera may also be present, but they generally form nomore than 10 % of the rock (cf. Mabrouk 2013).

The environment of Late Cretaceous chalk deposition ismuch debated, but it is probable that the water was deep,perhaps 200 m or more. Coccoliths are forming today in waters60–100 m deep, and the depth of chalk accumulation musthave been greater. Although chalks may be broadly regarded asdeep-sea deposits, the molluscan fauna and other biota in manyCretaceous chalks indicate only shelf depths. Chalk depositionwas controlled by two main factors: a global rise of eustatic sealevel and the lack of erosion on adjacent land areas.

The conventional stratigraphic approach to sea-levelchange is to interpret palaeobathymetric variations in faciessuccessions and to measure the degree of flooding of thecontinents through time from observations of the changingposition of the shoreline (Christie-Blick 1990). The validity ofthe eustatic control on a regional and especially intercontinen-tal scale depends on the reliability of facies interpretation andthe precision of the biostratigraphic correlation (Hallam1984). An alternative method for determining sea-levelchange involves the recognition of unconformitiy-boundeddepositional sequences (e.g. Haq et al. 1987, 1988). Mostsequence boundaries form in response to an increase in therate of sea-level fall or to a decrease in the rate of subsidence,regardless of the sediment supply, rendering a correlation ofmajor sequence boundaries possible between all basins con-nected with the open ocean (Christie-Blick et al. 1990). Inaddition to this, the Exxon Mesozoic–Cainozoic sea-levelcurve of Haq et al. (1987, 1988), inferred as being “global”,has been worldwide correlated to sequence stratigraphy andchemostratigraphy to assess and enhance the above linksbetween sea-level changes, system tracts, sequence bound-aries as well as remarkable geochemical and isotopic excur-sions (e.g. Accarie et al. 1993; Jarvis et al. 2001).

From a chemostratigraphic point of view, major positiveδ13C excursions are associated with an increase in the rate ofwithdrawal of isotopically negative carbon in the form oforganic matter promoting the enrichment of the residual dis-solved inorganic carbon in the heavy isotope. Such organic-rich periods are mostly connected to sea-level rise (e.g. theCenomanian–Turonian boundary), which in turn establishes arelationship between positive δ13C shifts and the rising ofeustatic sea level (Scholle and Arthur 1980; Berger andVincent 1986; Arthur et al. 1987; Hilbrecht and Hoefs 1989;Weissert 1989; Jenkyns et al. 1994; Mitchell et al. 1996; Voigtand Hilbrecht 1997; Weissert et al. 1998; Jarvis et al. 2001;Mabrouk et al. 2007; Wendler 2013). However, Jarvis et al.(2001) argued that not all periods of sea-level rise displayassociated positive δ13C excursions (in the Culver Cliff sec-tion, for example, the sea-level rise of the upper–middleCenomanian and upper Cenomanian stratigraphic sequencesare not associated with positive δ13C but rather demonstratenegative shifts).

In the following, additional correlations of the carbonisotope data of the Tunisian Campanian–earliestMaastrichtianchalk Abiod Formation of Le Kef area with coeval publishedCampanian carbon isotopes curves are proposed, adjoiningthe correlation proposed by Jarvis et al. 2002. Consequently,an attempt will be made to correlate the Abiod Formationcarbon isotope signatures and trends with published Campa-nian sea-level curves and their associated sequence stratigra-phy (Haq et al. 1987, 1988; Hancock 1993; Lüning et al.1998) via the established correlation with the English Campa-nian Trunch borehole curve as was proposed in Jarvis et al.(2002). Furthermore, a new vertical geochemical characteri-zation of the section, based on CaCO3 and Mn contents andTi/Al, Zr/Al and Si/Al ratios, is also presented. An assessmentof possible eustatic controls on the different geochemical andisotopic signals recorded in the Abiod Formation of Tunisiathird-order stratigraphic sequences is lastly inferred and com-pared to the model proposed by Jarvis et al. (2001).

Geological setting

The Le Kef of the “Tunisian Trough”, NW Tunisia, containssome of the thickest Cretaceous and Tertiary successions inTunisia. The Abiod Formation is abnormally thick around LeKef, and its three common members are particularly welldeveloped, with a lower and upper chalky units and an inter-calating marly member.

The Jebel El Djebil section constituted the main area ofsampling and is situated at around 8°43′ E longitude, and36°15′ N latitude (Fig. 1). The town of Le Kef is located atabout 1 km west of the section, and the El Merdja Valleybounds the whole area to the south. The area contains outcropsranging in age from Triassic to Quaternary (Fig. 1). Thesection at El Djebil exposes the uppermost part of theConiacian–Santonian Kef Formation (lateral equivalent ofthe Aleg Formation), the Campanian–Maastrichtian AbiodFormation and the basal few metres of the overlyingMaastrichtian–Paleocene El Haria Formation. The latter isweathered and not well exposed in this area, and consequentlywas sampled at Kodiet ez Zarbia (Fig. 1), located about 10 kmsouthwest of El Djebil.

Bio-lithostratigraphy

The Abiod Formation of El Djebil consists of three units,lower and upper carbonate members, and a middle marlymember (Fig. 2). The thickness of the Abiod reaches around500 m in this area, which is considerably greater than in mostother areas of Tunisia (e.g. Burollet 1956; Ben Ferjani et al.1990; Negra 1994; Mabrouk 2003). Examination of the

Arab J Geosci

lithological variation within each member permitted furthersubdivision of the logged section at El Djebil (Fig. 1) into:

– Unit (LKF)sk represents the uppermost part of the KefFormation (Fig. 2);

– Unit (LKF)ca1 represents the lower member of the AbiodFormation and is subdivided into three subunitsS1(LKF)ca1, S2(LKF)ca1 and S3(LKF)ca1 (Fig. 2);

– Unit (LKF)ma represents the middle member of the AbiodFormation and is constituted of subunits S1(LKF)ma,S2(LKF)ma and S3(LKF)ma (Fig. 2);

– Unit (LKF)ca2 corresponds to the upper member of theAbiod Formation and is subdivided into S1(LKF)ca2,S2(LKF)ca2 and S3(LKF)ca2 (Fig. 2);

– Unit (LKF)se is the base of the overlying El Haria For-mation (Fig. 2).

Eighteen samples consisting mainly of interbedded whitechalks, light grey marls and interbedded limestones wereanalyzed aiming to constrain the biostratigraphy of the LeKef section at El Djebil. The used zonal scheme was basedon Caron (1985) and modified by Premoli Silva and Sliter(1994).

Following the stage boundary definition of Hardenbol et al.(1998) and the time scale of Gradstein et al. (2012), the entireAbiod Formation at Le Kef is judged to be of Campanian age

(Fig. 2). The described microfauna exhibit excellent preserva-tion and are both abundant and diverse. Six biostratigraphicintervals were distinguished, and in all of them (exceptGansserina gansseri Biozone), the zonal marker wasidentified.

Interval (I) between 11 and 102 m

Lithologically, this interval includes the uppermost part of theKef Formation (Fig. 3) and most of the lower Abiod member[(LKF)sk, S1(LKF)ca1, and lower-upper part of S2(LKF)ca1]and mainly consists of metric intercalations of marl withdecimetric limestones overlain by interbedded chalks and verylight grey marly chalks. In thin section, the facies is composedof wackestones moderately rich in planktonic foraminifera(Fig. 3).

This interval is characterised by the occurrence ofGlobotruncana arca, Globotruncana bul lo ides,Globotruncana l inneiana, Globotruncana hi l l i,Contusotruncana fornicata, Contusotruncana patelliformis,Globigerinollides praerihillensis, Globotruncanitastuatiformis, Globotruncanita elevata, Heterohelix globulosa,Heterohel ix globulosa, Heterohe l ix s t r ia ta andPseudotexularia elegans. This zone is characterised by thebiomarker Globotruncanita elevata, giving the sequence anEarly Campanian age.

Fig. 1 Location map for the Le Kef sections at El Djebil and at Kodiet ez Zarbia. Geology after the geological map (1/50,000) of Le Kef area (after “LeService Géologique de la Tunisie”)

Arab J Geosci

Interval (II) between 147 and 231 m

This interval comprises the upper part of the lower Abiodmember (Fig. 4) and the lower part of the middle member[S3(LKF)ca1 and S1(LKF)ma] and is constituted of interbeddedchalks and light grey marl with the predominance of marls.The microfacies corresponds to wackestone–packstone rich inplanktonic foraminifera. This interval mainly contains thesame assemblage mentioned in interval (I), with the appear-ance of Globotruncanita ventricosa, Globotruncanita rosettaand Laeviterohelix glabrans. The appearance of the indexspecies Globotruncanita ventricosa, indicates a Middle Cam-panian age.

Interval (III) between 261.5 and 327 m

The interval includes the middle and some of the upper part ofthe middle Abiod member corresponding to the upper part ofS2(LKF)ma and lower part of S3(LKF)ma). It is (Fig. 5) mainlycomposed of metric interbedded grey marls and marly chalks.In thin section, the facies corresponds to wackestones rich inbivalve debris and planktonic foraminifera. The faunal assem-blage is composed of Globotruncana arca, Contusotruncanafornicata, Contusotruncana patelliformis, Globotruncanitalaparenti, Globotruncanita ventricosa, Pseudotextulariaelegans, Radotruncana calcarata, Globotruncanitasubspinosa and Globotruncanita stuartiformis. This zone ischaracterised by Radotruncana calcarata, providing a Middleto Late Campanian age.

Interval (IV) between 327 and 347.5 m

It includes the mid–upper part of the middle Abiod member[S3(LKF)ma] and is constituted of medium grey marls andmarly chalk interbeds (Fig. 5). In thin section, the facies is apackstone rich in bivalve debris and planktonic foraminifera.This interval constitutes the Globotruncanella havanensiszone, which is from the last occurrence of R. calcarata tothe first occurrence of Globotruncanita aegyptiaca. However,the marker species, was first observed in the interval (III). Theage attribution is assigned to theGlobotruncanella havanensiszone, indicating a Late Campanian age.

Interval between (V) 347.5–485.5 m

This interval includes the uppermost part of the middle mem-ber and the upper Abiod member [corresponding to the upperpart of the lithological subinterval S2(LKF)ca2, and most ofsubinterval S3(LKF)ca2] and is composed (Fig. 6) of paleyellow limestones intercalated with thinner dark marl layers.In thin section, the facies is a packstone very rich in planktonicforaminifera.

Fig. 2 Lithostratigraphic summary and biozonation of Le Kef section atEl Djebil, NW Tunisia

Arab J Geosci

The same assemblage was observed as in the underlyinginterval with the appearance of species such as Ventilabrellamulticamerata, Globotruncanita stuarti, Rugoglobigerinahexacamerata, Rugoglobigerina rugosa, Globotruncanaaegyp t i aca, Globo t runcane l l a pe ta lo i d ea andGlobotruncanel la havanens is. The presence ofGlobotruncana aegyptiaca indicates a Late Campanian age.

Interval (VI), base of El Haria

It is starting from 493m at El Djebil section but corresponds tomost of Kodiet ez Zarbia section (KEZ)se. It corresponds tomedium grey to green marls alternating with decimetric lightgrey marlstones (Fig. 7). Inoceramid debris is also abundant atthe base. In thin section, the rock is composed of packstonesrich in planktonic foraminifera and containing abundant bi-valve debris. The base of El Haria yielded the assemblageobserved above, but with the occurrence of Globotruncanitaconica. The index species of the Gansserina gansseri Zonewas not observed, but the presence ofGlobotruncanita conica

indicates a Late Campanian to Earliest Maastrichtian age forthe logged El Haria Formation.

Age attribution

Earlier micropalaeontological studies, carried out on theAbiod Formation in Tunisia, have attributed a Campanian–Maastrichtian age to the formation. The integratedlithostratigraphic and biostratigraphic study of Robaszynskiet al. (2000) on the Abiod Formation at Kalaat es Senan ofCentral Tunisia subdivided the formation into seven litholog-ical units (Figs. 2 and 8) and yielded a Campanian–earlyMaastrichtian age based on the successive occurrence of thezonal markers: Globotruncanita elevata, Globotruncanaventricosa, Globotruncana calcarata, Globotruncanafalsostuarti, and Gansserina gansseri. Jarvis et al. (2002)succeeded in establishing a lithostratigraphic and

Fig. 3 aOverview of the uppermost beds of Kef [unit (LKF)SK] Forma-tion marls and the transition to the Abiod Formation located on the southside of El Djebil. Note the figure for scale, the base of the Abiod isindicated by the white arrow. b Photomicrograph (PPL) from the upper-most part of the Kef Formation [unit (LKF)SK] showing a wackestonewith common planktonic foraminifera. Scale bar equals 100 mm

Fig. 4 aOverview of the lower Abiod member [unit (LKF)ca1] lookingNW from El Djebil. Note the indistinct bedding occurring in the middlepart of this member. Chalk-marl couplets are typically 1–2 m thick. bPhotomicrograph (PPL) from the lower Abiod member [subintervalS2(LKF)ca1] showing a wackestone–packstone rich in planktonic forami-nifera. The micrite is enriched in fine-grained silt-sized glauconite. Scalebar equals 250 mm

Arab J Geosci

biostratigraphic correlation of the Abiod Formation betweenLe Kef (El Djebil) and Kalaat es Senan. The middle marlymember is much thicker at Le Kef, contrasting with a thinnerupper carbonate member compared to Kalaat es Senan. Tencorrelatable sedimentary packages were identified, andemploying this lithostratigraphic correlation, Jarvis et al.(2002) proposed more precise positions of key ammonite,planktonic foraminifera and calcareous nannofossils eventsin the Le Kef section.

In this study, the Abiod Formation at Le Kef has beenfurther subdivided into nine lithological intervals, but still inagreement with the subdivisions of Burollet (1956), and hasbeen assigned a Campanian age (Fig. 8). Our age attribution isbased on the consecutive occurrence of the zonal markers:Globotruncanita elevata, Globotruncana ventricosa,Globotruncana calcarata, Globotruncanella havanensis andGlobotruncana aegyptiaca. However, the last 8 m of theuppermost Abiod Formation at Le Kef was notbiostratigraphically analysed, making an early Maastrichtianage for the uppermost part of the formation (summit of theUpper Abiod Member) possible. However, Robaszynski et al.(2000) placed the Campanian–Maastrichtian boundary near

the base of the Upper Abiod Member, in contrast to earlierbiostratigraphic studies (Caron 1985; Haq et al. 1988; BenFerjani et al. 1990; Negra 1994). Based on our findings, thebulk of the Abiod Formation at Le Kef is here assigned anolder (Campanian to probably earliest Maastrichtian at the topof the upper member) age. Differing positions of the Campa-nian–Maastrichtian boundary is attributable, in part, to the re-definition of the base of the Maastrichtian with respect to theTethyan planktonic foraminiferal biozonation (i.e. within theGansserina gansseri zone; Hardenbol et al. 1998). In oursummary log for the Le Kef section (Fig. 2) used in subse-quent correlations, we will consider both our biozonations andthat of Robaszynski et al. (2000) at Kalaat es Senan extrapo-lated to Le Kef by Jarvis et al. (2002), and therefore, theCampanian–Maastrichtian stage boundary is assigned to alower level (around 425 m) compared to an age attributionbased on the studied 18 samples alone (Fig. 8).

Based on the occurring foraminiferal assemblages, thewhole section was deposited in a deep water, probably upperto middle bathyal environment. In general, sedimentation oc-curred in oxygenated conditions even though, in some intervals,Quadrymorphina and inoceramid shell fragments are observed.These forms usually co-exist in low oxygen, organic-richmuds.

Fig. 5 a General view of the middle Abiod member [unit (LKF)ma]looking NE to the NW flank of Jebel El Djebil. b Photomicrograph(PPL) of lower beds of the middle Abiod member [subintervalS1(LKF)ma] showing a wackestone–packstone texture with planktonicforaminifera and bivalve fragments. Scale bar equals 100 mm

Fig. 6 aView of rythmic bedding of chalk intercalated with thinnermarlsin the upper Abiod member [subinterval S1(LKF)ca2]. The hammer headrests at 410,30 m height of the section; the shaft is 30 cm long. bPhotomicrograph (XPL) from the upper Abiod member [subintervalS1(LKF)ca2], a packstone rich in planktonic foraminifera. Scale barequals 50 μm

Arab J Geosci

Methods and results

High-resolution geochemical analyses of around 500 samplesfrom the uppermost part of Kef, entire Abiod and base of ElHaria formations was undertaken throughout this study usingthe inductively coupled plasma atomic emission spectroscopy(ICP-AES) techniques following standard sample preparationprocedures (Jarvis 1992; Totland et al. 1992). A nominal 1-mspacing between samples was adopted, and where needed,such as across formation boundaries, additional samples wereanalysed to improve geochemical resolution. Analyses werecarried out on whole rock. Samples taken from the Le Kef andKodiet ez Zrabia sections were first rinsed in deionised water(18 MΩ) to remove adhering particles, which could contam-inate the geochemical signatures. They were oven dried over-night (50°), and broken up into millimeter- to centimeter-sizedchips in layers of thick polythene bags using a mallet and ironplate. The resulting chips were rinsed in deionised water andplaced in an oven for up to 2 days (50–60°) until completelydry. The chips were ground in an agate mill to a fine powder

and finally stored in glass containers. Oven dried samples(105° overnight) were weighed (0.25 g) and well mixed with1.25 g lithium metaborate flux, then fused at 1,050 °C in afurnace for 20–25 min. The resulting melt was dissolved in0.8 M HNO3, with a final dilution to 250 ml 0.5 M HNO3. Ablank was prepared by dissolving 1.25 g of LiBO2 in 0.8 MHNO3, and then diluted in the same way as the samples. Dataquality was assessed by the dissolution and analysis of well-characterised international rock reference materials (Table 1)run with each batch of samples. Final analyses of CaO, Al2O3,MnO, SiO2, TiO2 and Zr were carried out using the ICP-AES(Jobin-Yvon JY 70 Plus Spectrometer). The overall reproduc-ibility (Table 1) for the element determinations was generallygood (<2 %) for elements present at high concentration, butpoor (>10 %) for trace elements (Zr) when present at lowconcentrations. The accuracy of the analyses was determinedby plotting average values obtained for selected referencesmaterials analysed with each sample batch against their pub-lished values.

A 2-m nominal spacing resolution (around 250 samples)was adopted for carbon stable isotope determinations. Theanalytical techniques for determining the 13C/12C ratios incarbonates are well established and can be quickly employed.Details of the technique may be found in Williams (1984) andJenkyns et al. (1994) with references cited therein).

Samples were analysed in the stable-isotope laboratory atOxford University.

Final geochemical and carbon stable isotope data for eachsection are presented in Tables 2 and 3 and where samplepositions are listed as stratigraphic height above base enablingthe geochemical signatures of each formation (Aleg, Abiodand El Haria) to be established and to be plotted against thelithostratigraphic log.

Campanian δ13C improved global correlation

The Le Kef section has been previously correlated with theTrunch borehole reference section as well as the Elles (Tunsia)and Bidart (France) sections (cf. Jarvis et al. 2002) based onthe carbon stable isotope curves. Figure 9 shows a revisedcorrelation of the Le Kef section with published northwesternPacific ocean, North African, and European sections with thetwo major carbon isotope events of the middle and upperCampanian established by Jarvis et al. (2002), providingexcellent correlative data. Supplementary chemostratigraphicties were added where the carbon isotope curve shows signif-icant comparable short-term trends and inflexion points in thedifferent sections. In total, 14 tie points between the carbonisotope curves were identified and these compare well withthe 11 tie points proposed by Jarvis et al. (2002). Thechemostratigraphic correlation (numbered from CC1 toCC14) can be described, from bottom to top, as follows:

Fig. 7 a General view of the basal El Haria Formation at Koudiet ezZarbia showing indistinct bedding of decimetric limestones intercalatedwith thick grey marls [interval (KEZ)se]. The author is standing on aprominent limestone containing abundant large inoceramids. b Photomi-crograph (PPL) from the basal El Haria Formation of Koudiet ez Zarbia[interval (KEZ)se]. A wackestone–packstone texture rich in well-preserved planktonic foraminifera. Scale bar equals 50 μm

Arab J Geosci

Fig. 8 Comparison of thedifferent lithostratigraphicsubdivisons and biozonations ofthe Abiod Formation proposed byBen Ferjani et al. (1990);Robaszynski et al. (2000), andthis study. Ft formation, Mbmember, K.SM.bKalaat es Senanmembers, LKF In Le Kef litho-logical intervals,MMaastrichtian,EHEl Haria, Ge Globotruncanitaelevata, Gg Gansserina gansseri,Gf Globotrunca falsostuarti. GhGlobotruncanella havenensis

Arab J Geosci

(CC1) A sharp increase in δ13C occurs in the upperMarsupites testudinarius Zone at Trunch (also in Jarviset al. 2002) correlating with similar increase at Site 869(lower L. grilli), Lägerdorf–Kronsmoor and Culver Cliff.This positive carbon isotope curve defines theSantonian––Campanian Boundary Event of Jarvis et al.(2002).(CC2) A minimum in the upper Offaster pilula Zone(Jarvis et al. 2002) at Trunch correlates with minima inthe Culver Cliff, Lägerdorf–Kronsmoor and Site 869profiles.(CC3) A δ13C minimum (slightly below the tie-point 3maximum of Jarvis et al. 2002) occurring in the lowerCeratolithoides aculeus at Le Kef correlates with a sim-ilar trough at Site 869 and in the Bidart section, andprobably corresponds to a trough in the lowerGonioteuthis quadrata Zone at Trunch and atLägerdorf-Kronsmoor, but is apparently located in theuppermost O. pilula zone at Culver Cliff.(CC4) A δ13C minimum at Le Kef and Miskar, probablycorresponds to similar peaks at Trunch occurring in thelower G. quadrataZone. The carbon isotope values tendto increase above.(CC5) A δ13Cminimum corresponding to to tie-point 4 ofJarvis et al . (2002) at Le Kef, and Trunch.Palaeontologically, it is associated with the mid-Globotruncana elevata zone at Le Kef and to the mid-Gonioteuthis quadrata Zone at Trunch.(CC6) This corresponds to tie-point 5 of Jarvis et al.(2002). This correlation is based on a sharp increase inthe carbon isotope curve identified in most sections but isless developed at Lägerdorf–Kronsmoor. A broad posi-tive isotope excursion defines the Mid-Campanian Event(Jarvis et al. 2002) and falls within the upper Belemnitellamucronata Zone at Trunch and near the base of theGlobotruncana ventricosa Prsz at Le Kef.(CC7) A sharp maximum of δ13C, which falls within themiddle–upper part of the G. ventricosa zone at Le Kefand Miskar and in the lower B. mucronata Zone atLägerdorf–Kronsmoor, Culver Cliff and Trunch.(CC8) This corresponds to tie-point 6 of Jarvis et al.(2002) and is defined by a reversal from decreasing toincreasing δ13C occurr ing in the uppermostGlobotruncana ventricosa zone at Le Kef and in theB. mucronata Zone at Culver Cliff and Trunch.(CC9) This corresponds to tie-point 8 of Jarvis et al.(2002). The carbon isotope curve falls at Le Kef, Miskar,Elles, Culver Cliff and Trunch. However, the falling trendis less well developed at Lägerdorf–Kronsmoor.Palaeontologicaly, the CC9 occurs within the uppermostGlobotruncana calcarata Zone at Le Kef, Miskar andElles, and in the mid-B. mucronata Zone at Trunch andLägerdorf-Kronsmoor. T

able1

Dataforreferencematerialsobtained

afterlithium

metaboratefusion

Major

elem

ents

(wt%

)Mean

SD

Ref

Mean

SDRef

Mean

SD

Ref

Mean

SD

Ref

Mean

SD

Ref

Mean

SD

Ref

CaO

55.1

152.1

32.1

0.9

30.8

36.2

0.3

34.1

55.5

1.3

55.0

49.3

1.3

47.8

2.8

0.1

2.6

Al 2O3

0.26

0.01

0.30

<0.01

nd0.05

<0.01

nd0.01

0.014

0.01

0.02

2.36

0.05

2.39

14.1

0.22

13.67

MnO

0.006

0.0003

0.01

0.061

0.002

0.06

0.007

0.0003

0.01

0.003

0.0003

0.002

0.085

0.002

0.09

0.052

0.001

0.05

SiO2

0.844

0.03

0.97

<0.1

nd0.06

0.08

0.02

0.2

<0.1

nd0.11

9.61

0.27

8.60

68.2

1.35

62.78

TiO

20.014

0.001

0.02

0.0014

0.001

0.01

0.0012

0.001

nd0.0015

0.001

nd0.125

0.003

0.13

0.609

0.01

0.63

Trace

elem

ents(μg/g)

Zr

114

87

7nd

95

nd8

6nd

355

35164

5160

Arab J Geosci

Table 2 Geochemical and Carbon stable isotope data for Le Kef section

Height (m) Lithology/Units Elements (%) Isotope

CaO CaCO3 Al2O3 SiO2 MnO TiO2 Zr δ13C (‰)

2.20 C 50.0 89.2 1.41 5.07 0.030 0.073 16.5 1.19

5.10 MC 47.2 84.2 2.66 7.46 0.036 0.140 21.7 1.52

11.00 M 40.2 71.7 6.06 15.46 0.031 0.297 34.8

12.30 C 49.1 87.6 2.80 8.39 0.037 0.144 21.8 1.32

13.50 C 48.4 86.4 1.33 4.81 0.030 0.073 16.7

14.85 M 41.0 73.1 5.50 14.00 0.034 0.283 34.9

16.10 C 47.6 85.0 2.57 8.22 0.050 0.134 21.3 1.23

17.20 MC 44.1 78.6 4.09 11.28 0.037 0.215 27.8

18.30 MC 43.8 78.1 3.52 9.80 0.037 0.190 23.7

19.35 C 48.6 86.8 2.15 6.84 0.048 0.111 18.4 1.15

20.50 MC 44.8 79.9 3.10 8.34 0.045 0.163 25.3

21.60 C Kef/Abiod 53.5 95.4 1.48 4.66 0.049 0.079 12.9 0.90

22.80 C 50.5 90.2 1.64 5.19 0.043 0.085 17.1

23.70 MC 45.6 81.3 2.65 7.45 0.034 0.142 22.1 1.79

24.85 C 48.5 86.5 2.17 6.04 0.045 0.111 14

26.15 M 41.3 73.7 4.51 10.76 0.033 0.220 28.8

27.70 C 50.5 90.2 1.23 3.55 0.061 0.062 10.5 1.38

29.00 C 49.5 88.4 1.63 4.62 0.047 0.085 15.1

30.05 MC 46.6 83.2 2.96 7.67 0.062 0.146 18.9 1.61

31.05 MC 46.9 83.6 2.42 6.30 0.060 0.119 18.9

32.07 MC 45.6 81.4 1.78 6.30 0.035 0.104 17.4 1.57

33.30 C 52.5 93.7 1.56 4.48 0.058 0.075 15.8

34.75 C 51.4 91.7 1.60 4.34 0.055 0.083 15.5 1.58

35.90 C 48.0 85.6 1.69 4.55 0.054 0.081 11.8

37.10 C 50.3 89.8 1.51 4.57 0.061 0.080 14.8 1.75

38.30 C 50.5 90.1 1.67 4.88 0.062 0.084 15.2

39.60 C 50.8 90.7 2.16 5.89 0.062 0.104 17.2 1.74

41.15 MC 45.5 81.2 2.27 6.24 0.057 0.118 20.8

42.20 MC 47.5 84.8 2.19 6.18 0.059 0.110 19.1 1.75

43.35 C 48.6 86.7 2.39 7.91 0.026 0.136 21.4

44.40 C 51.3 91.5 1.49 4.48 0.050 0.077 15.5 1.71

45.60 C 53.1 94.8 1.18 3.85 0.051 0.063 14.4

46.75 C 52.1 93.0 1.09 3.44 0.052 0.058 10.5 1.46

47.80 C 51.2 91.3 1.72 5.08 0.049 0.075 13.8

49.15 C 52.8 94.2 1.00 3.11 0.046 0.057 13.3 1.70

50.30 C S1(LKF)ca1/S2(LKF)ca1 53.4 95.4 0.78 2.60 0.048 0.044 12.8

51.30 C 52.8 94.3 0.98 3.14 0.038 0.051 12.6 1.66

52.25 MC 47.5 84.8 1.34 4.38 0.038 0.075 14.7

53.50 C 52.8 94.3 1.00 3.23 0.038 0.051 14.0 1.22

54.70 MC 44.0 78.5 3.33 11.57 0.014 0.180 24.8

55.90 C 53.4 95.2 0.87 2.87 0.045 0.046 11.4 1.62

57.00 C 52.1 93.0 0.83 2.84 0.043 0.041 7.8

58.15 MC 47.2 84.1 1.01 3.57 0.035 0.055 11.3 1.73

59.30 C 49.7 88.8 1.10 3.55 0.030 0.058 10.3

60.45 C 54.7 97.5 0.47 1.63 0.059 0.029 10.3 1.49

61.55 C 51.2 91.4 0.78 3.00 0.054 0.046 13.0

62.65 C 53.3 95.2 0.89 3.35 0.044 0.047 12.4 1.57

Arab J Geosci

Table 2 (continued)



63.65 C 51.8 92.4 0.52 2.23 0.046 0.035 13.0 1.59

64.75 C 51.2 91.4 0.67 2.62 0.046 0.034 9.9

65.70 C 53.7 95.9 0.63 2.28 0.052 0.036 12.4 1.55

66.85 C 53.0 94.5 0.97 3.66 0.048 0.049 12.3

67.90 C 51.9 92.7 0.40 1.43 0.060 0.026 10.4

69.30 C 54.3 97.0 0.51 2.08 0.061 0.034 13.4 1.52

70.25 C 52.7 94.0 1.27 4.34 0.040 0.066 14.0

71.20 C 53.2 94.9 0.53 1.92 0.048 0.029 11.3 1.70

72.10 C 53.2 94.9 0.63 2.23 0.050 0.034 11.8

73.00 C 54.0 96.4 0.63 2.48 0.053 0.032 10.4 1.62

74.00 C 55.3 98.6 1.23 3.31 0.051 0.053 9.8

74.90 C 53.1 94.7 0.57 1.98 0.055 0.032 6.4 1.65

75.90 C 54.1 96.6 0.33 1.42 0.063 0.024 11.7

77.00 C 49.9 89.0 1.00 3.60 0.046 0.054 12.3 1.37

78.00 C 54.5 97.3 0.54 2.21 0.058 0.029 10.2

78.90 C 52.2 93.2 0.66 2.71 0.050 0.049 12.6 1.65

80.00 C 48.8 87.2 1.72 5.18 0.044 0.079 13.7

80.90 C 52.6 93.9 0.84 2.73 0.047 0.040 10.5 1.47

81.95 C 49.1 87.7 1.06 3.48 0.039 0.051 13.8

82.80 C 53.0 94.7 1.12 3.69 0.041 0.060 12.9 1.80

83.90 C 53.8 96.1 0.90 2.85 0.049 0.047 14.0

84.90 C 47.6 85.0 1.03 3.47 0.043 0.056 15.4 1.46

85.90 C 51.2 91.5 0.67 2.56 0.049 0.040 12.5

86.75 C 48.7 86.9 2.25 6.47 0.049 0.106 17.4 1.31

87.90 MC 47.1 84.0 2.70 7.83 0.040 0.139 24.8

88.40 C 49.9 89.0 1.86 6.06 0.039 0.094 17.3 1.57

90.90 C 49.3 88.0 1.65 4.68 0.065 0.079 13.1

91.90 C 52.8 94.2 0.72 2.25 0.044 0.036 9.0 1.42

93.05 C 48.3 86.1 1.44 4.57 0.030 0.074 14.5

94.20 C 49.1 87.6 1.16 3.89 0.030 0.065 13.6 1.39

95.20 C 49.3 88.0 0.50 1.49 0.045 0.025 10.2

96.50 C 52.7 94.0 0.61 2.24 0.044 0.033 10.1 1.54

97.55 MC 46.6 83.2 3.11 9.70 0.026 0.176 24.5

98.55 C 52.9 94.5 0.27 0.73 0.031 0.013 9.7 1.97

99.00 C 54.4 97.1 0.85 2.74 0.037 0.043 12.6

99.85 C 54.2 96.8 0.74 2.33 0.046 0.037 12.6

100.50 C 52.2 93.1 1.21 3.57 0.038 0.057 13.6 1.40

101.30 C 53.4 95.2 0.74 2.33 0.044 0.041 11.8

101.70 M 41.1 73.4 3.46 10.80 0.037 0.198 25.4 1.34

102.80 C 52.5 93.6 1.09 3.51 0.038 0.052 11.8

103.90 C 53.5 95.4 0.61 2.18 0.040 0.036 10.5 1.45

105.25 C 53.9 96.2 0.65 2.29 0.035 0.039 11.0

106.60 C 55.3 98.6 1.15 3.30 0.038 0.062 9.7 1.45

107.55 C 53.3 95.1 0.85 2.69 0.032 0.046 13.0

108.50 C 50.3 89.8 0.71 2.38 0.035 0.039 9.6 1.79

109.50 C 49.3 87.9 0.63 1.99 0.037 0.036 11.3

110.55 C 52.6 93.8 0.63 2.01 0.039 0.039 12.3 1.36

Arab J Geosci

Table 2 (continued)



111.60 C 54.2 96.8 0.70 2.52 0.040 0.038 12.6 1.55

112.60 C 52.7 94.1 0.88 3.11 0.039 0.047 12.0

113.55 C 53.0 94.6 0.60 1.92 0.042 0.033 11.2

114.50 C 52.0 92.9 0.61 2.21 0.046 0.039 14.6 1.83

115.50 C 48.5 86.5 0.69 2.16 0.045 0.037 7.0

116.55 C 47.8 85.2 1.19 3.44 0.034 0.059 14.7 0.88

117.55 C 53.5 95.5 1.03 3.11 0.041 0.052 14.5

118.50 C 50.9 90.9 0.95 3.12 0.040 0.052 12.1 1.86

119.45 M S2(LKF)ca1/S3(LKF)ca1 41.8 74.6 3.98 13.52 0.020 0.217 30.1

120.45 C 51.7 92.3 1.03 3.10 0.036 0.049 8.3 1.54

121.40 MC 47.4 84.6 1.00 3.01 0.033 0.048 8.7

122.40 MC 44.7 79.8 0.76 2.24 0.036 0.036 6.9 1.25

123.40 C 54.1 96.5 0.90 2.98 0.040 0.043 12.2

124.40 C 53.6 95.6 0.92 3.26 0.043 0.053 14.6 1.51

125.40 C 52.8 94.3 1.05 3.45 0.045 0.053 13.0

126.35 C 53.4 95.3 0.87 3.02 0.040 0.047 12.3 1.82

127.20 C 48.5 86.5 2.56 6.89 0.040 0.113 17.5

128.00 C 50.7 90.4 0.72 2.66 0.043 0.043 13.3 1.71

129.50 MC 45.3 80.8 3.36 9.00 0.035 0.191 25.7

131.30 C 50.7 90.5 1.33 3.80 0.042 0.058 10.5 1.41

132.25 C 51.3 91.6 0.72 2.57 0.044 0.042 11.2

133.25 C 52.6 93.9 1.35 3.90 0.047 0.061 13.3 1.69

134.25 C 52.3 93.4 0.82 2.94 0.041 0.046 12.4

135.30 C 52.0 92.8 0.89 2.71 0.047 0.043 7.3 1.47

136.50 MC 46.3 82.7 1.95 5.80 0.036 0.101 13.4

137.45 C 52.8 94.2 0.62 2.23 0.049 0.035 11.7 1.54

138.20 C 49.8 89.0 2.17 6.53 0.022 0.105 19.6

139.10 C 48.3 86.2 2.55 7.15 0.027 0.115 19.7 1.65

140.10 C 53.8 96.0 0.84 2.75 0.037 0.042 13.4

141.05 MC 45.0 80.2 3.83 10.18 0.035 0.195 25.7 1.58

142.10 C 52.3 93.3 0.98 3.58 0.036 0.051 12.3

143.40 C 47.8 85.3 1.31 4.14 0.046 0.065 15.6 1.63

144.50 C 52.7 94.1 1.13 3.50 0.038 0.053 10.3

145.80 C 51.1 91.3 1.09 3.31 0.043 0.052 12.3 1.77

147.00 C 50.9 90.7 1.62 4.92 0.040 0.079 15.0

148.20 C 51.5 92.0 1.25 3.71 0.044 0.063 13.8 1.41

149.30 C 50.4 89.9 2.05 5.92 0.039 0.096 16.6

150.60 MC 43.7 77.9 3.79 9.83 0.034 0.196 24.8 1.53

151.55 C 49.2 87.9 1.46 4.11 0.040 0.063 8.9

152.65 C 51.9 92.6 1.94 5.60 0.046 0.086 15.3 1.78

153.80 C 51.1 91.1 1.85 5.16 0.047 0.089 17.2

154.90 C 50.2 89.6 1.07 3.00 0.046 0.049 8.1 1.86

156.00 C 52.7 94.0 1.27 3.71 0.046 0.061 15.5

157.00 C 49.5 88.4 1.46 4.10 0.044 0.070 14.2 1.80

158.25 MC 45.0 80.4 2.14 5.87 0.038 0.111 14.7

159.15 C 49.5 88.4 2.64 7.11 0.038 0.130 18.5 1.83

160.20 C 50.6 90.2 1.14 3.39 0.041 0.062 9.8

Arab J Geosci

Table 2 (continued)



161.50 MC 47.2 84.1 3.39 8.72 0.035 0.168 25.1 1.81

162.65 C 51.0 90.9 1.08 3.26 0.040 0.043 10.1

163.60 C 51.4 91.7 1.26 4.11 0.049 0.066 15.0 1.92

164.50 MC 46.2 82.4 3.26 8.79 0.047 0.161 23.1

165.70 MC Lower/Middle 47.3 84.5 1.31 4.11 0.044 0.072 13.0 1.92

166.80 MC 44.9 80.1 3.84 10.16 0.039 0.197 24.9

167.80 C 47.7 85.1 2.66 7.72 0.036 0.141 22.1 1.96

168.90 MC 44.7 79.8 3.44 9.47 0.047 0.175 23.4

170.10 C 50.1 89.4 2.16 6.32 0.070 0.113 19.5 1.70

171.20 MC 43.9 78.3 4.74 12.67 0.034 0.232 31.1

172.20 MC 47.3 84.5 2.07 5.51 0.059 0.100 17.9 1.71

173.20 C 53.1 94.7 0.73 4.47 0.040 0.044 11.2

174.10 C 50.2 89.5 1.44 3.85 0.049 0.057 13.9 1.76

175.00 C 52.2 93.1 1.30 3.93 0.048 0.065 15.2

175.75 M 40.1 71.5 4.36 11.06 0.033 0.218 27.1 1.92

176.80 C 51.1 91.2 1.70 4.66 0.051 0.085 15.5

177.80 MC 44.8 79.9 4.36 11.71 0.028 0.212 29.1 2.09

178.90 MC 43.2 77.0 4.13 10.77 0.041 0.196 25.9

180.00 MC 44.6 79.5 4.21 11.05 0.029 0.213 29.7 2.09

181.10 C 48.0 85.7 1.95 5.24 0.047 0.092 12.0 1.77

182.00 MC 43.7 78.0 3.52 10.81 0.019 0.192 25.5

182.80 C 48.6 86.7 2.17 5.85 0.051 0.109 16.8

183.70 C 49.1 87.7 2.59 7.10 0.049 0.135 24.0 1.70

184.70 C 47.7 85.1 2.81 7.00 0.044 0.136 20.0

185.75 MC 44.7 79.7 4.14 10.02 0.035 0.203 26.9 1.66

187.10 C 50.0 89.2 1.89 5.53 0.036 0.098 16.5

188.10 C 49.3 87.9 1.94 5.52 0.037 0.104 19.4 1.82

189.10 MC 43.7 78.0 3.79 9.43 0.030 0.198 23.6

190.30 C 51.2 91.4 2.01 5.18 0.034 0.100 18.0 1.55

191.10 MC 46.7 83.4 3.30 8.41 0.025 0.161 24.3

192.00 MC 47.4 84.5 2.44 6.48 0.032 0.117 20.1 1.86

193.00 MC 45.5 81.2 3.26 8.23 0.033 0.170 23.5 1.76

194.05 MC 45.3 80.9 2.09 5.92 0.040 0.112 19.4

195.25 MC 47.5 84.8 4.01 10.42 0.033 0.142 26.8 1.70

196.40 MC 46.3 82.6 1.99 6.00 0.036 0.110 19.3

197.40 MC 45.5 81.2 3.49 9.19 0.031 0.181 25.0

198.70 MC 46.0 82.1 1.47 4.43 0.032 0.139 13.6 1.39

199.80 MC 44.1 78.6 4.61 12.14 0.026 0.248 32.2

200.75 MC 44.1 78.6 4.59 12.24 0.024 0.241 32.9

201.70 C 49.0 87.4 1.27 4.11 0.033 0.071 15.8 1.72

202.80 MC 43.3 77.2 3.81 9.79 0.031 0.194 24.9

203.85 MC 42.5 75.8 2.71 7.62 0.029 0.153 25.1 1.63

204.95 MC 47.6 84.9 2.81 7.78 0.034 0.153 22.5

206.00 MC 46.9 83.6 2.72 7.58 0.033 0.147 23.6 1.78

207.00 C 49.7 88.7 3.19 10.54 0.025 0.175 27.7

208.00 MC 45.9 81.9 1.47 4.85 0.031 0.082 17.3 1.65

210.40 C 49.4 88.2 2.19 6.45 0.035 0.117 21.4

Arab J Geosci

Table 2 (continued)



211.25 MC 45.5 81.2 3.42 9.34 0.025 0.178 26.7 1.79

212.40 C 50.3 89.8 1.75 5.34 0.039 0.099 17.5

213.50 C 49.9 89.1 2.51 6.99 0.036 0.135 21.4

214.60 MC 47.2 84.1 1.74 5.27 0.033 0.136 15.2 1.68

215.60 MC 47.1 84.1 2.85 7.97 0.036 0.131 22.2

216.85 C 49.2 87.7 1.81 5.21 0.037 0.095 15.5 1.74

218.10 MC 45.1 80.4 1.94 5.42 0.030 0.176 14.1

219.20 C 48.2 86.0 0.89 2.94 0.040 0.045 12.3 1.82

220.20 MC 45.2 80.7 3.77 10.34 0.034 0.211 30.2

221.00 MC 44.0 78.5 3.29 8.97 0.040 0.180 26.5

222.00 C 51.0 90.9 1.74 5.56 0.043 0.098 18.0 1.71

223.10 M 41.1 73.4 4.85 13.83 0.027 0.258 33.1

224.10 C 47.8 85.3 3.21 8.70 0.038 0.180 25.4 1.89

225.15 MC 46.9 83.7 3.11 8.80 0.035 0.175 26.0

226.00 MC 47.0 83.9 1.76 5.12 0.043 0.098 17.6 1.71

226.90 C 49.9 89.0 2.14 6.19 0.045 0.116 19.1

227.80 C 48.3 86.1 2.67 7.87 0.044 0.154 22.9 1.75

228.80 MC 46.3 82.6 3.56 9.87 0.039 0.198 27.4

229.90 M S1(LKF)ma/S2(LKF)ma 39.3 70.1 5.96 15.86 0.027 0.340 42.7 1.72

230.90 M 39.9 71.3 4.74 13.09 0.024 0.302 34.2

231.90 C 48.0 85.6 2.17 7.45 0.042 0.133 22.2 1.57

233.00 MC 43.4 77.4 4.71 14.22 0.021 0.257 33.5

234.20 MC 44.2 78.8 3.61 10.30 0.036 0.204 27.9 1.64

235.20 M 35.1 62.7 6.33 17.30 0.021 0.365 42.0

236.30 C 49.0 87.4 2.06 7.41 0.040 0.125 20.3 1.64

237.50 M 38.1 68.0 7.41 20.12 0.024 0.316 46.8

238.60 M 40.7 72.6 5.48 14.87 0.019 0.285 37.8 1.69

239.60 M 40.0 71.3 3.91 12.29 0.025 0.267 30.9

240.80 M 35.0 62.4 5.41 15.48 0.022 0.377 36.3 2.12

242.05 MC 44.8 80.0 2.82 9.76 0.036 0.163 25.7

243.40 MC 42.2 75.4 4.47 13.95 0.023 0.249 35.6 1.85

244.75 C 51.1 91.2 1.08 3.01 0.039 0.038 12.5

245.80 M 36.9 65.9 8.45 23.99 0.027 0.353 58.4 1.68

246.90 M 36.0 64.2 6.99 20.21 0.017 0.388 47.4

247.90 MC 47.2 84.3 2.58 8.01 0.043 0.148 23.3 1.55

248.90 M 38.7 69.0 6.06 16.85 0.020 0.328 40.5

249.90 MC 42.2 75.3 4.66 12.46 0.030 0.252 34.5

250.90 MC 46.7 83.4 1.67 5.67 0.034 0.099 18.0 1.59

252.00 M 41.3 73.6 4.35 12.31 0.032 0.267 31.1

253.00 C 48.4 86.4 2.41 7.52 0.041 0.140 20.5 1.66

254.10 M 35.7 63.7 5.56 15.99 0.020 0.300 40.3

255.15 M 38.6 68.8 4.99 15.73 0.025 0.316 40.7 1.41

256.35 MC 43.9 78.4 4.10 13.08 0.051 0.239 31.3

257.50 M 39.3 70.1 5.62 17.02 0.028 0.319 42.4 1.77

258.60 C 48.7 86.9 1.74 6.70 0.039 0.103 17.6

259.20 M 40.4 72.2 6.14 17.56 0.024 0.260 39.4 1.80

260.20 M 40.5 72.2 5.46 15.80 0.020 0.294 38.1

Arab J Geosci

Table 2 (continued)



261.40 M 41.0 73.2 4.06 12.27 0.031 0.234 32.6 1.71

262.40 MC 44.1 78.8 3.87 11.30 0.030 0.214 27.2

263.40 MC 42.9 76.5 3.39 10.32 0.025 0.187 23.3 1.95

264.50 MC 42.4 75.7 3.61 10.85 0.021 0.217 25.5

265.45 C 49.8 88.9 1.62 6.08 0.033 0.097 17.3 1.24

266.40 MC 42.2 75.2 4.50 12.91 0.023 0.221 30.7

267.50 MC 42.8 76.4 5.05 14.54 0.025 0.212 33.2 1.64

268.60 C 49.2 87.8 1.59 6.05 0.029 0.088 15.8

269.75 MC 42.6 76.0 4.53 13.52 0.025 0.243 31.3 1.51

270.70 M 40.8 72.9 4.53 13.85 0.019 0.256 32.5

271.70 MC 46.7 83.4 2.60 8.57 0.028 0.210 20.1 1.42

272.80 MC 42.5 75.8 4.55 14.03 0.018 0.251 32.3

273.80 M 38.6 68.8 4.81 14.16 0.021 0.271 32.3 1.68

274.80 M 38.9 69.5 5.05 14.43 0.022 0.336 34.1

276.00 M 42.0 74.9 5.25 15.22 0.026 0.292 39.0

277.20 M 41.5 74.1 4.09 12.48 0.020 0.225 32.0 1.58

278.40 MC 44.4 79.3 3.28 10.68 0.020 0.188 27.9

279.40 M 36.6 65.4 6.54 19.00 0.026 0.355 45.3 1.41

280.30 M 38.5 68.7 5.70 16.78 0.027 0.279 38.4

281.30 M 38.5 68.7 6.09 18.67 0.021 0.350 45.1 1.34

282.30 M 35.7 63.7 6.69 21.14 0.021 0.425 51.1

283.20 MC 47.4 84.6 2.39 8.04 0.036 0.145 21.7 1.40

284.10 MC 43.0 76.7 4.57 13.90 0.023 0.260 33.5

285.10 MC 43.0 76.7 3.62 11.76 0.020 0.212 27.6 1.44

286.00 MC 45.4 81.1 4.11 12.65 0.023 0.194 27.8

286.90 MC 42.9 76.6 3.03 10.14 0.024 0.209 22.9 1.57

288.15 MC 43.9 78.4 3.14 10.24 0.022 0.186 26.5

289.10 MC 43.9 78.4 4.13 12.65 0.019 0.234 29.4 1.58

290.20 MC 44.0 78.5 4.20 12.99 0.018 0.231 32.1 1.48

293.30 MC 43.5 77.6 3.51 11.49 0.016 0.197 25.2

294.10 M 39.0 69.6 5.05 14.35 0.025 0.281 34.3 1.74

295.10 MC 44.2 78.9 2.40 8.27 0.019 0.219 18.7

296.10 MC 42.5 75.9 4.47 13.21 0.018 0.251 32.6

297.10 MC 42.3 75.4 3.58 11.34 0.017 0.208 27.4 1.88

298.20 M 39.8 71.0 5.30 15.50 0.022 0.255 35.1

299.30 M 40.6 72.4 5.34 14.09 0.026 0.295 38.6 1.71

300.20 MC 43.2 77.1 4.39 13.18 0.023 0.249 33.9

301.20 MC 42.6 76.0 4.21 12.66 0.023 0.245 31.4

302.30 C 47.7 85.2 2.80 9.41 0.022 0.164 23.0 1.71

303.50 MC 42.8 76.3 4.01 11.81 0.018 0.230 33.6

304.60 MC 44.4 79.3 3.20 9.61 0.028 0.187 26.8 1.61

305.60 MC S2(LKF)ma/S3(LKF)ma 44.8 79.9 3.28 10.60 0.031 0.189 26.4

306.60 C 50.6 90.3 1.55 5.59 0.030 0.094 18.0 0.96

307.50 M 40.3 71.9 4.18 12.46 0.021 0.228 30.1

308.50 M 37.5 66.8 6.34 18.05 0.020 0.351 42.0 1.33

309.40 MC 44.7 79.8 3.39 10.97 0.019 0.184 24.6

310.30 MC 45.0 80.4 2.27 7.69 0.027 0.128 21.8 1.26

Arab J Geosci

Table 2 (continued)



311.40 M 41.9 74.8 3.77 11.53 0.026 0.203 28.7

312.40 MC 45.0 80.4 3.92 9.68 0.041 0.197 25.2 1.61

313.40 MC 44.9 80.1 3.56 10.72 0.024 0.182 25.5

314.50 M 41.7 74.5 1.70 4.82 0.032 0.079 14.4 1.60

315.60 MC 43.4 77.4 4.70 13.85 0.023 0.248 31.5

316.80 C 49.6 88.5 2.17 7.51 0.025 0.119 19.5 1.70

317.70 C 49.4 88.1 0.52 3.11 0.039 0.030 10.6

318.65 C 48.5 86.6 2.16 7.40 0.023 0.121 20.9 1.50

319.15 M 40.1 71.6 5.68 15.65 0.021 0.288 35.9

320.70 C 48.1 85.9 2.60 8.65 0.024 0.142 20.8 1.29

321.75 MC 42.5 75.9 4.04 12.13 0.025 0.211 29.1

322.70 MC 44.3 79.0 2.92 9.09 0.025 0.169 22.0 1.35

323.70 MC 43.4 77.5 4.14 12.24 0.024 0.228 28.8

324.70 MC 46.2 82.4 3.75 11.04 0.019 0.188 25.1 0.90

325.80 M 41.8 74.5 3.53 11.08 0.019 0.201 27.8

327.20 MC 44.9 80.2 2.74 7.42 0.040 0.155 21.9 1.30

328.30 MC 44.3 79.0 4.11 12.13 0.024 0.217 29.8

329.30 C 48.6 86.7 2.64 9.15 0.025 0.135 20.0 1.75

330.25 C 53.0 94.7 0.66 2.17 0.042 0.035 9.9

331.35 MC 42.1 75.2 2.74 9.35 0.018 0.150 20.8 1.65

332.45 C 47.9 85.5 2.49 8.33 0.022 0.136 20.6

333.45 MC 45.5 81.1 2.98 9.73 0.018 0.159 23.5 1.17

334.50 MC 43.8 78.2 2.92 9.69 0.019 0.173 20.0

335.30 M 41.8 74.6 3.44 11.05 0.017 0.210 25.6 1.54

336.20 C 47.7 85.1 1.59 5.50 0.034 0.091 16.8

337.25 M 39.7 70.9 4.65 14.46 0.018 0.237 29.6 1.82

338.20 M 40.3 72.0 4.71 14.85 0.020 0.225 30.3

339.20 MC 42.2 75.4 4.17 13.05 0.024 0.188 26.2 1.87

340.10 MC 43.8 78.1 2.99 10.01 0.023 0.166 21.3

341.20 M 39.3 70.2 3.41 11.46 0.017 0.251 24.5 1.81

342.40 MC 46.5 82.9 2.22 7.58 0.029 0.128 21.6

343.30 C 50.6 90.3 0.99 4.38 0.035 0.056 11.4 1.62

344.30 MC 44.5 79.4 3.48 12.74 0.017 0.197 25.8

345.35 M 34.5 61.6 6.64 20.17 0.016 0.362 44.1 1.32

346.30 MC 43.6 77.7 5.67 20.73 0.032 0.204 41.6

347.35 M 41.7 74.4 3.87 14.14 0.016 0.216 28.4 1.58

348.35 MC 44.6 79.5 3.52 12.57 0.016 0.187 26.8

349.30 MC 42.5 75.8 3.82 13.57 0.016 0.204 27.5 1.56

350.30 M 41.4 73.9 3.55 11.97 0.017 0.191 28.2

351.25 M 39.8 71.0 4.71 15.13 0.014 0.240 29.7 1.32

352.20 MC 47.2 84.2 2.32 7.69 0.023 0.128 20.1

353.30 MC 44.8 79.9 3.05 11.30 0.024 0.158 22.4 1.27

354.40 MC 46.9 83.7 2.42 9.74 0.019 0.141 22.2

355.50 M 40.1 71.6 4.49 13.23 0.018 0.228 28.6 1.09

356.55 MC 43.6 77.7 2.70 10.86 0.026 0.146 21.9

357.55 MC 42.1 75.2 3.61 12.41 0.020 0.191 27.4 1.34

358.50 M 39.6 70.7 4.72 15.17 0.019 0.250 33.3

Arab J Geosci

Table 2 (continued)



359.50 MC 44.7 79.7 3.27 11.23 0.020 0.193 24.3 1.33

360.50 C 48.8 87.1 2.34 9.70 0.026 0.130 21.6 1.21

361.70 MC 43.3 77.2 3.60 13.16 0.021 0.202 29.8

362.70 C 48.0 85.7 1.85 9.89 0.028 0.097 18.8 0.89

363.70 MC 44.1 78.8 3.82 12.74 0.020 0.178 27.7

364.90 MC 47.2 84.3 2.47 9.21 0.022 0.139 24.1

365.70 MC 44.9 80.2 1.50 6.16 0.030 0.091 17.6 1.00

366.65 MC 44.7 79.8 2.52 9.05 0.022 0.137 21.2

367.80 MC 42.4 75.7 2.36 8.38 0.019 0.184 17.4 1.48

368.80 MC 46.8 83.4 3.44 11.07 0.021 0.176 27.9

369.90 MC 43.6 77.9 3.42 11.14 0.018 0.185 26.6 1.03

370.80 M 40.8 72.8 4.53 13.71 0.018 0.240 29.8

371.70 C 50.9 90.9 1.52 5.96 0.024 0.092 20.4 1.31

372.80 C 48.4 86.4 1.90 6.85 0.022 0.105 19.0

374.00 MC 42.5 75.8 4.61 15.36 0.017 0.200 30.3 1.12

374.90 M 35.2 62.7 4.62 15.21 0.016 0.248 32.1

375.90 M 37.5 66.9 5.40 18.67 0.015 0.291 38.9

376.85 MC 43.8 78.2 3.97 14.48 0.019 0.215 30.0 1.51

377.90 MC 42.7 76.1 4.15 14.73 0.017 0.232 33.8

378.80 MC 43.4 77.4 2.54 9.79 0.019 0.140 21.2 1.20

379.80 MC 44.1 78.7 2.74 9.98 0.017 0.147 25.2

380.70 M 40.8 72.8 4.34 14.13 0.018 0.227 30.3 1.39

381.60 C Middle/upper 48.7 86.9 3.02 10.52 0.020 0.112 23.6

382.55 C 47.7 85.1 1.45 7.14 0.020 0.085 18.1 1.33

383.55 M 40.9 73.1 3.92 12.55 0.017 0.217 31.3

384.50 MC 42.5 75.9 3.18 10.78 0.019 0.177 25.7 1.29

385.40 C 51.0 91.0 1.04 6.71 0.019 0.059 15.7

386.40 C 49.1 87.6 1.08 7.15 0.026 0.061 16.4 1.17

387.45 MC 43.8 78.2 3.83 12.93 0.023 0.206 31.6

388.50 MC 46.9 83.7 2.05 8.41 0.028 0.116 21.2 1.48

389.60 MC 47.5 84.8 1.33 7.59 0.031 0.077 14.1

390.70 C 47.8 85.3 0.71 6.98 0.029 0.049 14.1 1.46

391.60 MC 45.5 81.1 1.41 6.99 0.028 0.076 15.3

392.70 C 50.3 89.7 1.25 7.80 0.031 0.072 14.0 1.34

393.60 C 49.2 87.8 1.29 6.71 0.028 0.072 17.8

394.40 C 49.6 88.5 1.58 5.95 0.026 0.085 18.6 1.62

395.65 MC 46.3 82.6 3.06 9.68 0.020 0.168 27.1

396.80 C 51.8 92.5 0.76 3.71 0.033 0.049 13.8 1.26

397.90 C 52.3 93.3 0.82 3.89 0.032 0.052 14.1 1.44

398.90 C 51.4 91.7 1.15 4.52 0.022 0.071 16.8

400.00 C 47.7 85.0 1.16 4.41 0.019 0.101 12.9

401.05 MC 46.7 83.4 2.82 9.12 0.023 0.110 20.4 1.63

402.00 MC 45.2 80.7 0.65 2.94 0.028 0.039 11.9

403.00 C 50.4 89.9 1.36 4.82 0.026 0.053 14.2 1.74

404.05 MC 44.9 80.2 3.75 11.56 0.019 0.239 37.7

405.10 C 50.8 90.7 0.54 3.14 0.031 0.039 13.2 1.49

406.35 C 53.7 95.7 0.37 2.73 0.035 0.030 11.4

Arab J Geosci

Table 2 (continued)



407.50 C 53.2 94.9 0.69 3.92 0.032 0.040 14.0 1.48

408.65 C 53.3 95.0 0.64 3.65 0.036 0.036 11.6

409.50 C 51.1 91.3 0.71 3.82 0.033 0.043 12.3 1.67

410.30 MC 43.4 77.5 3.54 10.65 0.022 0.203 38.8

411.65 C 51.3 91.6 0.54 3.19 0.028 0.035 7.9 1.52

412.50 C 53.8 96.1 0.51 3.26 0.032 0.028 11.4

413.45 C 51.3 91.6 0.54 3.96 0.033 0.029 8.1 1.52

414.45 C 52.2 93.2 0.42 3.68 0.038 0.025 11.8

415.35 C S1(LKF)ca2/S2(LKF)ca2 49.6 88.5 0.25 2.74 0.029 0.019 12.2 1.25

416.40 C 52.7 94.1 0.36 3.38 0.037 0.027 16.1

417.40 C 52.0 92.8 0.38 3.80 0.035 0.025 8.4 1.52

418.30 C 52.6 93.8 0.37 3.84 0.038 0.025 10.8

419.20 C 52.9 94.5 0.23 3.70 0.039 0.022 9.2 1.43

420.25 C 48.8 87.0 0.29 3.61 0.031 0.023 10.5

421.25 C 54.5 97.2 0.21 3.63 0.033 0.021 9.5 1.52

422.20 C 54.3 96.9 0.40 3.93 0.036 0.027 12.3

423.15 C 54.6 97.5 0.41 3.56 0.030 0.022 12.5 1.37

424.30 C 51.6 92.2 0.41 3.69 0.035 0.026 12.4

425.20 C 52.6 93.9 0.38 3.84 0.032 0.031 11.9

426.10 C 51.7 92.2 0.57 4.39 0.033 0.028 9.0 1.62

427.20 C 52.4 93.5 0.56 3.56 0.037 0.039 8.1

428.20 C 51.5 91.9 0.39 3.33 0.035 0.025 11.8 1.49

429.30 C 53.8 96.0 0.40 3.65 0.035 0.029 11.6

430.10 C 47.9 85.5 0.39 3.34 0.029 0.025 10.7 1.51

431.10 C 49.4 88.1 0.32 3.33 0.032 0.025 12.4

431.90 C 50.3 89.7 0.37 4.08 0.032 0.028 12.8 1.70

433.00 C 51.6 92.0 0.43 3.81 0.036 0.026 11.8

434.20 C 53.4 95.2 0.41 4.62 0.033 0.029 12.1 1.56

435.30 C 50.6 90.3 0.34 4.45 0.038 0.030 12.3

436.25 C 53.2 95.0 0.40 3.96 0.036 0.031 12.5

436.90 C 50.4 90.0 0.38 3.98 0.038 0.030 10.3 1.29

437.60 C 51.7 92.2 0.31 3.99 0.038 0.027 13.3

438.50 C 50.9 90.8 0.61 4.82 0.036 0.032 13.1

439.50 C 52.9 94.3 0.57 4.75 0.045 0.037 11.5 1.65

440.55 C 51.3 91.5 0.81 5.94 0.042 0.041 10.8

441.60 C 52.3 93.4 0.55 3.84 0.041 0.036 12.2 1.60

442.55 C 47.9 85.5 0.52 4.19 0.037 0.042 16.0

443.50 C 47.6 85.0 0.48 4.08 0.045 0.035 15.9 1.69

444.50 C 50.7 90.5 0.31 3.12 0.042 0.029 14.0

445.35 C 53.3 95.0 0.53 3.58 0.048 0.031 11.3 1.64

446.20 C 48.6 86.7 0.42 3.32 0.044 0.031 8.7

447.10 C 52.2 93.2 0.54 3.47 0.044 0.034 11.7 1.32

448.00 C 52.8 94.2 0.67 4.18 0.046 0.038 12.1

449.00 C 49.7 88.7 0.49 3.15 0.040 0.029 10.9 1.44

449.90 C 48.9 87.3 2.54 7.37 0.047 0.128 19.4

451.00 C 50.3 89.8 0.62 3.04 0.040 0.041 6.8

452.00 C 52.3 93.3 0.58 3.88 0.046 0.039 11.4 1.70

Arab J Geosci

Table 2 (continued)



453.15 C 52.8 94.1 0.82 4.26 0.043 0.045 13.9

454.00 C 52.9 94.4 0.45 3.30 0.050 0.034 8.9 1.61

454.80 C 52.4 93.5 1.06 4.67 0.040 0.055 16.0

455.80 MC 42.0 75.0 4.75 13.11 0.032 0.281 40.0 0.99

456.90 C 49.4 88.1 0.76 3.96 0.039 0.038 8.5

457.80 C 51.7 92.3 0.57 3.63 0.039 0.039 14.0 1.57

458.70 C 52.8 94.3 0.78 3.57 0.042 0.037 11.8

459.70 MC 43.5 77.6 6.00 15.96 0.025 0.327 45.6 1.48

460.70 C 51.6 92.1 0.52 3.77 0.044 0.040 15.7

461.70 C 50.7 90.5 0.80 4.11 0.040 0.046 14.3 1.71

462.80 C 52.8 94.2 0.59 3.12 0.043 0.039 11.6

463.80 C S2(LKF)ca2/S3(LKF)ca2 50.0 89.2 2.02 6.47 0.033 0.116 21.3 1.60

464.80 C 51.8 92.4 0.97 4.39 0.040 0.057 16.1

465.60 C 48.9 87.2 0.89 3.71 0.040 0.051 12.5 1.70

466.40 C 53.6 95.6 0.61 3.18 0.048 0.036 12.8

467.40 C 48.4 86.4 0.79 3.79 0.042 0.052 14.4 1.63

468.30 C 51.5 92.0 0.59 3.38 0.041 0.040 13.1

469.05 C 51.0 90.9 0.78 3.66 0.038 0.046 13.4 1.48

469.95 C 50.1 89.5 1.89 6.12 0.038 0.090 15.5

471.00 C 52.5 93.7 0.61 3.51 0.043 0.035 10.9 1.69

471.90 C 52.3 93.4 0.74 4.01 0.038 0.040 10.6

472.70 C 52.9 94.4 0.77 4.05 0.039 0.043 11.2 1.79

473.70 C 51.4 91.8 0.80 4.02 0.047 0.047 14.3

474.60 C 51.8 92.4 0.82 4.02 0.037 0.049 12.9 1.86

475.25 C 51.5 91.9 0.75 4.13 0.046 0.048 14.3

476.20 C 51.0 91.0 0.82 4.36 0.039 0.053 12.9 1.87

477.10 C 51.0 91.1 0.74 3.77 0.042 0.050 10.1

478.00 C 51.0 91.0 0.77 3.80 0.043 0.044 12.0 1.69

478.80 MC 47.4 84.6 2.58 8.16 0.040 0.142 23.7

479.45 C 49.7 88.7 1.13 5.03 0.039 0.060 12.2

480.00 MC 47.4 84.7 2.88 8.59 0.038 0.153 23.0 1.37

481.00 C 51.7 92.2 1.28 5.16 0.047 0.069 14.2 1.62

481.70 C 49.7 88.6 0.90 4.20 0.046 0.050 14.6

482.50 C 51.0 91.0 1.32 5.38 0.047 0.065 15.7 1.73

483.70 MC 44.3 79.0 2.68 8.60 0.034 0.140 23.6

484.70 C 52.7 94.0 1.16 5.54 0.041 0.054 13.4 1.77

485.45 C 50.4 89.9 1.85 6.73 0.036 0.098 19.4

486.25 C 52.5 93.6 1.12 5.42 0.034 0.057 12.4 1.73

486.75 C 48.6 86.7 2.52 8.20 0.030 0.132 23.3

487.80 C 52.1 93.0 0.86 4.43 0.030 0.047 12.9 1.61

488.55 MC 42.9 76.6 1.64 5.57 0.022 0.084 17.6

489.50 C 52.3 93.4 0.96 4.37 0.031 0.050 14.2 1.46

490.30 MC 47.4 84.5 1.15 4.47 0.031 0.059 8.5

491.00 C 51.0 91.0 1.08 3.35 0.045 0.056 11.6 1.45

491.95 C 49.2 87.9 2.12 6.73 0.030 0.102 17.5

493.00 C Abiod/El Haria 49.7 88.7 1.29 4.62 0.026 0.065 11.0

493.90 C 50.1 89.4 1.95 6.72 0.024 0.103 19.1 0.39

Arab J Geosci

(CC10) Chemostratigraphic correlation 10 is a majorcarbon isotope event marked as tie-point 9 by Jarviset al. (2002). This level corresponds to the UpperCampanian Event. It is manifested by a well-definednegative excursion at Le Kef, Trunch and Culver Cliff.In the other sections (Site 869, Miskar, Elles,Lägerdorf–Kronsmoor), the negative excursion is lessprominent but it can be identified either at the base ofthe G. aegyptiaca Zone (Tethys Domain) or within themid-B. mucronata Zone (Boreal Domain).(CC11) The δ13C curve shows a reversal from rising tofalling values at Le Kef, Miskar, Culver Cliff and Trunch.This chemostratigraphic tie-point occurs within the upperGlobotruncana aegyptiaca-base Gansserina gansserizone at Le Kef and within the mid–upper B. mucronataZone at Trunch.

(CC12) This corresponds to tie-point 10 of Jarvis et al.(2002). The δ13C values increase to reach a maximum atthis level. This isotope event (identified at Miskar, LeKef, Lägerdorf-Kronsmoor, Culver Cliff and Trunch) canbe correlated between the base of the Gansserinagansseri Zone and the upper B. mucronata Zone.(CC13) It corresponds to the last prominent negative ex-cursions at Miskar and Trunch and probably falls withinthe Gansserina gansseri Zone of the Tethys Domain andto the uppermost B. mucronata zone of the Boreal Realm.(CC14) This is the final chemostratigraphic correlation be-tween all the sections and corresponds to tie-point 11 ofJarvis et al. (2002), which is manifested by a positive peakin the δ13C curve. The positive excursion is well-defined atBidart and also Trunch (baseBelemnitella lanceolataZone)marking the base of the Maastrichtian. This event falls

Table 2 (continued)



494.90 MC 46.3 82.6 2.83 9.02 0.022 0.143 22.3

495.90 MC 45.3 80.8 2.55 8.23 0.021 0.128 15.7 1.18

496.90 MC 45.4 81.1 3.70 10.93 0.020 0.170 25.7 0.80

Sample positions are listed as stratigraphic height above base of section

C chalk,Mmarl, MCmarly chalk, AbAbiod; EH El Haria

Table 3 Geochemical and Carbon stable isotope data for Kodiet ez Zarbia section

Depth Lithology Elements (%) Isotope

Sample (KEZ) Height (m) CaO CaCO3 Al2O3 MnO SiO2 TiO2 Zr δ13C (‰)

1 1.2 C 52.5 93.7 1.09 0.03 4.35 0.06 13.6 1.67

2 1.9 MC 46.2 82.4 2.68 0.02 7.77 0.13 19.4 1.38

3 2.5 C 51.2 91.4 1.57 0.022 6.10 0.08 16.6 1.42

4 2.8 MC El Haria/Abiod 43.8 78.2 3.32 0.019 10.11 0.16 22.8 1.81

5 3.5 MC 47.6 84.9 2.70 0.021 8.98 0.14 21.2 1.76

6 4.2 M 39.0 69.6 5.56 0.021 15.20 0.25 31.4 1.35

7 5.3 MC 43.4 77.5 4.88 0.020 13.22 0.22 30.8 1.58

8 6.3 MC 45.2 80.6 2.52 0.021 8.37 0.13 20.7 1.62

9 7.6 M 34.3 61.2 5.53 0.016 14.90 0.26 29.8 1.46

10 8.8 M 41.7 74.4 4.31 0.018 12.06 0.21 29.4 1.64

11 10 MC 42.5 75.8 3.79 0.022 10.65 0.18 24.9 1.53

12 11.2 M 41.6 74.2 5.33 0.018 13.47 0.24 29.6 1.58

13 12.3 MC 46.5 82.9 3.46 0.018 9.92 0.16 24.8 1.53

14 13.3 M 36.8 65.6 8.18 0.014 21.07 0.38 41.5 1.52

15 14.5 MC 45.1 80.5 2.80 0.020 8.14 0.13 21.5 1.64

16 15.7 M 35.3 63.1 5.72 0.014 14.5 0.27 35.6 1.79

Sample positions are listed as stratigraphic height above base of section

C chalk,Mmarl, MCmarly chalk, AbAbiod, EH El Haria

Arab J Geosci

approximately at the boundary between the Abiod and theEl Haria Formation in the Le Kef section and is alsoprobably located here within the base of the Maastrichtian.

δ13C and sea-level curves

On a global scale, and following the Haq et al. (1987, 1988)curve, Campanian sea-level change demonstrates major re-gression periods at the Santonian–Campanian boundary(Globotruncanita elevata Zone), in the Middle Campanian(upper Globotruncana ventricosa Zone) and in the UpperCampanian (lower Gansserina gansseri Zone). These areseparated by successive transgression and highstand periods.Cycles of lesser amplitude are also present, and when added tothe latter constitute six sequence boundaries (Fig. 10) separat-ing the highstand system tract (HST) and the lowstand system

tract (LST). In addition, in Egypt, Lüning et al. (1998)established three major regression maxima (sequence bound-aries) comparable (Fig. 10) to those of Haq et al. (1987, 1988)and falling approximately within the above zones.

Three major Campanian transgressive maxima separatedby intervals of lower sea-level are identified in NWEurope byHancock (1990, 1993). These maximum flooding surfaces(MFS) correlate well with similar maxima of Haq et al.(1987, 1988). Jarvis et al. (2002) established a correlationbetween the δ13C profile of the Trunch Borehole with regionalsea-level curves for NW Europe (Hancock 1993) and Egypt(Lüning et al. 1998), and also with the global Exxon curve(Haq et al. 1987, 1988). The curves were calibrated based onwell-constrained biostratigraphic data. Jarvis et al. (2002)noted strong evidence for a correlation between Campanianpositive carbon isotope excursions and phases of sea-levelrise. The bases of δ13C excursions appear to correspond

SE

2.0 2.5 3.0

δ13C (‰)

20 m

G. gansseri

G. calcarata

G. aegy-ptiaca

0.5 1.0

1.5 2.0 2.5

1.5 2.0 2.5

U. sissinghi

?U. trifidum

B. parca parca

B. hayi

L. grilli

B. hayi

C. aculeus

C. verbeeki

U. gothicum

? G. stuarti

G. ventricosa

G. marei

δ13C (‰)

E. eximus

G. calcarata

G. elevata

G. ventricosa

G. ventricosa

G. calcarata

G. havanensisG. aegyp-tiaca

G. conica

C. aculeusB. hayi

U. gothicusR. magnus

R. levis

R. magnus

?U. trifidus

B.p. constricta

T. orienatus

L. praequadratus

50 m

U. trifudus

IsS1

IsS2

IsS3

IsS3

IsS4

IsS5

IsS6

IsS7IsS8

IsS4

IsS5

R. calciformis

R. contusa

C. aculeus

U. gothicus

U. trifidus

E. eximus

10 m

δ13C (‰)

L. praequa-dratus

U. trifidus

L. quadratus

M. murus

δ13C (‰)

UCaE

MCaE

0.0 2.0 4.0δ13C (‰)

10

m

Site 869Pacific ocean

1.75 2.00 2.25

?U. trifidum

E. eximus

D. concavata

G. elevata

R. rugosa

G. ventricosa

G. calcarata

G. falsostuarti

R. levis

U. gothicum

U. trifidumU. gothicum

? B. p. constricta

G. calcarata

G. elevata

T. orienatus

10 m

δ13C (‰)

Miskar W1Tunisia

Elles Tunisia

1.0 1.5 2.0

1.0 1.5 2.0δ13C (‰)

Le KefTunisia

BidartFrance

O. pilula

O. pilula

G. quadrata

B. mucronataG. quadrata

B. lanceolata

B. mucronata

20 m

δ13C (‰)

LägerdorfKronsmoorGermany

1.0 1.5 2.0 2.5

1.0 1.5 2.0 2.5

10 m

δ13C (‰)

O. pilula

O. pilula

G. quadrata

G. quadrataB. mucronata

? B. mucronata

δ13C (‰)

Culver CliffEngland

10 m

H. burgensis

B. dissinilis

E. eximiusR. anthophorus

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Trunch boreholestratigraphy

Fig. 9 Carbon isotope stratigraphy and correlation of the northwesternPacific Ocean, North African and European Campanian-basalMaastrichtian sections. Carbon isotope profiles are solid lines. Generaltrends atMiskar, Elles, Le Kef, Bidart, Lägerdorfand Trunch are indicatedby three-point moving averages. Variable vertical scales are used tomatchthe middle and upper Campanian events. Thin solid grey lines are bound-aries between isotopic correlations. Dashed thin grey lines are additionalchemostratigraphic correlations. Major isotope events are indicated bythick solid grey lines. Planktonic foraminifera and nannofossil datums areshown for comparison, with black arrows showing the first and last

occurrence datum. Site 869 biostratigraphy and δ13C data are based onJenkyns et al. (1995); Miskar biostratigraphy is based on Bailey et al.(2000) and Mabrouk et al. (2005, 2006); Miskar δ13C data are based onMabrouk et al. (2005, 2006); Elles biostratigraphy and δ13C based on Liet al. (2000); Le Kef biostratigraphy based on Robaszynski et al. (2000)and this study; Bidart biostratigraphy and δ13C based on Clauser (1994);Lägerdorf δ13C data based on Schönfeld et al. (1991); δ13C Culver Cliffbased on Jenkyns et al. (1994); Trunch borehole biostratigraphy and δ13Cbased on Jenkyns et al. (1994) and Jarvis et al. (2002)

Arab J Geosci

broadly to low stands, with maxima in the lower parts oftransgressive system tracts. This correlation implies a domi-nance of eustatic over regional tectonic forcing, as the threemain phases of eustatic change were synchronous in NorthernEurope and North Africa.

Figure 10 shows the relationship between the δ13C profileof Le Kef and the Trunch Borehole curve, concluded from theabove global correlation, both compared to sea-level curves ofNorthwestern Europe (Hancock 1993), Egypt (Lüning et al.1998) and worldwide (Haq et al. 1987, 1988), recalibratedbased on Jarvis et al. (2002). The transgressive maximumspanning the Santonian–Campanian stage boundary and cor-responding to a positive carbon isotope excursion at Trunch ismissing at Le Kef as indicated by both the abovechemostratigraphic correlation and biostratigraphic data. Themid-Campanian positive excursion (MCaE) registered at LeKef (upper Globotruncanita ventricosa zone), and correlatedwith Trunch, corresponds to a transgressive maximum of Haqet al. (1987, 1988) and to a sea-level rise following a mid-Campanian regression particularly well developed in Egypt.This major isotopic event at Le Kef coincides with a majorlithological change from chalk to marl (transition from the

lower chalk member to the marly middle member, Fig. 9). Thenegative δ13C upper Campanian event of Le Kef correlateswith similar well-defined excursion at Trunch (Figs. 9 and 10).This major isotopic signal correlates with regressive systems(Fig. 10) identified in the three published curves (Haq et al.1987, 1988; Hancock 1993; Lüning et al. 1998). The upperCampanian event falls below the transition frommarl to chalkfacies at Le Kef and is approximately dated within the base ofthe Gansserina gansseri zone (Fig. 9). These observations re-confirm the relationship between positive δ13C excursions andperiods of sea-level rise (e.g. Jenkyns et al. 1994), and indicatethat the maxima of these excursions occur in the lower parts oftransgressive system tracts (e.g. Mitchell et al. 1996; Jarviset al. 2001, 2002). By contrast, minima in the δ13C curvecorrespond to regressive systems associated to eustatic falls.

Based on the good datum calibration and carbon isotopecorrelation between the trunch borehole and Le Kef section(Fig. 9) and taking the well-dated (as we previously proposed inJarvis et al. 2002) middle Campanian (78.7 Ma, CC6) isotopeevent and the upper Campanian (74.8Ma, CC10) isotope event aschemostratigraphic correlation ties between the Exxon globaleustatic curve, the third order cycles, the trunch borehole and Le

Fig. 10 Sea-level change versus carbon isotope stratigraphy of the LeKef section (grey curve) and the Trunch borehole (black). The δ13C curvesare three-point moving average data. The δ13C curve is calibrated againstthe time scale of Gradstein et al. (2012), using Campanian base (83.5Ma)and Maastrichtian base (71.3 Ma), and assuming a constant rate ofsedimentation in the Trunch section. The carbon isotope curve of LeKef section is calibrated using the estimated dates for the MCaE and the

UCaE based on the chemostratigraphic correlation with Trunch δ13Ccurve (Jarvis et al. 2002; Mabrouk 2003). The sea-level curves followthe re-calibration of Jarvis et al. (2002). The positive δ13C of the MCaEcorresponds to a transgressive system tract; the negative δ13C of theUCaE corresponds to a regressive system tract.MCaEmiddle Campanianevent, UCaE upper Campanian event, LST lowstand systems tract, TSTtransgressive system tract, HST highstand system tract

Arab J Geosci

Kef (Figs. 10 and 11), the Abiod Formation at Le Kef section isinferred to include five third order cycles (UZA), which corre-spond to five stratigraphic sequences (Fig. 11). It is our belief thatsequence stratigraphy can be concluded from chemostratigraphicties as the global correlation of the Campanian carbon isotopescurves is well calibrated and well proven by several authors (e.g.Jarvis et al. 2002; Mabrouk 2003, 2013; Wendler 2013).

Geochemistry, δ13C and sea-level curves

Figure 12 shows a correlation between δ13C, manganese (Mn,Mn/Ca and Mn/Al) and sea-level curves for the Le Kef sec-tion. TheMn profile shows a strong resemblance to theMn/Caratio curve reflecting the fact that Mn is predominantly acarbonate-bound element (e.g. Pratt et al. 1993). The relation-ship is further emphasised by the Mn/Al ratio profile, whichshows the highest values in the lower and upper members.However, within the middle marly member, the ratio is almostconstant, which indicates that Mn is partly controlled by the

detrital supply, but that the highest manganese concentrationsare essentially associated with the carbonate phase. Geochem-ically and under reducing conditions, manganese dissolves insediments and then migrates upwards by diffusion in the poresolutions (Michard 1969). Under oxidising conditions, man-ganese precipitates then as dioxides and oxyhydroxides to beincorporated into marine sediments (e.g. Burdige and Gieskes1983; Calvert and Pedersen 1996). Microbial decompositionof organic matter under anoxic conditions may result in thedeposition of authigenic Mn minerals (such as rhodochrosite),and under reducing environment, to the dissolution ofMn intothe pore water. The mobilisation of the pore water from anoxicto oxic conditions will precipitate Mn as oxyhydroxides.However, manganese enrichment of sediment pore waters iscaused by two main processes (Pomerol 1983): (1) incorpo-ration of abnormally Mn-rich oceanic waters and (2) dissolu-tion upon burial of manganese oxides.

Within a chemostratigraphic context, manganese has pre-viously been proposed as a potential stratigraphic tool tocorrelate and/or characterize sections (e.g. Accarie et al.

Fig. 11 Inferred sequencestratigraphic subdivisions of theLe Kef section based on theproposed correlation betweenδ13C and eustatic curves of Fig. 5.Le Kef section is assumed toinclude five third order cycles(UZA) corresponding to fivestratigraphic sequences

Arab J Geosci

1993; Jarvis et al. 2001; Mabrouk et al. 2007; Jarvis et al.2008). In this study, sequence boundaries are correlated withmanganese minimum, which are also, as it has been saidabove, mainly associated to δ13C curve minima. On the otherhand, manganese maxima are associated to MFS, or generallyto transgressive systems, and correlate positively with theδ13C profile. The positive relationship between δ13C and Mn

is related to the increase in organic matter supply, which isknown to induce an enrichment of the carbonate phase in 13CandMn (e.g. the Cenomanian–Turonian anoxic event). This isin accordance with previous studies establishing a positiverelationship between δ13C, sea-level rise and manganese max-imum (e.g. Jenkyns et al. 1994; Murphy 1998). Furthermore,the mid-Campanian isotopic event (MCaE) is characterised by

Fig. 12 Relationship between manganese profiles, δ13C curve, and sea-level change. High Mn corresponds to maximum δ13C and sea-level riseor maximum flooding surfaces. Regressive systems are associated to lowmanganese and low δ13C values. The negative UCaE is associated to aMnminimum.Black horizontal linesare sequence bundaries, dashed greyhorizontal lines correspond to the maximum flooding surfaces. Greyarrows show positive peaks in Mn and δ13C curves. The δ13C and Mn

curves are three-point moving average data. The carbon isotope curve ofLe Kef section is calibrated using the estimated dates for the MCaE andthe UCaE based on the chemostratigraphic correlation with the Trunchδ13C curve. The sea-level curves follow the re-calibration of Jarvis et al.(2002).MCaEmiddle Campanian event, UCaE upper Campanian event,LST lowstand systems tract, TST transgressive system tract, HSThighstand system tract

Fig. 13 Relationship between δ13C, CaCO3, Mn, Ti/Al, Zr/Al, Sr/Alprofiles and sea-level curves. High δ13C, Mn, CaCO3, Ti/Al, Zr/Al andSi/Al correspond to sea-level rise or maximum flooding surfaces. Se-quence boundaries are associated to lowmanganese and low δ13C signalsas well as low Ti/Al. Black horizontal lines are sequence boundaries,dashed grey horizontal lines correspond to the maximum flooding

surfaces. The carbon isotope curve of Le Kef section is calibrated usingthe estimated dates for the MCaE and the UCaE based on thechemostratigraphic correlationwith the Trunch δ13C curve.MCaEmiddleCampanian event, UCaE upper Campanian event: LST lowstand systemstract, TST transgressive system tract, HST highstand system tract

Arab J Geosci

a positive δ13C excursion correlating with a Mn maximumand corresponds to a sea-level rise (Figs. 11, 12 and 13). Theupper Campanian isotopic event (UCaE) negative δ13C ex-cursion corresponds to Mn minimum (although a small offsetexists between the two excursions) and falls within thelowstand system tract of Haq et al. (1987, 1988). This offsetmay be explained (e.g. Mabrouk et al. 2007; Jarvis et al. 2008)by a lower organic carbon flux generating first lower δ13C andsubsequently leading to lower manganese in the interstitialporewater (i.e. lowering the Mn flux).

Figure 13 shows a correlation of the δ13C, CaCO3, Mn, Ti/Al, Zr/Al and Si/Al with sea-level curves. As indicated above,the long-term decreasing trend of manganese corresponds tooverall increasing Ti/Al, Zr/Al and Si/Al, which renders Mnpreferentially connected to the carbonate phase. Carbonate con-tent exhibits a long-term decreasing trend broadly following thatof manganese but returns to high levels in the uppermost Cam-panian. Higher fluctuations of the Ti/Al, Zr/Al and Si/Al in theupper carbonate member are caused by the lower aluminiumcontent and probably not to a remarkable increase in variation ofthese elements. Overall, the carbonate content shows a tendencyto increase throughout the transgressive systems. Within theupper member, the CaCO3 contents shows a minimum at se-quence boundaries and lowstand system tracts, displays a max-imum atmaximum flooding surfaces and an increase throughoutthe transgressive systems. This behaviour is in accord with thesequence stratigraphic model of Robaszynski et al. (1998) and

the published geochemical results of the Culver Cliff by Jarviset al. (2001). Low Ti/Al, Zr/Al and Si/Al ratios characterise thesequence boundaries and highstand system tracts HST, whereasincreasing ratios are associated to LST, reaching a maximum atthe transition to the transgressive system (TST), where it re-verses to lower values but later shows a positive excursion at theMFS. It is worth noting that the Campanian is previouslydocumented, based on stable oxygen isotopes calculations byAbreu et al. (1998) and Clarke and Jenkyns (1999), as overlycharacterised by decreasing temperatures and cooler climate.

On the other hand, Li et al. (2000) argued in their multi-disciplinary study of the El Kef and Elles sections (the latter isaround 70 km southeast of El Kef section) that lowstandsystem tracts are associated with generally increased terrige-nous influx, low kaolinite/chlorite ratios+micas ratios, highTOC and high Sr/Ca ratios, whereas high sea levels areconnected to the reverse conditions. The authors establishedshort term climate variations based on high or low kaolinteversus chlorite and micas ratios and therefore attributedlowstand system tracts to cool/arid climate (higher chloriteand micas contents) intermitted by warmer–humid periods(higher kaolinite). If we combine our findings to those of Liet al. (2000), we may imply that cooler/arid climates can beascribed to low Mn–CaCO3 contents and low-to-rising Ti/Al(or Si/Al, Zr/Al) ratios. On the other hand, Jarvis et al. (2001)explained that higher Ti/Al ratios in chalks are indicative ofincreased current energy and siliciclastic supply.

Fig. 14 Comparison between the idealised relationship betweenchemostratigraphy, sequence stratigraphy and sea-level proposed byJarvis et al. 2001 (shown in black bold curves) and the present relation-ship between chemostratigraphy, sea-level, and sequence stratigraphy forthe uppermost Abiod Formation at Le Kef. Stratigraphic sequence bound-aries for Le Kef are based on the δ13C correlation to the Exxon curve.δ13C, CaCO3, Mn, Ti/Al and sea-level change show comparable

relationship to that proposed by Jarvis et al. (2001). High δ13C, Mn,CaCO3 and Ti/Al correspond to sea-level rise. Sequence boundaries areassociated to low manganese and low δ13C signals as well as low Ti/Al.Thick grey horizontal lines are sequence bundaries, transgressive systemsand maximum flooding surfaces. TS transgressive systems, SB sequenceboundaries, MFSmaximum flooding surfaces

Arab J Geosci

Chemostratigraphic behaviour of a stratigraphicsequence

Jarvis et al. (2001) proposed an idealised relationship betweenchemostratigraphy, depositional sequences and sea-levelcurves (Fig. 14). To further investigate the relationships be-tween this model with our chemostratigraphic correlation,eustasy and sequence stratigraphy, we have plotted the δ13Cand elemental geochemical data for the upper part of theAbiod Formation (Fig. 14), which constitutes a stratigraphicsequence lasting for around 3.7 Ma (75 Ma–71.3 Ma). Fig-ure 14 displays the idealised relationship betweenchemostratigraphy, depositional sequences and sea-level(after Jarvis et al. 2001) in bold black curves, whereas theactual relationship for the upper part of Le Kefchemostratigraphy and the sequence stratigraphy is shown ingrey curves. There is fair agreement between the proposedmodel of Jarvis et al. (2001) and that of Le Kef.

Sequence boundaries are mainly characterised by a mini-mum in manganese, CaCO3 and a low Ti/Al ratio (can be alsoSi/Al and Zr/Al). However, the minimum δ13C predicted bythe Jarvis et al. (2001) model occurs slightly above the se-quence boundary. The correspondence between the Jarviset al. (2001) model for the lowstand system tract with thegeochemical signatures characterising that of the upper mem-ber is found for Ti/Al (or Zr/Al and Si/Al) curves marked byan increase in these ratios. The δ13C curve shows a similarincrease to that of the model but only within the upper part ofthe lowstand system, by contrast, in the lower part, the curve ismainly falling. The manganese curve shows no correspon-dence with the model as it increases rather than decreases. Thetransgressive system tract is characterised by increasing δ13C,Mn, CaCO3 and Ti/Al ratio. The maximum flooding surfacecorresponds to a rise in carbonate, manganese and Ti/Al ratio.However, δ13C here shows a small maximum, which conflictswith the Jarvis et al. (2001) model and where δ13C decreasesaround MFS. Moreover, in the highstand system tract, onlythe decreasing Ti/Al ratio and the increasing carbonate contentcorrespond with the model of Jarvis et al. (2001). Manganese,by contrast, rises and δ13C plateaus at quite high levels ratherthan falling to low values as predicted by the model. Despitethese discrepancies, the LeKef data and the idealisedmodel ofJarvis et al. (2001) show sufficient agreement to warrantfurther investigation, indeed the argument is remarkably goodgiven the complex geodynamic development, structural his-tory, palaeoenvironment setting and the potential for localvariation in sea level at Le Kef area.

Conclusions

The established relationship between the carbon isotope curveof the Abiod Formation and sea-level fluctuations during the

Campanian confirms the usefulness of δ13C curves as a toolfor estimating eustasy (cf. Jenkyns et al. 1994; Jarvis et al.2002; Mabrouk et al. 2007). Positive shifts of δ13C are asso-ciated to sea-level rise (e.g. the MCaE), whereas negativeshifts are related to regressive systems (e.g. UCaE),supporting the argument that δ13C can be considered as anindependent method for estimating first order eustatic sea-level cycles (Mitchell et al. 1996; Voigt and Hilbrecht 1997;Jarvis et al. 2002). Based on the relationship between thecarbon isotope curve and the global Exxon sea-level curve,five stratigraphic sequences (third order cycles) were identi-fied in the Abiod Formation of Tunisia indicating that a highresolution stratigraphy may be attained through suchcorrelation.

The established relationship between δ13C, CaCO3, Mn,Ti/Al, Zr/Al and Si/Al, provides vigorous criteria for furtherunderstanding sequence stratigraphy models and identifyingsea-level change. Such new understanding of stratigraphicsequences sets to identify and validate geochemical sequencesand can be further used to correlate between well-knownreservoir and/or source rock pelagic and hemi-pelagichorizons.

Acknowledgements Professors I. Jarvis and RTJ Moody are greatlyacknowledged. Dr Sandra de Cabrera is thoughtfully acknowledged.

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