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Sequence Stratigraphy, 
Sea
Level
Change and Palaeoenvironments via Chemostratigraphy: Regional to Global
Correlations*
By
Amina Mabrouk1, Ian Jarvis2, Habib Belayouni1, Amanda Murphy2, and Richard T.J. Moody3
Search and Discovery Article #40244 (2007)
Posted June 30, 2007
*Adapted from extended abstract prepared for oral presentation at AAPG Annual Convention, Long Beach, California, April 104, 2007.
1Faculte des Sciences de Tunis, Département de Géologie, Université de Tunis El Manar, 2092 Tunis, Tunisia ([email protected])
2School of Earth Sciences & Geography, CEESR, Kingston University, Penrhyn Road, Kingston upon Thames KT12EE, UK ( [email protected] )
3Moody-Sandman Associates, ‘Haslemere’ Gordon Road, Curdridge, Hants S032 2BE, UK. ([email protected])
Fourteen d13C events are recognised in four Cenomanian sections in England and are isochronous with respect to biostratigraphic datums. Events in the Middle and Upper Cenomanian are readily identified in Italy. A d13C correlation of Campanian sections in England, France, and Tunisia is demonstrated using 11 isotope events, which enable calibration of Boreal and Tethyan biostratigraphic schemes.
Carbon isotope profiles predominantly follow eustatic
sea-level, with rising d13C
accompanying transgression and falling
d13C
accompanying regression. Significant positive carbon excursions are broadly
associated with major transgressive events. Sr/Ca ratios and the Mn contents of
pelagic carbonates vary systematically with respect to sea-level change.
Increasing Sr/Ca ratios during periods of sea-level fall are attributed to the
release of Sr from aragonite dissolution and replacement in subaerially exposed
platform carbonates. Falling Sr/Ca ratios accompanied the re-establishment of
shallow-water carbonate factories during sea-level rise.
Mn flux increases with rising sea-level, with Mn reaching a
maximum around each maximum flooding surface, before decreasing again through
the overlying highstand systems tract, representing a period of relative
constant carbonate supply.
Correlations between variations in Sr/Ca ratios and Mn content with sequence stratigraphy in the English Cenomanian are consistent with published data from other Mesozoic successions.
Elemental chemostratigraphy provides a means of developing a sequence stratigraphic framework in pelagic carbonate successions. This framework clearly needs to be constrained by geological evidence, but offers a powerful new tool for sequence analysis and correlation.
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Pelagic and hemipelagic sediments are predominantly composed of stable primary low-Mg calcite and are frequently characterised by low-permeabilities. In addition, subaerial exposure horizons and early interaction with meteoric fluids are normally absent due to the exclusively open-ocean setting prevailing during the deposition of such facies. Consequently, relatively uniform compositions and minimal early or late diagenesis, commonly characterise these sediments and validated the wide and successful use of carbon and oxygen stable isotopes (e.g., Scholle and Arthur, 1980; Arthur et al., 1987; Gale et al., 1993; Pearce and Jarvis, 1995; Mitchell et al., 1996; Voigt and Hilbrecht, 1997; Voigt, 1999; Jarvis et al., 2001; Mabrouk et al., 2005) and, to a lesser extent, elemental chemostratigraphy (e.g., Renard, 1986; Jarvis et al., 2001; Stoll and Schrag, 2001; Jenkyns et al., 2002) as a mean for correlating sedimentary barren sequences. In this study, geochemical studies of eight pelagic carbonate successions of Late Cretaceous age in England, France, Italy, and Tunisia (Figure 1) will be used to illustrate and enhance the potential of isotopic and elemental chemostratigraphy for international correlations and the interpretations of sedimentary sequences. Analytical procedures for the determination of whole rock contents in Si, Ti, Al, Fe, Mn, Mg, Ca, Na, K, P, Ba, Sr and Zr are presented elsewhere (Murphy, 1998; Jarvis, 2003; Mabrouk, 2003). Results are presented in weight percent oxide for ‘major’ elements and as mg g-1 (parts per million) for ‘trace’ elements. Carbon and oxygen stable-isotope ratios were determined at the University of Oxford, following the method of Jenkyns et al. (1994). Results are reported in the δ notation, in parts per thousand or ‘per mille’ (‰) relative to the Vienna Pee Dee Belemnite (VPDB) international standard. Reproducibility was better than 0.1 ‰ for both carbon and oxygen. Elemental and isotopic numerical data for the Culver Cliff study are reported in Murphy (1998) and for the El Kef study in Mabrouk (2003).
Mitchell et al. (1996) described seven isotope events in the Cenomanian at Speeton, North Yorkshire (Figure 1): an Albian / Cenomanian Boundary Event (ACBE); three Lower Cenomanian events (LCE I – III); two Middle Cenomanian events (MCE I, II); and the Cenomanian / Turonian Boundary Event (CTBE), which were correlated to southern England and northern Germany. A compilation of published and new carbon isotope data (Figure 2) from sections in northern (Speeton), eastern (Trunch), and southern (Culver, Dover) England (Figure 1) demonstrates that these and several additional events provide a basis for detailed correlation of sections throughout the country, despite significant differences in thickness and facies between the northern and southern provinces. Comparison with the positions of biostratigraphic datums (Figure 2) demonstrates that the d13C events are isochronous within the resolution provided by zonal events and marker bed biostratigraphy. In addition to the seven isotope events recognised previously, nine additional correlation levels are shown in Figure 2. Carbon stable-isotope profiles for two Tethyan (Figure 1; El Kef, Tunisia and Bidart, France), and one Boreal site (Trunch, England) are correlated in Figure 3. The biostratigraphic control on these correlations is considerably poorer than that available for the Cenomanian, but calcareous nannofossil, foraminiferal, and macrofossil evidence (Burnett, 1990; McArthur et al., 1992, 1993; Clauser, 1994; Wood et al., 1994; Robaszynski et al., 2000; Jarvis et al., 2002. Mabrouk, 2003) is consistent with the proposed isotope correlations. The shapes of the three curves are remarkably similar, but absolute d13C values are lower at El Kef. This offset to lighter d13C values probably reflects a primary depletion in seawater on Tethyan carbonate platforms (Jarvis et al., 2002; Mabrouk, 2003). On the other hand, as in the Cenomanian, the carbon isotope stratigraphy of the Campanian shows systematic variation that enables detailed correlation on an intercontinental scale, despite the absence of unequivocal interregional biostratigraphic markers.
Carbon
Isotopes and Related
The Exxon global Mesozoic – Cenozoic
However, an eustatic curve for the Cenomanian,
constrained by detailed ammonite biostratigraphy, has been presented by
Gale et al. (2002). In addition, comparison between biostratigraphically
well constrained regional
It is notable that the two main positive carbon
isotope excursions of the Santonian / Campanian Boundary and Mid-Campanian
events both follow periods of major
The Upper Campanian isotope and eustatic
Within the resolution of existing data, therefore,
there seems to be a remarkably close correspondence between carbon
isotope and eustatic
A Sr/Ca profile for the Cenomanian of Culver is shown
in Figure 5, plotted against the sequence
stratigraphic framework of Robaszynski et al. (1998) with the additional
Sequence 5a of Jarvis et al. (2001). The Sr/Ca profile displays seven
short-term
The observed relationships between the Sr/Ca profile
and the sequence stratigraphy are consistent with
Current data (Renard, 1985, 1986; Stoll and Schrag,
2001; Steuber, 2002; Steuber and Veizer, 2002) suggest that Sr/Ca ratios
rose progressively through the Mid- to Late Cretaceous, a period of
generally rising eustatic
The overall decrease in Mn contents through the
Cenomanian (Figure 5) has been interpreted
as resulting from a decreasing detrital Mn supply (Jarvis et al., 2001),
as indicated by an inverse correlation with carbonate content and
relatively constant background Mn/Al ratios. However, the short-term Mn
Carbonate/clay ratios and the Mn flux increased with
rising
One of the largest Mn peaks at Culver Cliff occurs
around the Cenomanian / Turonian boundary (Figure
5), the
Idealised stratigraphic relationships between Mn and
Sr/Ca in pelagic carbonates, sequence stratigraphic units, and eustatic
A combination of Mn and Sr data offers criteria to
develop sequence stratigraphic schemes in pelagic carbonate successions.
Other geochemical data provide additional constraints for sequence
stratigraphic interpretation. Based on studies of the Culver Cenomanian,
Jarvis et al. (2001) demonstrated that carbonate contents increase in
response to rising
The Cenomanian and Campanian studies demonstrate that
remarkably consistent relationships exist between carbon isotope
profiles and eustatic
The strontium content of sediments also responds to
Furthermore, manganese exhibits consistent but different relationships to sequences, with minima around sequence boundaries and through lowstands, rising values from the transgressive surfaces through transgressive sequence tracts, maxima around maximum flooding surfaces, and declining values through highstands. The positive Mn anomaly previously associated with the large positive d13C excursion spanning the Cenomanian / Turonian boundary is not tied to the abnormal oceanic conditions accompanying Oceanic Anoxic Event 2, but is related to normal marine processes. Our study demonstrates that the combination of elemental and isotopic studies enables improved regional to global correlation which would better constrain local and regional geological models as well as petroleum system evaluation.
Elemental data for Culver were obtained by AMM during doctoral work funded by the UK Natural Environmental Research Council (CASE award GT4/93/12/G) in collaboration with the British Geological Survey (BGS). AM acknowledges British Council Chevening Scholarship TUN0100022, during which some of this work was undertaken. Research support by BG Exploration & Production for the Tunisia study is gratefully acknowledged. Isotopic analyses were undertaken in collaboration with Dr Hugh Jenykns (University of Oxford); Julie Cartlidge operated the PRISM mass spectrometer at Oxford on which these data were generated. Heather Stoll (Williams College, Massachusetts) kindly provided digital data from her chemostratigraphic studies.
Arthur, M.A., Schlanger, S.O., and Jenkyns, H.C., 1987, The Cenomanian/Turonian Oceanic Anoxic Event, II: Palaeoceanographic controls on organic matter production and preservation, in Marine Petroleum Source Rocks, eds. J. Brooks and A.J. Fleet, Spec. Publ: Geol. Soc. London, v. 26, p. 401-420. Burnett, J.A., 1990, A new nannofossil zonation scheme for the Boreal Campanian: Int. Nannofossil Assoc. Newslett., v. 12, p. 67-70. Clauser, S., 1994, Études Stratigraphiques du Campanien et du Maastrichtien de l'Europe Occidentale Côte Basques, Charentes (France), Limbourg (Pays-Bas). Biochronologie, Magnétostratigraphie, Stratigraphie Isotopique, Radiochronologie Comparée de Domaine Océanique et des Régions Stratotypiques. Contribution à La Paléoclimatologie du Crétacé Superieur. Doc. : BRGM, v. 235, 243 p. Gale, A.S., Jenkyns, H.C., Kennedy, W.J., and Corfield, R.M., 1993, Chemostratigraphy versus biostratigraphy: data from around the Cenomanian-Turonian boundary: Jour. Geol. Soc. London, v. 150, p. 29-32. Gale, A.S., Kennedy, W.J., Burnett, J.A., Caron, M., and Kidd, B.E., 1996, The late Albian to early Cenomanian succession at Mont Risou near Rosans (Drôme, SE France): An integrated study (ammonites, inoceramids, planktonic foraminifera, nannofossils, oxygen and carbon isotopes): Cretaceous Res., v. 17, p. 515-606.
Gale, A.S., Hardenbol, J., Hathway,
B., Kennedy, W.J., Young, J.R., and Phansalkar, V., 2002, Global
correlation of Cenomanian (Upper Cretaceous) sequences: evidence for
Milankovitch control on
Hancock, J.M., 1989,
Hancock, J.M. (1993, Transatlantic
correlations in the Campanian-Maastrichtian stages by eustatic changes
of
Haq, B.U., Hardenbol, J., and Vail,
P.R., 1987, Chronology of fluctuating
Haq, B.U., Hardenbol, J., and Vail,
P.R., 1988, Mesozoic and Cenozoic chronostratigraphy and
Hay, W.W., DeConto, R.M., Wold, C.N.,
Wilson, K.M., Voigt, E., Schulz, M., Wold, A.R., Dullo, W.-C., Ronov,
A.B., Balukhovsky, A.N., and Söding, E., 1999, Alternative global
Cretaceous paleogeography, in Evolution of the Cretaceous
Ocean- Jarvis, I., 2003, Sample preparation in ICP-MS, in Handbook of Inductively Coupled Plasma Mass Spectrometry, eds. K.E. Jarvis, A.L. Gray and R.S. Houk: Viridian, Woking, p. 172-224.
Jarvis, I., Murphy, A.M., and Gale,
A.S., 2001, Geochemistry of pelagic and hemipelagic carbonates: criteria
for identifying systems tracts and
Jarvis, I., Mabrouk, A., Moody, R.T.J.,
and De Cabrera, S.C., 2002, Late Cretaceous (Campanian) carbon isotope
events, Jenkyns, H.C., Geczy, B., and Marshall, J.D., 1991, Jurassic manganese carbonates of central Europe and the early Toarcian anoxic event: Jour. Geol., v. 99, p. 137-149. Jenkyns, H.C., Gale, A.S., and Corfield, R.M., 1994, Carbon- and oxygen-isotope stratigraphy of the English Chalk and Italian Scalia and its palaeoclimatic significance: Geol. Mag., v. 131, p. 1-34. Jenkyns, H.C., Jones, C.E., Grocke, D.R., Hesselbo, S.P., and Parkinson, D.N., 2002, Chemostratigraphy of the Jurassic System: applications, limitations and implications for palaeoceanography: Jour. Geol. Soc. London, v. 159, p. 351-378.
Lewy, Z., 1990, Transgressions,
regressions and relative Lüning, S., Marzouk, A.M., Morsi, A.M., and Kuss, J., 1998, Sequence stratigraphy of the Upper Cretaceous of south-east Sinai, Egypt: Cretaceous Res., v. 19, p.153-196. Mabrouk, A., 2003, Chemostratigraphy and correlation of a chalk petroleum reservoir: the Upper Cretaceous Abiod Formation, Tunisia: Ph.D. Thesis, Kingston University, Kingston upon Thames, 476 p. Mabrouk, A., Jarvis, I., Belayouni, H., Moody, R. T. J., and de Cabrera, S., 2005, An integrated chemostratigraphic study of the Campanian-Early Maastrichtian deposits of the Offshore Miskar Field in southeastern Tunisia: SIS, d13C and d13O isotopes, and elemental geochemistry: Stratigraphy 2, 3, p. 193–216. McArthur, J.M., Kennedy, W.J., Gale, A.S., Thirlwall, M.F., Chen, M., Burnett, J., and Hancock, J.M., 1992, Strontium isotope stratigraphy in the Late Cretaceous - intercontinental correlation of the Campanian-Maastrichtian boundary: Terra Nova, v. 4, p. 385-393. McArthur, J.M., Thirlwall, M.F., Gale, A.S., Kennedy, W.J., Burnett, J.A., Mattey, D., and Lord, A.R., 1993, Strontium isotope stratigraphy for the Late Cretaceous: a new curve, based on the English Chalk, in High Resolution Stratigraphy, eds. E.A. Hailwood and R.B. Kidd: Geol. Soc. London Spec. Publ., 70, 195-209. Mitchell, S.F., Paul, C.R.C., and Gale, A.S., 1996, Carbon isotopes and sequence stratigraphy, in High Resolution Sequence Stratigraphy: Innovations and Applications, eds. J.A. Howell and J.F. Aitken: Geol. Soc. London Spec. Publ., v. 104, p. 11-24. Murphy, A.M., 1998, Sediment and Groundwater Geochemistry of the Chalk in Southern England: PhD Thesis, Kingston University, Kingston upon Thames, 288 p. Niebuhr, B., Wood, C.J., and Ernst, G., 2000, Isolierte Oberkreide - vorkommen zwischen Wiehengebirge und Harz, in Stratigraphie von Deutschland III. Die Kreide der Bundesrepublik Deutschland, eds. M. Hiss, J. Schönfeld and A. Thiermann: Cour. Forsch, Senckenberg, v. 226, p. 101-109.
Paul, C.R.C., 1992, Milankovitch
Pearce, T.J., and Jarvis, I., 1995, High-resolution chemostratigraphy of Quaternary distal turbidites: a case study of new methods for the analysis and correlation of barren sequences, in Non-biostratigraphical methods of dating and correlation, eds. R.E. Dunay and E.A. Hailwood: Geol. Soc. Spec. Publ., v. 89, p. 107-143. Renard, M., 1985, Géochimie des Carbonates Pélagiques. Mis en Évidence des Fluctuations de la Composition des Eaux Océaniques depuis 140 Ma. Essai de Chimiostratigraphie. Doc: BRGM, v. 85, 650 p. Robaszynski, F., Gale, A.S., Juignet, P., Amédro, F., and Hardenbol, J., 1998, Sequence stratigraphy in the Upper Cretaceous series of the Anglo-Paris Basin: exemplified by the Cenomanian stage, in Mesozoic and Cenozoic Sequence Stratigraphy of European Basins, eds. P.-C.d. Graciansky, J. Hardenbol, T. Jacquin and P.R. Vail: SEPM Spec. Publ., 60. SEPM (Society for Sedimentary Geology), Tulsa, p. 363-386. Robaszynski, F., Gonzáles Donoso, J.M., Linares, D., Amédro, F., Caron, M., Dupuis, C., Dhondt, A.V., and Gartner, S., 2000, Le Crétacé Supérieur de la région de Kalaat Senan region, Tunisie centrale. Litho-biostratigraphie intégrée: zones d'ammonites, de foraminifères planctonique et de nannofossiles du Turonian Supérieur au Maastrichtien: Bull. Centre Rech. Explor.-Prod. Elf Aquitaine, v. 22, p. 359-490. Scholle, P.A., and Arthur, M.A., 1980, Carbon isotope fluctuation in Cretaceous pelagic limestones: potential stratigraphic and petroleum exploration tool: AAPG Bull., v. 64, p. 67-87. Steuber, T., 2002, Plate tectonic control on the evolution of Cretaceous platform-carbonate production: Geology, v. 30, p. 259-262. Stoll, H.M., and Schrag, D.P., 2000, High-resolution stable isotope records from the Upper Cretaceous rocks of Italy and Spain: Glacial episodes in a greenhouse planet?: Geol. Soc. Am. Bull., v. 112, p. 308-319.
Stoll, H.M., and Schrag, D.P., 2001,
Sr/Ca variations in Cretaceous carbonates: relation to productivity and
Tsikos, H., Jenkyns, H.C., Walsworth-Bell, B., Petrizzo, M.R., Forster, A., Kolonic, S., Erba, E., Premoli-Silva, I.P., Baas, M., Wagner, T., and Sinninghe Damsté, J.S., 2004, Carbon-isotope stratigraphy recored by the Cenomanian/Turonian Oceanic Anoxic Event: correlation and implications based on three key localities: Jour. Geol. Soc. London, v. 161, p. 711-719.
Voigt, S., and Hilbrecht, H., 1997,
Late Cretaceous carbon isotope stratigraphy in Europe: correlation and
relations with
Voigt, E., Hay, W.W., Höfling, R., and
DeConto, R.M., 1999, Biogeographic distribution of late Early to Late
Cretaceous rudist-reefs in the Mediterranean as Wood, C.J., Morter, A.A., and Gallois, R.W., 1994, Appendix 1. Upper Cretaceous stratigraphy of the Trunch borehole. TG23SE8, in Geology of the Country around Great Yarmouth. Memoir for 1:50,000 Sheet 162 (England and Wales) with an Appendix on the Trunch Borehole by Wood and Morter., eds. R.S. Arthurton, S.J. Booth, A.N. Morigi, M.A.W. Abbott and C.J. Wood: HMSO, London, p. 105-110.
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