Sea-level reconstruction for Turonian sediments from Tanzania based on integration of sedimentology, microfacies, geochemistry and micropaleontology

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doi: 10.1016/j.palaeo.2015.08.013
Author(s): Wendler, Ines; Wendler, Jens E.; Clarke, Leon J.
Author Affiliation(s): Primary:
Bremen University, Department of Geosciences, Bremen, Germany
Other:
Smithsonian Institution, United States
National Institute of Geology and Geoecology, Romania
Middle East Technical University, Turkey
Manchester Metropolitan University, School of Science and the Environment, United Kingdom
Volume Title: Advances and perspectives in understanding Cretaceous sea-level change
Volume Author(s): Wagreich, Michael, editor; Haq, Bilal U.; Melinte-Dobrinescu, Mihaela C.; Sames, Benjamin; Yilmaz, Ismail Omer
Source: Palaeogeography, Palaeoclimatology, Palaeoecology, 441( Part 3), p.528-564; Joint 2nd United Nations Educational, Scientific and Cultural Organiation-International Union of Geological Sciences; IGCP 609; Climate-environmental deterioration during greenhouse phases; causes and consequences of short-term Cretaceous sea-level changes; and the European Science Foundation EARTHTIME-EU sequence stratigraphy workshop on Eustasy and sequence stratigraphy in the Cretaceous greenhouse, Bucharest, Romania, Aug. 23-25, 2014, edited by Michael Wagreich, Bilal U. Haq, Mihaela C. Melinte-Dobrinescu, Benjamin Sames and Ismail Omer Yilmaz. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0031-0182 CODEN: PPPYAB
Note: In English. Includes appendices. 129 refs.; illus., incl. 3 tables
Summary: Despite many advances in sea-level research, the nature of cyclic eustatic sea-level fluctuations during warm periods without, or with much reduced, polar ice remains enigmatic. Recently published δ18O records from extremely well-preserved Turonian microfossils from Tanzania do not support the contentious idea of glacio-eustatic control of global sea-level changes during the warmest period of the Cretaceous. For the same locality (site TDP 31) we reconstruct relative sea-level changes based on sequence stratigraphy and integration of sedimentology, microfacies, geochemistry, and micropaleontology. Four local sequence boundaries (SBs TuTz1-4) are recognized: at the base, middle, and top of the Helvetoglobotruncana helvetica Zone and in the late Turonian. The lowstands are characterized by increased grain size, enhanced organic carbon flux, faunal assemblage changes, and bulk δ13Corg and foraminiferal δ13Cf and δ18Of minima. Strong benthic and planktic foraminiferal turnovers above the top middle Turonian SB TuTz3 probably reflect shallowing (from upper slope to outer shelf) and/or eutrophication. The TDP 31 age model is refined through inter-regional comparison of planktic foraminiferal ranges and δ13C records from three other South Tethyan localities (ODP Holes 762C and 763B, Exmouth Plateau, and the Guru section, Tibet). This age model enables correlation of the regressive events at a global scale and suggests that, within stratigraphic uncertainty, the TDP 31 depositional sequences are synchronous with the global Turonian third-order sequences and are likely driven by eustasy. These correlations, together with recent astrochronological and radiometric dating, indicate a considerably younger age (91.17 ± 0.52 Ma) for the top H. helvetica Zone than currently assumed, resulting in zonal duration of 2.35 ± 0.52 myr. Foraminiferal stable-isotope data from TDP 31 indicate slight surface- and bottom-water warming during the regressions and possibly a minor surface-water salinity decrease, which is inconsistent with glacio-eustatic forcing of Turonian third-order sea-level cycles and is more in line with the model of aquifer-eustasy. Abstract Copyright (2016) Elsevier, B.V.
Year of Publication: 2016
Research Program: ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Africa; Asia; Benthic taxa; Biostratigraphy; C-13/C-12; Carbon; Chemical composition; China; Cretaceous; East Africa; Exmouth Plateau; Far East; Foraminifera; Guru Section; IGCP; Indian Ocean; Invertebrata; Isotope ratios; Isotopes; Leg 122; Lithostratigraphy; Mesozoic; Microfacies; Microfossils; O-18/O-16; ODP Site 762; ODP Site 763; Ocean Drilling Program; Oxygen; Paleo-oceanography; Planktonic taxa; Productivity; Protista; Sea-level changes; Sedimentology; Stable isotopes; Tanzania; Tanzania Drilling Project; Turonian; Upper Cretaceous; Xizang China
Coordinates: S100150 S100150 E0393844 E0393844
S195315 S195314 E1121515 E1121514
S203512 S203511 E1121232 E1121231
Record ID: 2016023423
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands