DOI: 10.1016/j.palaeo.2015.08.013
论文题名: Sea-level reconstruction for Turonian sediments from Tanzania based on integration of sedimentology, microfacies, geochemistry and micropaleontology
作者: Wendler I. ; Wendler J.E. ; Clarke L.J.
刊名: Palaeogeography, Palaeoclimatology, Palaeoecology
ISSN: 0031-0182
出版年: 2016
卷: 441 起始页码: 528
结束页码: 564
语种: 英语
英文关键词: Cretaceous
; Foraminifera
; Grain size
; Sea level
; Sequence stratigraphy
; Stable isotope
英文摘要: 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. © 2015 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/68694
Appears in Collections: 过去全球变化的重建
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作者单位: Department of Geosciences, Bremen University, P.O. Box 330440Bremen, Germany; School of Science and the Environment, Faculty of Science and Engineering, Manchester Metropolitan University, Chester Street, Manchester M1 5GD, United Kingdom
Recommended Citation:
Wendler I.,Wendler J.E.,Clarke L.J.. Sea-level reconstruction for Turonian sediments from Tanzania based on integration of sedimentology, microfacies, geochemistry and micropaleontology[J]. Palaeogeography, Palaeoclimatology, Palaeoecology,2016-01-01,441