DOI: 10.1016/j.palaeo.2012.11.011
论文题名: The expression of the Cenomanian-Turonian oceanic anoxic event in Tibet
作者: Bomou B. ; Adatte T. ; Tantawy A.A. ; Mort H. ; Fleitmann D. ; Huang Y. ; Föllmi K.B.
刊名: Palaeogeography, Palaeoclimatology, Palaeoecology
ISSN: 0031-0182
出版年: 2013
卷: 369 起始页码: 466
结束页码: 481
语种: 英语
英文关键词: Cenomanian-Turonian
; OAE 2
; Phosphorus
; Stable isotopes
; Tibet
; Trace metals
英文摘要: The Gongzha section of Tibet, China is located at the northern margin of the Indian Plate (SE Tethys) and is characterized by hemipelagic grey marls and marly limestones, light grey limestones and silty limestones, but no organic-rich sediments. High-resolution biostratigraphy reveals an expanded Cenomanian-Turonian (CT) boundary interval and the δ13C record includes the main features of the classical positive carbon-isotope excursion that characterizes the CT oceanic anoxic event. The biotic response inferred from the foraminifera suggests that oxic to dysoxic conditions prevailed, except for a short interval marked by peak abundance of Heterohelix that indicates a significantly dysoxic environment during the δ13C "b" peak excursion. The overall decreasing trend in redox-sensitive trace elements (RSTE) during the maximum δ13C excursion confirms the absence of significant longer-lasting anoxia in the Gongzha section. Enrichments in RSTE are linked to phases of increased detrital input. Chemical weathering indices suggest that the upper Cenomanian sediments accumulated under an increasingly hot and humid climate that culminated near the CT boundary. In the early Turonian lower weathering indices suggest a warm, drier climatic regime with reduced continental runoff. Phosphorus mass-accumulation rates show a significant peak at the onset of the positive δ13C excursion, followed by a decrease up to the basal Turonian. This pattern is positively correlated with the long-term decrease in detrital index as also observed in numerous other CT boundary sections (e.g., Eastbourne, Pueblo, and Whadi El Ghaib, Sinaï). Long-term phosphorus accumulation in the Gongzha section is therefore associated with changes in detrital input. The overall decreased detrital input can be explained by the increasingly remote continental sources due to the major transgression at the end of Cenomanian, coupled with changes in continental weathering intensity linked to increasingly more arid climate conditions. © 2012 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/69906
Appears in Collections: 过去全球变化的重建
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作者单位: Institut de Géologie et de Paléontologie, Université de Lausanne, Quartier Unil-Dorigny, Bâtiment Anthropole, CH-1015 Lausanne, Switzerland; Geology department, Aswan Faculty of Science, South Valley University, Aswan 81528, Egypt; Department of Geology, Federal University of Pernambuco, Cidade Universitária, 50.740-530, Recife - PE, Brazil; Institute of Geological Sciences, University of Bern, Baltzerstrasse 1-3, CH-3012 Bern, Switzerland; Institute of Sedimentology, Chengdu University of Technology, Erxianqiao, Chengdu 610059, Sichuan, China
Recommended Citation:
Bomou B.,Adatte T.,Tantawy A.A.,et al. The expression of the Cenomanian-Turonian oceanic anoxic event in Tibet[J]. Palaeogeography, Palaeoclimatology, Palaeoecology,2013-01-01,369