Date of Award

8-2020

Document Type

Thesis

Degree Name

Master of Science (MS)

College/School

College of Science and Mathematics

Department/Program

Earth and Environmental Studies

Thesis Sponsor/Dissertation Chair/Project Chair

Ying Cui

Committee Member

Sandra Passchier

Committee Member

Matthew Gorring

Subject(s)

Geology, Stratigraphic--Eocene

Abstract

The Early Eocene hyperthermals are a series of transient global warming events that occurred between 54.09 and 52.63 Ma, and are considered as ancient analogues for future climate change. These hyperthermal events are well studied in the deep sea sites, but have not been investigated in the eastern Tethys Ocean. Here, we report new major and trace element geochemistry and stable carbon isotope data of the Early Eocene strata deposited in a shallow marine foreland basin prior to the main stage of India-Asian continent collision at Qumiba section in the Tingri County, southern Tibet. These geochemical data are used to reconstruct the paleoenvironment and past carbon cycle dynamics in the Early Eocene. The collision of India with Asia continent led to the formation of the Himalayas and the demise of the Tethys Ocean. This tectonic event played a significant role in the paleotopography, paleoceanography and paleoclimate of the southeastern Tethys. The youngest marine sediments (Enba Formation and Zhaguo Formation) represent the closure of the Tethys Ocean, and suggest an age of 53.67 to 52.63 Ma. Major element geochemistry and weathering indices indicate that the Eocene southeastern Tethys may have experienced periodic pulses of nutrient-rich detrital sediments, weathering supplies and the development of hypoxia in the water column, consistent with the warm and humid climate in the Early Eocene.

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