Deep Ocean Circulation Changes During the Mid-Pleistocene Transition ...

• Main Author: Symes, Emily
• Format: Thesis
• Language: English
• Published: University of Delaware 2023
• Subjects: Southern Ocean; Pacific
• Online Access: https://dx.doi.org/10.58088/3228-ma46; https://udspace.udel.edu/handle/19716/33505

The Mid-Pleistocene Transition (MPT), occurring between ~1250 to 700 Ka (1.25 to 0.7 Ma) marks a fundamental change in Earth’s climate system when the glacial cyclicity of Earth changed from 41 to 100 Kyr. This observed change cannot be explained due to variations in solar insolation only suggesting changing internal climate dynamics might have driven the transition. The South Pacific represents the largest fraction of the Southern Ocean and hence an important target region for studying internal climate dynamics during the MPT. Here, we use sediment core U1541 (54˚13’S, 125˚25’W, 3604 m) collected during the International Ocean Discovery Program (IODP) Expedition 383 to investigate changes in deep ocean circulation and the role of these changes played in solidifying the conditions of the MPT. In this thesis, we present an authigenic Nd isotope (expressed as Nd) time series from Site U1541 from 1500 – 500 ka. Nd shifts can be interpreted as tracking changes in the mixing proportions of two water mass end ...