Late Pliocene to early Pleistocene millennial-scale climate fluctuations and sea-level variability: A view from the tropical Pacific and the North Atlantic
In light of the need for high-fidelity, quantitative projections of future climate change, it is mandatory to understand climate variability at timescales that do justice to the tempo of anthropogenic climate change (i.e., sub-millennial). At the same time, information on the lower-frequency (i.e.,...
| Main Author: | |
|---|---|
| Format: | Doctoral or Postdoctoral Thesis |
| Language: | English |
| Published: |
2017
|
| Subjects: | |
| Online Access: | https://archiv.ub.uni-heidelberg.de/volltextserver/22942/ https://archiv.ub.uni-heidelberg.de/volltextserver/22942/1/DissKJ_10mb.pdf https://doi.org/10.11588/heidok.00022942 https://nbn-resolving.org/urn:nbn:de:bsz:16-heidok-229425 |
| Summary: | In light of the need for high-fidelity, quantitative projections of future climate change, it is mandatory to understand climate variability at timescales that do justice to the tempo of anthropogenic climate change (i.e., sub-millennial). At the same time, information on the lower-frequency (i.e., orbital-scale) baseline characteristics of climate change underlying the short-term variability is required for a full mechanistic understanding. Such information can be obtained from time intervals of Earth’s history that comprise climatic boundary conditions as they are to be encountered in the near future. In this context, this thesis aims to contribute toward accurately deciphering past climate fluctuations and sea-level variability on glacial-interglacial (G-IG) to (sub-)millennial timescales during past times of “near-modern” paleogeography and warmer-than-present climatic boundary conditions – the late Pliocene to early Pleistocene (~2.75–2.4 million years ago [Ma], Marine Isotope Stages [MIS] G6–95). This time period falls within the transition from a warmer Pliocene climate without larger-scale Northern Hemisphere ice sheets to a progressively cooler Pleistocene climate dominated by a stronger response of the climate/cryosphere system to orbital forcing, widely being termed “intensification of Northern Hemisphere Glaciation” (iNHG). The target interval includes MIS 100 through 96, three large-amplitude G-IG cycles (~1‰ in benthic δ18O) that represent the culmination of iNHG. The first part of this thesis focuses on identifying the mechanisms that regulated G-IG primary productivity changes in the Eastern Equatorial Pacific (EEP) upwelling system, which constitutes an important component of the Earth’s atmospheric and marine carbon budget. For this purpose, high-resolution carbon isotopes from benthic and planktic foraminiferal calcite, and sand-accumulation rates have been investigated for the time interval between ~2.65 and 2.4 Ma (MIS G1–95) at Ocean Drilling Program (ODP) Site 849, which is located in the ... |
|---|