Investigating the influence of sea surface temperatures on southeastern African hydroclimate during the Mid-Pleistocene Transition
Abstract
There are large gaps in our understanding of what is potentially driving hydroclimate variability in eastern Africa during the Mid-Pleistocene Transition (MPT). The MPT is a particularly interesting time in Earth's history, showing a change in glacial-interglacial variability from mostly symmetrical cycles with a period of 41,000 years, to asymmetric cycles of 100,000 years. Existing records in eastern Africa show conflicting trends in aridity, and support different regional climate drivers.
To examine the potential influence of western Indian Ocean sea surface temperatures (SSTs) on tropical eastern African hydroclimate at the MPT, we investigate marine and terrestrial organic geochemical biomarkers from International Ocean Discovery Program (IODP) Expedition 361 Site U1476 sediment cores, located on the Davie Ridge in the Mozambique Channel. Alkenones, long-chain ketones produced by surface-dwelling marine phytoplankton, are a well-established proxy for inferring past SSTs. Terrestrial leaf wax δ2H values are correlated to precipitation δ2H values, and can be used to infer past changes in hydroclimate. Furthermore, leaf wax δ2H values have shown a linear relationship with the amount of rainfall in the tropics, allowing the use of leaf wax δ2H values to track the amount affect at Site U1476. We will present new records of alkenones for sea surface temperatures (SSTs) and long chain n-alkanoic acid hydrogen isotopes for terrestrial hydroclimate from ~1.5 - 0.5 Ma to evaluate the potential role western Indian Ocean SSTs may have played in shaping continental hydroclimate in this region during a significant global climate interval.- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2022
- Bibcode:
- 2022AGUFMPP22C0856H