A north-southward expansion of sea surface temperature in the Indo-Pacific Warm Pool during Marine Isotope Stage 11: preliminary study Adnya Pratiwi (a*), Rima Rachmayani (b), Mutiara Putri (b)
a) Earth Science Study Program, Faculty of Earth Science and Technology, Institut Teknologi Bandung, Bandung, Indonesia
*32422301[at]mahasiswa.itb.ac.id
b) Environmental and Applied Oceanography Research Group, Faculty of Earth Sciences and Technology, Institut Teknologi Bandung, Bandung, Indonesia
Abstract
Marine Isotope Stage (MIS) 11 is a period of long interglacial that happened around 400,000 years ago. Studies have shown that the level of CO2 during the peak of this period is closer to pre-industrial CO2 gases level which leads to the consideration of MIS 11 as one of the analogues of current interglacial. Study on this period therefore allows us to have an illustration about the becoming of the current interglacial. Indo-Pacific Warm Pool (IPWP) that is located in the heart of Maritime Continent (MC) is the largest body of warm water that has a role in the global climate circulation. Its spatial sea surface temperature (SST) variability is often associated to seasonal variation of Inter-Tropical Convergence Zone (ITCZ) position, El-Nino Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) cycle in inter-annual timescale. Recent study on land terraces shows that Sunda Shelf region was under subsidence condition with a rate between 0.2 - 0.3 mm.yr-1 which then leads to possibility of an emerged Sundaland (a biogeographic region that connects Malay Peninsula, Sumatra, Java, and Borneo Island) during MIS 11 period. IPWP SST response to this change is still unknown. Therefore, in this study, we aim to study the SST spatial distribution in the IPWP during the MIS 11 by comparing published d18O and Mg/Ca data from foraminifera core samples located in the South China Sea region and off the coast of north-west Australia. By comparing proxies data in this region, we aim to investigate the changes of northern and southern IPWP bordure which is characterized by 28 degC isotherm during MIS 11. We hypothesize that this 28 degC isotherm is in a higher latitude during MIS 11 than during MIS 1 in South China Sea and north-west coast of Australia, due to the emerged Sundaland during MIS 11 period that blockade the surface warm water from the Pacific Equatorial to Indian Ocean.
