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dc.rights.licenseCC-BY-NC-ND
dc.contributor.advisorReichart, G.J.
dc.contributor.advisorBrummer, G.J.
dc.contributor.advisorDe Nooijer, L.
dc.contributor.advisorTjallingii, R.
dc.contributor.authorRammos, I.
dc.date.accessioned2011-07-25T17:04:59Z
dc.date.available2011-07-25
dc.date.available2011-07-25T17:04:59Z
dc.date.issued2011
dc.identifier.urihttps://studenttheses.uu.nl/handle/20.500.12932/7632
dc.description.abstractThe Asian Monsoon system influences to a great extent the weather of the tropics and subtropics of the eastern hemisphere. Dominant factors that determine the strength of the monsoon are sea surface temperature (SST) and related heat transport across the equator. Since the tropical monsoon causes intra-annual variability in SST, reconstructing the short-term variability in seawater temperature and cross-equatorial heat transport is the only way to understand the development of the monsoon system over time. The objective of this study is to compare well-known sediment records of the Northern Arabian Sea with the low-latitude Indian Ocean in terms of sediment supply and heat transport during the last glacial-interglacial. Sea surface temperatures (SST) and intra-annual temperature variations can be reconstructed from δ18O and Mg/Ca of planktic foraminifera. Comparison of the foraminifera-based SST reconstructions of core INATEX-08 with SST reconstructions from the Northern Arabian Sea allows for a detailed reconstruction of glacial-interglacial evolution in heat transfer across the Arabian Sea. The agemodel of INATEX-08 is constructed using stable oxygen isotopes of the calcite of G. sacculifer and the disappearance of Pink G.ruber. All δ18O records were correlated to the composite benthic δ18O record of Martrat et al., 2007 from the Iberian margin, which enables a good correlation between Southern and Northern cores. Temperature reconstructions of INATEX-08 are based on calcite chemistry of single foraminiferal shells of G. ruber. Individual size and weight analyses are performed to test variability of size-normalized weights over time. From the same specimens, Mg/Ca is determined to establish variability in sea surface temperatures. Results are compared to other temperature reconstructions based on 1) the use of similar proxies in different cores and 2) the use of other proxies applied to these cores (Uk37 and TEX86). Detailed variations of sediment composition in INATEX-08 were acquired non-destructively by XRF scanning, showing: 1) Strongly reduced lithogenic concentrations during MIS 6 and slightly reduced concentrations during MIS 4 and the LGM, 2) The last deglacial (around 12kyrs) shows the strongest increase in lithogenic material and highest lithogenic concentrations, 3) Zr/Rb ratios show a strong increase of the coarse-grained lithogenic fraction during the deglacial (12Kyrs) and 4) The high Zr/Rb ratios during the LGM, MIS 4 and MIS 6 suggest a reduction of the lithogenic sand fraction during glacial periods. A comparison between SST proxies applied to cores from the Southern and Northern Arabian Sea shows that 1) the difference between LGM and Holocene is similar for all cores with a slightly larger difference for INATEX-08 and colder temperatures for NIOP 478, 2) TEX86-based temperature reconstructions result in the largest difference, with warmer average temperature during the interglacial compared to the other proxies, and colder average temperature during the glacial, 3) Mg/Ca-based reconstructions reveal that SST ranges of the Holocene become larger as one moves from the South to the North with the temperature range for NIOP 478 being the largest, 4) TEX86 results in higher SST values than obtained using Mg/Ca and Uk37.
dc.description.sponsorshipUtrecht University
dc.format.extent2839236 bytes
dc.format.mimetypeapplication/pdf
dc.language.isoen
dc.titleOcean-based heat transfer across the equator in the Arabian Sea over Glacial and Interglacial transitions
dc.type.contentMaster Thesis
dc.rights.accessrightsOpen Access
dc.subject.keywordsArabian Sea, Temperature proxies, XRF scanning, Equatorial heat exchange, Laser ablation ICP-MS
dc.subject.courseuuGeology


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