A Late Pleistocene Record of Highstand Shedding and Dust Flux from the Inner Sea of the Maldives: Si...

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" A Late Pleistocene Record of Highstand Shedding and Dust Flux from the Inner Sea of the Maldives: Site U1467, Iodp 359 "
Mohammadi, Obeyd Guo, Junhua

Document Type	:	Latin Dissertation
Language of Document	:	English
Record Number	:	1053442
Doc. No	:	TL52559
Main Entry	:	Mohammadi, Obeyd
Title & Author	:	A Late Pleistocene Record of Highstand Shedding and Dust Flux from the Inner Sea of the Maldives: Site U1467, Iodp 359\ Mohammadi, ObeydGuo, Junhua
College	:	California State University, Bakersfield
Date	:	2020
Degree	:	M.S.
student score	:	2020
Note	:	109 p.
Abstract	:	The Inner Sea of the Maldives is an isolated basin in the Indo-Pacific with significant archival potential for climate-driven sedimentation. In this study, high-resolution bulk sediment data of drift deposits from basinal Site U1467B of Expedition 359 of the International Ocean Discovery Program were profiled via powder X-ray diffraction and energy dispersive X-ray fluorescence methods for their mineralogical composition and isotopic characteristics. Time-frequency analysis of the machine-derived results (241 samples) reveal an orbitally-paced cyclical character to the relative abundance of strontinum-enriched aragonite and aluminium-normalised terrestrial proxies over a core encompassing the past 2 ma (<80 mbsf). Preserved peak intensity oscillations between high points in shallow-water carbonate components (aragonite and strontium) and background pelagic rain (low-magnesian calcite) are in turn a mineralogical reflection of sea-level driven modal changes to the available accommodation space at the locus of carbonate precipitation: the carbonate platform top and slope. The variability expressed within the interpreted terrestrial molar ratios (E/Al) appears to correspond to the rise and fall of regional-scale continental aridity (India and Asia) and winter wind vigour (South Asian monsoon). As in the Arabian Sea, both local carbonate variability and regional dust flux exhibit the mode switch characteristic of the mid Pleistocene Revolution. Taken together, these signals construct the necessary context through which the varied and mixed carbonate-siliciclastic development history of the Maldives can be grasped in simple relative terms and in turn subsumed within an insolation-driven inflow model with corresponding implications for the broader history of the Western Indo-Pacific realm.
Descriptor	:	Geochemistry
	:	Paleoclimate science
	:	Sedimentary geology
Added Entry	:	Guo, Junhua
Added Entry	:	California State University, Bakersfield