Heavy mineral assemblage of marine sediments as an indicator of provenance and east antarctic ice sheet fluctuations

Abstract

AbstractRecords of fluctuations of the East Antarctic Ice Sheet (EAIS) are best preserved in proximal marine sediments. The examined section is a part of a drillcore at Site U1359 of IODP (Integrated Oceanic Drilling Program) 318 located at the eastern levee of Jussieau submarine channel off the coast of Wilkes Land. Drillcore U1359 from 200 m below seafloor (mbsf) to 600 mbsf represents samples from Mid-Miocene to Late Miocene. Heavy media separation, characterization of heavy minerals and quantification of their population were carried out using scanning electron microscopy and electron microprobe analysis. Relative abundance of various minerals at different depths revealed that amphiboles and pyroxene show antipathic relationship at some depths. Multiple sources for supply of sediments at drillhole Site U1359 have been proposed with both magmatic and metamorphic minerals and rock fragments contributing clastic sediments. Factor analysis was carried out to test this inference. Six factors were obtained out of which the first three explain 76.6% of the variance. Relating variability of the factors to the provenance allows inference of four major ice advance phases during Mid to Late Micene which are largely positively correlatable with the global climate record.