Sedimentology of lower Pliocene to Upper Pleistocene diamictons from IODP Site U1358, Wilkes Land margin, and implications for East Antarctic Ice Sheet dynamics

• Main Authors: Orejola, Nadine, Passchier, Sandra, Brinkhuis, Hendrik, Escutia Dotti, Carlota, Klaus, Adam, Fehr, Annick, Williams, Trevor, Bendle, James AP, Bijl, Peter K, Bohaty, Steven M, Carr, Stephanie A, Dunbar, Robert B, Flores, Jose-Abel, Gonzalez, Jhon J, Hayden, Travis G, Iwai, Masao, Jimenez-Espejo, Francisco J, Katsuki, Kota, Kong, Gee Soo, McKay, Robert M, Nakai, Mutsumi, Olney, Matthew P, Pekar, Stephen F, Pross, Joerg, Riesselman, Christina, Roehl, Ursula, Sakai, Toyosaburo, Shrivastava, Prakash Kumar, Stickley, Catherine E, Sugisaki, Saiko, Tauxe, Lisa, Tuo, Shouting, van de Flierdt, Tina, Welsh, Kevin, Yamane, Masako, Scientists, Iodp Expedition 318
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: eScholarship, University of California 2014
• Subjects: continental shelf; geochemistry; heavy minerals; particle size; provenance; Marine Biology & Hydrobiology; Environmental Sciences; Biological Sciences; Earth Sciences; Antarctic; East Antarctic Ice Sheet; Mertz Glacier; Victoria Land; Wilkes Land; Wilkes Subglacial Basin; Antarc*; Antarctic Science; Ice Sheet; Iceberg*
• Online Access: https://escholarship.org/uc/item/9953d634

AbstractDuring the early Pliocene a dynamic marine-based ice sheet retreated from the Wilkes Land margin with periodic ice advances beyond Last Glacial Maximum position. A change in sand provenance is indicative of a more stable Mertz Glacier system during the Late Pleistocene. East Antarctic Ice Sheet (EAIS) dynamics were evaluated through the analysis of marine diamictons from Integrated Ocean Drilling Program (IODP) site U1358 on the Adélie Land continental shelf. The warmer than present conditions of the early Pliocene coupled with the site's proximity to the landward sloping Wilkes Subglacial Basin provided the rationale for the investigations at this site. Based on visual core descriptions, particle size distributions, and major and trace element ratios, we interpret the origin of lower Pliocene strata by intermittent glaciomarine sedimentation with open-marine conditions and extensive glacial advances to the outer shelf. Heavy mineral analyses show that sand-sized detritus in the lower Pliocene strata was sourced from local intermediate to high-grade metamorphic rocks near Mertz Glacier. In contrast, Pleistocene diamictons exhibit a larger contribution from a prehnite-pumpellyite greenschist facies suggesting supply via iceberg rafting from northern Victoria Land. From this sedimentological evidence, we postulate a shift from a dynamic EAIS margin in the early Pliocene to possible stabilization in the Pleistocene.