USING REWORKED FORAMINIFERA AS AN INDICATOR OF LATE HOLOCENE CLIMATE CHANGE ON THE ANTARCTIC PENINSULA MARGIN

Sediment core NBP10-01 JKC-62 collected from the margin of James Ross Island (JRI), northern Weddell Sea during cruise NBP10-01 of the RVIB Nathaniel B. Palmer was analyzed for benthic foraminifera to reconstruct environmental and glacial conditions through the late Holocene. Two lithologic units were identified; Unit 1 was comprised of sand to gravel size sediments while Unit 2 was comprised of silty-clay sized sediments. Benthic foraminiferal analysis of the core reveals two major environmental changes corresponding to biofacies. The lowermost biofacies (40 cm to 320 cm) is characterized by the rapid decrease in abundance of Nonionella iridea and increase in abundance of Globocassidulina subglobosa, which indicates ice shelf and sea ice formation. The uppermost biofacies (0 cm to 40 cm) is dominated by reworked Cretaceous foraminifera identified as Bolivina incrassata. The occurrence of the reworked Cretaceous foraminifera suggests significant erosion of Cretaceous sediments off of James Ross Island by Swift Glacier into the adjacent marine environment, which coincides with a record of late Holocene warming interpreted from the JRI ice core (Mulvaney et al, 2013).