TRACE ELEMENTAL GEOCHEMISTRY OF BENTHIC FORAMINIFERA LIVING ON THE AUSTRALIAN MARGIN

As part of a larger project to generate high resolution records of sea surface temperature changes that have occurred offshore southern and eastern Australia over the last two millennia, multicore samples were taken to obtain modern analog data from water depths ranging from ~500 to ~1020m. Benthic foraminifera from the top 2cm of sediment cores were picked and analyzed for trace elemental composition with a laser ablation ICP-MS at the Australian National University, avoiding contamination and allowing measurements of recently generated chambers. A variety of living (Rose Bengal stained) epifaunal and infaunal species were chosen for analysis (e.g., Cibicidoides wuellerstorfi, Uvigerina peregrina, Uvigerina hispidula, Pullena bulloides, Globocassidulina subglobosa, Chilostomella oolina, and Melonis sp.) to compare surface and subsurface species. Analysis of benthic foraminiferal Mg/Ca ratios can provides insights and calibration data to investigate bottom water temperature along a relatively unexplored region of the deep-sea. Additional trace elemental ratios (e.g., Sr/Ca, Mn/Ca, Cd/Ca, B/Ca, and Ba/Ca) were comparing between living (stained) specimens from the same sediment depths to assess vital effect and compare epifaunal with infaunal taxa.