Proposed drill site near the Ross-Amundsen ice divide, West Antarctica
Describes conditions near the Ross-Amundsen ice divide, and discusses candidate drill sites in context of the science objectives outlined in the lead proposal for the project. We identify a preferred site for the Western Divide Core (WDC).
To ... summarize: - A suite of short (~100m) ice cores extracted during ITASE traverses in central West Antarctica all show very well preserved records of seasonal chemistry and recent global-scale volcanic eruptions. - Sites near the divide with thick ice and moderate accumulation are most likely to satisfy the science requirements. - We make use of available geochemical and geophysical data and ice-flow models to identify a preferred drill site that is 24 km southwest of the present-day ice divide. Radar-detected internal stratigraphy upstream from the site is smoothly varying. The combination of thick ice (3465m) and moderate accumulation (21.5 cm/yr ice equivalent) at the site should produce a core with stratigraphy that can be resolved annually back to ~44ka BP. Age at 96% depth (3325m) is expected to be ~112ka BP. - Co-ordinates for the site are 79.4676 S, 112.0859W, but sites within a kilometer of this location will likely have equivalent characteristics.
Ice thickness and internal layer depth data were collected with a ground-based, ice-penetrating radar study as part of the U.S. International Trans-Antarctic Science Expedition (US-ITASE) traverse in West Antarctica from 01 November 2001 to 10 January 2003.
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