Non-climate influences on stable isotopes at Taylor Mouth, Antarctica

TLDR: In this article, the late-Holocene trends in δ 18 O differ significantly in two ice cores (30 km apart) from the area of Taylor Dome, Antarctica, and the authors assess two leading possible causes for the observed differences: (1) Relative to Taylor Mouth, Taylor Mouth may collect snow from more sources with distinct isotopic compositions.

Abstract: The late-Holocene trends in δ 18 O differ significantly in two ice cores (30 km apart) from the area of Taylor Dome, Antarctica. It is unlikely that the trend in the core from Taylor Mouth (the flank site) is due to a standard δ 18 O-surface temperature relationship. Assuming that the Taylor Dome (near-summit) core records local climate variations common to both cores, we assess two leading possible causes for the observed differences: (1) Relative to Taylor Dome, Taylor Mouth may collect snow from more sources with distinct isotopic compositions. (2) Vapor motion during prolonged near-surface exposure may cause post-depositional isotope enrichment at Taylor Mouth, where the accumulation rate is low. Our model of firn pore-space vapor and sublimating ice grains suggests that post-depositional processes can modify δ 18 O values by several %o. Isotopic samples from areas with significantly different accumulation rates near Taylor Mouth could differentiate between possibilities (1) and (2).