Oxygen-isotope (δ18O) evidence of Holocene hydrological changes at Signy Island, maritime Antarctica

A record of Holocene hydrological changes has been produced from variations in oxygen-isotope composition (δ 18 O) preserved in freshwater lake sediments from maritime Antarctica. Small amounts (<5%) of authigenic carbonate have been extracted from a non-marl sediment core from Sombre Lake, Signy...

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Bibliographic Details
Published in:The Holocene
Main Authors: Noon, P. E., Leng, M. J., Jones, V. J.
Format: Article in Journal/Newspaper
Language:English
Published: SAGE Publications 2003
Subjects:
Paleontology
Earth-Surface Processes
Ecology
Archeology
Global and Planetary Change
Antarctic
Southern Ocean
Antarctic Peninsula
Weddell Sea
Weddell
Signy Island
Holo
Sombre Lake
Antarc*
Antarctica
Sea ice
Online Access:http://dx.doi.org/10.1191/0959683603hl611rp
http://journals.sagepub.com/doi/pdf/10.1191/0959683603hl611rp
Description
Summary:A record of Holocene hydrological changes has been produced from variations in oxygen-isotope composition (δ 18 O) preserved in freshwater lake sediments from maritime Antarctica. Small amounts (<5%) of authigenic carbonate have been extracted from a non-marl sediment core from Sombre Lake, Signy Island (60°43'S, 45°38'W). Oxygen-isotope and particle-size analysis provide a sensitive record of hydrological events in the lake arising from local and regional climate phenomena. The climate affects δ 18 O through snowpack volume and glacier activity in the catchment, lakewater temperatures, the input versus evaporation balance and the duration of seasonal lake ice cover. The most depleted (negative) δ 18 O values are associated with influxes of meltwater at times of glacier advance or retreat. Enriched (positive) δ 18 O values occur during more arid, warmer conditions with longer periods of open water in summer. This isotope record can be used to determine century-scale to decadal variability in air circulation and moisture origin. Strong similarities with other Holo cene proxy records from the Weddell Sea and Antarctic Peninsula Region are apparent, including the mid-Holocene climate optimum followed by the Neoglacial and, most recently, late twentieth-century climatic warming. The oxygen-isotope record from Sombre Lake illustrates the importance of remote islands in contribu ting to our understanding of teleconnections in atmospheric and oceanographic circulation, sea-ice extent, air temperatures and precipitation in the Southern Ocean.

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