Journal of Geological Society of India (Online archive from Vol 1 to Vol 78)

Meloth Thamban ¹, C. M. Laluraj ¹, Sushant S. Naik ¹, Arun Chaturvedi ²

Affiliations
1 National Centre for Antarctic and Ocean Research, Headland Sada, Vasco-da-Gama, Goa - 403 004, IN
2 Geological Survey of India (Antarctica Division) NH-5P, N.I.T., Faridabad - 121001, IN

Abstract

Antarctic ice core records have provided unprecedented information on past climatic changes and forcing factors on decadal to millennial timescales. The glaciochemical and stable isotope records of a shallow ice core from the coastal Dronning Maud Land (East Antarctica) were used here to reconstruct the coastal Antarctic environmental variability during the past ~470 years. Sea salt ion data indicate a significant additional contribution of chloride ions compared to sea water values, possibly through atmospheric scavenging. The nitrate (NO₃ ^-) profile exhibit significant temporal shifts than that of the sulphate (SO₄ ^2-), with a major shift around 1750 AD. The changes in NO₃ ^- record are synchronous with the proxy record of solar activity ( ¹⁰Be profile from a South Pole ice core), suggesting enhanced NO₃ ^- values during periods of reduced solar activity like the Dalton Minimum (~1790-1830 AD) and Maunder Minimum (~1640- 1710 AD). The δ¹⁸O records reveal that the more negative V values were coeval with several events of increased NO₃ ^- concentrations, suggesting enhanced preservation of NO₃ ^- during periods of reduced air temperatures. The δ¹⁸O and δD records of the core also suggest significant short-term and long-tem variability with more negative values indicating relatively lower air temperatures prior to 1715 AD. The δ¹⁸O records also revealed a significant warming of 2.7°C for the past 470 years, with a warming of ~0.6°C per century.

Keywords

Glaciochemistry, Stable Isotope, Ice Core, Solar Activity, Dronning Maud Land, Antarctica.

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