Glacial-interglacial climatic variations at the Schirmacher Oasis, East Antarctica: The first report from environmental magnetism

Anish Kumar Warrier, B. S. Mahesh, Rahul Mohan, Rajasekhariah Shankar, Rajesh Asthana, Rasik Ravindra

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Abstract

We discuss in this paper the first detailed environmental magnetic record of glacial-interglacial climatic variations in the Schirmacher Oasis, East Antarctica. We determined environmental magnetic properties and inter-parametric ratios (χlf, χfd %, χARM, SIRM, χARM/SIRM, χARMlf, χARMfd, SIRM/χlf, S-ratio and HIRM) for sediment samples of a core from the Sandy Lake. Accelerator mass spectrometer (AMS) 14C dates were obtained on the organic matter from bulk sediment samples. The sediment core spans the past ~42.5cal. ka B.P. The magnetic minerals are mainly detrital and catchment-derived, as there is no evidence for the presence of authigenic greigite, bacterial magnetite or diagenetic dissolution. The last glacial period is characterized by a high concentration of ferrimagnetic minerals such as titanomagnetite (high values of χlf, SIRM etc.) and coarse magnetic grain size (low χARM/SIRM and χARMlf values and high S-ratio values). Deglaciation in the Schirmacher Oasis began around 21cal. ka B.P. as suggested by the low magnetic mineral concentration. The Holocene period is characterized by relatively warm climatic events as seen in the low values of magnetic susceptibility which is primarily contributed by fine-grained titanomagnetite resulting from pedogenesis (high χfd % values). Several of the relatively warm and cold events that we deciphered from the environmental magnetic data are correlatable with lake sediments from the Schirmacher Oasis and other ice-free areas in East Antarctica and from ice-core records on the Antarctic Plateau.

Original languageEnglish
Pages (from-to)249-260
Number of pages12
JournalPalaeogeography, Palaeoclimatology, Palaeoecology
Volume412
DOIs
Publication statusPublished - 05-10-2014

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All Science Journal Classification (ASJC) codes

  • Oceanography
  • Ecology, Evolution, Behavior and Systematics
  • Earth-Surface Processes
  • Palaeontology

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