Implications of quartz grain microtextures for onset Eocene/Oligocene Glaciation in Prydz Bay, ODP Site 1166, Antarctica

Kari Strand, Sandra Passchier, Jari Näsi

Research output: Contribution to journalArticle

59 Scopus citations

Abstract

This paper presents the results of the scanning electron microscopic (SEM) analysis of quartz grains from a selection of samples at Site 1166. Ocean Drilling Program Leg 188 drilled Site 1166 on the Prydz Bay continental shelf, Antarctica, to document onset and fluctuations of East-Antarctic glaciation. This site recovered Upper Pliocene-Holocene glacial sediments directly above Cretaceous through Lower Oligocene sediments recording the transition from preglacial to early glacial conditions. SEM analysis of quartz grains at Site 1166 was used to characterize the glacial and preglacial sediments by their diagnostic textures. Angular edges, edge abrasion as well as arcuate to straight steps, are the most frequent features in glacial deposits. The highest frequency of grains with round edges is present in Middle-Late Eocene fluvio-deltaic sands. However, angular outlines, fractured plates with subparallel linear fractures and edge abrasion indicating glacier influence are also present. Preglacial carbonaceous mudstone and laminated gray claystone show distinctive high relief quartz grains and some chemical weathering on grain surfaces. The results of the microtextural analysis of quartz grains are used to verify some critical periods of ice sheet evolution, such as the transition from the East Antarctic preglacial to glacial conditions on the continental shelf from Middle/Late Eocene to Late Eocene/Early Oligocene time.

Original languageEnglish
Pages (from-to)101-111
Number of pages11
JournalPalaeogeography, Palaeoclimatology, Palaeoecology
Volume198
Issue number1-2
DOIs
StatePublished - 15 Sep 2003

Keywords

  • Antarctica
  • Eocene/Oligocene glaciation
  • Glacial sedimentation
  • Ice sheet evolution
  • Quartz sand
  • Scanning electron microscope
  • Surface texture

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