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Abstract

Thin coal seams found in the Lions Cove Formation, Polonia Glacier Group (Middle Eocene, upper part) at King George Bay, King George Island (South Shetland Islands, West Antarctica), represent lustrous (vitrine) brown-coal metaphase. The coal from the lower seam represents carbonized wood, probably angiosperm, that from the upper ones originated due to accumulation of branches or larger wood fragments and leaf remains. These coals are slightly older than metaxylite brown coal previously described from Admiralty Bay on King George Island, and dated at Eocene-Oligocene boundary. Both coal occurrences are evidences for a warm climate which prevailed in the Antarctic Peninsula sector during the Arctowski Interglacial (ca 50—32 Ma).
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Abstract

Anthracite coal matter fills irregular voids in dolostones of the Upper Proterozoic Höferpynten Formation in the Hornsund area, south Spitsbergen. The coals are of organic origin, as indicated by a variety of coal-petrographic studies, and by association with algal structures. They probably derived from bitumina accumulated in voids of dolostone at an early diagenelic stage. The degree of coalification (graphitization) is high but diversified, suggesting several coalification stages, probably related t o successive metamorphic events. The oldest changes may correspond to initial stage of t h e greenschist-amphibolite phase of regional metamorphism, with temperatures of over 500°C and pressure of over 20,000 MPa . Multiphase graphite crystallites which occur in t h e coal are mainly fibrous. There are also crystallites which precipitated from gaseous phase, and pyrolitic graphite; they may have originated due to action of mesothermal solutions which had produced ore-bearing veins.
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