Analyses of hydrocarbon gases and sulphate in sediments from the King George Basin, Antarctica ...

• Main Authors: Whiticar, Michael J, Suess, Erwin
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 1990
• Subjects: Geological sample; Gravity corer Kiel type; ANT-IV/2; Polarstern; Antarc*; Antarctica; Bransfield Strait
• Online Access: https://dx.doi.org/10.1594/pangaea.707463; https://doi.pangaea.de/10.1594/PANGAEA.707463

Thermogenic hydrocarbons, formed by the thermal alteration of organic matter, are encountered in several piston core stations in the King George Basin, Anatarctica. These hemipelagic sediments are being deposited in an area of active hydrothermalism, associated with the back-arc spreading in the Bransfield Strait. The lateral extent of sediments infiltrated by the hydrothermally influenced interstitial fluids is characterized by basalt diapiric intrusions and is delineated by an acoustically turbid zone in the sediments of the eastern part of the basin. Iron-sulphide-bearing veins and fractures cut across the sediment in several cores; they appear to be conduits for flow of hydrothermally altered fluids. These zones have the highest C2+ and ethene contents. The thermogenic hydrocarbons have molecular C1/(C2 + C3) ratios typically < 50 and delta13CH4 values between -38‰ and -48‰, indicating an organic source which has undergone strong thermal stress. Several sediment cores also have mixed gas signatures, ... : Supplement to: Whiticar, Michael J; Suess, Erwin (1990): Hydrothermal hydrocarbon gases in the sediments of King George Basin, Bransfield Strait, Antarctica. Applied Geochemistry, 5(1-2), 135-147 ...