Isotope Geochemistry of Volcanic Rocks from the Barton Peninsula, King George Island, Antarctica

• Published in: Journal of earth science (Wuhan, China) China), 2011-02, Vol.22 (1), p.40-51
• Main Authors: Hwang, Jeong, Zheng, Xiangshen, Ripley, Edward M., Lee, Jong-Ik, Shin, Dongbok
• Format: Article
• Language: English
• Subjects: Alterations; Antarctica; Basalt; Biogeosciences; Calcite; Earth and Environmental Science; Earth science; Earth Sciences; Eocene; Fractionation; Geochemistry; Geology; Geotechnical Engineering & Applied Earth Sciences; High temperature; Islands; Isotopes; Magma; Paleocene; Peninsulas; Rocks; Sulfides; Sulfur; Volcanic rocks; Volcanoes; Water temperature; 乔治王岛; 南极; 同位素地球化学; 巴顿; 洋中脊玄武岩; 火山岩; 硫同位素组成; 蚀变作用
• ISSN: 1674-487X; 1867-111X
• DOI: 10.1007/s12583-011-0156-y

C, O, H, S and Sr isotopes were investigated to characterize the isotopic composition of the Paleocene-Eocene volcanic rocks in Barton Peninsula, King George Island, Antarctica. The analyzed samples of volcanic rocks cover a range from basalt to andesite. The δ 13C and 61SO values of calcite in volcanic rocks range from -7.5‰ to -3.2‰ and 0.4‰ to 5.1‰, respectively. The homogenous δ 13C cal and depleted δ18 Ccal values relative to primary magmatic values reflect the effect of high temperature alteration of volcanic rocks. The δ18 O of volcanic rocks ranges from -1.1‰ to 7.2‰, and the majority of values are significantly lower than those of primary magmatic values. The low δ18 O WR values are compatible with high temperature alteration. The initial values of 87Sr/86Sr of volcanic rocks span a narrow range from 0.703 312 to 0.703 504 which belong to the present mid-oceanic ridge basalt. The values of 87Sr/86Sr of volcanics in the Barton Peninsula are similar to those determined in the Fildes Peninsula, King George Island. The δD WR and H2O contents of volcanic rocks range from -74‰ to -66‰ and 0.67 wt.% to 2.74 wt.%, respectively. The higher δD WR and H2O wt.% of volcanic rocks relative to fresh basalts also result from high temperature alteration. Sulfur isotope compositions of the volcanic rocks range from -12.5‰ to -7.0‰; these values may represent fractionation accompanying partial oxidation of magmatic S or incorporation of some bacteriogenic sulfide. The low S contents and negative correlation with C and H2O reflect the formation of calcite and breakdown of sulfide as a result of high temperature water-rock interaction.