Chinese Journal of Polar Research

ADVANCES IN POLAR SCIENCE ›› 1993, Vol. 4 ›› Issue (1-English): 12-25.

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CHARACTERISTICS OF Nd AND Sr ISOTOPES AND TRACE ELEMENTS FOR LATE CRETAEOUS VOLCANIC ROCKS IN KING GEORGE ISLAND, ANTARCTICA: IMPLI- CATIONS FOR SOURCE OF THE VOLCANICS FROM DEPLETED MANTLE

 Wang Yinxi1, Shen Yanbin2 and Yang Jiedong1   

  1. 1Modern Analytical Center, Nanjing University, Nanjing 210008, China 2Nanjing Institute of Geology and Palaeontology, Academia Sinica, Nanjing 210008, China
  • Online:1943-03-30 Published:1943-03-30
  • Contact: Wang Yinxi
  • Supported by:

    The project supported by the State Antarctic Committee and the National Natural Science Foundation of China.

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Abstract:

Rb-Sr isotopic isochron dating of the volcanic rock samples from the Upper Cretaceous Half Three Point Formation on the King George Island is 71.33±0.3 Ma. Correlative study of εND(T)-147Sm/144Nd, 143Nd/144Nd-87Sr/86Sr, 87Sr/86Sr-Sr and 87Sr/86Sr-K2O/(K2O+Na2O) indicated that the volcanic rocks were chiefly derived from the depleted mantle source and generally were not mixed crust materials. Of the samples 6 were given the mean Sm-Nd model age (TDMNd) of 443.3±20.6 Ma possibly indicating the age of chemical variation event in the magma source of the study area. Features of the trace elements indicated that the rocks from the Half Three Point Formation are of typical eale-alkaline volcanic suite and similar to those from the Tertiary volcanic rocks of the Fildes Peninsula, being the same products of the island-arc volcanic activity.

Key words: Late Cretaceous Rb-Sr dating, Nd-Sr isotopes, trace elements, petrgenesis