Chinese Journal of Polar Research

ADVANCES IN POLAR SCIENCE ›› 1997, Vol. 8 ›› Issue (2-English): 89-95.

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New 40Ar/39Ar age evidence for the Cretaceous volcanic rocks of the Mount Bowles Formation in Livingston Island, South Shetland Islands

 Zheng Xiangshen1, Hu Shiling1, Liu Jiaqi1 and Francesc Sàbat2   

  1. 1Institute of Geology, Chinese Academy of Sciences, Beijing 100029, China 2Universitat de Barcelona, Facultat de Geologia, 08028 Barcelona, Spain
  • Online:1947-06-30 Published:1947-06-30
  • Contact: Zheng Xiangshen
  • Supported by:

    This project is supported by National Natural Science Foundation of China (No. 49673176) and the National Science & Technology Committee of China (85-03-04) and Chinese Academy of Sciences (KJ85-08-03).

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Abstract:

The age of the volcanic rocks of the Mount Bowles Formation (MBF) on the eastern part of Livingston Island, South Shetland Islands, Antarctica is redetermined by using 40Ar/39Ar and laser microarea isochron age dating method with a continuous laser system and mass spectrometer. The isochron ages of an andesite sample and a basaltic andesite sample are (105.62±2.11) Ma and (111.48±2.23) Ma with the 40Ar/39Ar initial ratios of 295.3 and 294.6 respectively, being almost the same as the atmospheric value, which proves that there exists no excess argon in these rocks. The 40Ar/39Ar plateau age of an aplite sample is (96.7±1.6) Ma and the calculated isochron age is 96.6 Ma, which indicates that the aplite occurred after lava eruption. These data suggest that the MBF volcanic rocks were formed during Cretaceous.

Key words: Mount Bowles Formation, 40Ar/39Ar age dating, Livingston Island, Antarctica