Coeval granitic magmatism in the southern segment of the Liupanshan at the SW margin of the NCC: Implications for Paleoproterozoic extension

  • Author(s): Huan Xu, Jin-Hai Luo, Jia You, Yi-Fei Li, and Guan-Xu Chen
  • DOI: 10.3319/TAO.2017.03.14.01
  • Keywords: North China Craton, Liupanshan fault system, Paleoproterozoic, A-type granite, Helan aulacogen
  • The Liupanshan granitoid zone formed during the Paleoproterozoic
  • The Paleoproterozoic granites were characterized by A-type granite
  • The granites are related to extension within the Helan aulacogen

The ages of the Shizuizi, Baojiashan and Duanjiaxia granites are poorly con­strained. They are exposed along the southern segment of the Liupanshan fault sys­tem at the southwestern margin of the North China Craton. They form a NW-trending belt of coeval A-type granitic magmatism, characterized by high Si, alkalis, Rb/Sr, and Ga/Al. Their trace element characteristics include relative enrichments in K, Rb, and Th, and depletions in Ti, Ta, Nb, P, and Sr. Zircons from the granite yield U-Pb age of 1738 ± 15 Ma for the Baojiashan granite which has similar zircon U-Pb ages with Shizuizi (1778 Ma) and Duanjiaxia (1802 Ma) granites. The granite has negative εNd(t) of -22.5 to -20.0 and the two-stage model ages of 2.29 - 2.45 Ga. An analysis of the regional tectonics suggests that the granites were emplaced during Paleoprotero­zoic extension at the southwestern margin of North China Craton, where magmatism was caused by tectonic activity related to the development of the Helan aulacogen.

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