Silurian-Devonian and Jurassic Thermal Events in the Ordos Basin, China: Indications from K-Ar Dating on Illites

作     者：Hans Ahrendt Klaus Wemmer Hans-J rgen Behr 

作者机构：Institute of Geology and Dynamics of LithosphereUniversity of Gttingen G ttingen GermanyInstitute of Geology and Dynamics of LithosphereUniversity of Gttingen G ttingen GermanyInstitute of Geology and Dynamics of LithosphereUniversity of Gttingen G ttingen Germany 

出 版 物：《Acta Geologica Sinica(English Edition)》 (地质学报（英文版）)

年 卷 期：1996年第70卷第4期

页      面：435-446页

核心收录：

学科分类：070903[理学-古生物学与地层学(含：古人类学)] 0709[理学-地质学] 07[理学] 

主　　题：illite K-Ar dating illite crystallinity thermal event Ordos basin 

摘      要：In the Ordos basin, two distinct thermal events of different ages have been identified for the first time by means of K-Ar dating combined with illite crystallinity analysis. For the Late Triassic and Late Permian samples, the K-Ar ages of the 0.2μm fractions (159-173 Ma) reflect an illitization age related to the Yanshanian movement and indicate a short thermal event in the Middle Jurassic; the K-Ar ages of the 2 μm fractions (210-308 Ma) are interpreted as mixed ages of detrital material and authigenic illites. The K-Ar ages of both 0.2μm and 2μm fractions of a Middle Cambrian sample (368 Ma and 419 Ma) correspond to the ages of the metamorphism and earliest granite intrusion in the northern Caledonian Qinling fold zone (380-420 Ma) and show a thermal event during Silurian-Devonian time.