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利用伊利石K-Ar测年法,结合伊利石结晶度分析,首次在鄂尔多斯盆地确定出两期不同时代热事件。晚三叠世和晚二叠世<0.2μm粒级的岩石样品的K-Ar年龄(159-173Ma)反映了与燕山运动有关的伊利石化年龄,指示有一期中侏罗世的热事件;其<2μm粒级的K-Ar年龄(210-308Ma)则被解释为碎屑物和自生伊利石的混合年龄。中寒武世<0.2μm和<2μm粒级的岩石样品K-Ar年龄(368Ma与419Ma)对应于北秦岭加里东褶皱带变质作用与最早期花岗岩侵入的时代(380-420Ma),表明在志留-泥盆纪发生了一期热事件。
Based on the K-Ar dating of illite and the analysis of illite crystallinity, two heat events of different ages were identified for the first time in the Ordos Basin. The K-Ar ages (159-173 Ma) of Late Triassic and Late Permian <0.2 μm rock samples reflect the age of the Yilishan-related illite, indicating a Middle Jurassic thermal event, K-Ar ages of 2 μm (210-308 Ma) are interpreted as the mixed ages of clastic and authigenic illite. The K-Ar ages (368Ma and 419Ma) for the Middle Cambrian <0.2μm and <2μm fractions correspond to the age of the Caledonian metasedimentary metamorphism and the earliest granite intrusions in the North Qinling (380-420Ma) Stay - a period of Devonian thermal event.