Ph.D. student XU Jianqiang and his supervisor Prof. LI Zhong investigate the provenances of the Jurassic clastic rocks in Zichuan area, north Luxi Uplift based on the sandstone detrital compositions and LA-MC-ICP-MS in situ dating of detrital zircons, with an aim to investigate important implications for the paleogeographic configuration and tectonic evolution of eastern North China block during Jurassic, a key stage in the Mesozoic tectonic evolution of the North China block.

This research proposes that an evident mountain or provenance region once increasingly developed along the northern margin of North China block during Early to Late Jurassic (182-155 Ma) due to the continuous collision of the Siberia and North China-Mongolian plates, easily shed mass clastic materials southward into the inner North China block and became the major provenance of Jurassic sediments in Luxi Uplift. Moreover, during that period, the Sulu orogen had little effect on the sedimentary paleogeographic framework of the eastern North China block, and the supposed plateau did not exist in there.

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Fig. 1. U-Pb ages versus εHf(t) values plot of detrital zircons.

Fig. 2. Tectonic-paleogeographic configuration of the eastern NCB during Early-Middle Jurassic (a), Middle-Late Jurassic (b) and Early Cretaceous (c).