Kwangsian orogeny was proposed by Mr. Ding Wenjiang (V K Ting) in 1929. It is a tectonic movement represented by the unconformity between Devonian and underlying strata. It is generally recognized that Kwangsian orogeny is the response and concrete manifestation of Caledonian orogeny in South China and has a profound impact on the evolution and reconstruction of South China palaeo-plate. However, owing to lack of relevant evidences for a long time, the understandings of its initiation time, advancing progress, and influences have not been accurate and in-depth enough.
According to Academician Chen Xu et al. from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, to know the Ordovician strata in southern Jiangxi and northern Guangdong is the key to solve this problem. The Ordovician of the Yongxin-Chongyi area in southern Jiangxi feature continuous black graptolite-bearing strata. Its top is in unconformable contact with Devonian system. However, there are serious division and correlation problems in this set of black clastic rock series of Ordovician system. After restudy of relevant important graptolite species, Chen discoveres that Longxi Formation is the deposits in Upper Ordovician Sandbian period. The overlying Shi-kou Formation and Huamianlong Formations are recognized herein as a part of the Hanjiang Formation which can date back to a time equivalent to early Upper Ordovician Katian. After redefining the division and correlation of Ordovician system in Yongxin and Chongyi, Chen Xu et al concludes that: The cataclysm of biofacies and lithofacies between black graptolite-bearing strata of Longxi Formation and thick clastic rock series of Hanjiang Formation above them indicated that the initiation time of Kwangsian orogeny in southern Jiangxi is early Upper Ordovician Katian.
This research result is published in the recent SCIENCE CHINA (Earth Sciences) in English. It is one of the papers clicked on and downloaded most frequently in this journal. Its Chinese version will be published soon.
CHEN Xu, ZHANG YuanDong, FAN JunXuan, CHENG JunFeng & LI QiJian. 2010. Ordovician graptolite-bearing strata in southern Jiangxi with a special reference to the Kwangsian Orogeny. Science China (Earth Sciences), 53 (11): 1602-1610.
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