| 老挝甘蒙省晚白垩世农波组下段孢粉分析及成钾时代 |
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| 关键词:potash salt Laos sporopollen unconformity |
| 基金项目:国家973项目“中国陆块海相成钾规律及预测研究”(编号: CB403006) |
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| The Sporo-pollen Analyses and Ore-forming Age of Nong Bok Formation in Khammouane, Laos |
| The study of salt-bearing strata in Laos has an important significance for clarifying evolution law and potash deposit genesis in the whole Khorat plateau and its sub-basin. There has existed controversy among researchers both in China and abroad concerning the age of salt-bearing strata. The authors analyzed sporopollen over the potassium salt layer of ZK012 in the Wentai mining area of Khammouane, Laos. According to the characteristics of sporopollen, the authors define it as Classopollis-Ephedripites-Exesipollenites assemblage. In combination with the discovery of the index fossils of Callistopollenites, Normapolles, Cicatricosisporites, Clavatipollenites, Asteropollis and Trisolissporites, the authors hold that the age of sporopollen assemblage in ZK012 drill hole is between Turonian and Santonian of Late Cretaceous, and the climate condition should be a hot, tropical and south subtropical environment. A comparative analysis of the sedimentary characteristics of ZK309 drill hole was also made, which has the same depositional sequence as ZK012. In addition, the unconformity between the evaporate and the underlying sandstone was found at the bottom of ZK309. On such a basis, the authors consider that the Yanshanian movement in early Late Cretaceous caused the rising of the earth crust and the tectonic deformation of this area. Ancient seawater was retained in the big trap structure of Khorat basin along with the regression, and evaporites were deposited under the condition of subsequent arid climate. |
| ZHONG Xiao-yong,YUAN Qin,QIN Zhan-jie,WEI Hai-cheng,SHAN Fa-shou.2012.The Sporo-pollen Analyses and Ore-forming Age of Nong Bok Formation in Khammouane, Laos[J].Acta Geoscientica Sinica,33(3):323-330. |
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