湖南1∶25万怀化幅区域地质调查主要成果及新认识

    New understanding and achievements in regional geological survey of 1∶250 000 Huaihua sheet, Hunan province

    • 摘要: 1∶25万怀化幅图区主要位于扬子陆块东南缘,自西向东划分为武陵断弯褶皱带、沅麻盆地、雪峰冲断带及邵阳坳褶带4个构造单元。通过此次调查研究,取得了以下主要进展及成果: 基本查明了区内板溪群与高涧群的相变关系及界线; 提出了南华纪长安期沿雪峰山与涟邵盆地的结合带存在一凹陷槽; 对区内岩浆岩侵入时代和期次做了详细的划分,建立了岩浆演化序列; 结合同位素年龄数据,系统地对白马山—龙山复式岩基带及其周边的中酸性—酸性花岗岩体侵入时代、火山岩系的喷发时代进行了统一厘定; 查明了雪峰造山带的构造变形特征、构造样式以及沅麻盆地的构造特征和形成演化过程。

       

      Abstract: In this regional geological survey project, 1∶250 000 Huaihua sheet is located in the southeastern margin of the Yangtze block, and it is divided into four tectonic units from west to east: Wuling fault-bend fold belt, Yuanma basin, Xuefeng thrust belt and Shaoyang depression fold belt. Through investigation, the sedimentary relationship and its boundary between Banxi Group and Gaojian Group are found out in the study area. It is proposed that a depression formed in Chang’an stage of Nanhuan Period lies at the junction of Lianshao Basin and Xuefeng Mountain. The intrusive stages are divided, and the sequence of magmatic evolution is established. Combined with isotopic dating data, the intrusive ages and erupted ages of Baimashan-Longshan complex and its surrounding granites are ascertained. The tectonic deformation characteristics and tectonic patterns of Xuefeng orogenic belt are identified; the formation and evolution process of Yuanma basin are established.

       

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