New understanding and achievements in regional geological survey of 1∶250 000 Huaihua sheet,Hunan province
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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 mar-gin 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 re-lationship and its boundary between Banxi Group and Gaojian Group are found out in the study area.It is pro-posed 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.Com-bined with isotopic dating data,the intrusive ages and erupted ages of Baimashan-Longshan complex and its sur-rounding granites are ascertained.The tectonic deformation characteristics and tectonic patterns of Xuefeng oro-genic belt are identified;the formation and evolution process of Yuanma basin are established.
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Key words:
- Hunan /
- Yangtze block /
- Banxi Group /
- Xuefeng orogenic zone /
- Yuanma basin /
- Huaihua
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