雪峰山大地构造的基本特征初探  

A PRELIMINARY STUDY ON TECTONICS OF THE XUEFENG MOUNTAINS, WESTERN HUNAN

作　　者：陈海泓[1] 孙枢[1] 李继亮[1] 王清晨[1] 彭海波 徐树桐 许靖华 

机构地区：[1]中国科学院地质研究所,北京100029 [2]安徽省地质矿产局地质科学研究所,合肥230001 [3]瑞士苏黎世理工大学地质研究所

出　　处：《地质科学》1993年第3期201-210,共10页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：国家自然科学基金

摘　　要：雪峰山具有碰撞型造山带的特征。造山作用发生在中生代。根据碰撞造山带的薄壳板块构造模式,可以划分出俯冲壳楔,仰冲壳楔与构造混杂岩三个基本单元。作为俯冲壳楔的杨子板块由前陆盆地与前陆褶冲带所表征,而作为仰冲壳楔的华南板块则以刚性基底推覆体与盖层推覆体所标示,以往称之为板溪群的岩石似应根据其构造特征划分为刚性基底推覆体(具 Smith 地层学意义)和陆壳碰撞作用形成的构造混杂带。The Xuefeng Mountains, located in western part of Hunan Province, South China, is composed mainly of a slightly metamorphosed sequence traditionaly called 'Banxi Group'. Several schools of thoughts on the tectonic nature of the mountains exist, most of which agree that the region represents an important tectonic boundary. Meanwhile, the explanation of a long lasting old landmass of the region has also been widely quoted in geological literatures-In this paper, the authors present opposite evidence against the old notion. In fact, the Xuefeng Mountains can be interpreted as a Mesozoic orogenic belt produced by the collision of two continental blocks: Yangtze and Huanan. Three basic tectonic units, i.e., overriding crus-tal wedge, underthrusting crusta! wedge and tectonic melange, can be recognized on the basis of thin-skinned plate tectonic model proposed by Hsu (1981). The Yangtze block, as an underthrusting plate, is characterized by a foreland basin ranging from late Triassic to Cretaceous in age and a fold-thrust belt, while the Huanan block, represented by rigid basement nappes and sedimentary cover, plays an overriding role in the mountain building processes. The concept of the 'Banxi Group' as a Precambrian stratigraphic unit should be reinterpreted as two different tectonic units: rigid basement nappes with stratigraphic sequence, and tectonic melange. Detailed field features of these tectonic units are discussed, and tectonic evolution of the re-gion is summarized in the present paper.

关 键 词：雪峰山 中生代 造山作用 大地构造 

分 类 号：P548.2[天文地球—构造地质学]