摘要
黔南坳陷构造线主体呈NNE至近SN向展布,与坳陷南部NW向-近EW向罗甸断坳以及北部NEE向黔中隆起构造线走向不一,具有明显的构造变形调节特征。经结合地震、MT以及区域地质资料分析,黔南坳陷发育有浅变质与结晶双层结构基底,深部结晶基底表现出明显的"岛链"状结构特征,可能是扬子古陆的外缘增生部分;坳陷总体经历了南华-志留纪、泥盆纪-早三叠世、中三叠世-侏罗纪三期成盆与新元古代早期末、志留纪、中三叠世以来三期隆升,发育了从被动大陆边缘、到前陆、到改造三种盆地类型。今构造格局与变形样式实为多期构造变形形迹的复合、联合与叠加。总体上,坳陷今表层面貌呈现为隔槽式褶皱、是典型的山前逆冲推覆构造发育区发育的侏罗山式构造样式,纵向上可划分为震旦系-下古生界(下)、上古生界(中)及中新生界(上)三个构造层,其中下构造层以发育基底卷入的冲断变形构造为主,中构造层以发育与断层相关的冲起变形构造为主,上构造层以发育滑动褶皱与断展褶皱为主;坳陷今表层构造多受其深层"岛链"状结晶基底结构所控制。
The southern Guizhou depression is located in the southwestern margin of the Xuefengshan uplift,its structural outline spreads from NNE to SN,it has the accommodate trait.Based on seismology,MT （telluric electromagnetic sounding ） and geologic survey,the study shows there are different strikes towards the southern Luodian rift-depress and northern Middle Guizhou uplift,and there is a two-layer epimetamorphosed and deep-seated crystallized basement in the southern Guizhou depression.The deep-seated layer represents obviously a structural character of an island chain,which is exterior hyperplasia of the Yangtze ancient landmass.The depression has gone through three periods for basin formation （Neoproterozoic Nanhua Period and Silurian,Devonian-Early Triassic,Middle Triassic-Jurassic） and three periods for basin and orogen transforming （Early Neoproterozoic,Silurian,Middle Triassic）.There are four types of basins from the active marginal basin to passive marginal basin,foreland basin,reformation basin in the southern Guizhou depression,and the modern structural pattern and mode are actually resulted from compound,association and superposition of multistage tectonic deformations.As a whole,the depression morphology represents an inter-groove drape,exhibits a Jurassic mountain structural pattern of a thrust nappe,which can be divided into three structural layers（lower structural layer of the Sinian-lower Paleozoic,middle structural layer of upper Paleozoic and upper structural layer of the Mesozoic-Cenozoic）.The lower structural layer mostly develops a thrusting-breakup structural pattern of layer-immixture.The middle structural layer mostly develops a crush-up structural pattern of spread-correlation.The upper structural layer mainly yields surge folds,fault-propagation folds and pop-up structures.Generally,the surface structural system of the southern Guizhou depression is controlled by the deep crystallized basement of the island chain.
出处
《大地构造与成矿学》
EI
CAS
CSCD
北大核心
2010年第1期20-31,共12页
Geotectonica et Metallogenia
基金
国土资源部油气资源战略选区调查与评价项目"黔南桂中海相地层油气资源前景评价"(项目编号XQ-2007-01)资助
关键词
黔南坳陷
构造变形
成因解析
southern Guizhou depression
structural transfiguration
genetic interpretation
structural pattern
