摘要
长虹湖地区NE(E)向平移断裂旁侧或之上发育大量走滑成因湖泊.从单个湖泊来看,其成因有以下5种:单成因的Ⅰa型、Ⅱb型,复合成因的Ⅰc型+Ⅰa型、Ⅰc型+Ⅱb型、Ⅰa型+Ⅱb型.湖泊成因类型充分反映出断裂的左旋走滑特征,从而指示Ns向的区域挤压应力场,及第四纪以来高原北缘地壳表层总体处于挤压构造体制之中.湖泊中沉积物薄、少或无,无湖岸阶地与高位湖积物发育,湖泊周围成熟斜坡(365±57)ka的OSL年龄等表明,湖泊主要形成于中更新世以后.
There are a great lot present-day lakes occurring in the Changhonghu area, northern Qinqhai-Tibet Plateau. According to the planimetric position relations with faults,these lakes can be divided into two classes:The first class is rather far from faults and their forming concern little of faults, and mainly arosed by humpping up of the earth's surface under N-S regional compressing.The second class occurs by the side of NE or NEE strike-slip faults and their forming was closely related to the faults.The types of the strike-slipped lakes can be classified to ' Ⅰ a' type and ' Ⅰ c' type which are extensional, and ' Ⅱ b' type which are compressional.The ' Ⅰ a' type lake extend in S-N direction while the primary fault is in NE direction ,and in NE direction while the primary fault is in NEE direction.' Ⅰ a' type lake was caused by triangle structural depression because of pulling apart of subfault beside the primary fault. The ' Ⅰ c' lake extend congruously with fault-strike,and was caused by lozenge basin formed from dispersing.The bearing of trend of ' Ⅱ b' lake is in EW direction while the primary fault is in NE direction.and is in NW directional while the primary fault is in NEE direction.'Ⅱ b' lake was caused by structural depression of derived anticline beside the primary fault.There are five possible combined genetic types for each strike-slip lake: type I a,like Yongshuihu and Jifenghu i.e.,Ⅱb like Chezhehu and Gedouhu i.e. ; type Ⅰ c + I a like Liaoxiehu-Shimanhu.type Ⅰ c + Ⅱ b like Jingyuhu.type Ⅰa + Ⅱ b like Changhonghu.Thinness and (or) lack of sediment in the lakes.no terrace and high-level lacustrine deposit,declare that the lakes developed after mature slope around the lakes.Since the OSL age of slope-forming is 365±57 ka, so the lakes formed after Middle Pleistocene.The genetic types of the strike-slip lakes indicated reasonably sinistral strike-slipping of the faults and N-S directional regional compressive stress fields.The surface layer of the crust on the northern margin of the highland has been being in compressed-system approximately since Quaternary.
出处
《新疆地质》
CAS
CSCD
2003年第4期455-458,共4页
Xinjiang Geology
基金
1:25万目末县一级电站幅和银石山幅区域地质调查项目(19991300009051)终期成果
关键词
走滑湖泊
挤压体制
长虹湖
青藏高原
新构造
Qinghai-Tibet Plateau
Changhonghu area
strike-slipped lake
compression system
