西北地质
西北地質
서북지질
NORTHWESTERN GEOLOGY
2015年
2期
150-158
,共9页
构造演化%应力场%走滑%冲断改造%和什托洛盖盆地
構造縯化%應力場%走滑%遲斷改造%和什託洛蓋盆地
구조연화%응력장%주활%충단개조%화십탁락개분지
tectonic evolution%stress field%strike-slip and thrust reformation%Hoxtolgay basin
和什托洛盖盆地位于新疆西北部，是在西准噶尔晚古生代造山带逆冲推覆构造系统之上发育的一个中新生代沉积盆地。关于盆地演化和盆地性质的认识分歧较大。为了恢复盆地形成与演化历史，分析盆地性质，采用改造型盆地的研究思路，开展了地震剖面构造解析和区域地质综合研究。结果表明，三叠纪以来该区至少经历了3个成盆与改造期：印支期为挤压坳陷盆地，形成了和什托洛盖盆地的雏形；燕山期为伸展坳陷盆地，晚期遭受走滑冲断改造，盆地现今南北对冲的构造格局基本形成；喜山期主要表现为先存断裂复活，盆地隆升并遭受强烈改造，最终形成现今的构造地貌形态。尽管不同成盆期的区域应力场和盆地性质各具特点，但各成盆期后期改造阶段的区域应力场特征基本一致，主要受盆地北缘谢米斯台山山前断裂向南冲断和达尔布特断裂左行压扭走滑所形成的压扭应力场控制。因此，和什托洛盖盆地总体是一个由区域应力场性质在中新生代发生多次改变所形成的走滑冲断改造盆地。
和什託洛蓋盆地位于新疆西北部，是在西準噶爾晚古生代造山帶逆遲推覆構造繫統之上髮育的一箇中新生代沉積盆地。關于盆地縯化和盆地性質的認識分歧較大。為瞭恢複盆地形成與縯化歷史，分析盆地性質，採用改造型盆地的研究思路，開展瞭地震剖麵構造解析和區域地質綜閤研究。結果錶明，三疊紀以來該區至少經歷瞭3箇成盆與改造期：印支期為擠壓坳陷盆地，形成瞭和什託洛蓋盆地的雛形；燕山期為伸展坳陷盆地，晚期遭受走滑遲斷改造，盆地現今南北對遲的構造格跼基本形成；喜山期主要錶現為先存斷裂複活，盆地隆升併遭受彊烈改造，最終形成現今的構造地貌形態。儘管不同成盆期的區域應力場和盆地性質各具特點，但各成盆期後期改造階段的區域應力場特徵基本一緻，主要受盆地北緣謝米斯檯山山前斷裂嚮南遲斷和達爾佈特斷裂左行壓扭走滑所形成的壓扭應力場控製。因此，和什託洛蓋盆地總體是一箇由區域應力場性質在中新生代髮生多次改變所形成的走滑遲斷改造盆地。
화십탁락개분지위우신강서북부，시재서준갈이만고생대조산대역충추복구조계통지상발육적일개중신생대침적분지。관우분지연화화분지성질적인식분기교대。위료회복분지형성여연화역사，분석분지성질，채용개조형분지적연구사로，개전료지진부면구조해석화구역지질종합연구。결과표명，삼첩기이래해구지소경력료3개성분여개조기：인지기위제압요함분지，형성료화십탁락개분지적추형；연산기위신전요함분지，만기조수주활충단개조，분지현금남북대충적구조격국기본형성；희산기주요표현위선존단렬복활，분지륭승병조수강렬개조，최종형성현금적구조지모형태。진관불동성분기적구역응력장화분지성질각구특점，단각성분기후기개조계단적구역응력장특정기본일치，주요수분지북연사미사태산산전단렬향남충단화체이포특단렬좌행압뉴주활소형성적압뉴응력장공제。인차，화십탁락개분지총체시일개유구역응력장성질재중신생대발생다차개변소형성적주활충단개조분지。
Hoxtolgay basin,located in northwestern Xinjiang,is a Mesozoic-Cenozoic sedimentary basin developed on the thrust nappe system of the west Junggar orogenic belt formed in late Pale-ozoic.There exists an ongoing debate in understanding of the basin prototype and its evolutionary history in Mesozoic-Cenozoic period.To restore the history of formation and evolution,and de-termine the type of the basin,research ideas of reformed basin was applied to analysis of forma-tion and development of the basin,the comprehensive geological studies and seismic structural a-nalysis were carried out as well.Results show that the formation and evolution of Hoxtolgay Ba-sin in Mesozoic-Cenozoic age is mainly influenced by west Junggar orogeny,and can be subdivided into at least three basin formation and reformation periodssince Triassic,respectively Indosinian,Yanshanian and Himalayan period.The prototype of the basin in Indosinianis a compressional de-pression controlled by the east-westtrending Xiemisitaishan piedmont thrust fault,and developed an extensional depression with a large scale subsidence in Yanshan period.At late Yanshanian, the basin was strongly reformed by folding and thrusting,and the north-south ramp framework of the basin wasformed.The sedimentary area of the basin was greatly narrowed and restricted to the middle depression belt of the basin in late Yanshanian to Himalayan period,and mainly exhib-ited the characteristics of the reactivity and inheritance of the pre-existing faults.Although the tectonic stress fields and basin features are different in different stages of formation and develop-ment of the basin,their regional tectonic stress fields are generally the same or similar in the later stage of each basin development,mainly due to Xiemisitaishan Piedmont fault thrusting south-ward and Daerbute sinistral transpressional faulting.It is therefore concluded that Hoxtolgay ba-sin is generally a strike-slip and thrust reformed basin caused by the changes of the regional tec-tonic stress fields in the process of basin evolution.
