摘要
该区已识别出三个重力构造,即:霍玛吐滑片、托斯台滑褶、高泉膏盐岩雏底辟。本文概述了重力构造特征,探讨了重力构造形成的地质条件,并定量计算了重力滑动构造的失稳初滑角。
Three gravity structures,Huomatu sliding block,Tuositai sliding folds and Gaoquangypsum-salt diapir,are recognized in the west part of the south margin of the JunggarBasin.Huomatu sliding block is located at the north Tianshan Mountains foreland to the south of Hutubi—Dushanzhi region.It is 140 km long from east to west,28 km wide inN-S direction,3.5 km thick on average.It covers an area of 2740 km^2 and the volumeis 9450 km^3.The sliding mass consists of Tertiary sediments.The sliding sheet is formedby less-compacted argillaceous rock of the Eogene Anjihaihe Formation.The high-pressureanomaly was resulted from the unbalance between compaction and liquor draining as wellas its hydrocarbon generation.With the methods of balanced section,bow and arrow andwidth compensation of unload area,maximum slide distance was determined to be 15 km,and primitive slide angle 5-6°.The Tuositai sliding fold is located at the north Tianshan Mountains to the south ofWusu.It is a big gravity-slide structure mainly formed by Mesozoic sediments.The slidingmass stretches 30 km long in E-W direction,10 km wide in S-N direction,2 km thick.It covers an area of 260 km^2 and the volume is 540 km^3.The bottom sliding sheet consistsof the Upper Triassic Xiaoquangou Formation and the less-compacted argillaceous rock ofthe Lower Jurassic Sangonghe Formation.The high-pressure anomaly is resulted by largeamount of unloading due to denudation of the upper strata in the late stage and the impe-diment of the release of argillaceous pore-pressure.Its primitive slide angle is measured tobe 8°by quantitative calculation.The Gaoquan embryonic diapir was developed in the Upper Tertiary Taxihe Forma-tion in the Sikeshu sag.It stretches nearly E-W direction,covers an area of 140 km^2 andis buried at 2000 km deep.The diapir was resulted from gypsum and rock-salt that archedthe overlying strata.The formation cause of this structure are:1.the reverse of densitiesfrom gypsum and salt to overlying strata;2.the induction of fault movement;3.the dif-ferentia
出处
《石油与天然气地质》
EI
CAS
CSCD
北大核心
1990年第3期275-282,共8页
Oil & Gas Geology
