阿尔金造山带东段地质构造演化概论
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摘要
阿尔金造山带曾是一个早古生代拗拉槽,其两侧地质体具有极为相似的地质构造特征。该区构造演化可以概括为:晚太古代至早元古代处于底侵造壳阶段,经吕梁旋回发生克拉通化,出现中元古代稳定型盖层沉积。加里东旋回中叶,经过短暂的拗拉、裂陷,分裂的塔柴板块又重新聚合。华力西旋回该区以剥蚀夷平作用为主,仅在山间断陷或山前凹陷的局部地段沉积有上泥盆统磨拉石建造。石炭纪发生短暂小规模海侵。侏罗纪全区进入陆相发育阶段。区内岩浆活动频繁,燕山旋回为最高潮。在喜山旋回,随着印度板块与欧亚板块的碰撞,该区也被卷入青藏高原总体的巨大演变之中。早期由边缘断陷转化为大型断陷盆地,至上新世湖水淹没了大部地区;晚期,随着阿尔金迅速崛起,塔里木—柴达木板块再度分裂,南盘抬升,北盘下降。文章最后探讨了阿尔金左行斜滑地震断裂带的控震作用。
The Altun orogenic belt was an Early Plaeozoic aulacogen, on both sides of whichthe geological bodiesv were very similar in tectonic features. The tectonic evolution of thisregion could be generalized as follows: During the period of Late Archean to Early Protero-zoic era. this region underwent a stage of hasal-intruded crust-building and, after Iuliangcycle. was cratonized and deposited with the Middle Proterozoic stable sediments. In the middle period of Caledonian cycle the Tarim-Qaidam plates were converged again after a shortperiod of fault-depression and division, The Variscan cycle in this region was characterizedchiefly by denudation and planation. and only a little Devonian Molasse formation was de-posited in the intermountain fault depressions and foreland depressions. A short-term andsmall-scale transgression appeared in carbonifrous period, but up to Jurassic the whole re-gion entered the stage of continental facies. There were frequent magmatic activities thatreached the climax in Yanshanian cycle. In Himalayan cycle this region was also involved in-to the huge changes of Qinghai-Tibetan Plateau following the collision of the Indian Plateand Euroasian Plate. The marginal fault-depression was transformed into a large basin,most of which were drowned by lake water in Pliocene. and then the Tarim-Qaidam Platewas splitted a second time, uplifted in the south and downwent in the north. companyingwith the rapid raising of the Altun Mountain. At last the earthqunke-controlling action ofthe Altun left oblique-slide seismic fault zone has been discussed in this paper.
The Altun orogenic belt was an Early Plaeozoic aulacogen, on both sides of whichthe geological bodiesv were very similar in tectonic features. The tectonic evolution of thisregion could be generalized as follows: During the period of Late Archean to Early Protero-zoic era. this region underwent a stage of hasal-intruded crust-building and, after Iuliangcycle. was cratonized and deposited with the Middle Proterozoic stable sediments. In the middle period of Caledonian cycle the Tarim-Qaidam plates were converged again after a shortperiod of fault-depression and division, The Variscan cycle in this region was characterizedchiefly by denudation and planation. and only a little Devonian Molasse formation was de-posited in the intermountain fault depressions and foreland depressions. A short-term andsmall-scale transgression appeared in carbonifrous period, but up to Jurassic the whole re-gion entered the stage of continental facies. There were frequent magmatic activities thatreached the climax in Yanshanian cycle. In Himalayan cycle this region was also involved in-to the huge changes of Qinghai-Tibetan Plateau following the collision of the Indian Plateand Euroasian Plate. The marginal fault-depression was transformed into a large basin,most of which were drowned by lake water in Pliocene. and then the Tarim-Qaidam Platewas splitted a second time, uplifted in the south and downwent in the north. companyingwith the rapid raising of the Altun Mountain. At last the earthqunke-controlling action ofthe Altun left oblique-slide seismic fault zone has been discussed in this paper.
引文
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