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地质力学学报:2001,7(3):193-200
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阿尔金山北缘早古生代岩浆活动的构造环境
(中国地质科学院地质力学研究所, 北京 100081)
TECTONIC ENVIROMENTS OF MAGMATISM IN EARLY PALEOZOIC IN THE NORTH ALTYN TAGH, CHINA
(1.Institute of Geomechanics, CAGS, Beijing 100081, China;2.Xinjiang Geological Survey, Urumoqi 830011, China)
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投稿时间:2001-05-06    
中文摘要: 阿尔金山北缘地处塔里木盆地和柴达木盆地之间的阿尔金断裂的西北,是青藏高原北部边界地区。该区花岗岩类主要形成于早古生代以来,为钙碱性岩系(碱性程度不高),发育Ⅰ型和A型两种花岗岩类,缺少S型花岗岩。早古生代与蛇绿岩伴生的双峰式火山岩系属于亚碱性系列,其中的玄武岩主要为拉斑系列,流纹岩属钙碱系列。花岗岩类构造环境分析和判别结果表明,阿尔金山北缘早古生代处在破坏性活动板块边缘,构造环境可能经历了早古生代活动陆缘的(火山)岛弧、中生代大陆造陆抬升以至新生代的后造山作用演化过程。火山岩类的构造环境分析结果表明,玄武岩类可能具有洋脊区、岛弧区和板内区各种构造环境,流纹岩类则主要处在板内区。以上分析说明早古生代"阿尔金洋"的存在。
Abstract:The North Altyn Tagh is located at the northewst area to Altyn Fault between Tarim and Qaidam Basins. Granitoids from this area formed mainly in Ordovician,and are classified as calc alkaline based on alkaline-lime index,and metaluminous and peraluminous on Shand's index. I and A-types are the principal granitoids,no S-type granitoids found here. Volcanic rocks occurring together with ophiolite suite in this area,mainly of Early Paleozoic,consist of pillow basalts and rhyolites,and smaller amounts of trachybasalts,basaltic trachyandesites and dacites,belonging to subalkali and showing bimodal distribution in SiO2-Na2O+K2O plot. Major-and trace-element trectonic discrimination of the granitoids shows the evolution of tectonic environments from destructive active plate margin/volcanic arc in Early Paleozoic,the continental apeirorogenic uplift in Mesozoic and post orogenic in Cenozoic of North Altyn Tagh. Tholeiitic basalts had formed in several environments from MORB to island arc and within-plate. Acid volcanic rocks here of calc alkali series may belong to within plate environment only. The existing of "Altyn Ocean" in early Paleozoic is then deduced from the analyses above.
文章编号:     中图分类号:P542.4    文献标志码:
基金项目:国家攻关305项目(96-915-06-01B)和国家地质调查项目(K1.1.2.3)
引用文本:
陈宣华,王小凤,杨风,等,2001.阿尔金山北缘早古生代岩浆活动的构造环境[J].地质力学学报,7(3):193-200.DOI:
CHEN Xuan-hua,WANG Xiao-feng,YANG Feng,et al,2001.TECTONIC ENVIROMENTS OF MAGMATISM IN EARLY PALEOZOIC IN THE NORTH ALTYN TAGH, CHINA[J].Journal of Geomechanics,7(3):193-200.DOI:

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