STUDY ON VOLCANIC ROCKS AND THEIRSTRUCTURAL ENVIRONMENT OF LATETRIASSIC EPOCH IN CHACHAXIANGKAAREA IN QINGHAI PROVINCE
STUDY ON VOLCANIC ROCKS AND THEIRSTRUCTURAL ENVIRONMENT OF LATETRIASSIC EPOCH IN CHACHAXIANGKAAREA IN QINGHAI PROVINCE
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发表时间：
2004
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通讯作者：
Hu Qing-hua
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作者：
Hu Qing-hua
通过对该火山岩的岩石学特征、空间分布、火山机制、火山岩与晚三叠世侵入岩的关系以及察查乡卡周围构造带的研究，确定该火山岩的时代为晚三叠世，岩石地层单位为鹅乐山群。为一套陆相喷发火山岩，在大海滩-独库龙洼地区呈北西向展布。中-高钾、高钙、低钛，属钙碱性系列，火山喷发由强到弱，岩性上由中酸性岩逐渐变为中酸性岩，岩浆活动由挤压变为侵入。柴达木盆地的火山岩是东昆仑火山带都兰-鄂拉山火山喷发带的一部分。这表明其形成的构造环境为消耗带中的造山带地区。它是由下地壳的岩浆向上流动，与上地壳的物质混合，最终喷发而成。构造环境属造山环境。火山岩可能形成于大陆边缘环境，由于A型俯冲作用，产生一系列右旋走滑断裂带，岩石体积变大，出现强烈的热流体，导致岩浆从这些断裂带喷发到地表。
By studying the petrology, the space distribution, the volcanic mechanism, the relationship between the volcanic rock and the intrusive rock of late Triassic Epoch, and the structural zone around Chachaxiangka,the age of the volcanic rock is late Triassic Epoch.The rock stratum unit is Ngoloshan Group. It is a suit of continental eruption volcanic rock, distributing toward NW direction in Dahaitan-Dukulongwa area. Medial-high potassium, high calcium, low titanium, subordinating tocalc-alkaline series.Volcanic eruption acted from strong to weak as medium rocks became gradually into medium-acid rocks in Lithology, and extrusion changed into intrusion in magma activity. The volcanic rocks of Caidamu basin.And being a part of Dulan-Elashan moutain volcanic eraption belt in eastern Kunlun volcanic belt of late Triassic Epoch. This indicates the tectonic environment is orogenic belt region in consume zone. It is formed when magma of the lower Earth's crust streams up,while mingled with the material of the upper Earth's crust, and erupted finally. Tectonic environment belongs to orogenic environment. The volcanic rocks may be formed in continental marginal environment, as a result of A-type subduction,brought a series of dextral rotation strick-slip fault zone,apetuer of rocks became larger, and emerged intense hot fluid,caused magma erupted to the earth's surface from these fault zone.