藏西北黑石北湖一带新近纪火山岩的特征及构造意义
Dong AG. Geological characteristics of Neogene volcanic rocks in the Heishi North Lake area, northwestern Tibet, and their implications for the Neogene tectonic evolution.
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摘要: 青藏高原西北部黑石北湖一带发育的橄榄安粗岩系列火山岩具有由早到晚从基性到中性连续演化的特征，3期火山活动期次分明，以中心式喷发为主，K-Ar年龄分别为9．23Ma、3．19Ma和3Ma。该火山岩的稀土元素、微量元素、同位素组成特征与藏北其他地区的新生代火山岩基本相近。火山活动为新构造活动的响应，受控于青藏高原隆升过程中产生的走滑断裂。Abstract: Volcanic rocks of the shoshonite series in the Heishi North Lake area, northwestern Tibet have the characteristics of continuous evolution from basic andesite in the early period to intermediate volcanic rocks in the late period. Three phases of volcanism may be distinguished. The volcanism was dominated by central eruption. The three phases have K-Ar ages of 9.23 Ma, 3.19 Ma and 3 Ma respectively. The characteristics of the REE, trace elements and isotopic compositions of the volcanic rocks are essentially close to those of Cenozoic volcanic rocks in other areas of northern Tibet, which show that the volcanic rocks have the features of mixing and hybridization of deep magma and shallow magma. Volcanic activities were the response to the neotectonic activities and were controlled by strike-slip faults produced during the uplift of the Qinghai-Tibet Plateau.
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