| 新疆巴里坤县大加山一带碱性花岗岩的特征及构造环境探讨 |
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| 引用本文： | 王伟健.新疆巴里坤县大加山一带碱性花岗岩的特征及构造环境探讨[J].新疆地质,1996(2). |
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| 作者姓名： | 王伟健 |
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| 作者单位： | 新疆维吾尔自治区地质矿产局第二区域地质调查大队 |
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| 摘 要： | 大加山一带的碱性花岗岩按侵入先后可分为碱长花岗岩单元、钠闪石碱性花岗岩单元、霓石钠门石碱性花岗岩单元，由它们构成大加山超单元。这些岩石大都含碱性暗色矿物，从矿物组合看具贫水特征，岩石化学方面显示高硅、高碱、贫铝、镁、钙等特征；微量元素显示钾、铷、钍富集，锶、钡等强烈亏损特点；稀土元素总量较高，轻稀土较重稀土富集，并具有强的负铕异常。就位机制为断裂扩张并具顶蚀型被动定位类型，同源岩浆演化具反序列演化特点。上述特征和区域构造环境分析表明，大加山一带碱性花岗岩为非造山环境下形成的Ａ型花岗岩。
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| 关 键 词： | 巴里坤，大加山，碱性花岗岩，单元，定位机制，成因类型，构造环境 |
THE FEATURES AND TECTONIC SETTING OF ALKALIGRANITES FROM DAJIASHAN REGION,BARKOL COUNTY, XINJIANG |
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| Wang Weijian.THE FEATURES AND TECTONIC SETTING OF ALKALIGRANITES FROM DAJIASHAN REGION,BARKOL COUNTY, XINJIANG[J].Xinjiang Geology,1996(2). |
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| Authors: | Wang Weijian |
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| Abstract: | According to the intrusve sequonce,the alkaligranites from Dajiashan region can be divided into alkali-feldspar granite unit, riebeckite alkali-granite unit and aegirine alkaligranite unit. Dajiashan superunit is made up of these unites. All these rocks contain dark minerals. The mineral assemblages indicatend that the rocks are poorly aquiferous. The petrochemical features of the granites are rich in Si,K and Na and poor in Al,Mg and Ca. The trace elements of the granites show that the relative concentrations of K,Rb and Th are much higher but Sr and Ba are much lower in the granites from Dajiashan region than that from the oceanic-ridge granite. The granites possess high REE concentration and dstrong Eu negative anomalies.and their LREE are much more enriched thean their HREE. The emplacement mechanism possess fanlt expansion and stoping. The comagmatic evolutionary sequence showes inversion sequence. All the above mentioned features of the granites and tectonic analyese demonstrate that the granites,from Dajiashan region are of A-type ,which were formed in late Permian anorogenic stage of the evolution of the Altaids. |
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| Keywords: | Barkol Dajiashan alkaligranites unit emplacement mechanism original type tcctonic setting |
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