| 火久伟,冯小明,黄登鹏,蔡国华,杨春霞.西藏打加错东I型花岗岩的地球化学特征及构造意义[J].矿产勘查,2019,(6):1274-1284 |
| 西藏打加错东I型花岗岩的地球化学特征及构造意义 |
| I-type granites geochemical characteristics and structural significance of eastern Dajia lake, Tibet |
| 投稿时间：2019-01-10 |
| DOI： |
| 中文关键词: 岩石地球化学特征 构造环境 I型花岗岩 打加错东 |
| 英文关键词: geochemical characteristics of rocks, tectonic setting, I type granite, Dadongdong |
| 基金项目:中国调查局成都地质调查中心基础项目；西藏1:5万打加错东地区4幅区域地质矿产调查(编号:12120113034400)资助。 |
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| 全文下载次数: 143 |
| 中文摘要: |
| 打加错东岩体位于冈底斯—下察隅晚燕山—喜马拉雅期岩浆弧南亚带,侵入岩广泛分布,年龄介于56-65Ma,属于始新世。打加错东岩体具有钙碱性－高钾钙碱性、过铝质,SiO2含量为65.49%～70.32%,K2O/Na2O＞1,碱度率AR数值为2.02～2.73,铝饱和指数A/CNK值介于0.80～1.08之间,A/NK值介于1.34～1.72之间。微量元素整体较为亏损,稀土元素总量总体偏低,显示轻稀土富集、重稀土弱亏损的特征。本文研究认为打加错东始新世侵入岩来源于基性岩部分熔融,同时有部分壳源成份夹物,构造环境为火山弧环境,同时向碰撞环境过渡,具有双重性特点。它们的形成与喜马拉雅时期,雅鲁藏布江洋块继续向北俯冲有关,形成打加错东地区规模最为强烈的岩浆活动。 |
| 英文摘要: |
| The Dajia lake east rock mass is located in the Gangdisi-Xiachayu-Y anshan-Himalayan magmatic arc south sub-zonal. The intrusive rocks are widely distributed, with an age of 56-65 Ma, belonging to the Paleocene. The Dadongdong body has calc-alkaline-high potassium calc-alkaline and peraluminous, SiO2 content is 65.49-70.32%, K2O/Na2O>1, alkalinity AR value is 2.02-2.73, aluminum saturation index A/CNK value is between 0.80 and 1.08, and the A/NK value is between 1.34 and 1.72. The total amount of trace elements is relatively low, and the total amount of rare earth elements is generally low, indicating the characteristics of light rare earth enrichment and heavy rare earth loss. In this paper, it is considered that the Indosinian intrusive rocks are closer to the partial melting products of the metamorphic sandstone, and the tectonic setting is a volcanic arc environment, and the transition to the collision environment has dual characteristics. Their formation was related to the northward subduction of the Yarlung Zangbo River block during the Himalayan period, forming the most intense magmatic activity in the survey area. |
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