内蒙古莫力达瓦旗哈达阳绿泥石白云母构造片岩LA-ICP-MS锆石U-Pb年龄及其地质意义
LA-ICP-MS zircon U-Pb age of the chlorite-muscovite tectonic schist in Hadayang, Morin Dawa Banner, Inner Mongolia, and its tectonic significance
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摘要: 嫩江—黑河构造带地处松嫩地块与兴安地块的结合部位，一直以来是业内学者关注的焦点。在构造带内内蒙古莫力达瓦旗哈达阳一带野外实地调研过程中，发现一套变质变形程度与周围地质体差异很大的地层。岩石组合为绿泥石白云母构造片岩、二云母微晶片岩、黝帘白云糜棱片岩等。采用LA-ICP-MS技术获得的绿泥石白云母构造片岩中锆石U-Pb年龄为413.9Ma±2.7Ma。通过分析区域地质演化历史及不同时代地质体特征，认为沿红山梁—哈达阳—依克特一带存在一条构造混杂堆积岩带，这套强变形岩石应为构造混杂岩带的一部分，其原岩形成时代为早泥盆世，后期构造定位应与嫩江—黑河构造带最后于早石炭世末拼合作用有关。
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关键词:
- 哈达阳 /
- 白云母构造片岩 /
- LA-ICP-MS锆石U－Pb年龄 /
- 嫩江—黑河构造带 /
- 早泥盆世
Abstract: Located at the junction of Songnen massif with Xingan massif, the Nenjiang-Heihe tectonic belt has long been the focus of geologist's attention. During the field work in Nenjiang area, the authors found a new suite of strata whose deformation and metamorphism are greatly different from those of surrounding geological bodies. Rocks exhibit such combinations as chlorite-muscovite tectonic schist, biotite-muscovite microlite schist and zoisite-muscovite mylonite schist. Geochronological research was conducted on chlorite-muscovite tectonic schist, which yielded a zircon U-Pb(LA-ICP-MS) age of 413.9Ma±2.7Ma. Based on the analysis of regional geological evolution history and geological characteristics of different ages, the authors hold that there is an tectonic mélange belt along Hongshanliang-Hadayang-Yikette area. This suite of strongly deformed rocks should be part of the tectonic melange belt, and the original rock was formed in the Early Devonian. The late structural location was related to the collage effect of Nenjiang-Heihe tectonic belt which occurred in late Early Carboniferous period. -
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