沿雅鲁藏布江缝合带东坡、日喀则等蛇绿岩体磁异常特征及其找矿标志
发布时间：2018-12-27 11:32
【摘要】：航空磁测△T图上清楚显示出沿雅鲁藏布江缝合带具有南北两条航磁异常,地质研究确认沿雅鲁藏布江缝合带的蛇绿岩体呈带状东西向延续近2000 km,但已知主要含铬蛇绿岩体分布于雅鲁藏布江南岸。在罗布莎和泽当地表观测到断续分布着含铬蛇绿岩体,地质研究程度较高,岩体规模不大。向西地表有出露日喀则岩体,再西段有当穷、普兰、东坡等规模巨大的岩体。航空磁测图上显示出日喀则、东坡、普兰、当穷等岩体与清晰的航磁异常对应。对上述岩体进行的地面磁测准确地确定了已知岩体与航磁异常的关系,位于雅鲁藏布江东段的罗布莎与泽当岩体属于其南部强航磁异常北缘的负异常范围内的小岩体。西部沿江含铬蛇绿岩体是断续分布的,呈短条带状或较大的三度体;地面磁测异常突出反映出地表岩体磁铁矿分布的不均匀性,在岩体边缘(包括近岩体围岩)的蛇纹石化较强,磁异常亦较强,并由此较准确地圈定出岩体范围。航磁异常反映出岩体内部有相对富积的磁性矿物和磁性体,它们可能来自深部含Fe O、Fe2O3等矿物在岩浆上涌到上地壳由于蛇纹石化而生成了Fe3O4,当温度低于480℃时形成较强的磁性。反演计算了磁性体位于3~5 km深度上,虽然蛇绿岩体及其围岩中存在的磁铁矿非直接来源于地幔物质,但含铬蛇绿岩体的岩浆物质是生成磁铁矿的主要物质贡献者。由此将航磁和地面磁测异常与大地电磁法、反射地震等方法结合可以给出岩体深部结构的地球物理特征,这有利于圈定找矿的远景地段。
[Abstract]:The aeromagnetic T map clearly shows two aeromagnetic anomalies along the Yarlung Zangbo suture zone. Geological studies confirm that the ophiolite along the Yarlung Zangbo suture zone extends in a zonal east-west direction for nearly 2000 km,. But the main chromium-bearing ophiolite is known to be distributed on the south bank of the Yarlung Zangbo River. Chromium-bearing ophiolitic bodies are observed intermittently on the surface of Robusa and Zedang. The geological studies are relatively high and the scale of the rocks is not large. To the west there are exposed Xigaze rock bodies, and then the west section of Dang poor, Plain, East Slope and other large rock mass. The aeromagnetic maps show that the Xigaze, Dongpo, Plain and Dangfang rock masses correspond to clear aeromagnetic anomalies. The relationship between the known rock mass and aeromagnetic anomaly is accurately determined by the surface magnetic survey of the above rock mass. The Rocksa and Zedang rock bodies located in the eastern section of the Yarlung Zangbo River belong to the small rock mass within the negative anomaly range of the northern margin of the strong aeromagnetic anomaly in the south of the rock mass. The chromium-bearing ophiolitic rock bodies in the western part of the Yangtze River are distributed intermittently, with short banded or larger cubic bodies. The surface magnetic anomaly highlights the heterogeneity of the distribution of magnetite in the surface rock mass. The serpentine and magnetic anomalies are stronger at the edge of the rock mass (including the surrounding rock mass), and the range of the rock mass is delineated more accurately. Aeromagnetic anomalies reflect relatively rich magnetic minerals and magnetic bodies inside the rock body, which may be derived from minerals such as Fe O _ 2O _ 3 in the deep layer, which upwelled to the upper crust of magma and formed Fe3O4, due to serpentinization. When the temperature is below 480 鈩，
本文编号：2392993
[Abstract]:The aeromagnetic T map clearly shows two aeromagnetic anomalies along the Yarlung Zangbo suture zone. Geological studies confirm that the ophiolite along the Yarlung Zangbo suture zone extends in a zonal east-west direction for nearly 2000 km,. But the main chromium-bearing ophiolite is known to be distributed on the south bank of the Yarlung Zangbo River. Chromium-bearing ophiolitic bodies are observed intermittently on the surface of Robusa and Zedang. The geological studies are relatively high and the scale of the rocks is not large. To the west there are exposed Xigaze rock bodies, and then the west section of Dang poor, Plain, East Slope and other large rock mass. The aeromagnetic maps show that the Xigaze, Dongpo, Plain and Dangfang rock masses correspond to clear aeromagnetic anomalies. The relationship between the known rock mass and aeromagnetic anomaly is accurately determined by the surface magnetic survey of the above rock mass. The Rocksa and Zedang rock bodies located in the eastern section of the Yarlung Zangbo River belong to the small rock mass within the negative anomaly range of the northern margin of the strong aeromagnetic anomaly in the south of the rock mass. The chromium-bearing ophiolitic rock bodies in the western part of the Yangtze River are distributed intermittently, with short banded or larger cubic bodies. The surface magnetic anomaly highlights the heterogeneity of the distribution of magnetite in the surface rock mass. The serpentine and magnetic anomalies are stronger at the edge of the rock mass (including the surrounding rock mass), and the range of the rock mass is delineated more accurately. Aeromagnetic anomalies reflect relatively rich magnetic minerals and magnetic bodies inside the rock body, which may be derived from minerals such as Fe O _ 2O _ 3 in the deep layer, which upwelled to the upper crust of magma and formed Fe3O4, due to serpentinization. When the temperature is below 480 鈩，
本文编号：2392993
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