| 羌塘盆地岩浆岩分布特征——来自高精度航空重磁的认识 |
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| 引用本文：魏岩岩,曹宝宝,周道卿,郑宇舟,胡夏炜,段宏伟,胡悦,肖梦楚,赵睿.2025.羌塘盆地岩浆岩分布特征——来自高精度航空重磁的认识[J].地球学报,46(3):519-532. |
| DOI：10.3975/cagsb.2024.111302 |
| 摘要点击次数: 50 |
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| 基金项目:自然资源部“航空地球物理与遥感地质重点实验室青年创新基金”(编号: 2023YFL03)、中国地质调查局地质调查项目“西部重点油气调查区航空物探调查”(编号: DD20230319)和“重点地区航空地球物理调查”(编号: DD20230012) |
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| 中文摘要:羌塘盆地岩浆活动强烈, 地表出露多处已知岩浆岩体。岩浆活动不仅可以反映盆地构造演化特征, 而且对盆地油气生成保存也具有重要意义, 因此研究盆地的岩浆岩特征既可以为盆地的构造演化提供依据, 又可以服务于羌塘盆地的油气及矿产资源调查。本文基于羌塘盆地实测高精度航空重磁数据, 利用位场转换处理等方法实现隐伏岩体范围圈定, 结合区域地质及野外物性测量分析, 总结典型岩体对应的航空重磁异常特征, 通过物性特征与地球物理场之间的联系, 开展(隐伏)岩浆岩填图, 形成基性-超基性岩体、中酸性岩体及火山岩分布图。结果表明, 研究区岩浆岩十分发育, 种类繁多, 火山岩、中酸性侵入岩和基性-超基性岩是引起区域升高正磁场和局部重磁异常的主要因素; 在南羌塘坳陷以及北羌塘坳陷普若岗日、格拉丹东等地识别出多处隐伏侵入岩体, 对油气成藏具有重要意义; 在北羌塘东部地区识别出大片隐伏火山岩, 推测其深部可能存在低密度异常体。研究成果提高了对羌塘盆地岩浆岩及其分布规律的认识程度, 为区域基础地质研究、盆地演化及油气矿产资源评价等提供更可靠的依据。 |
| 中文关键词:羌塘盆地 隐伏岩体 航磁 航重 物性特征 |
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| Magmatic Rock Distribution in the Qiangtang Basin: Understanding from High-precision Airborne Gravity and Magnetic Survey |
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| Abstract:Qiangtang Basin had experienced strong magmatic activities and many magmatic bodies are exposed on the surface. The magmatic activity reflects the tectonic evolution characteristics of the basin, and also plays an important role in the formation and preservation of oil and gas in the basin. Therefore, study of the magmatic rock characteristics of the basin provides a basis for understanding the tectonic evolution of the basin, and also facilitates investigation of oil, gas, and mineral resources in the basin. Based on high-precision airborne gravity and magnetic data from the Qiangtang Basin, this paper first uses airborne gravity and magnetic potential field conversion processing and other methods to achieve the scope of buried rock mass. Then, a large number of rock physical properties collected in the field were analyzed statistically, combined with geological and geochemical results, the typical airborne gravity and magnetic characteristics of the rock mass were summarized. The analysis showed that volcanic rocks, intermediate acid intrusive rocks and basic and ultrabasic rocks are the main factors causing local anomalies of the elevated positive and heavy magnetic fields in the region. Based on the connection between physical characteristics and geophysical field, magmatic rock mapping was carried out, and the distribution of basic-ultrabasic rock mass, acid-neutral rock mass and volcanic rock mass was established. The results showed that the Mesozoic intrusive rocks and Cenozoic volcanic rocks are very developed in and around the investigation area, which are the most important geological factors causing the changes of gravity and magnetic anomalies in this area. It is of great significance for oil and gas accumulation to identify a number of hidden intrusive rock bodies in the South Qiangtang Depression and Puruo Kangri and Gladandong areas in the North Qiangtang Depression. A large number of buried volcanic rocks have been identified in the eastern part of North Qiangtang Depression, and it is speculated that there may be low-density anomalous bodies in the deep part. The research results not only improve the understanding of the distribution characteristics of magmatic rocks, but also provide a reliable basis for the regional geological structure, basin evolution and oil and gas resources evaluation. |
| keywords:Qiangtang Basin buried rock aeromagnetic survey airborne gravity survey physical property analysis |
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