基于地球物理的广东省地壳热结构研究

The thermal structure of the earth is an important issue for geodynamics, geothermal science and geological studies. There are several lines of evidence that indicate that the lithosphere of Southeastern China had been thinned since the Mesozoic. This evidence includes the widespread development of factures, magma intrusions, volcanic eruptions and earthquakes. Such late Cenozoic tectonic activity is indicative of a warm crustal geotherm in Guangdong province, and has resulted in numerous active hot springs and indicative of regional geothermal potential. Geophysical methods provide the cornerstone for studies of the internal structure of the earth. The project will take advantage of geophysical data to study the thermal structure of Guangdong Province, and in doing so will make up for lack sufficient surface heat flow data. This project will use geophysical data to obtain fine boundary condition and constrain condition, as well as the distribution of a special thermal tectonic which is widespread in Guangdong Province, the low seismic velocity layer(one hypothesis is that the low velocity layer is indicated of very high heat production and high temperature in the middle crust). We will use the well-established one-dimensional steady-state heat conduction equation of the crustal geotherm and get high precision 3D temperature distribution, geothermal parameters and physical significance of low level layer in this region with high performance computing. We will analysis the different tectonic units crustal lateral heterogeneity and trace of asthenosphere movement (e.g., asthenosphere upwelling and lithospheric thinning) combining our geothermal model with field observations of crustal fractures and the locations of buried granite, in order to investigate the effect of factors such as temperature structural changes, analyze the crustal magma activity, tectonic plate movement and deformation of intraplate mechanisms. This will provide a better understanding of tectonic evolution of southern China and magmatic tectonic activity in eastern China and will alleviate local energy shortages.

地球内部温度结构是地球动力学和地热学及其他重要分支学科研究的重要课题. 中生代以来中国东南大陆岩石圈明显减薄，板内断裂构造发育，岩浆侵入、火山喷发、地震活动剧烈且持续，形成了复杂的深部构造和典型的广东地热异常区。地球物理是探测地球内部结构的基础。本项目为了弥补大地热流信息匮乏的不足，将充分利用地球物理资料获得精细的边界条件和约束条件，以及中国东南地区的特殊热构造层-低速层的空间展布，结合钻孔资料建立广东地区的一维稳态热传导方程。通过高性能计算得到区内高精度3D温度展布、地热参数和低速层的物性，结合断裂和隐伏花岗岩的分布全方位多角度分析不同构造单元地壳温度变化的横向不均匀性及软流圈运动的痕迹（如软流圈上涌及岩石圈减薄），探讨温度结构变化的影响因素，分析壳内岩浆活动、构造运动及板内变形机制，为深入认识华南地区的构造演化过程和中国东部的岩浆构造活动提供机理，并能缓解当地的能源紧缺问题。

地球内部温度结构是地球动力学和地热学及其他重要分支学科研究的重要课题；有效开发地热资源可有效缓解珠江三角洲及周边地区的能源危机。广东省存在大量的地热资源，中生代以来中国东南大陆岩石圈明显减薄，板内断裂构造发育，岩浆侵入、火山喷发、地震活动剧烈且持续，形成了复杂的深部构造和典型的广东地热异常区。地球物理是探测地球内部结构研究的基础。本项目以研究地热田地球物理特征为出发点，重点对重磁资料进行分析和处理，得到广东省莫霍面的展布，地层分布，隐伏花岗岩展布，沉积断陷盆地范围，居里等温面深度图等，结合构造运动分析了地热田的地球物理特征，并结合广东省的地热特征为进一步寻找地热田提出了建议。此外，根据重磁资料获得的地质模型，结合钻孔资料建立广东地区的一维稳态热传导方程，建立广东省3D温度模型。