【作者】 付媛媛；

【导师】 刘庆生；

【作者基本信息】 中国地质大学 ， 固体地球物理学， 2005， 硕士

【摘要】 岩石圈结构、组成及演化研究是现代地球科学的前缘与热点。本论文选题是将地球物理学、岩石学和地质学等学科的基本理论与思维相结合，依据研究区磁卫星磁场与航空磁异常的数据，研究苏鲁地区超高压变质带深部磁性结构，并应用岩石圈磁性结构与深部地球动力之间相互关系的基本准则，探讨郯庐断裂带以东华北克拉通与扬子克拉通碰撞的动力学模式。 研究过程中根据Jacobsen提出的不同上延高度位场的残差异常对应岩石圈内某一深度范围的场源物性分布特征，对研究区航磁数据进行多尺度异常分离处理，提取出反映不同尺度的场源信息。经对比分析，将上延10—30km的化极航磁残差异常近似对应上地壳场源的磁性特征，上延60—100km的化极航磁残差异常近似对应中地壳；化极卫星磁异常近似代表下地壳至上地幔顶部场源的分布。该方法计算结果可能存在一定误差，但物理意义明确，算法稳定、简单，可以作为一种地壳或岩石圈磁性结构半定量分析方法。 为获得研究区视磁化率分布，本文利用等效偶极源方法，对不同尺度的磁异常进行正反演，获得磁性体磁化率的空间分布特征。并据此作为分析研究区磁性分区特征及场源岩性解释的基础。 为获得磁性体的空间分布，对航磁数据采用三维欧拉反褶积方法反演磁性体边界和深度。 上述三种方法处理与反演的结果，成为本次研究的基础。通过对比分析并结合其它资料，确定了超高压变质带地壳深部磁性结构，进而尝试建立不同时期俯冲动力学背景下超高压变质带折返机制和华北与扬子克拉通碰撞的概念模式。 本次研究取得成果具体如下： 1．将航磁异常与卫星磁异常结合，尤其是航磁长波长磁异常与400公里高度磁卫星磁场对比，分析研究不同尺度的磁异常特征，为研究区深部磁性结构分析提供基础。依据化极上延航磁残差异常、卫星磁异常及其对应的视磁化率，得到了研究区三维空间磁性结构。一般规律为：中酸性岩石，如花岗岩、花岗闪长岩与花岗片麻岩区表现为低磁性特征；基性超基性岩大多分布规模小，引起的磁异常不明显；基底深变质岩表现出较强磁异常。 2．根据不同尺度磁异常特征，对研究区进行了构造分区。共划分出华北克拉通、扬子克拉通及苏鲁造山带三个Ⅰ级构造单元；郯庐断裂带、鲁西台隆、徐淮断隆、苏北胶南地体和苏北断坳五个Ⅱ级构造单元。这些结果与区域地质构造基本一致。 3．研究区深部存在明显北西向分布的大尺度地质体，自鲁西台隆跨过郯庐断裂带，经胶南、日照进入黄海。磁性体项界面埋深约为19km，在郯庐断裂以西略浅，以东略深，大致反更多还原

【Abstract】 Research on lithosphere is the forward position of the contemporary geosciences. The data of geophysics, petrology and geology are integrated to study the deep magnetic structure of the ultra-high-pressure metamorphic belt in Sulu. The intensive dynamic processes which have occurred after the collision between the Sino-Korean and Yangtze cratons are discussed based on the study.In this study, three methods (upward-continuation, equivalent source and euler deconvolution) are used to process the aeromagnetic data and satellite magnetic data. The magnetic structure of crust is obtained.According to Jacobsen, the information corresponded to various deep layers can be obtained when the gravity or magnetic data are processed by upward continuation. The property of upper crust can be deduced from the residual anomaly which is got by subtracting the anomaly at 10km from the total anomaly and the anomaly at 30km from the anomaly at 10km. Similarly, subtracting the anomaly at 60km from the anomaly at 30km and the anomaly at 100km from the 60km correspond to the magnetic sources in the middle crust. The large-scale and deep-seated terranes and structures in the lower crust can be interpreted from the satellite magnetic anomaly. Through this method may produce much big error, it is easy to calculate and has clear geophysical principle. It can be a semi-quantative approach.The apparent susceptibility can be received by an equivalent source technique. The spacial distribution of apparent susceptibility is obtained by inversing various scale magnetic anomaly.The depth and horizontal position of magnetic object are estimated by Euler deconvolution. The technique is based on Euler’s homogeneity relationship and requires no prior knowledge of the source magnetization direction. It has been widely used in automatic aeromagnetic interpretation.The results are as following:1. According to the characteristic of magnetic anomaly and the distribution of faults, the study aero can be divided into three main tectonic units (Sino-Korean, Sulu orogenic belt and Yangtze更多还原