东海地球物理场及深部地质构造研究

IOCAS-IR > 海洋环流与波动重点实验室

	东海地球物理场及深部地质构造研究
其他题名	Geophysical Field and Deep Tectonic Features
	韩波
学位类型	博士
	2008-05-25
学位授予单位	中国科学院海洋研究所
学位授予地点	海洋研究所
关键词	东海地球物理场深部构造莫霍面居里面磁性基底小波分析解析延拓
摘要	东海及邻域位于东亚大陆边缘，包括宽阔的陆架，相对较窄的陆坡和西太平洋典型的沟－弧－盆体系。这一地区地质结构、区域构造和形成演化的研究不仅对了解欧亚与太平洋二大板块间的相互作用和全球板块构造发展有重要意义；而且对于寻找丰富的油气和天然气水合物资源，维护我国海洋主权和权益，进行地质灾害预测，保护海洋环境，促进国民经济建设均具有重要意义；同时，对于探索印支运动以来亚洲东部大陆的构造演化也非常重要。独特的大地构造位置，丰富的矿产资源使其成为国内外地学研究的热点，也成为中日海洋划界，海洋主权与权益争夺的重要地区。本文以《我国海域1：100万地质地球物理系列图编制》项目为依托，收集东海及邻域岩石物性资料，利用东海及邻域重力异常数据和磁力异常数据进行地球物理场特征分析，并进行重磁资料数据处理，主要有解析延拓和小波分析，同时反演了深部界面，包括莫霍面深度，地壳厚度，磁性基底深度和居里面深度，通过地质地球物理综合解释，进而研究区域地质特征和构造区划，并对东海的构造演化进行讨论。利用东海及邻域最新重力数据进行解析延拓处理中，本文提出分区进行不同延拓高度的解析延拓处理，即从浙闽隆起到东海陆架盆地区，进行上延20km处理；从东海陆坡到琉球弧前盆地区，进行上延10km处理；从琉球海沟到菲律宾海区，进行上延5km处理，在此基础上获得了综合上延布格重力异常数据，并分析其变化规律。随着延拓高度的增加，浅部异常压制增大，异常曲线更加圆滑，深部构造特征更明显，东海布格重力异常自西向东的变化规律更清晰。经过计算统计，分区计算处理方法可行，所得结果可信。小波分析是重磁场位场分解的有效工具，不仅能提取深部异常，还能更好地将区域异常和局部异常分离。利用东海及邻域最新的布格重力异常数据资料，将小波分析与解析延拓方法相结合，分析对比向上延拓20km的布格重力异常结果与小波分析4阶逼近布格重力异常结果，求取东海及邻域莫霍面的深度，并对重力场及莫霍面深度进行初步研究。其中小波4阶逼近结果代表莫霍面形态，小波4阶细节结果代表东海及邻域凹陷形态。本文计算的东海莫霍面深度在12～34 km之间变化，莫霍面呈现两凹两凸形态，起伏变化很大。东海地壳厚度为6～34km，东海陆架地区地壳厚度变化与大陆地区相比并不明显，显著减薄开始于冲绳海槽地区，琉球岛弧处地壳厚度明显再度增加，认为东海地壳自西而东从陆壳－过渡壳－洋壳逐渐过渡的。东海磁性基底主要为火山岩、变质岩和火成岩。磁性基底深度起伏变化较大，东海研究区磁性基底深度在4～12 km之间变化，在各个地区磁性基底深度变化不一，编制的磁性基底深度等值线图反映了磁性基底的展布。东海居里面总体趋势由陆壳向洋壳变浅，整个东海海域居里面深度在14～29 km之间变化，深度等值线呈浑圆状，并且居里面不是单一的递增或递减的变化，而是呈现起伏变化的特征。东海地区重磁异常最明显特征是沿NE或NNE向展布，是断裂与构造分带的综合反映。根据东海重磁异常图、莫霍面深度图、地壳厚度图、磁性基底深度图及居里面深度图的分析结果认为，东海总的区域构造背景为东西分带，南北分块。东西分带是印支运动以来的主要构造特征，是中生代以来欧亚板块与太平洋板块相互作用在东海地区的反映；南北分块是印支以前的主要构造特征，是早中生代以前中国陆核形成发育，块体多次结合分离，最终形成中国大陆这一过程的反映。自西向东划分为浙闽隆起区、东海陆架盆地、钓鱼岛岩浆岩带（东海陆坡）、冲绳海槽盆地、琉球隆褶区和菲律宾海盆六大构造单元。本文应用最新的重力、磁力、地震和区域地质资料，在对物性进行了比较全面分析的基础上，利用先进的数据处理技术，首次提出了分区延拓处理方法和混合处理法，并在实际应用中取得非常好的效果；获得了东海及邻域莫霍面、居里面、磁性基底等几个主要深部界面，综合分析了各个界面的特点和相互之间的关系；进一步探讨了这一地区的深部地壳结构，为油气和天然气水合物等矿产资源调查与评价提供了新成果。
其他摘要	East China Sea and adjacent regions lie in the margin of East Asian continental and which conclude broad shelf and narrow slope and trench-arc-basin system of the West Pacific Ocean. The study on geologic constitution and regional structure and formation and evolution is significant to understand the interacting of Eurasia Plate and Pacific Plate and global plate structure development. It is also significant to search abundant oil gas and hydrate and maintain maritime sovereignty and reservation and it is also to geological catastrophic forecast and marine environment protection and national economic construction. At the same time, it is also significant to search East Asia continental geological evolution since Indo-Chinese epoch. Its unique geotectonic position and abundant mineral resources make it become geological hotspot between domestic and overseas and it become important region for marine delimitation and dominion and rights and interests dispute between China and Japan. Based on “Geological-Geophysical Map Series of China Seas (1:1,000,000)”, we collect petrophysics data of East China Sea and adjacent regions and analyze geophysical field with gravity and magnetic anomaly data and process the data by utilizing upward continuation and wave analysis methods. At the same time calculate deep interfaces which conclude Moho depth and Crust thickness and Magnetic boundary depth and Curie depth. Study areal geological feature and tectonic division according to geological and geophysical integrated interpretation and discuss tectonic evolution. The multiple-height upward continuation processing technology was applied to Bouguer gravity anomaly data from the different area, i.e. upward 20km for Zhe-Min Uplift to Continental Slope, upward 10km for the Okinawa Trough to the Ryukyu Island Arc, and upward 5km for the Ryukyu Trench to the Philippine Sea. Thus the multiple-height gravity anomaly data were obtained and used to retrieve Moho buried depths and analyzed the results show that the characteristics which gravity anomaly contours become smoother and the deep structures become clearer with the increase of the continuation height, which is more meaningful for studying the crust and geologic structure of East China Sea. Wave analysis is the effective tool to decompose of gravity and magnetic field and it not only can extract deep anomaly but also can effectively separate regional anomaly and local gravity. Based on the new Bouguer gravity data of East China Sea and adjacent regions, upward continuation and wave analysis methods are combined in the paper and Bouguer anomaly results of upward 20 km and the 4th order wave approximation are compared and Moho buried depths is calculated in the paper. Analyze and discuss the characteristics of deep structures and anomaly of the 4th order wave result approximation represents Moho and the 4th order detail wave result represents depressions of East China Sea and adjacent regions Moho buried depth changes between 12 and 34 km and Crust thickness changes between 6 and 34 km and the whole Moho shows concave-convex-concave-convex configuration. Each region is different in East China Sea and adjacent regions. In Continental Shelf region, the crust thickness doesn’t change obviously. The thickness of crust begins to thin evidently in Okinawa Trough and middle crust disappears there. In Ryukyu Island Arc region, the crust thickness increases again and upper crust increases most obviously. We deduce it transients from continental crust-transition type crust-oceanic crust from west to east. Magnetic boundary depth contour map reflects the magnetic boundary spread and magnetic boundary of East China Sea are mainly volcanic rock and metamorphic rock and igneous rock. Magnetic boundary depth changes greatly from 4km to 12km in different regions. Curie depth turns into shallow from continental crust to oceanic crust and the whole Curie depth changes from 14km to 29km and contours appear absolute round shape. Curie depth map manifests fluctuant changeable feature rather than singular increasing or descending changeable feature. Gravity and magnetic anomalies of East China Sea manifest NE and NNE spread and are the integrated reflection of fracture and structure. The whole regional tectonic background of East China Sea manifest east-west zoning and south-north blocking feature according to gravity and magnetic anomalies map and Moho and Crust and Magnetic boundary and Curie depth maps. East-west zoning is the main tectonic feature since Indo-Chinese epoch and it is the reflection of Eurasia Plate and Pacific Plate interaction since Mesozoic. South-north blocking is the main tectonic feature before Indo-Chinese epoch and it is the reflection of Chinese Mainland after formation and development of Chinese nuclear and integration and separation of block time after time. There are namely Zhe-min Uplifted Fold Zone and East China Sea Shelf Basin and Tiaoyu Island Magmatic Zone (East China Sea Slope) and Okinawa Trough Basin and Ryukyu Uplifted Fold Zone and Philippine Basin tectonic units. The new gravity and magnetic and seismic and areal geological data are used in the paper and we firstly propose multiple-height upward continuation and mixed processing technology and they obtain excellent result in practice application on the base of analyzing petrophysics and utilizing advanced data processing technology. We calculate deep interfaces which conclude Moho depth and Crust depth and Magnetic boundary depth and Curie depth of East China Sea and we analyze complexly the feature and relation of each interface. We further discuss deep crust structure and it offers new result for investigation and evaluation of oil and gas and natural gas hydrate etc mineral resources.
页数	112
语种	中文
文献类型	学位论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/819
专题	海洋环流与波动重点实验室
推荐引用方式 GB/T 7714	韩波. 东海地球物理场及深部地质构造研究[D]. 海洋研究所. 中国科学院海洋研究所,2008.

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