物探与化探2011，Vol.35Issue(3)：290-297,8.
磁异常三维解析信号所揭示的中国东部及邻近海域岩浆岩特征
MAGNETIC ACTIVITIES IN EASTERN CHINA AND ADJACENT SEAS REVEALED BY 3D ANALYTIC SIGNALS OF MAGNETIC DATA
摘要
Abstract
Analytical signals estimated from total field magnetic anomalies in eastern China and adjacent seas are found to be more accurate in detecting locations, depths, and boundaries of magmatic bodies than original magnetic anomalies.The depth distributions of magmatic sources differ significantly between different tectonic blocks.The North China Craton shows high analytical signal amplitudes and large lateral extensions, but the detected magmatic sources are mostly deeply buried at depths up to 10 km or larger.This indicates strong magmatic activities in the lower to middle crust of the craton from tectonic reactivation.Due to tectonic uplifting and magmatic intrusions, the Sulu-Dabie Orogen has mainly shallowly buried magmatic bodies with depths smaller than 5 km.The Yangtze Block shows predominantly deeply buried magmatic sources, but unlike North China Craton, the magmatic activities in the Yangtze Block appear to be very weak and the calculated analytical signal amplitudes there are very small.The Cathaysia Block and its offshore northeastward extension is dominated by relatively isolated and shallow magmatic bodies (mostly ＜ 5 km) that are mainly caused by the subduction of the Palco-Pacific Plate in the late Mesozoic.Depths of magmatic sources in the East China Sea correlate well with basement uplifts and depressions caused by Cenozoic continental margin rifting.The Ryukyu Archipelago corresponds with a very quiet magnetic zone and shows deeply buried magmatic sources, and these observations support the reasoning that the Ryukyu Archipelago itself is not the volcanic arc from the subduction of the Philippine Sea Plate but is composed of accretionary materials and/or continental blocks separated from the Eurasian Plate by opening of the Okinawa Trough.The true volcanic arc is represented by a volcanic belt slightly to the west of the Ryukyu Archipelago.关键词
磁异常/三维解析信号/岩浆活动/中国东部Key words
magnetic anomaly/ analytical signal/ magmatic activity/ eastern China分类
天文与地球科学引用本文复制引用
张少武,李春峰..磁异常三维解析信号所揭示的中国东部及邻近海域岩浆岩特征[J].物探与化探,2011,35(3):290-297,8.基金项目
国家自然科学基金项目(40876022),国家重点基础研究发展规划项目(973项目)子课题(2007CB411702),国家高技术研究发展计划(863计划)重点课题(2008AA093001),教育部新世纪优秀人才基金资助 （40876022）
