全国航磁ΔT异常与中国地学断块构造

NATIONWIDE AEROMAGNETIC ΔT ANOMALIES AND CHINA'S GEOSCIENCE BLOCK STRUCTURES

经过近50多年航磁工作,发现和圈定了全国大中型沉积盆地及沉积岩总厚度,评价了各沉积盆地的找油气方向,发现一系列重要条带状构造带及断块状构造区,它们断错镶嵌组成中国地学中的断块构造图景,其中近东西向的阴山—天山构造带,勾绘了亲西伯利亚构造域(准噶尔、松辽、佳木斯断块南界)。西昆仑—秦岭—大别构造带组成了古中华构造域(塔里木、柴达木—阿拉善、华北—胶辽断块)的南界;可可西里—金沙江构造带展现了亲冈瓦纳构造域(羌塘、革吉—班戈、冈底斯—拉萨、喜马拉雅断块)的东北边界;钦州—杭州构造带围限出华夏—南海构造域(华夏断块、东海陆架、台湾海峡、珠江口—海南岛断块及南海海盆)的北部边界。在镶嵌地学断块中,南北走的裂谷构造带,边幕型弧块构造带及环形构造区,在航磁异常图中展示明显,且与隐伏的油气资源、煤田及铁矿富集区关系密切,是当前全国找矿的重要方向。中国陆壳历经复杂的裂解、增生、拼贴、重力调整、热力均衡演化活动,这些活动被地球旋转非均衡性作用和地慢的上涌及沉降动力学所控制。

As a result of more than fifty year's aeromagnetic work,large-and medium-sized sedimentary basins and the total thickness of their sedimentary rocks have been discovered and delineated,the targets for oil and gas exploration in each sedimentary basin have been evaluated,and a series of important banded tectonic belts and block-like tectonic regions have been discovered,whose dislocation mosaic frameworks constitute the block tectonic pattern in China's geoscience. In this pattern,the nearly EW-trending Yinshan-Tianshan tectonic belt depicts Siberia-affinity tectonic domain( southern boundary of Junggar,Songliao,Jumusi block); West Kunlun-QinlingDabie tectonic belt constitutes the southern boundary of paleo-Chinese tectonic domain( Tarim,Qaidam-Alxa,North China-Jiaoliao block); Hoh Xil-Jinshajiang tectonic belt displays the northeastern boundary of Gandwana-affinity tectonic domain( Qiangtang,Ge' gyai-Baingoin,Gangdise-Lhasa,Himalaya block); Qinzhou-Hangzhou tectonic belt delimits the northern boundary of Cathaysian-South Sea tectonic domain( Cathaysian block,East Sea shelf,Taiwan Straits,Zhujiang estuary-Hainan Island block and South Sea basin). In the mosaic geoscience block,NS-trending rift tectonic belts,marginal curtain-style arc block tectonic belts and annular tectonic regions are distinctly displayed in the aeromagnetic anomaly map,and are closely related to the concealed oil-gas resources,coal fields and iron ore concentration areas,thus serving as the important targets in current nationwide ore-prospecting work. China's continental crust has experienced complex breakup,accretion,collage,gravity adjustment,and thermal isostatic evolution. These activities were controlled by the nonuniform action of the revolution of the Earth and mantle upwelling as well as subsidence dynamics.