Interpretation of aeromagnetic anomalies of the Sulu region, eastern China and implications for deep geology |
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Authors: | Zhao Sutao Liu Qingsheng Qiao Qingqing and Fu Yuanyuan |
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Institution: | (1) Graduate School, China University of Geosciences, Wuhan, 430074, China;(2) Institute of Geophysics and Geomatics, China University of Geosciences, Wuhan, 430074, China;(3) Department of Geophysics, Peking University, Beijing, 100871, China |
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Abstract: | By using data on the 1:100 000 aeromagnetic anomalies of the Sulu orogenic belt, we designed three simulated geotraverses,
in which deep seismic reflection and other geophysical investigations have been completed. Based on the features of magnetism
of the three profiles, and under the constraints of deep seismic reflection data, together with the magnetism of the core
petrology at the Chinese Continental Scientific Drilling (CCSD) pilot-hole and areal geology, the three inversions of magnetic
anomalies are carried out. The characteristics of terrane structure are presented: the rocks are mostly composed of eclogite,
marble, and gneiss at the depth of 5 km. At the depth between 5 and 7 km under the surface, inverse magnetic bodies are mainly
the ultra high pressure metamorphic (UHPM) rock slices containing a lot of coesite-bearing eclogite. At the depth between
7 km and the bottom of upper crust are the rocks of the gneiss, granite and granite diorite that underwent ultra high pressure
metamorphic process. Middle crust (10–19 km) is mostly composed of UHPM gneiss and granite that intruded later. The rocks
of acid and basic granulite dominate the lower crust. Based on the inversed results of the three simulated geotraverses, we
know that the UHPM rock slices of the three profiles are dipping north, stacking each other and being uplifted to the earth’s
surface, which may be the result of the North China craton’s subduction and exhumation in the Triassic.
Translated from Geological Science and Technology Information, 2007, 26(2): 107–112 译自: 地质科技情报] |
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Keywords: | aeromagnetic anomaly rock magnetism deep geology Sulu orogenic belt |
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