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| Titel |
Interpretation of aeromagnetic anomalies of the Sulu ultrahigh-pressure (UHP) metamorphic belt, eastern China |
| VerfasserIn |
N. Qiu, Q. S. Liu |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250022072
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| Zusammenfassung |
| The Sulu ultra-high pressure (UHP) metamorphic belt in eastern China is well known as the
eastern extension of the Qingling-Dabie orogenic belt formed by subduction and collision
between the Sino-Korean and Yangtze cratons. The main hole of the Chinese Continental
Scientific Drilling (CCSD) project is located at the southern segment of the Sulu UHP
metamorphic belt (34º25´N/118º40´E), about 17 km southwest of Donghai county. Integrated
geophysical investigations using gravity, magnetic, deep seismic reflection, magnetotelluric,
and geothermal observations were carried out for area around the CCSD main hole, drawing
more attention for interpretation lithospheric structures in the Dabie-Sulu terranes over the
last decade.
However, less effort have been so far fulfilled for interpretation and research of
aeromagnetic data in this study area. Lately, the aeromagnetic survey acquired
with line spacing of 500m, allows us to distinguish key geological structural style
within upper crust and probe relationships between magnetic structure and deep
geodynamics in Sulu UHP metamorphic belt. This paper proposed results for geological
interpretation of aeromagnetic anomalies to reveal crustal magnetic structure in this study
area.
The inversion of aeromagnetic data using Euler deconvolution technique based on
differential similarity transformation, combined with regional geological background and
borehole magnetic data, shows that magnetic sources are appeared mainly NNE-SW trending
corresponding to granite diorite, retrogressed eclogites and acid and basic granulite-facies
rocks around Tanlu fault with different depths, magnetization directions and structural indices
in crust. The northward dipping to the surface of the shallow magnetic sources reveals that
they may have been resulted from the subduction of Yangtze carton and returned along the
original path in Triassic period. This subduction resulted in part of the continental crust
subsiding into the upper mantle. The deep intracontinental subduction maybe continuous
converge between the Sino-Korean and the Yangtze cratons. Therefore, there is still
required further research evidence to illustrate by what means of thinning, intrusion
and rifting the lithosphere in the eastern China during the Cretaceous and Eogene. |
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