Postcollisional mafic igneous rocks record crust-mantle interaction during continental deep subduction.
Zi-Fu Zhao1, Li-Qun Dai, Yong-Fei Zheng
1CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China.
Scientific Reports
|December 5, 2013
Summary
Continental subduction to mantle depths is evidenced by coesite and microdiamond. This geological process facilitates crust-mantle interaction, recorded in postcollisional mafic rocks, offering insights into convergent plate margins.
Area of Science:
- Geology
- Geochemistry
- Petrology
Background:
- Continental subduction to mantle depths is a key process in orogenic belts.
- Crust-mantle interaction is crucial for understanding tectonic evolution.
- The Dabie-Sulu orogenic belt provides a natural laboratory for studying these phenomena.
Purpose of the Study:
- To investigate the mechanisms of crust-mantle interaction during continental subduction.
- To analyze the geochemical signatures of postcollisional mafic igneous rocks.
- To establish postcollisional mafic rocks as analogs to arc volcanics for studying subduction processes.
Main Methods:
- Analysis of coesite and microdiamond in metamorphic rocks.
- Geochemical analysis of whole-rock trace elements and Sr-Nd-Pb isotopes.
- Zircon U-Pb geochronology and Hf-O isotope analysis.
Main Results:
- Recognition of continental subduction to mantle depths based on ultrahigh-pressure minerals.
- Postcollisional mafic igneous rocks show geochemical inheritance from subducted continental crust.
- Evidence of melt-peridotite reaction transferring crustal signatures to mantle sources.
Conclusions:
- Continental subduction leads to significant crust-mantle interaction.
- Postcollisional mafic rocks in the Dabie-Sulu belt record this interaction.
- These rocks serve as valuable analogs for studying subduction zone processes globally.
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