Petrochemistry of peridotites from North China: Significance for lithospheric mantle evolution |
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| Authors: | Zheng Jianping Yu Chunmei Yuan Xiaoping Yin Li Jiao Shujuan Tang Huayun Zhang Zhihai and Lu Fengxiang |
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| Institution: | (1) State Key Laboratory of Geological Processes and Mineral Resources, Faculty of Earth Sciences, China University of Geosciences, Wuhan, 430074, China |
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| Abstract: | A petrochemical analysis was undertaken of peridotitic xenoliths in volcanic rocks that erupted from the Paleozoic to the
Cenozoic within the eastern part of the North China craton, and the peridotites as tectonic intrusion in the Early Mesozoic
from the Sulu orogen. The results show that the cratonic mantle, which was refractory and existed when the kimberlites intruded
in the Paleozoic, had almost been replaced by the newly accreted fertile lithospheric mantle during the Mesozoic-Cenozoic.
The erosion, metasomatism, and intermingling caused by the accreted asthenospheric material acting on the craton mantle along
the weak zone and deep fault (such as the Tanlu fault) in the existing lithosphere resulted in the lithospheric thinning at
a larger scale 100 Ma ago (but later than 178 Ma). The largest thinning would be in the Eogene. The upwelling asthenospheric
material transformed into accreted lithospheric mantle due to the asthenospheric temperature falling in the Neogene (leading
to relatively slight lithospheric incrassation), and finally accomplished mantle replacement. The peridotitic body in the
Sulu orogen represents the products spreading from the modified cratonic lithospheric mantle.
Translated from Earth Science—Journal of China University of Geosciences, 2006, 31(1): 49–56 译自: 地球科学—中国地质大学学报] |
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| Keywords: | peridotite petrochemistry mantle replacement eastern North China block |
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