Article ID Journal Published Year Pages File Type
4691680 Tectonophysics 2015 7 Pages PDF
Abstract

•Lower crustal xenoliths and terrain granulites show large magnetic differences.•Stratified magnetic lower crust is preserved in the North China Craton.•Underplating of basaltic magmas since the late Mesozoic played a key role.

The magnetic properties of lower crustal xenoliths, and outcropping granulites suggest that magnetically stratified lower crust is preserved in the northern North China Craton. The upper layer (~ 24–33 km) is represented by strongly magnetic granulite-facies terrains, in which the mafic granulites have the highest susceptibility (κ, mean 67.92 × 10−3 SI) and natural remanent magnetization (NRM, mean 0.59 A m−1). In contrast, the lowermost layer (~ 33–42 km) is mainly composed of mafic granulites and pyroxenites sampled as xenoliths, which are weakly magnetic with κ and NRM of 0.9–1.5 × 10−3 SI and 0.04–0.1 Am−1, respectively. The formation of the weakly magnetized lowermost crustal layer is associated with continuous underplating of mantle-derived basaltic magmas at the pre-existing crust–mantle boundary from the late Mesozoic to Cenozoic. We suggest that this magnetically stratified lower crust may be widespread beneath the North China Craton.

Related Topics
Physical Sciences and Engineering Earth and Planetary Sciences Earth-Surface Processes
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