Geochemical and isotopic imprints of early cretaceous mafic and felsic dyke suites track lithosphere-asthenosphere interaction and craton destruction in the North China Craton

Abstract

The North China Craton (NCC) underwent significant lithospheric destruction during the Mesozoic, although the mechanisms and timings associated with this process remain debated. The extensive magmatism associated with craton destruction includes dyke suites of diverse composition derived from lithospheric and asthenospheric sources. Here we investigate lamprophyre, dolerites and felsic dyke suites from the Laiyuan complex in North Taihang Mountain of the NCC. Zircon UPb dating shows weighted mean ages in the range of 110–115 Ma, 117–126 Ma and 127–130 Ma for the lamprophyres, dolerites and felsic dykes and their εHf (t) values show a range of −17.2 to −3.7, −23.3 to −14.2 and − 22.3 to −17.2, respectively, with an evident increase through time suggesting increasing input of asthenospheric components in the mafic suite. We present major, trace and REE data on these rocks which suggest that the mafic dykes experienced limited crustal contamination and were dominated by olivine and clinopyroxene fractional crystallization. The Laiyuan mafic dykes were derived through partial melting mantle previously enriched by subduction-related fluids, within amphibole- and garnet-stability field with increasing input of asthenospheric material through time. The felsic dykes show adakitic feature with magma generation through the reworking of ancient basement rocks induced by heat input from underplated mafic magma which was derived from the partial melting of enriched lithospheric mantle. Subsequently, the enriched mantle-derived magmas migrated through lithospheric faults and were emplaced as dolerite dykes at ~117 Ma. The asthenosphere upwelling contributed to the thermo-mechanical erosion along weak zones, and the limited lithosphere-asthenosphere interaction generated the lamprophyres during ~115 Ma to 110 Ma. Our data suggest that both delamination and thermo-mechanical erosion contributed to the craton destruction of the NCC during Early Cretaceous.