Petrochemical characteristics of the Mesozoic-Cenozoic volcanic rock in Huanghua basin

Abstract

Based on the data from typical core sampling, combined with K-Ar dating, petrochemistry, trace elemental geochemistry and isotopic compositions of the Mesozoic-Cenozoic volcanic rock in the Huanghua basin, Bohai region, the geochemical features of the volcanic rock were studied. The rocks fall into four groups: Cenozoic basalt, Mesozoic late Cretaceous basaltic-trachyandesite, Mesozoic late Cretaceous trachy-dacite and liparite, and Mesozoic early Triassic dacite. The distribution pattern of the main elemental abundance of late Mesozoic shows a typical bimodal. Chronologically, for the volcanic rock, the amount of SiO₂ decreases gradually, the contents of Fe₂O₃,FeO,CaO,MgO,TiO₂,P₂O₅ and MnO increase little by little. The Cenozoic basalt is derived from the asthenospheric mantle. The late Cretaceous basaltic-trachy-andesite is derived from the enriched lithospheric mantle. In late Cretaceous and early Palaeogene, the felsic volcanic rock may be derived from fractional melting of the crust.

Keywords

Mesozoic-Cenozoic era / volcanism / petrochemistry / Huanghua basin

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