Acta Scientiarum Naturalium Universitatis Pekinensis
HAN Baofu, WANG Shiguang
The Cenozoic basalt from Chifeng region, North China, are characterized by Al2O3=12.51%-14.42%, Na2O>K2O, and TiO2>2.00%. They are continental flood basalt, produced by fissure-type volcanism in the Miocene. The basalts chemically belong to the tholeiitic series and were derived from asthenospheric source regions. Two processes would be responsible for the generation of the basalts. The basaltic magma was first generated by partial melting of peridotites in the mantle, followed by fractionation of olivine from the magma. The magma formed at depth of the mantle ascended into a chamber within the continental crust, where it could cease moving up further and concentrated to some extent. It was in the chamber that some of olivine crystallized early was fractionated from the magma. Then, the remaining olivine would reacted with the magma, resulting in the development of clinopyroxene rim around olivine. It is suggested that the fractional crystallization of olivine from the magma is probably a common process to the formation of continental flood basalts.
continental flood basalt,
HAN Baofu,WANG Shiguang. General Features and Origin of Cenozoic Basalts from Chifeng Region, North China[J]. Acta Scientiarum Naturalium Universitatis Pekinensis.
韩宝福,王式guang. 赤峰地区新生代玄武岩的基本特征及成因[J]. 北京大学学报（自然科学版）.
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