Mesozoic dyke swarms in the north of North China.

Dyke swarms are products of typhonic magma which may provide important information about the crust-mantle evolution. This work studies comparatively several dyke swarms in the north of North China, including the Early Mesozoic Datong carbonatite-lamprophyre dyke swarms, Early Mesozoic Chifeng dioritic porphyrite-diabasic dyke-swarms, Mesozoic Linxi diabasic dyke-swarms, and North-Beijing Late Mesozoic bimodal dyke swarms. Thus it is revealed that there were two successive processes of underplating and accompanying extension in the Mesozoic in North China. Comparison of the Early Mesozoic, Late Mesozoic, and Protozoic dyke swarms in North in certain extent reflects revolution of the mantle composition in North China.