贵州镇远地区钾镁煌斑岩产出控制因素浅析OA北大核心CSCDCSTPCD

The Maping Iamprophyre in the Zhenyuan area of Guizhou Province is the first one containing primary diamonds discovered in China,which was formed in the middle Caledonian period.In light of features of sedimentary formations,the fact that lamprophyre often contains early xenoliths and that this rock occurs at bending points of flanks of the NE-trending anticlines of the Caledonian period,this work suggests that this rock intruded in the Caledonian when sedimentary formations have ended folding.In the early Caledonian tectonic movement,sedimentary formations firstly underwent plastic transformation to form folds and mountains,and then a large number of fracture structures developed.With compressive and shear stresses,fold inflections of vertical bending folds formed penetrative weak-structure portions,which can serve as migration conduits for magma due to deep magmatic thermal upwelling.The EW-trending basement faults in the Sibao stage controlled the distribution of the EW-trending lamprophyre,and the Caledonian folds and their bends exerted a key control on lamprophyre bodies.It is thus considered that the diamond survey in this region should be conducted around the fold bends with diamond prospecting information.