The Volcanic Facies And Volcanic Apparatus Study Of Mesozoic Volcano Rocks In West Ujimqin, Inner Mongolia

West Ujimqin of Inner Mongolia entered a new period of geological evolution during the Mesozoic,that the Pacific plate subducted Eurasian plate.In the eastern part of Inner Mongolia,have formed a set of N E,N-trending ridges and fault basin and accompanied by intense volcanic activity.Volcanismformed the UpperJurassicJ3 mk,J3mnand earlyCretaceous K1 b volcanic basins.We found in study area that the characteristics of the three groups of volcanic rocks " a neutral of the two acid-folder",by the volcanic region of the three groups of mineral composition,texture,structure,occurrence,symbiotic combination of various types of rocks comprehensive analysis.However Baiyingaolao formation is acidic lava and volcaniclastic rock.Manitu formation is intermediate lava.Manketou Obo formation is acidic lava and volcaniclastic rock.We identified effusive phase,off the air accumulation phase,debris flow accumulation phase,caving accumulation phase,volcanic channel phase,sub-volcanic facies,volcanic eruption-sedimentary facies 7 types of volcanic facies.We divided volcanic structure in study area into three ? grade volcano-tectonic depression(eruption basin,volcano-tectonic depression),12 ? grade volcanic bodies(shield volcano,stratovolcano,dome-shapedvolcaniccone volcanoeruptioncenter).On the spatial and temporal distribution of magmatism in the study area think that in west Ujimqin of Inner Mongolia Mesozoic volcanic activity controlled by the movement of the Pacific plate.Massive volcanic rock along the NNE zonal concentrated on the continental margin,showing the characteristics of an active continental margin.The location of Mesozoic magmatism in the area should be the continental plate side near the edge of the continental margin,or the transition zone of the plate.Its evolution reflects a complete orogenic cycle,and the entire orogenic cycle in the tectonic stress field reversal has occurred many times,however it wholely shows the relative extension of the EarlyCretaceous of the change process from the LateJurassic ofsqueezing.