| Gawei Ji rock were located in eastern Zongwulong Rock tectonic belt which sandwiched between the North Qaidam tectonic belt and southern Qilian structural zone.It includes fine-grained diorite,containing fine-grained biotite monzonite granite,granite porphyry and syenite granite and exposes about 150km~2.In this paper,the author analyzed the petrography,rock geochemical characteristics,age characteristics and genetic types of Gawei Ji rock in details by lord,trace element geochemistry,U-Pb zircon dating and combined with field geological characteristics.The author explores the background of tectonic magmatic rocks formed,source material,and the evolution of services for cases of long structural zone closing time significance by these data.This study fine-grained diorite belongs to high-K calc-alkaline sodic rocks unsaturated aluminum and magnesium andesite belonging to the class,including the fine-grained biotite monzogranite belonging to too weak potassium aluminum iron-rich calc-alkaline rocks,potassium-rich porphyry belonging to stronger than aluminum potassium calc-alkaline–shoshonite and syenogranite belonging to too weak aluminum high-K calc alkaline rocks.Zircon U-Pb dating of fine grained diorite data show formed in 261.3±5.9Ma,granite porphyry emplaced in 262.4±2.5Ma,syenogranite forming age of 262.8±3.9Ma,and the fine particles containing biotite monzonite granite to the age of the sample is not collected,in accordance with its wild contacting relationship that is consistent with its three kinds of age should be formed,both the PermianDiorite series belong to type I,formed in an island arc subduction period,the fine particles containing biotite monzonite granite,granite porphyry belonging to S series,syenite granite belonging to different high S-type granites are formed in the same collision phase.Diorite,monzonite granite,granite porphyry,syenite granite display component polarity on geochemistry,belong to the product development process with different orogenic and reflects orogeny duration of not less than 1.7 million years.Gawei Ji rock evolved on the basis of Carboniferous-Early Permian plume role in theformation of triple rift.Afterwards,as Anima Ocean northward subduction subduction trigger-orogenic tectonic events led to the formation of rock Gawei Ji.Arc appears diorite displays the first closing time of the Zongwulong tectonic belt was 261.3±5.9Ma,and the subduction direction was north. |
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