Structural Survey And Structural Analysis Of The Extruded Facies Guojialing Granodiorite In Jiaodong Area

There are many world-famous gold deposits such as Sanshan Island gold deposit,Linglong gold deposit and Jiaojia gold deposit in Jiaodong area which is the third largest gold deposit area in the world.The previous researches are focused on the granites related to the gold deposits in the region and the studies of these granite rocks structural features are scarce.This paper takes The Guojialing granodiorite as the main object of study and surveys the structure of pluton.On the basis of the field structural survey mapping,indoor structure measurement,projection and strain analysis of granodiorite,the following knowledge is obtained:1.The spatial distribution characteristics of the Guojialing granodiorite structural plane are revealed through field structural survey mapping.The Guojialing type granodiorites develop a group of conjugate structural planes oriented by potassium feldspar and dark minerals(amphibole and biotite),with the direction of nee-see and NE respectively.The strike of S1 structural plane is centralized distributed in the nee-see direction,with a tendency of 342° ? 47° and an inclination of 19° ? 58°.The S2 structural plane has a concentrated distribution of NE,with a tendency of 108° ? 175° and a concentrated inclination of 26° ? 57°.The strike Angle of S1 and S2 structural planes is 40°±10°,and the obtuse Angle is between 110° ? 135°.2.The petrological three dimensional structural surface characteristics of Guojialing type granodiorite are analyzedThree-dimensional structural measurements of the orientations of the guo-Jialing granodiorite indoor samples show that one group of conjugate structural planes of the Guo-Jialing granodiorite tends to NE SE and the other group tends to NEE NNW.The occurrence trend of extruded surface texture and some xenoliths mainly concentrated in NE-SW direction and tended to NW.The trend of the developed extension plane in the rock mass is mainly NW-SE and SW.The direction of the angular bisector of the extruded plane of rock mass is consistent with that of the angular bisector of the acute Angle of the conjugate structural plane.The strike of the extensional plane is perpendicular to the strike of the extruded plane and nearly parallel to the strike of the angular bisector of the obtuse Angle of the conjugate structural plane.3.The strain types of Guojialing granodiorite are analyzed by using the microstrain measurement method of rockThe tectonic deformation ratio of the inertia ellipse of the quartz grains under the microscope of the Guo-Jialing type granodiorite optical flakes shows that the average X/Y axis ratio of the quartz grains is 1.213,the average Y/Z axis ratio is 1.559,and the average K value is 0.465.Logarithmic Flinn graphic discrimination results show that the strain type is general compression strain and the structural rock type is SL type.4.Based on the Mesozoic tectonic environment and the structural characteristics of Guo-Jialing granodiorite in Jiaodong area,the structural model of Guo-Jialing granodiorite embeds is analyzedMesozoic cretaceous period,jiaodong region by NW-SE to extrusion,asthenosphere upwelling,lower crust and mantle mixed molten lava bottom invasion,magma in extrusion under the action of gravity and area along the NE-to NEE fault zone emplacement,long axis is NE to rock mass,rock mass during the emplacement due to NW-SE to squeeze under the action of forming a group to directional conjugate figured out and dark mineral potassium conjugate structure characteristic of surface.The direction of the sharp Angle of the conjugate structural plane is NE-SW direction,consistent with the direction of the rock mass extrusion surface,indicating the maximum extension direction of The Guo-Jialing type granodiorite rock mass.The direction of the obtuse Angle of the conjugate structural plane is n W-SE direction,which is consistent with the direction of the rock mass extensional plane,indicating the direction of the maximum principal compressive stress of the Guo-Jialing type granodiorite,which is matched with the regional stress direction of the early Cretaceous of Mesozoic in Jiaodong area.