Magnetic Fabrics Of The Xuehuading Granitic Pluton In Western Nanling Range And Its Geological Significance

This paper based on the field geological investigation,by the methods of petrology?feldspar phenocryst orientation measurement?magnetic fabric?rock magnetism,we researched the deformation features?emplacement process and ways and its geotectonics settings of Xuehuading granite rock.The results show that Xuehuading granite rock lithology is mainly hornblende biotite monzonitic granite,secondary lithologic is biotite granodiorite.The magnetic susceptibility(Km)is lower,and is mainly coming from biotite,very little magnetic susceptibility comes from magnetite which can use to control the inner fabric features.Eldspar phenocryst orientation results show that preferred orientation of eldspar phenocryst consistent with the orientation of magnetic lineation,which indicates the magnetic fabric features of Xuehuading granite rock are primary flow structure;the The magnetic susceptibility anisotropy(P)is lower with a weak deformation which conform to the magmatic emplacement features.And the magnetic susceptibility anisotropy(P)is getting weaker from the middle part to the sides of the rock,while the strain type switch from compressed type to elongated strain,which also indicates structural environment switch from compressed type to elongated type with a obvious passive emplacement feature.Generally the magnetic lineation of Xuehuading granite rock extends in NE or SSW direction which indicates magma flows to the south and the north direction while invading;the magnetic lineation inner the rock parallel to the long axis direction of rock,while the magnetic lineation of the sides intersect with the rock sides in a low angle and point to the outside of the rock which indicates the former magma invades along with the faults lines,the following magma invades along the side faults and flow into the inner side.The magnetic foliation dips toward in SW-NE direction shows the invasion of magma inner and side were controlled by SW-NE pressing strength with a expansion direction consistented with the direction of principal axis of the rock,also meaned that the invasion was long controlled by NNW faults.We suggest the expansion of the dyke causes the invasion of the Xuehuading granite rock along with the faults.