THE MAGNETIC FABRIC CHARACTERISTICS OF ROCKS FROM ZHONGJIA TIN DEPOSIT AND THE VICINITY, FUJIAN PROVINCE

The magnetic fabric of rocks is a reflection of the susceptibility anistropy of the rocks concerned.Magnetic fabric analysis is used in determining the structural features,and the direction of the stresses that produced such features. Study of magnetic fabric features of the Zhongjia tin deposit,Fujian,shows a very small susceptibility anisotropy( P )of the rocks indicating an overall weak deformation.However the relatively well developed magnetic schististosity with poorly developed magnetic lineation in the quartzose sandstone suggests a NW-SE compression resulting in a flattening in this direction.The marked NW-SE magnetic lineation developed in the volcanic rocks may indicated their flow direction that agrees with the compression.The susceptibility anisotropy of hydrothermally altered rocks is generally lower than that of metamorphozed quartzose sandstone as a result of part reduction of their susceptibility anisotropy.So evidently,the application of magnetic fabric analysis to weakly deformed rocks may be helpful just as in Zhongjia.It is also of significance to the estimation of the rock strain and of hydrothermal homogenization of the preexisting magnetic anisotropy and to the determination of the flow direction of volcanic rock flow,eventually to the search for the paleovolcanic crater.