福建中甲锡矿及其外围岩石磁组构特征

磁组构成分析是利用岩石磁化率各向异性研究构造变形特征及其应力作用方式和方向的方法,研究表明,中甲地区岩石各向异性度Ｐ值比较小,反映本区总体变形较弱,但变质石英砂岩相对变形较强。变质石英砂岩磁面理发育,磁线理较弱,显示压扁变形,变形主压应力方向是ＮＷ－ＳＥ向。火山（碎屑）岩具有明显的磁线理,反映流纹构造特征;最大磁化率轴方向屡示本区火山岩流体构造为ＮＷ－ＳＥ向。矿化蚀变岩和矿石的磁各向异性度Ｐ值明显

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.