Fabric Characteristics of the Olivine from No.2 Mining Area in the Jinchuan Deposit, Gansu Province

In No.2 mining area of the Jinchuan deposit, Gansu province, the olivine from mafic-ultramafic rocks show the characteristics of minerals oriented arrangement.The fabric features of the olivines from lherzolite, plagioclase lherzolite and pyroxene dunite have been studied in this paper.The results show the characteristics of type-"A"100 (010)fabric, the Nm001 is the point maximum of the foliation and the slip direction is001.Combined with the fabric characteristics of Ng100 and Np010, the slip plane should be the (100)and (010), and this belongs to the low temperature slip system((100)001or(010)001).All of these characteristics mentioned above indicate that, these rocks may be formed under the shallow crust environment with low pressure and low stress state.The mafic-ultramafic rocks in the No.2 mining area were served as the products of the crystalline differentiation during the second stage of sulfide-bearing magma ascending in the Jinchuan deposit.Combined with the variation characteristics of tectonic stress field in this deposit, the olivine alignment has reflected the structure of the mineralization period, and the axis of olivine has a rotation from west to east.