Geological characteristics and genesis of rock body-type tin deposits in the Dayishan ore field

Abstract: Rock body-type tin deposits in Dayishan, Hunan, occur in the Late Jurassic Jietou unit of the Tangshipu super-unit. The ore is slightly below the medium grade and easy to dress. The deposits are large in size and formed in a restricted environment, showing vertical zoning. Regional structures, magmatic rocks, country rocks and restricted environment jointly control the occurrence and size of the rock body-type tin deposits. In this paper the genesis of the rock body-type tin deposits is analyzed. As the magma is differentiated and evolved in a restricted environment, ore-forming elements are unevenly distributed, causing the intrusion of the Jietou unit to be rich in W and Sn and an ideal metallogenic model of rock body-type tin deposits is formed in the front or uparching portion of the intrusion. From above downward the rock body-type tin deposits show the characteristics of vertical zoning of alteration and mineralization from high to low temperatures.