ON THE GENESIS OF JINCHUAN COPPER-NICKEL SULFIDE DEPOSIT
Yang Hequn(Xi'an Institute of Geology and Mineral Resources, CAGS)
The paper discusses the genesis of Jinchuan copper-nickel sulfide deposit located in Gansu province, China, on the basis of a vast amount of geological and geochemical data. The main conclussions from this study are as follows:( 1 ) This deposit is considered to be formed by multiple intrusion of polyphase melts. What intruded for the first and second times were silicate magma carrying sulfide droplets and olivine grains ; the third time was su-Ifide ore magma carrying a great number of olivine grains;while the fourth time was sulfide ore magma only carrying a little impurity.( 2 ) All of the various polyphase melts were differentiate of the same ore-bearing magma in its interim-magma-chamber.( 3 ) The minerogenetic mother's body was ore-bearing tholeiitic picrite magma originated from the continental mantle.( 4 ) The tectonic setting of mineralization belongs to fracture zone in craton.