Origin of the Mesozoic intrusions in the Sierra de la Luna,Chile:Evidence from zircon U-Pb dating and geochemistry
The Sierra de la Luna iron-copper deposit is located in the IOCG(Iron Oxide Copper Gold)metal-logenic belt of the coastal mountain belt in the central-northern part of Chile,and on the southern edge of the primary controlling structural Atacama fault zone.Magmatic activities are frequent in the area,and the intrusive rocks are mainly diorite in this area.According to this study,the diorite in this area possesses quasi-aluminous and calcium alkaline geochemical features.The La/Nb ratio in diorite is greater than 1.5,and the La/Ta ratio is greater than 22.The trace element map shows significant depletion of Nb,Ta and Ti,indicating that the source area of diorite magma originated from the lithospheric mantle associated with subduction.The LA-ICP-MS zircon U-Pb age of diorite is(108.2±1.9)Ma,indicating that it is a product of magmatic activity in the late Early Cretaceous.Structural environment analysis shows that the north-south trending AFZ(Atacama Fault Zone)and the parental magma were formed during the subduction of the Pacific Nazca Plate beneath the South American Plate.The deep-seated intrusions of diorite formed through partial melting and crystal fractionation processes are closely related to the formation of IOCG deposits in this area.
magma source areaformation mechanismiron oxide-copper-golddioriteChile
万方数据
维普
