Shangri Chundu Copper Porphyry Body Geochemical Characteristics And Diagenetic Mechanism Studies

The completion of my thesis was subsidized by project of mineralization regularity study of Chundu porphyry copper deposit, Xianggelila,Yunnan. The Chundu porphyry copper deposit lies in the southern of famous Zhongdian-Yidun arc orogen.The thesis find out the relation of mineralization and alteration by analysing the feature of mineralization and wall rock alteration.The analysis by researching the petrological feature of intrusive rock in Chundu orefield that based on learning about regional geological background,geologic feature of orefield and deposit.The mode of petrosal formation was established preliminary by exploring surroundings of plate tectonics when rock was formed,source of material of rock, evolution of magma and temperature and pressure force when rock was produced.The exploring was based on the study of the geochemical feature of major element,microelement,rare earth elements and chronology of isotope.The mode is foundation that research mineralization regularity Chundu copper ore deposit.The main cognition from the thesis is:There are fierce alteration of wall rock and visible zonality of alteration in the orefield surrounding the metallogenic rock mass.The copper mine is major distribution in kali silicification zone, silicification and biotitization zone, silification zone and sericitolite zone.There are little copper mine in other zone.The connection of alteration and mineralization is close.The level of mineralization are decided by the types of alteration and the production situation of orebody are conditioned by the distribution of alteration zone.The kali silicification zone that trended to NW and sloped to NE is important targetvolume that prospecting mine in orefield.The diorite porphyrite and granodiorite-porphyry are major intrusive rock in the Chundu orefield.Their content of oxides are close to approximate Chinese diorite porphyrite and Chinese granodiorite-porphyry.They all belong to calc-alkali magma series.Their LLE for example Sr,K,Rb,Ba,Th are enriched and HFSE for example Ta,N,P,Hf,Ti are deficit. The chondrite's standardized diagram of intrusive rock in Chundu belong to LREE enriched type.The diorite porphyrite's age is older than the granodiorite-porphyry in Chundu. They were produced in Indo-Chinese epoch.The intrusive rock in Chundu were made indowngoing tectonic setting.It was controlled by crystallization differentiation that the evolutionary process of diorite porphyrite's magma.And it was jointly controlled by crystallization differentiation and partially fusion that the evolutionary process of granodiorite-porphyry's magma.Both rock are came from same magma but was produced in different stage of magmatic evolution.That is proved that differentiation level of intrusive rock in Chundu that is neutral-acidity rock series.The intrusive rock in Chundu is in the nature of adakites.It reflect that there are mineralize feature of adakitic rocks and prospecting foreground in orefield in Chundu.The diorite porphyrite and granodiorite-porphyry are products from constantly tachytely magma of different component and produced in different times when Ganzi-Litang oceanic lithosphere subduct to west. After time that produced diorite porphyrite when andesite-basalt magma evolved into dacite magma,the granodiorite-porphyryIt was produced through the dacite magma intruded on vulnerable zone on the bottom of diorite porphyrite mass.