Yunnan Machangqing gold porphyry Cu-Mo deposit, magmatism and ore genesis

Title: Yunnan Machangqing gold porphyry Cu-Mo deposit, magmatism and ore genesisAuthor: Guo XiaodongDegree-granting units: China University of Geosciences (Beijing)Keywords: magmatism;; genesis;; porphyry copper-molybdenum mine;; Machangqing;; YunnanSummary:

Machangqing copper-gold deposits of molybdenum, "three rivers" ore belt and Himalayan alkali-rich porphyry deposits related to the typical one, produced in the continental collision environment. Through research, identification of the magmatic evolution of the mining sequence, alteration and mineralization zoning laws, fluid evolution and ore-controlling factors, reveals its Magnetic lifter mineralization mechanism proposed mineralization model to explore the mineralization potential.

Machangqing established mining magmatic evolution sequence, the initial magma composition will be divided into three, namely, porphyritic granite lamprophyre composition, syenite porphyry monzonite porphyry composition and alkaline granitic porphyry lamprophyres combination. Preliminary investigation, porphyritic granite lamprophyre composition formed in about 50Ma, constitute ore rock; syenite porphyry monzonite porphyry combination formed in about 36Ma, a major ore-bearing rocks; alkaline granite plaque combination of rock lamprophyre intrusion latest, intrusion age of about 32Ma. Study found that a combination of magma in the development 36Ma dioritic dark microgranular enclaves, and the emergence of disseminated pyrite and magnetite-based, reflecting the combination of this magma gold and copper-molybdenum mineralization related to experience a strong crust-mantle magma mixing .

Ore-controlling characteristics by structural studies to determine the vertical stress during invasion rock formed by magma intrusion exposure is the http://www.999magnet.com/products/131-magnetic-lifter main control structure style rock ore-controlling structures, control of fissures within the rock body porphyry Mo, Cu mineralization, tectonic controls on the contact zone contact metasomatic Cu, Mo, Au, Fe mineralization, near the contact zone between the slip layer control broken with altered rock and quartz vein-type compound Au, Ag, PbZn mineralization, with much exposed rock formations in the tensile fracture with control of epithermal-type Au, Ag, PbZn, Sb mineralization, reflecting the magma intrusion exposure characteristics of ore-controlling structure system. Rock-forming elements are present in the core level of sub-band;

Based on deposit geology, alteration and mineralization types, combination ore-forming elements, fluid evolution, isotope geochemistry and ore-controlling structures and other aspects of research, proposed Machangqing copper-gold deposits and gold-molybdenum factory Qing gold belong to the same magma - Construction - the product of ore-forming system, mineralization in space and time in close quarters, the type of spatial distribution of alteration and mineralization characteristics clearly demonstrate the ore-bearing fluids from the magma out of crystal fractionation and accumulation in the process of outward migration of the corresponding metals picture, the table Mingma plant Qing ore zone diagenetic mineralization is controlled by the same dynamic system. As demonstrated for hydrothermal mineralization and porphyry mineralization from the contact zone → → → close touch with the contact zone is far forward, factories and mines from Baoxing section → chaos → cave Mine section head Qing - Qing gold ore block factory forming temperature, salinity and pressure decreased, the trend of mineralization depth faded;

Alkali-rich rock originated in the crust-mantle transition zone or thickened crust, a continental collision orogenic environment within the formation of potassium adakites. And mineralization related to porphyry syenite porphyry monzonite porphyry with vein-based portfolio, they can provide the material forming, fluid and power are limited, dark microgranular enclaves indicate its rapid crystallization of magma, not conducive to the formation of large ore-forming fluids effectively. A pulse, B and D veins pulse overlap in space, zoning is not obvious, and the characteristics of the mineralization is not strong, reflecting large-scale fluid exsolution does not exist, there is the North Contact Zone gold and copper-lead-zinc-molybdenum-based space also explains the phenomenon of overlap, and there is no large-scale ore-forming fluids, these factors may limit the deposit scale.Degree Year: 2009