Using Quantitative Textural Analysis Method To Reveal The Formation Of Ore-induced Intrusion

Using quantitative textural analysis method in genesis of igneous rocks is one ofthe leading edge of scientific topics today, but its application in the study of theore-forming intrusions still blank. In this study, the author uses quantitative texturalanalysis method of igneous to quantify the K-feldspar phenocrysts and quartzphenocrysts from10samples in the drilling through the granite porphyry on the basisof detailed petrographic description of Maojin, Moate, Xinjiang. Access to a numberof textural parameters, and try to reveal the kinetics processes of the ore-formingintrusions and inner link with gold mineralization. Research shows that Maojingranite porphyry rocks contain more than~30vol.%of K-feldspar phenocrysts andquartz phenocrysts, this implies that Maojin granite porphyry rock experienced frozenmagma activation. Phenocrysts chipping, cracks are filled with quartz and carbonateand diffuse type carbonation in matrix suggest that the fluid activation mechanism isconsistent with transmagmatic fluid mineralization mechanism. the CSDs of quartzphenocrysts and K-feldspar phenocrysts show the absence of small crystals iscomsistent with frozen magma chamber activation and resorption phenomenon ofphenocrysts. Of particular note is, although granite porphyry is relativelyhomogeneous during visual observation, quantitative textural parameters of quartzphenocrysts and K-feldspar phenocrysts reveal significant changes with depth.According to textural parameters trends with depth，Maojin granite porphyry rockmay potentially be fed by four pulses of fluid, and has four barrier layers of magma.the lower barrier layers of magma show CSDs concave down and phenocrystsovergrowth. Because the transmagmatic fluid pulse injection, may also leads totemperature oscillation and decreases mineral saturation and causes pre-existingcrystals coarsening. As the boundaries of the80m depth, increase of R-values ofshallow part may be due to accumulation of fluid in the lower barrier layer, and causeovergrowth of mineral; increase of R-values of deep part may be caused by the fluidaccumulated in the lower barrier layer and lead to excessive pressure, generatepressure during explosion occurred when the fluid break through the barrier layer. the pulse frequency in the shallow part is greater than the deep part is the result of theprocess of fluid channels and cooling process of magma. According to the evidenceand analysis, we can conclude that, the formation of Maojin granite porphyry rockexperienced a strong fluid activation. the magma in the deep crustal is frozen due to alarge number of K-feldspar and quartz crystal crystallization.A massive injection offoreign fluid causes the frozen magma rapid expansion and lower viscosity, thus themagma transient activation and rise rapidly. When the magma reaches the shallowcrustal, the phase separation of fluid will cause the periodic magma internal pressureraising and lowering, and pulsatile fluid activity. When a high degree of consolidationof top of magma intrusion, it will have sufficient capacity to prevent the continuedrapid increase fluids, the internal pressure of magma continued to improve and lead tothe fluid lateral drain. If the orebody and mineralization revealed by drilling ZKL001are the product of ore fluid lateral drain, so the depths of the northwest of Maojingranite porphyry rock will have a greater potential for deep prospecting.