Petrologic And Chronological Study Of The Granite Belt Which Locate From Gao Gong To The North Part Of GeNie In YiDun Island Arc

In the granite belt which locate from GaoGong to the north part of GeNie in YiDun island, the GaoGong rock mass formed in the 101 ma, Quer Shan rock formed in the 100 ma, CuoMolong mass formed in the 97 ma, Rong Yicuo has a pullover cuo rock mass formed 97 ma. Ha Gala formed in the 97 ma. They were formed in late Yanshanian and post-orogenic sports products. Spatially located in island arc back-arc area, fracture and short ke deer township hole- city- day rain fault zone by clamping, granite emplacement of the rock mass with shallow depth, much to batholith, rock strain, rock tumor output. Main oxides of average compared with the average Chinese acidic rock chemical composition, SiO2 content is higher than China acidic rock standard values. Rock has rich silicon, potassium, poor titanium, the characteristics of aluminum, magnesium, calcium, sodium, they are high in potassium calcium alkaline peraluminous granite. In conformity with the composition characteristics of type A granite. Granite has rb, thorium and uranium, hafnium, strong enrichment of neodymium, strontium, titanium strongly losses. In the process of magmatic differentiation degree is high, plagioclase has a large amount of separation;Barium element loss is a product granite belt intracontinental magmatism of important evidence, explain away from island arc tectonic environment; High field strength elements niobium, tantalum relative enrichment also confirmed this point of view;Titanium obvious loss of the ilmenite also has strong separation from magma; Heavy rare earth elements is higher means that the residual magma source area without garnet; The proportion of light rare earth rare earth concentration degree is high, light and heavy rare earth overall fractionation is not obvious; Because of granite have strong europium losses, so as to standardize the chondritic after the distribution curve of standard "yan" type distribution. In conformity with the composition characteristics of type A granite. Granite tectonic environment in the relevant graphic lagged in the post-tectonic granite area, or later structure- after granite area, reflect A post-orogenic crust uplift increased after the melting process of stretching, first for A2 type granite,namely the post-orogenic a-type granite, the distribution characteristics of the instructions with the formation of A collision post-tectonic environment of granite formation and basic magma crystallization separation has nothing to do with, but directly from the crust shallow rock engineering. Velvet in accordance with the measures of the source area of the granite argillaceous YanFeng most and very uniform; High tribute, chola mountain, nie(north), cuo Malone has source area of rock mass containing a certain amount of basic volcanic rocks. A pullover measures of rock mass in 15% melting line, close to 7 kbar, 825 ℃ when the melt; Gong nearly35% molten rock mass line, the high temperature higher than 825 ℃, close to 900 ℃;Chola mountain, nie(north) of rock mass, cuo Malone has its melting degree of rock mass and the temperature is higher than 35% melting line, temperature higher than900 ℃. Overall degree of differentiation of granite belt in this area are high, in which case nie(north) granite rock mass the differentiation degree of the best. Priority residual plagioclase in source region. Accessory mineral apatite, ilmenite, zircon in the source area also have residual, magma source area do not have plenty of hornblende and garnet remaining conditions. Magma formation and enrichment of ore-forming elements in the fluid system in the volatile components of metallogenic only when the magma reaches saturation occurs. And if if plasma in chlorine and sulfur elements to achieve a standard, is needed for saturated water content, thus speeding up the enrichment of ore-forming elements. The indicator elements of the granite belt is much greater than the standard value, explains the granite belt has good metallogenic conditions. Ore-forming fluid migration in space will be accompanied by a large number of alteration, the alteration effect only in the magma of volatile components in a relatively closed environment will show the wall rock alteration. The granite belt of granite have rich potassium, calcium, sodium, poor lower delta Eu outliers, alteration rock most has the characteristics of sodium potassium rich lean,visible in the granite belt of silicide and potassium phenomenon. This should be a sign of the granite belt contains a lot of ore fluid movement.