Geochemical Characteristics And Prospecting Significance Of Daocheng-Shangri-La Region Epigranite

Southwest Sanjiang is an important metallogenic belt of non-ferrous metals, copper, lead, zinc, silver, gold, tin and other potential advantages of resources. Daocheng-Shangri-La is located in the three areas above JIANGBEI Yidun arc with color, precious metals ore-forming the southern focus, is extremely complex and diverse geological structure has resulted in very favorable conditions for mineralization. Exposed through a broad area of shallow intrusive rocks System Petrological and geochemical study to examine the source of the material and the formation process of the research area of great significance to exploration.Daocheng in western Sichuan and Yunnan, Shangri-La, northeast of the junction zone, the distribution of a hypabyssal porphyry, the formation of Triassic age. Porphyry in the Triassic, has found a plan, Tetraogallus Ping,Songnuo, Dolma, such as porphyry copper deposit, Sichuan Province, is only found inside red Zhuo, Lang pull points, such as porphyry copper deposits.I passed on the western Sichuan-Yunnan region adjacent to the northeast of the comparative study of porphyry, porphyry found that these lanes are the South East - North West to the distribution and space can be divided into three porphyry zones, namely, the West zone (with Ping Tetraogallus ), in the zone (poulenc band) and East zone (Choying - zhuo with red). West Zone including the mud pond, Tetraogallus Ping, Chundu, Europe and other porphyry Cerato, lithology mainly quartz diorite porphyry, diorite followed porphyrite, a small amount of quartz porphyry; in the band, including Asia Miscellaneous waves are, in Suga, Songnuo, plan, such as porphyry, quartz diorite lithology porphyrite mainly, followed by quartz porphyry, a small number of two-granite-porphyry; East zone including Choying , Hung Cheuk, such as the Lang porphyry, diorite lithology for porphyrite, quartz diorite porphyry, a small amount of quartz porphyry.Rock chemistry in the study area into the Triassic shallow porphyry for the sub-alkaline series, and further to determine the rock chemistry, which are mainly calc-alkaline rock series. Overall, the plan-rock SiO2 content is higher and the red Zhuo, Lang La region porphyry low SiO2 content, which is in a rock diorite porphyry is the same as the main body.In trace elements, the plan, Tetraogallus rock Ping Ba and high Sr content, Y, Yb, and Nb content in the lower ratio in the spider diagram of trace elements, the rock mass to Ba and Sr-rich and the strong loss of Nb, micro - loss characterized by Ta and Ti. Loss of Nb and Ti represents a magmatic arc characteristics, Ba and Sr enrichment, indicating that plagioclase in the magma source region can not stabilize the existence of deep magmatic origin, which is equivalent to the depth of the mantle or subduction zone of crust-mantle mixed layer. Rock performance for the enrichment of light rare earth-based and accompanied by a strong fractionation effect, and low content of heavy rare earth elements, and almost no fractionation, no Eu anomaly. Rock with the geochemical characteristics of adakites.Red Zhuo, Lang La rock, the Ba and Sr content than the plan, low rock Tetraogallus Ping, Y, Yb, and Nb content in the lower ratio in the spider diagram of trace elements in order to Ba, Th, U enrichment , Nb, Ta, Sr, P, Ti is characterized by the loss. Nb, Ta showed a loss of the characteristics of island-arc environment, Sr, P losses showed that there is a certain amount of crustal materials, Ba, U, Th enrichment, suggesting the existence of magma source region (deep) fluid flow. Rb / Sr ratio is 0.03 ~ 0.1, appears as close to the mantle of crust-mantle mixed layer characteristics. Hung Cheuk - La Lang rock REE characteristics of the region similar to poulenc, Tetraogallus Ping porphyry areas, generally speaking, the trace elements of rock with classic adakite There was a significant difference.As the red Zhuo - La Lang region and poulenc porphyry, porphyry Tetraogallus Ping region alteration in the rock mass, chemical composition, origin and evolution of magma, such as ore-bearing rock there are great differences, suggesting that the two Prospecting among potential is different.The author suggested that Daocheng-Shangri-La area in order to plan, Tetraogallus Ping represented porphyry rock band has been extended eastward into the territory of Sichuan province, but in Sichuan Province Red Zhuo, Lang and other regions of the Triassic porphyry Body found in porphyry copper deposit, little hope.