| Yangla copper mine is located in the central region of northwest Yunnan Jinsha River Paleo-Tethys tectonic zone, because of poor geographical environment and the region’s natural terrain complexity, far in deposits genetic type, prospecting direction, formation and evolution of tectonic discrimination and other there is considerable controversy on the issue. Multifaceted analysis and research petrological characteristics of this article will be mine intrusive rocks and geochemical characteristics, rock types and causes of tectonic environment. On this basis, to discuss the evolution of rock diagenetic and tectonic settings, combined with previous studies, the main draw of understanding as follows:1. Yangla Copper Development in the region-acid intrusive rocks with a direction from north to south, followed by the Jiangbian, Linong and Lunong three-way distribution of rock, the main rock type quartz diorite, flower hillock diorite and monzonite granite and other components.2. Mining intrusive rocks belong to high-K calc-alkaline metaluminous-Weak SPGs, SiO2 content to maintain a good linear relationship with other oxides, with typical magmatic crystallization differentiation trend of evolution, showing the mining area pluton magma evolution of homologous features. Calculated by standard mineral intrusive rocks mainly of quartz, alkali feldspar, hornblende and plagioclase and other minerals, usually granite type I appear to standard mineral diopside characterized. Linong and Jiangbian rock samples appear a small amount of corundum molecules, most samples display containing 0.35 to 8.48% of the diopside, show and rock mass characteristics similar to I-type granites.3. Rock mass has some subduction zone magma characteristics, Nb/Ta ratios vary greatly and some elements overlap phenomenon, indicating that mining is dominated crust crust-mantle-derived magma mixing; Ba and Th relative to Rb have a more significant losses, Sr-. P weak losses, with increasing SiO2 content gradually reduced; granite showed enrichment in LILE Ba, K, Rb, U, Th elements, high field strength elements Ta, Sr, Nb, P, Zr, Ti, etc. relative loss. In summary, the core area of the island arc rock mass exhibits the characteristics of I-type granites.Higher REE LREE fractionation significantly and strongly enriched in light rare earth and heavy rare earth fractionation is not obvious; Linong rock show in the performance of rock medium Eu anomalies and weak exception of cerium, Lunong rock show moderate negative Eu anomaly and moderate cerium anomalies in REE graph, Jiangbian rock show weak negative Eu anomalies and weak exception cerium.Through the Ba, Sr, Sm, Gd and Eu in potassium feldspar and plagioclase distribution proportion of differences, Ba and Sr weak losses of the separation of potassium feldspar and plagioclase crystallization.Right LREE curve smoothing, line changes relatively stable, these features reflect the various rock substances are likely to come from the crust-mantle mixed source.4. Yangla mine early intrusive rocks formed in the Jinsha River ocean basin westward Changdu-Lanping under a land mass of the island arc subduction late into the Changdu-Simao land mass and Zhongzan land happen continent-continent collision after collision orogeny stage, rock formation process may have an early crust due to collision, subduction and mix added, mainly formed after the collision tectonic environment. Rock bottom by the invasion of mantle-derived magma generated in the mining area of the original magma and felsic magma mixing after the invasion to the surface to the rock strains of rock and features exposed branches. Magma stop the event, marking the end of the whole orogenic period, Yangla copper zone intrusive rocks with each rock has been initially formed.5. Through the newly designed Jiangbian ore block two national drilling ZKJ1-1, ZKJ2-1 sampling study, combined with previous data in Linong and Lunong rock were analyzed, the initial judge Jiangbian rock petrology and geochemistry, rock and genetic type, material sources and tectonic environment is consistent with Linong and Lunong rock, and laid a solid foundation for the future to carry out mine-related geological work. |
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