Geochemical Characteristics Of The Paleoproterozoic Magmatic Rocks In Taoyuan Copper

The study area is located in the southern section of the taihang mountains, tectonic position in central north China platform(Sino-korean paraplatform), where the magmatic rocks of Archean Wutai and Paleoproterozoic Lüliang periods outcropped. And the Paleoproterozoic magmatic rocks in Gantaohe group are the main research object of this paper. The study analyzed the main elements, trace elements and rare earth elements and isotopic on the basis of field observations and the microscopic identification of the paleoproterozoic luliang period volcanic and intrusive rocks in the taoyuan area, and by using the geochemical method to carry on the detailed research, to determine the evolution process of magmatic rocks and tectonic environment, and reveals its relationship with the effect of copper deposits.Research shows that the volcanic rocks of proterozoic era, which is consist of three large submarine volcanic eruption that can be divided into the corresponding Nansizhang,Nansi and Haoting cycle. Wutai period intrusive rocks are mainly granitic rocks, throughout the east of the study area, Xuting, Shiwopu, Mantianyu rock mass, that the main lithology is porphyritic granite, trondhjemite, monzonite. Luliang period volcanic rocks in the main lithology are basalt, basaltic breccia lava, basaltic agglomerate lava and tuff(including spilite). Basite intrusive rocks in the main, followed by acid rock, throughout the west,including Luyu, Zhangbeiwa, Loudi, Beishuiyu four Gabbro-diabase rock masses and Shipozui, Huaishuzhuang two quartz rock masses. And main lithology is gabbro diabase,diabase, the quartz-oligophyre.The study of luliang period of volcanic and intrusive rocks in the area of basite and acid testing and analysis of the main elements, rare earth elements and rare earth elements,show that the basite intrusive masses whose rock rich sodium poor potassium and belong to the normal Pacific Ocean type. And the aluminum index(ASI) is less than 1, so basic intrusive rocks is quasi aluminum type, the magma source material for the upper mantle.Luliang period volcanic rocks section show that the characteristics of spilite, show that the period of volcanic magmatism in addition to the normal crystallization differentiation, there are other role, such the hybrid effect in crystallization differentiation process, has the trend of the evolution in the direction of the potassium sodium. And the aluminum index of quartz-oligophyre in Huaishuzhuang rock mass is greater than 1.1, aluminum supersaturated type, less mantle source material, for carrying too much crustal material in the process of magma rising.The rare earth elements characteristic research shows that all the ∑REE of the basite in the area are higher and similar, La/Sm also similar, and the Eu anomaly very weak or noanomaly, all rare earth trend curves are similar. Quartz has a higher ∑REE, but due to the hybrid effect and plagioclase crystallization differentiation in the late age of magmatic rising emplacement, in the process of the plagioclase crystallization differentiation, so there is obvious Eu anomaly. Their REE patterns are different from the basalt( diabase) in this area, but also the standard S-type granites which often shows the " Seagull " REE patterns.Standardization spider diagram of trace elements reflect quartz-oligophyre is the late product of the magma evolution.The geochemical characteristics of luliang period volcanic and intrusive rocks show that magmatic rocks in the study area are homologous, and their evolutions have certain regularity. Massive volcanic eruptions and magma intrusion brings a wealth of mineral,forming a pre-enriched ore source rocks for the mineralization provides a prerequisite.