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Geochemistry Characteristics of Neoproterozoic Igneous Rocks and Related Uranium Mineralizations in Datian, Panzhihua and Xujie, Mouding, Southwestern China

Author: WangHongJun
Tutor: HeMingYou；LiJuChu
School: Chengdu University of Technology
Course: Geochemistry
Keywords: Neoproterozoic Adakite A-type granites Geochemistry Uranium mineralization
CLC: P588.121
Type: Master's thesis
Year: 2009
Downloads: 147
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Abstract

Kangdian axis widely exposed Neoproterozoic magmatic rocks (TTG combination) is the oldest of the Yangtze platform crystalline basement, where Ota and Xu Street mixed Proterozoic igneous complex developmental edge contact with uranium mineralization. Research and mixing uranium mineralization related complex rock geochemistry western margin of the Yangtze basement and uranium mineralization research has important geological significance. In this paper, this important scientific problem, Panzhihua Daejeon and mouding Xu Street Proterozoic igneous rock major and trace element geochemistry, and Pb isotope geochemistry analysis to explore the area magmatic origin and relationship with uranium mineralization. The main achievements are as follows: This is the first pair of Panzhihua Daejeon and mouding Xu Street area with uranium mineralization related to magmatic and tectonic evolution of the environment were discussed, that: (1) a combination of rock in the field TTG series (large Tianshi Ying diorite - Flower Beach longer granite) in the part of the quartz diorite magma with island arc geochemical characteristics, but rather spend a longer beach granite and granite veins and Daejeon part felsic dikes have Adakite Earth chemical characteristics; its causes may be related to subduction-related slab partial melting. (2) What Daejeon black rock is displayed with characteristics of A-type granites, showing extensional tectonic environments. (3) Pb isotopic data indicates that: diorite, quartz diorite, mafic dikes and gray granite (core) and other characteristics with orogenic magmatic rocks, crust-mantle mixing sources, but little mantle composition; granite veins body, granitic gneiss and augen gneiss with upper crustal geochemical characteristics. Part of K-feldspar phenocrysts granitic gneiss, diorite and granite rock samples have black Mody radiogenic Pb anomaly, reflecting the high Th, U join. Mouding Xu Street area amphibolite schist Geochemistry display environment for the formation of island arc environment, and Daejeon some quartz diorite and granitic gneisses similar environment. Fine-grained granite and part of the ore-bearing amphibolite schist rare characteristic curve similar to the A-type granites. Ore-bearing amphibolite schist by the transformation of the role of granite. Xu Street area of ??the environment and the formation of fine-grained granite pluton broadly consistent with what the black field, may all of Late Proterozoic Kangdian axis under the action of intracontinental extension product. This article discusses the 1101 field 505 and uranium mineralization Mouding controlling factors and uranium ore mineralization, studies suggest that: (1) 505 formation of uranium mineralization has undergone two main stages. Mixed - metasomatism make tonalite rocks series rocks occur albite, epidote and chlorite alteration. Uranium is activated transfer, the early formation of uraninite and rich U, Th in the background, the time associated with the uranium elements are Ta, Th, Zr, Hf, Cr and so on. Late stage, that silicification - hematite oriented - pitchblende formation stage, showing a significant tectonic fissures low temperature hydrothermal mineralization controls and features. It may be constructed further activities, derived from similar A-type granites further enrichment of uranium in the fault zone, the formation of industrial uranium mineralization. During this period the elements associated with uranium is relatively simple. Uranium due to mixing - metasomatism and fissures in the control of epithermal deposits. (2) mouding 1101 mineralized uranium mineralization are granite rock formations - mixed rock edge residue cover; mineralization in the granite contact zone output mix - accountable band; mineralization is controlled by tectonic and hydrothermal activity; experienced multi-period epithermal alteration. There are two more of uranium mineralization, ore-bearing rock withstood the early granite and felsic veins transformation, and sodium fractured longer Petrochemical, epidotization, rutile and so alteration, uranium is transferred to the micro-activated fissures, precipitated iron to form pyrite and chalcopyrite and possibly uraninite; late hydrothermal activity joined Ba, As, Ag, Pb, Zn and U, the formation of block sulfur antimony lead, zinc and manganese and there may be pitchblende. Uranium is mainly derived from fine-grained granite magmatism is granite mixed - metasomatism structurally controlled low-temperature hydrothermal uranium mineralization. 505 and 1101 Daejeon Mouding mineralization and tectonic evolution of the supercontinent Rodinia transition period coupled mineralization in the granite contact at the output mix - accountable band; mineralization is controlled by tectonic and hydrothermal activity, experienced a low temperature heat fluid alteration; ore granitic rocks subjected veins and felsic veins transformation. Uranium mainly from activities similar to A-type granites, there ore remobilization of uranium in rock, is a granite mixed - metasomatism in structurally controlled low-temperature hydrothermal uranium mineralization.

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CLC: > Astronomy,Earth Sciences > Geology > Petrology > Classification of rocks > Magmatic rocks ( igneous ) > Intrusive rocks, plutonic > Acid rock
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