Uranium Mineralization Characteristics and Ore-Controlling Factors in the Puluohe Area of the North Qinling Metallogenic Belt

2018 ◽  
Vol 08 (07) ◽  
pp. 1224-1232
Author(s):  
坤鹏 刘
Keyword(s):  
Controlling Factors ◽  
Uranium Mineralization ◽  
The North ◽  
Metallogenic Belt ◽  
North Qinling

scholarly journals SIMS U-Pb Dating of Uraninite from the Guangshigou Uranium Deposit: Constraints on the Paleozoic Pegmatite-Type Uranium Mineralization in North Qinling Orogen, China

Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 402
Author(s):  
Guolin Guo ◽  
Christophe Bonnetti ◽  
Zhanshi Zhang ◽  
Guanglai Li ◽  
Zhaobin Yan ◽  
...  
Keyword(s):  
Partial Melting ◽  
Fractional Crystallization ◽  
Secondary Ion Mass Spectrometry ◽  
Uranium Mineralization ◽  
Crustal Material ◽  
Early Devonian ◽  
The North ◽  
Low Degree ◽  
North Qinling ◽  
The One

Pegmatite-type uranium mineralization occurs in the Shangdan domain of the North Qinling Orogenic Belt, representing a significant uraniferous province. The Guangshigou deposit is the largest U deposit of the district. Within the North Qinling area, a series of Caledonian granitic igneous rocks intruded the Proterozoic metamorphic rocks of the Qinling Group in two magmatic stages: (i) the Early Silurian Huichizi granite that was derived from a low degree of partial melting of thickened lower basaltic crust combined with mantle-derived materials following the subduction of the Shangdan Ocean; and (ii) the Late Silurian–Early Devonian Damaogou granite and associated pegmatites derived from the same source but emplaced in a late tectonic post-collisional extension environment. In the Guangshigou deposit, the U mineralization mainly occurs as uraninite disseminated in U-rich granitic biotite pegmatites, which formed by assimilation-fractional crystallization magmatic processes. Petrographic observations showed evidence for coeval crystallization of uraninite and other rock-forming minerals of the host pegmatite including quartz, feldspar, biotite, zircon, monazite, apatite, and xenotime. In addition, the low U/Th ratios (~19) and Th, REE, and Y enrichments characterized a magmatic origin for uraninite, which was likely derived from fractionated high-K calc-alkaline pegmatitic magma that experienced various degrees of crustal material contamination. In situ U-Pb isotopic dating performed by Secondary-Ion Mass Spectrometry (SIMS) on uraninite from the Guangshigou deposit yielded a crystallization age of 412 ± 3 Ma, which is concomitant (within errors) with the emplacement age of the host pegmatite (415 ± 2 Ma) and constrained the U ore genesis to the Early Devonian, which corresponds to the late Caledonian post-collisional extension in the North Qinling area. Uraninite then experienced various degrees of metamictization and/or post-Caledonian hydrothermal alteration characterized by an alteration rim associated with coffinite, chlorite and limonite. Finally, the characteristics of the pegmatite-related Guangshigou deposit exhibiting Th-rich uraninite which was the product of assimilation-fractional crystallization of pegmatitic magma defined a model significantly different than the one established for the world-class Rössing deposit characterized by Th-poor uraninite hosted in alaskite dykes formed by low degree of partial melting of U-rich metasediments.

scholarly journals Uraninite from the Guangshigou Pegmatite-Type Uranium Deposit in the North Qinling Orogen, Central China: Its Occurrence, Alteration and Implications for Post-Caledonian Uranium Circulation

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 729
Author(s):  
Bin Wu ◽  
Christophe Bonnetti ◽  
Yue Liu ◽  
Zhan-Shi Zhang ◽  
Guo-Lin Guo ◽  
...  
Keyword(s):  
Uranium Deposit ◽  
Uranium Mineralization ◽  
Orogenic Belt ◽  
Central China ◽  
Qinling Orogen ◽  
Qinling Orogenic Belt ◽  
The North ◽  
Alteration Halo ◽  
North Qinling ◽  
Magmatic Event

The Guangshigou deposit is the largest pegmatite-type uranium deposit in the Shangdan domain of the North Qinling Orogenic Belt, which is characterized by the enrichment of uraninite hosted in biotite granitic pegmatites. At Guangshigou, uraninite commonly occurs as mineral inclusions in quartz, K-feldspar and biotite or in interstices of these rock-forming minerals with magmatic characteristics (e.g., U/Th < 100, high ThO2, Y2O3 and REE2O3 contents and low concentrations of CaO, FeO and SiO2). It crystallized at 407.6 ± 2.9 Ma from fractionated calc-alkaline high-K pegmatitic melts under conditions of 470–700 °C and 2.4–3.4 kbar as deduced by the compositions of coexisting peritectic biotite. The primary uranium mineralization took place during the Late Caledonian post-collisional extension in the North Qinling Orogen. After this magmatic event, uraninite has experienced multiple episodes of fluid-assisted metasomatism, which generated an alteration halo of mineral assemblages. The alteration halo (or radiohalo) was the result of the combined effects of metamictization and metasomatism characterized by an assemblage of goethite, coffinite and an unidentified aluminosilicate (probably clay minerals) around altered uraninite. This fluid-assisted alteration was concomitant with the albitization of K-feldspar subsequently followed by the coffinitization of uraninite during the major period of 84.9–143.6 Ma, as determined by U-Th-Pb chemical ages. Further investigations revealed that the metasomatic overprinting on uraninite initially and preferentially took place along microcracks or cavities induced by metamictization and promoted their amorphization, followed by the release of U and Pb from structure and the incorporation of K, Ca and Si from the fluids, finally resulting in various degrees of uraninite coffinitization. The released U and Pb were transported by alkali-rich, relatively oxidizing fluids and then re-precipitated locally as coffinite and an amorphous U-Pb-rich silicate under low to moderate temperature conditions (85–174 °C). The compositional changes in primary uraninite, its structure amorphization together with the paragenetic sequence of secondary phases, therefore, corroborate a combined result of intense metamictization of uraninite and an influx of alkali–metasomatic fluids during the Late Mesozoic Yanshanian magmatic event in the region. Hence, the remobilization and circulation of uranium in the North Qinling Orogen was most likely driven by post-Caledonian magmatism and hydrothermal activities related to large-scale tectonic events. In this regards, Paleozoic pegmatite-type uranium mineralization may represent a significant uranium source for Mesozoic hydrothermal mineralization identified in the Qinling Orogenic Belt.

scholarly journals Identification of coesite-bearing amphibolite in the North Qinling and its geological significance

2016 ◽  
Vol 61 (12) ◽  
pp. 1365-1378 ◽  
Author(s):  
ShiJie YANG ◽  
YunFei REN ◽  
Liang LIU ◽  
XiangKuan GONG ◽  
DanLing CHEN ◽  
...  
Keyword(s):  
Geological Significance ◽  
The North ◽  
North Qinling

Origin and genesis of Late Jurassic to Early Cretaceous granites of the North Qinling Terrane, China

Lithos ◽  
2019 ◽  
Vol 336-337 ◽  
pp. 242-257 ◽  
Author(s):  
Yuan-Shuo Zhang ◽  
Wolfgang Siebel ◽  
Song He ◽  
Yan Wang ◽  
Fukun Chen
Keyword(s):  
Early Cretaceous ◽  
Late Jurassic ◽  
The North ◽  
North Qinling

Eclogite origin and timings in the North Qinling terrane, and their bearing on the amalgamation of the South and North China Blocks

2011 ◽  
Vol 29 (9) ◽  
pp. 1019-1031 ◽  
Author(s):  
H. WANG ◽  
Y.-B. WU ◽  
S. GAO ◽  
X.-C. LIU ◽  
H.-J. GONG ◽  
...  
Keyword(s):  
North China ◽  
The South ◽  
The North ◽  
North Qinling
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