Metallogeny of the large-scale Carboniferous karstic bauxite in the Sanmenxia area, southern part of the North China Craton, China

2020 ◽  
Vol 556 ◽  
pp. 119851
Author(s):  
Xuefei Liu ◽  
Qingfei Wang ◽  
Lihua Zhao ◽  
Yongbo Peng ◽  
Yao Ma ◽  
...  
Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 353
Author(s):  
Xiaoyan Liu ◽  
Lin Li ◽  
Shengrong Li ◽  
M. Santosh ◽  
Yujie Li

The northern flank of the North China Craton (NCC) hosts a linear zone of gold, molybdenum, silver, lead, and zinc polymetallic ore deposits. Among these, the Yingfang Pb-Zn-Ag deposit is located in the central part of the Yanshan–Liaoxi metallogenic belt (YLMB) which extends for approximately 1000 km and forms part of the major mineralized zone. In this study, we characterize the mineralization and trace the ore genesis based on new sulfur and lead isotopic geochemistry and evaluate the timing of mineralization from Rb-Sr isotope dating of sulfides. The pyrite δ34S values range from +3.2‰ to +5.8‰ with a mean at +4.07‰, close to the values of mantle and meteorite sulfur. The 206Pb/204Pb values range from 16.833 to 18.956, 207Pb/204Pb from 15.374 to 15.522, and 208Pb/204Pb from 37.448 to 37.928. Five samples of sulfide, from the Yingfang deposit, yield a Rb-Sr isochron age of 135.7 ± 4.1 Ma. This age is close to the age of the adjacent Niujuan Ag-Au deposit and the associated Er’daogou granite, suggesting a close relationship between magmatism and metallogeny in this region. The S and Pb isotopes of the regional silver polymetallic deposits show similar sources of ore-forming materials. According to a compilation of the available age data on the Mesozoic ore deposits in the northern flank of the NCC, we divide the mineralization into the following four periods: 240–205 Ma, 190–160 Ma, 155–135 Ma, and 135–100 Ma. Mesozoic magmatism and mineralization in the Yingfang deposit mainly took place at 245 Ma and 145–135 Ma. We correlate the Pb-Zn-Ag mineralization to metallogeny associated with large-scale inhomogeneous lithosphere thinning beneath the NCC.


2019 ◽  
Vol 47 (1) ◽  
pp. 173-195 ◽  
Author(s):  
Fu-Yuan Wu ◽  
Jin-Hui Yang ◽  
Yi-Gang Xu ◽  
Simon A. Wilde ◽  
Richard J. Walker

The North China Craton (NCC) was originally formed by the amalgamation of the eastern and western blocks along an orogenic belt at ∼1.9 Ga. After cratonization, the NCC was essentially stable until the Mesozoic, when intense felsic magmatism and related mineralization, deformation, pull-apart basins, and exhumation of the deep crust widely occurred, indicative of destruction or decratonization. Accompanying this destruction was significant removal of the cratonic keel and lithospheric transformation, whereby the thick (∼200 km) and refractory Archean lithosphere mantle was replaced by a thin (<80 km) juvenile one. The decratonization of the NCC was driven by flat slab subduction, followed by a rollback of the paleo-Pacific plate during the late Mesozoic. A global synthesis indicates that cratons are mainly destroyed by oceanic subduction, although mantle plumes might also trigger lithospheric thinning through thermal erosion. Widespread crust-derived felsic magmatism and large-scale ductile deformation can be regarded as petrological and structural indicators of craton destruction. ▪ A craton, a kind of ancient continental block on Earth, was formed mostly in the early Precambrian (>1.8 Ga). ▪ A craton is characterized by a rigid lithospheric root, which provides longevity and stability during its evolutionary history. ▪ Some cratons, such as the North China Craton, can be destroyed by losing their stability, manifested by magmatism, deformation, earthquake, etc.


2019 ◽  
Vol 132 (3-4) ◽  
pp. 617-637 ◽  
Author(s):  
Yunjian Li ◽  
Guang Zhu ◽  
Nan Su ◽  
Shiye Xiao ◽  
Shuai Zhang ◽  
...  

Abstract Many metamorphic core complexes (MCCs) of Early Cretaceous age are documented in the northern part of the North China Craton (NCC), which formed in a backarc extensional setting. However, whether or not the MCCs are also present in the southern part of the NCC, and where the western boundary of backarc extension lies, remain unclear. We present new structural and geochronological data to show that Early Cretaceous structures in the Xiaoqinling region (China) lying in the southern part of the central NCC represent a Cordilleran-type MCC. The NW-dipping detachment zone on the northwestern edge of the Xiaoqinling MCC is a ductile extensional shear zone that is overprinted by a later brittle detachment fault. The footwall (lower plate) consists of Archean metamorphic rocks and Mesozoic plutonic rocks, and was cut by a series of ductile normal sense shear belts and later brittle normal faults that strike predominantly NE-SW. Both the ductile and brittle structures indicate that NW-SE extension was responsible for the development of the MCC. Geochronological data suggest that the MCC initiated at 138 Ma and lasted until 100 Ma, recording a protracted extensional history. The MCC experienced an early phase of crustal-scale normal faulting (138–126 Ma) and later isostatic doming (125–100 Ma), consistent with the “rolling-hinge” model. The Xiaoqinling MCC shows similar features and a similar evolution to other intraplate MCCs in the northern and southeastern parts of the NCC, and shows that the southern part of the NCC was also involved in intense backarc extension and magmatism. Distribution of these intraplate MCCs indicates synchronous backarc extension over a length of around 1800 km. Delamination of a flat oceanic slab during roll-back is consistent with such large-scale, synchronous extension in the overriding plate.


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