The uranium deposits in the Tuanyushan area of northern Qaidam Basin commonly occur in coal-bearing series. To decipher the U-enrichment mechanism and controlling factors in this area, a database of 72 drill cores, in...The uranium deposits in the Tuanyushan area of northern Qaidam Basin commonly occur in coal-bearing series. To decipher the U-enrichment mechanism and controlling factors in this area, a database of 72 drill cores, including 56 well-logs and 3 sampling wells, was examined for sedimentology and geochemistry in relation to uranium concentrations. The results show that coal-bearing series can influence uranium mineralization from two aspects, i.e., spatial distribution and dynamic control. Five types of uranium-bearing rocks are recognized, mainly occurring in the braided river and braided delta sedimentary facies, among which sandstones near the coals are the most important. The lithological associations of sandstone-type uranium deposits can be classified into three subtypes, termed as U-coal type, coal-U-coal type, and coal-U type, respectively. The coal and fine siliciclastic rocks in the coal- bearing series confined the U-rich fluid flow and uranium accumulation in the sandstone near them. Thus, the coal-bearing series can provide good accommodations for uranium mineralization. Coals and organic matters in the coal-bearing series may have served as reducing agents and absorbing barriers. Methane is deemed to be the main acidolysis hydrocarbon in the U-bearing beds, which shows a positive correlation with U-content in the sandstones in the coal-bearing series. Additionally, the 613C in the carbonate cements of the U-bearing sandstones indicates that the organic matters, associated with the coal around the sandstones, were involved in the carbonation, one important component of alteration in the Tuanyushan area. Recognition of the dual control of coal-bearing series on the uranium mineralization is significant for the development of coal circular economy, environmental protection during coal utilization and the security of national rare metal resources.展开更多
The distribution of selected critical elements in the sedimentary rocks of the Carboniferous coal-bearing series within the Polish Coal Basins is presented.Critical elements such as Be,Mg,Si,P,Sc,V,Co,Y,Nb,In,Sb,La,Ce...The distribution of selected critical elements in the sedimentary rocks of the Carboniferous coal-bearing series within the Polish Coal Basins is presented.Critical elements such as Be,Mg,Si,P,Sc,V,Co,Y,Nb,In,Sb,La,Ce,Hf,Ta,W,Bi were analysed using inductively-coupled plasma mass spectrometry(ICP/MS).Concentrations of elements such as Sb,Bi,In and,to a slightly lesser extent,Nb,as well as Sc,show average concentrations higher than those from the upper continental crust.The average concentrations of elements like Hf,Mg,P,Y,La,and Ce are slightly lower than in the upper continental crust.Other elements,such as Be,Co,Si,Ta,W and V have average concentrations that are similar,but slightly enriched or slightly depleted,relative to the upper continental crust.The research showed enrichment of some critical elements in the analysed samples,but not high enough that extraction would be economically viable.Statistical methods,which include correlation coefficients between elements and cluster analysis,reveal a strong positive correlation between elements like Be,Bi,Nb,Sc,Ta,W and V.Very high,almost total,positive correlation is also noted between La and Ce.展开更多
The close relationship between the genesis of coal metamorphism and the evolution of the regional tectonic framework is expounded on the basis of an analysis of the geological factors causing the metamorphic zonation ...The close relationship between the genesis of coal metamorphism and the evolution of the regional tectonic framework is expounded on the basis of an analysis of the geological factors causing the metamorphic zonation of the Late Palaeozoic coals in southern North China; in terms of the mechanism for the formation of palaeogeothermal anomalies, the effects of thermal groundwater on coal metamorphism is highlighted and a geological model for thermal groundwater metamorphism of coal established; with the concept of the palaeogeotherm-coal metamorphism system, the genesis of coal metamorphism is analysed according to the distribution pattern of three geological factors: heat source, heat-carrier and channel, and heat-collector.展开更多
Ordos is located in the western part of North China Platform and was subjected to erosion at the late stage of Caledonian movement when the platform was uplifted. Later, Variscian movement made this region subside and...Ordos is located in the western part of North China Platform and was subjected to erosion at the late stage of Caledonian movement when the platform was uplifted. Later, Variscian movement made this region subside and the paleo-North China Sea and Qilian Sea transgressed onto Ordos, from both the east and west sides during the展开更多
基金supported by the Major National Science and Technology Program of China (grants No. 2016ZX05041004)the National Natural Science Foundation of China (grant No. 41572090)High-level Talent Recruitment Project of North China University of Water Resource and Electric (grant No. 40481)
文摘The uranium deposits in the Tuanyushan area of northern Qaidam Basin commonly occur in coal-bearing series. To decipher the U-enrichment mechanism and controlling factors in this area, a database of 72 drill cores, including 56 well-logs and 3 sampling wells, was examined for sedimentology and geochemistry in relation to uranium concentrations. The results show that coal-bearing series can influence uranium mineralization from two aspects, i.e., spatial distribution and dynamic control. Five types of uranium-bearing rocks are recognized, mainly occurring in the braided river and braided delta sedimentary facies, among which sandstones near the coals are the most important. The lithological associations of sandstone-type uranium deposits can be classified into three subtypes, termed as U-coal type, coal-U-coal type, and coal-U type, respectively. The coal and fine siliciclastic rocks in the coal- bearing series confined the U-rich fluid flow and uranium accumulation in the sandstone near them. Thus, the coal-bearing series can provide good accommodations for uranium mineralization. Coals and organic matters in the coal-bearing series may have served as reducing agents and absorbing barriers. Methane is deemed to be the main acidolysis hydrocarbon in the U-bearing beds, which shows a positive correlation with U-content in the sandstones in the coal-bearing series. Additionally, the 613C in the carbonate cements of the U-bearing sandstones indicates that the organic matters, associated with the coal around the sandstones, were involved in the carbonation, one important component of alteration in the Tuanyushan area. Recognition of the dual control of coal-bearing series on the uranium mineralization is significant for the development of coal circular economy, environmental protection during coal utilization and the security of national rare metal resources.
文摘The distribution of selected critical elements in the sedimentary rocks of the Carboniferous coal-bearing series within the Polish Coal Basins is presented.Critical elements such as Be,Mg,Si,P,Sc,V,Co,Y,Nb,In,Sb,La,Ce,Hf,Ta,W,Bi were analysed using inductively-coupled plasma mass spectrometry(ICP/MS).Concentrations of elements such as Sb,Bi,In and,to a slightly lesser extent,Nb,as well as Sc,show average concentrations higher than those from the upper continental crust.The average concentrations of elements like Hf,Mg,P,Y,La,and Ce are slightly lower than in the upper continental crust.Other elements,such as Be,Co,Si,Ta,W and V have average concentrations that are similar,but slightly enriched or slightly depleted,relative to the upper continental crust.The research showed enrichment of some critical elements in the analysed samples,but not high enough that extraction would be economically viable.Statistical methods,which include correlation coefficients between elements and cluster analysis,reveal a strong positive correlation between elements like Be,Bi,Nb,Sc,Ta,W and V.Very high,almost total,positive correlation is also noted between La and Ce.
文摘The close relationship between the genesis of coal metamorphism and the evolution of the regional tectonic framework is expounded on the basis of an analysis of the geological factors causing the metamorphic zonation of the Late Palaeozoic coals in southern North China; in terms of the mechanism for the formation of palaeogeothermal anomalies, the effects of thermal groundwater on coal metamorphism is highlighted and a geological model for thermal groundwater metamorphism of coal established; with the concept of the palaeogeotherm-coal metamorphism system, the genesis of coal metamorphism is analysed according to the distribution pattern of three geological factors: heat source, heat-carrier and channel, and heat-collector.
文摘Ordos is located in the western part of North China Platform and was subjected to erosion at the late stage of Caledonian movement when the platform was uplifted. Later, Variscian movement made this region subside and the paleo-North China Sea and Qilian Sea transgressed onto Ordos, from both the east and west sides during the
