1.Objective,The Cretaceous succession is characteristic of the aeolian sedimentary system in the Ordos Basin,which is the major ore-bearing layer for the sandstone-type uranium deposits.Based on the research of paleon...1.Objective,The Cretaceous succession is characteristic of the aeolian sedimentary system in the Ordos Basin,which is the major ore-bearing layer for the sandstone-type uranium deposits.Based on the research of paleontology and magnetostratigraphy,formers believed it belonged to the Early Cretaceous(Huang YB,2010).However,the lack of intrusions or volcanic rocks for isotopic dating results in an unclear formation age for the Lower Cretaceous succession.Recently,tuffs were firstly discovered in the Luohandong Formation in the Zhenyuan area,Gansu Province,located in the southwestern Ordos Basin,China.The LA-ICP-MS zircon U-Pb dating of tuffs was carried out.The new ages can precisely constrain the depositional age of the Luohandong Formation and also provide significant indications for the study of regional volcanic activities,paleoclimate,basin evolution,and tectonic setting.展开更多
The tight tuff reservoir is an unusual type of unconventional reservoir with strong heterogeneity.However,there is a lack of research on the microscopic pore structure that causes the heterogeneity of tuff reservoirs....The tight tuff reservoir is an unusual type of unconventional reservoir with strong heterogeneity.However,there is a lack of research on the microscopic pore structure that causes the heterogeneity of tuff reservoirs.Using the Chang 7 Formation in Ordos Basin,China as a case study,carbon-dioxide gas adsorption,nitrogen gas adsorption and high-pressure mercury injection are integrated to investigate the multi-scale pore structure characteristics of tuff reservoirs.Meanwhile,the fractal dimension is introduced to characterize the complexity of pore structure in tuff reservoirs.By this multi-experimental method,the quantitative characterizations of the full-range pore size distribution of four tuff types were obtained and compared in the size ranges of micropores,mesopores and macropores.Fractal dimension curves derived from full-range pores are divided into six segments as D1,D2,D3,D4,D5 and D6 corresponding to fractal characteristics of micropores,smaller mesopores,larger mesopores,smaller macropores,medium macropores and larger macropores,respectively.The macropore volume,average macropore radius and fractal dimension D5 significantly control petrophysical properties.The larger macropore volume,average macropore radius and D5 correspond to favorable pore structure and good reservoir quality,which provides new indexes for the tuff reservoir evaluation.This study enriches the understanding of the heterogeneity of pore structures and contributes to unconventional oil and gas exploration and development.展开更多
The Tezoantla Tuff(«Cantera de Tezoantla»in Spanish)was designated as a‘Heritage Stone’by the International Union of Geological Sciences on October 22,2022,under revised criteria that were approved the sam...The Tezoantla Tuff(«Cantera de Tezoantla»in Spanish)was designated as a‘Heritage Stone’by the International Union of Geological Sciences on October 22,2022,under revised criteria that were approved the same year,being the first in Mexico and the second to be awarded a volcanic tuff.It is a volcanic ash tuff of Miocene age,with lowtemperature argillic hydrothermal alteration(zeolitization),that has been quarried for at least 400 years in the municipality of Mineral del Monte of the Comarca Minera UNESCO Global Geopark.Due to its aesthetic value(in particular,the white variety)and suitable physical properties,this stone has been used as building and sculpture material in notable monuments of Baroque,eclectic and Neoclassical styles of the state of Hidalgo and the historic center of Mexico City,most of which are cataloged in different lists of cultural heritage.In addition,it has been widely used in vernacular architecture and in industrial constructions that are part of the outstanding mining heritage of the geopark,with Cornish engine houses(19th century)standing out.展开更多
基金supported by the Science&Technology Fundamental Resources Investigation Program of China(2022FY101800)the National Science Foundation of China(92162212)the International Geoscience Programme(IGCP 675).
文摘1.Objective,The Cretaceous succession is characteristic of the aeolian sedimentary system in the Ordos Basin,which is the major ore-bearing layer for the sandstone-type uranium deposits.Based on the research of paleontology and magnetostratigraphy,formers believed it belonged to the Early Cretaceous(Huang YB,2010).However,the lack of intrusions or volcanic rocks for isotopic dating results in an unclear formation age for the Lower Cretaceous succession.Recently,tuffs were firstly discovered in the Luohandong Formation in the Zhenyuan area,Gansu Province,located in the southwestern Ordos Basin,China.The LA-ICP-MS zircon U-Pb dating of tuffs was carried out.The new ages can precisely constrain the depositional age of the Luohandong Formation and also provide significant indications for the study of regional volcanic activities,paleoclimate,basin evolution,and tectonic setting.
基金supported by the Strategic Cooperation Technology Projects of CNPC and CUPB(No.ZLZX2020-02)the National Science and Technology Special(No.2017ZX05049-006-001)+1 种基金the National Natural Science Foundation of China(No.41602137)Science Foundation of China University of Petroleum,Beijing(No.2462020YXZZ022).
文摘The tight tuff reservoir is an unusual type of unconventional reservoir with strong heterogeneity.However,there is a lack of research on the microscopic pore structure that causes the heterogeneity of tuff reservoirs.Using the Chang 7 Formation in Ordos Basin,China as a case study,carbon-dioxide gas adsorption,nitrogen gas adsorption and high-pressure mercury injection are integrated to investigate the multi-scale pore structure characteristics of tuff reservoirs.Meanwhile,the fractal dimension is introduced to characterize the complexity of pore structure in tuff reservoirs.By this multi-experimental method,the quantitative characterizations of the full-range pore size distribution of four tuff types were obtained and compared in the size ranges of micropores,mesopores and macropores.Fractal dimension curves derived from full-range pores are divided into six segments as D1,D2,D3,D4,D5 and D6 corresponding to fractal characteristics of micropores,smaller mesopores,larger mesopores,smaller macropores,medium macropores and larger macropores,respectively.The macropore volume,average macropore radius and fractal dimension D5 significantly control petrophysical properties.The larger macropore volume,average macropore radius and D5 correspond to favorable pore structure and good reservoir quality,which provides new indexes for the tuff reservoir evaluation.This study enriches the understanding of the heterogeneity of pore structures and contributes to unconventional oil and gas exploration and development.
基金Funding is provided by the projects CONACYT FORDECYTPRONACES(315487)PAPIME-DGAPA,UNAM(PE107617).
文摘The Tezoantla Tuff(«Cantera de Tezoantla»in Spanish)was designated as a‘Heritage Stone’by the International Union of Geological Sciences on October 22,2022,under revised criteria that were approved the same year,being the first in Mexico and the second to be awarded a volcanic tuff.It is a volcanic ash tuff of Miocene age,with lowtemperature argillic hydrothermal alteration(zeolitization),that has been quarried for at least 400 years in the municipality of Mineral del Monte of the Comarca Minera UNESCO Global Geopark.Due to its aesthetic value(in particular,the white variety)and suitable physical properties,this stone has been used as building and sculpture material in notable monuments of Baroque,eclectic and Neoclassical styles of the state of Hidalgo and the historic center of Mexico City,most of which are cataloged in different lists of cultural heritage.In addition,it has been widely used in vernacular architecture and in industrial constructions that are part of the outstanding mining heritage of the geopark,with Cornish engine houses(19th century)standing out.
