Major Sn deposits are commonly linked to crust-derived and highly evolved granites,with magma generation aided by mantle heating.However,whether and how the mantle components contribute to Sn polymetallic mineralizati...Major Sn deposits are commonly linked to crust-derived and highly evolved granites,with magma generation aided by mantle heating.However,whether and how the mantle components contribute to Sn polymetallic mineralization remains unclear.In this study,in combination with a compilation of equivalent data in the region,we provide new constraints on this issue based on detailed investigations on the petrogenesis and metallogenic significance of granitoids including the causative batholith and later granodiorite porphyry dike in the giant Dachang Sn deposit from South China.The former has zircon U-Pb ages of 93-91 Ma and belongs to highly evolved S-type biotite granite,which experienced fractionation of massive feldspar.The latter shows zircon U-Pb ages of 90 Ma and displays I-type granite features.The batholith was mainly derived from the dehydration melting of biotite in the metasedimentary sources,as revealed by the relatively low whole-rock Pb contents(<30 ppm)and high Ba/Pb ratios(2.71-17.1)and initial T(ti-zr)of 790℃.Compared with the adjacent crust-derived S-type granites(-24.8--5.1)and I-type granites(-11.0 to-5.2),the Dachang S-type biotite granites present higher zirconεHf(t)values(-9.1 to-2.1).Furthermore,the low magmatic zirconδ18O values(6.2‰)and higher apatite LREE(3277-4114 ppm)and Sr(1137-1357 ppm)contents than of arc-type basic rocks were discerned.These characteristics jointly hint the contributions of mantle components.The higher initial T(ti-zr)(>850℃),whole-rock Mg#(52 to 58),apatiteεNd(t)(-9.2 to-6.5)and zirconεHf(t)(-7.6 to 2.5)values but lower zirconδ18O values(6.33 to 8.30‰)of the later granodiorite porphyry dike than those of the batholith also suggest that mantle material was involved in the generation of the dikes,which is evident by the variational features of zircon and apatite trace elements.In addition,at the zircon Hf<12000 ppm and Eu/Eu*>0.05,the higher zirconΔFMQ values(mostly from-1.8 to 2.0)and H2O contents(100-1100 ppm)of the Dachang granitoids than the pure crust-derived S-type granites(ΔFMQ=mostly from-3.7 to-1.5;H2O<100 ppm)imply that mantle materials involved are relatively rich in water and oxidized.These suggest that the addition of mantle components is conducive to the extraction of Sn from metasedimentary sources,and moderately facilitates the increase of oxygen fugacity which still maintains the incompatibility of Sn in magmas withΔFMQ<2.Also,the involvement of mantle components upgrades the H2O contents in S-type magmas,favoring the migration of ore-forming elements from magmas to hydrothermal fluids.The sediment-derived causative granites displayed higherεHf(t)andεNd(t)values with greater Sn tonnages of their associated world-class Sn polymetallic deposits,supporting the opinion that the contributions of mantle components play an important role in the generation of giant Sn deposits.展开更多
Nanoparticles with high surface energy and chemical activity have drawn substantial attention in petroleum industry. Recently, Janus nanoparticles exhibited tremendous potential in enhanced oil recovery (EOR) due to t...Nanoparticles with high surface energy and chemical activity have drawn substantial attention in petroleum industry. Recently, Janus nanoparticles exhibited tremendous potential in enhanced oil recovery (EOR) due to their asymmetric structures and properties. In this study, a series of amphiphilic pseudo-Janus@OTAB (PJ@C18) nanoparticles with different concentrations of stearyltrimethylammoium bromide (OTAB) were successfully fabricated. The structures and properties of PJ@C18 were characterized by Fourier transform infrared spectroscopy and ζ-potential measurements. Based on the emulsification experimental results, the interaction models and the self-assembly behavior between hydrophilic nanoparticles (SiO_(2)@NH_(2)) and OTAB molecules at the oil/water interface were proposed, which was further confirmed via the measurements of the contact angle and dynamic interfacial tension. Interestingly, it was found that the change of pH value from 7.5 to 4.0 caused the type reversal of the PJ@C18-1000 stabilized Pickering emulsions. Furthermore, the PJ@C18-1000 stabilized Pickering emulsion system with excellent salt and temperature tolerances (10000 mg∙L^(–1), 90℃) significantly improved the oil recovery in the single-tube (more than 17%) and double-tube (more than 25%) sand pack model flooding tests. The findings of this study could help to better understand the construction mechanism of pseudo-Janus silica/surfactant assembly and the potential application of PJ@C18-1000 stabilized Pickering emulsions for EOR.展开更多
The article examines a window of opportunity that emerged between 1955 and 1957 and which could have resulted in the normalisation of Saudi Arabia’s relations with the People’s Republic of China,along with a few oth...The article examines a window of opportunity that emerged between 1955 and 1957 and which could have resulted in the normalisation of Saudi Arabia’s relations with the People’s Republic of China,along with a few other states from the communist bloc.As the article will show,this possibility emerged as a by-product of the Kingdom’s national security challenges during that juncture,and which in turn contributed towards its embrace of a strategy playing both sides of the Cold War divide against one another.This strategy elicited the desired American response which,hand in hand with changing Saudi assessments of regional threats by late 1956,consolidated the American-Saudi security partnership and foreclosed Sino-Saudi normalisation.While the Kingdom had‘moved on’by 1957,a reading of open Chinese sources from the late 1950s suggests that Beijing continued to harbour the hope that formal relations could be established.展开更多
基金supported by the National Natural Science Foundation of China (No.92162215)the Key Project of the Resource Exploration Bureau in Guangxi Province (Nos.201822,201918)+2 种基金the Key Project of the Department of Natural Resources in Guangxi Province (Nos.2019673,20201111)the 111 Plan under the Ministry of Education and the State Administration of Foreign Experts Affairs,China (No.B07011)the“Deep-time Digital Earth”Science and Technology Leading Talents Team Funds for the Central Universities for the Frontiers Science Center for Deep-time Digital Earth,China University of Geosciences (Beijing) (Fundamental Research Funds for the Central Universities,No.2652023001).
文摘Major Sn deposits are commonly linked to crust-derived and highly evolved granites,with magma generation aided by mantle heating.However,whether and how the mantle components contribute to Sn polymetallic mineralization remains unclear.In this study,in combination with a compilation of equivalent data in the region,we provide new constraints on this issue based on detailed investigations on the petrogenesis and metallogenic significance of granitoids including the causative batholith and later granodiorite porphyry dike in the giant Dachang Sn deposit from South China.The former has zircon U-Pb ages of 93-91 Ma and belongs to highly evolved S-type biotite granite,which experienced fractionation of massive feldspar.The latter shows zircon U-Pb ages of 90 Ma and displays I-type granite features.The batholith was mainly derived from the dehydration melting of biotite in the metasedimentary sources,as revealed by the relatively low whole-rock Pb contents(<30 ppm)and high Ba/Pb ratios(2.71-17.1)and initial T(ti-zr)of 790℃.Compared with the adjacent crust-derived S-type granites(-24.8--5.1)and I-type granites(-11.0 to-5.2),the Dachang S-type biotite granites present higher zirconεHf(t)values(-9.1 to-2.1).Furthermore,the low magmatic zirconδ18O values(6.2‰)and higher apatite LREE(3277-4114 ppm)and Sr(1137-1357 ppm)contents than of arc-type basic rocks were discerned.These characteristics jointly hint the contributions of mantle components.The higher initial T(ti-zr)(>850℃),whole-rock Mg#(52 to 58),apatiteεNd(t)(-9.2 to-6.5)and zirconεHf(t)(-7.6 to 2.5)values but lower zirconδ18O values(6.33 to 8.30‰)of the later granodiorite porphyry dike than those of the batholith also suggest that mantle material was involved in the generation of the dikes,which is evident by the variational features of zircon and apatite trace elements.In addition,at the zircon Hf<12000 ppm and Eu/Eu*>0.05,the higher zirconΔFMQ values(mostly from-1.8 to 2.0)and H2O contents(100-1100 ppm)of the Dachang granitoids than the pure crust-derived S-type granites(ΔFMQ=mostly from-3.7 to-1.5;H2O<100 ppm)imply that mantle materials involved are relatively rich in water and oxidized.These suggest that the addition of mantle components is conducive to the extraction of Sn from metasedimentary sources,and moderately facilitates the increase of oxygen fugacity which still maintains the incompatibility of Sn in magmas withΔFMQ<2.Also,the involvement of mantle components upgrades the H2O contents in S-type magmas,favoring the migration of ore-forming elements from magmas to hydrothermal fluids.The sediment-derived causative granites displayed higherεHf(t)andεNd(t)values with greater Sn tonnages of their associated world-class Sn polymetallic deposits,supporting the opinion that the contributions of mantle components play an important role in the generation of giant Sn deposits.
基金funding from the National Natural Science Foundation of China(Grant No.51974344)the Natural Science Foundation of Shandong Provincial(Grant No.ZR2019MEE077)the Fundamental Research Funds for the Central Universities(Grant No.19CX02064A).
文摘Nanoparticles with high surface energy and chemical activity have drawn substantial attention in petroleum industry. Recently, Janus nanoparticles exhibited tremendous potential in enhanced oil recovery (EOR) due to their asymmetric structures and properties. In this study, a series of amphiphilic pseudo-Janus@OTAB (PJ@C18) nanoparticles with different concentrations of stearyltrimethylammoium bromide (OTAB) were successfully fabricated. The structures and properties of PJ@C18 were characterized by Fourier transform infrared spectroscopy and ζ-potential measurements. Based on the emulsification experimental results, the interaction models and the self-assembly behavior between hydrophilic nanoparticles (SiO_(2)@NH_(2)) and OTAB molecules at the oil/water interface were proposed, which was further confirmed via the measurements of the contact angle and dynamic interfacial tension. Interestingly, it was found that the change of pH value from 7.5 to 4.0 caused the type reversal of the PJ@C18-1000 stabilized Pickering emulsions. Furthermore, the PJ@C18-1000 stabilized Pickering emulsion system with excellent salt and temperature tolerances (10000 mg∙L^(–1), 90℃) significantly improved the oil recovery in the single-tube (more than 17%) and double-tube (more than 25%) sand pack model flooding tests. The findings of this study could help to better understand the construction mechanism of pseudo-Janus silica/surfactant assembly and the potential application of PJ@C18-1000 stabilized Pickering emulsions for EOR.
基金special issue of Sino-Saudi Relations is a joint project of Asian Journal of Middle Eastern and Islamic Studies and King Faisal Center for Research and Islamic Studies,Saudi Arabia.
文摘The article examines a window of opportunity that emerged between 1955 and 1957 and which could have resulted in the normalisation of Saudi Arabia’s relations with the People’s Republic of China,along with a few other states from the communist bloc.As the article will show,this possibility emerged as a by-product of the Kingdom’s national security challenges during that juncture,and which in turn contributed towards its embrace of a strategy playing both sides of the Cold War divide against one another.This strategy elicited the desired American response which,hand in hand with changing Saudi assessments of regional threats by late 1956,consolidated the American-Saudi security partnership and foreclosed Sino-Saudi normalisation.While the Kingdom had‘moved on’by 1957,a reading of open Chinese sources from the late 1950s suggests that Beijing continued to harbour the hope that formal relations could be established.