The rhenium-osmium(Re-Os)isotope system is a powerful tool for dating organic-rich sedimentary rocks,yet the mechanisms of Re and Os uptake and their fractionation in different types of organic matter remain poorly un...The rhenium-osmium(Re-Os)isotope system is a powerful tool for dating organic-rich sedimentary rocks,yet the mechanisms of Re and Os uptake and their fractionation in different types of organic matter remain poorly understood.Here,we investigate the role of terrestrial organic matter(e.g.,wood of the species Taxodium distichum and charcoal generated from the same species in the laboratory)in Re and Os enrichment and isotope fractionation through laboratory experiments.The results show that charcoal has a significantly higher capacity to uptake both Re(68-77 times greater)and Os(1.7-2.2 times higher)compared to wood,with charcoal preferentially accumulating Re over Os,leading to higher^(187)Re/^(188)Os ratios.These findings highlight the important contribution of terrestrial organic matter,particularly charcoal,to Re and Os concentrations and isotope fractionation in shales,and the importance of organic matter type for chelating Re and Os as previously discussed.Furthermore,we discuss the potential of using Re to track organic carbon weathering,noting that the coupled release of Re and organic carbon during weathering provides new insights into carbon cycling processes.展开更多
The development of laser ablation inductively coupled plasma quadrupole tandem mass spectrometry(LA-ICP-Q-MS/MS)opens new opportunities to rapidly date a variety of hydrothermal minerals.Here we present in situ Lu-Hf ...The development of laser ablation inductively coupled plasma quadrupole tandem mass spectrometry(LA-ICP-Q-MS/MS)opens new opportunities to rapidly date a variety of hydrothermal minerals.Here we present in situ Lu-Hf and Re-Os dates for hydrothermal apatite and molybdenite,respectively.We further report the first in situ Lu-Hf dates for bastnäsite,dolomite,and siderite,and assess their potential for constraining ore deposit geochronology.For method validation,we report isotope-dilution Lu-Hf dates for apatite reference material Bamble-1(1102±5 Ma)and calcite reference material ME-1(1531±7 Ma),enabling improved accuracy on matrix-matched calibration for LA-ICP-MS/MS Lu-Hf dating.The new methods are applied to the Vulcan Iron-Oxide Copper-Gold(IOCG)prospect in the Olympic Cu-Au Province of South Australia.Such deposits have been difficult to accurately date,given the general lack of reliable mineral geochronometers that are cogenetic with IOCG mineralisation.Hydrothermal apatite Lu-Hf dates and molybdenite Re-Os dates demonstrate that mineralisation at Vulcan largely occurred at ca.1.6 Ga,contemporaneous with the world class Olympic Dam deposit.Our data also indicates that the Lu-Hf system in apatite is more robust than the U-Pb system for determining the timing of primary apatite formation in an IOCG system.We further demonstrate that dolomite can retain Lu-Hf growth ages over an extended time period(>1.5 billion years),providing constraints on the timing of primary ore mineral crystallisation during brecciation and IOCG mineralisation.Finally,late Neoproterozoic(ca.589–544 Ma)and Carboniferous(ca.334±7 Ma)Lu-Hf dates were obtained for texturally late Cubearing carbonate veins,illustrating that the carbonate Lu-Hf method allows direct dating of Cu remobilisation events.This has important implications for mineral exploration as the remobilised Cu may have been transferred to younger deposits hosted in Neoproterozoic sedimentary basins overlaying the Olympic IOCG province.展开更多
To analyze the differences in the transport and distribution of different types of proppants and to address issues such as the short effective support of proppant and poor placement in hydraulically intersecting fract...To analyze the differences in the transport and distribution of different types of proppants and to address issues such as the short effective support of proppant and poor placement in hydraulically intersecting fractures,this study considered the combined impact of geological-engineering factors on conductivity.Using reservoir production parameters and the discrete elementmethod,multispherical proppants were constructed.Additionally,a 3D fracture model,based on the specified conditions of the L block,employed coupled(Computational Fluid Dynamics)CFD-DEM(Discrete ElementMethod)for joint simulations to quantitatively analyze the transport and placement patterns of multispherical proppants in intersecting fractures.Results indicate that turbulent kinetic energy is an intrinsic factor affecting proppant transport.Moreover,the efficiency of placement and migration distance of low-sphericity quartz sand constructed by the DEM in the main fracture are significantly reduced compared to spherical ceramic proppants,with a 27.7%decrease in the volume fraction of the fracture surface,subsequently affecting the placement concentration and damaging fracture conductivity.Compared to small-angle fractures,controlling artificial and natural fractures to expand at angles of 45°to 60°increases the effective support length by approximately 20.6%.During hydraulic fracturing of gas wells,ensuring the fracture support area and post-closure conductivity can be achieved by controlling the sphericity of proppants and adjusting the perforation direction to control the direction of artificial fractures.展开更多
基金the funding of the National Natural Science Foundation of China(Nos.42222209,42303056)。
文摘The rhenium-osmium(Re-Os)isotope system is a powerful tool for dating organic-rich sedimentary rocks,yet the mechanisms of Re and Os uptake and their fractionation in different types of organic matter remain poorly understood.Here,we investigate the role of terrestrial organic matter(e.g.,wood of the species Taxodium distichum and charcoal generated from the same species in the laboratory)in Re and Os enrichment and isotope fractionation through laboratory experiments.The results show that charcoal has a significantly higher capacity to uptake both Re(68-77 times greater)and Os(1.7-2.2 times higher)compared to wood,with charcoal preferentially accumulating Re over Os,leading to higher^(187)Re/^(188)Os ratios.These findings highlight the important contribution of terrestrial organic matter,particularly charcoal,to Re and Os concentrations and isotope fractionation in shales,and the importance of organic matter type for chelating Re and Os as previously discussed.Furthermore,we discuss the potential of using Re to track organic carbon weathering,noting that the coupled release of Re and organic carbon during weathering provides new insights into carbon cycling processes.
基金supported by an Accelerated Discovery Initiative Grant(ADI RD02/260),entitled‘Integrated Exploration Under Deep Cover‘with joint funding from Fortescue and the Government of South AustraliaSG was further supported by an Australian Research Council Future Fellowship(FT210100906)The acquisition of isotope-dilution Lu-Hf dates was financially supported by the Mineral Exploration Cooperative Research Centre whose activities are funded by the Australian Government’s Cooperative Research Centre Program。
文摘The development of laser ablation inductively coupled plasma quadrupole tandem mass spectrometry(LA-ICP-Q-MS/MS)opens new opportunities to rapidly date a variety of hydrothermal minerals.Here we present in situ Lu-Hf and Re-Os dates for hydrothermal apatite and molybdenite,respectively.We further report the first in situ Lu-Hf dates for bastnäsite,dolomite,and siderite,and assess their potential for constraining ore deposit geochronology.For method validation,we report isotope-dilution Lu-Hf dates for apatite reference material Bamble-1(1102±5 Ma)and calcite reference material ME-1(1531±7 Ma),enabling improved accuracy on matrix-matched calibration for LA-ICP-MS/MS Lu-Hf dating.The new methods are applied to the Vulcan Iron-Oxide Copper-Gold(IOCG)prospect in the Olympic Cu-Au Province of South Australia.Such deposits have been difficult to accurately date,given the general lack of reliable mineral geochronometers that are cogenetic with IOCG mineralisation.Hydrothermal apatite Lu-Hf dates and molybdenite Re-Os dates demonstrate that mineralisation at Vulcan largely occurred at ca.1.6 Ga,contemporaneous with the world class Olympic Dam deposit.Our data also indicates that the Lu-Hf system in apatite is more robust than the U-Pb system for determining the timing of primary apatite formation in an IOCG system.We further demonstrate that dolomite can retain Lu-Hf growth ages over an extended time period(>1.5 billion years),providing constraints on the timing of primary ore mineral crystallisation during brecciation and IOCG mineralisation.Finally,late Neoproterozoic(ca.589–544 Ma)and Carboniferous(ca.334±7 Ma)Lu-Hf dates were obtained for texturally late Cubearing carbonate veins,illustrating that the carbonate Lu-Hf method allows direct dating of Cu remobilisation events.This has important implications for mineral exploration as the remobilised Cu may have been transferred to younger deposits hosted in Neoproterozoic sedimentary basins overlaying the Olympic IOCG province.
基金funded by the project of the Major Scientific and Technological Projects of CNOOC in the 14th Five-Year Plan(No.KJGG2022-0701)the CNOOC Research Institute(No.2020PFS-03).
文摘To analyze the differences in the transport and distribution of different types of proppants and to address issues such as the short effective support of proppant and poor placement in hydraulically intersecting fractures,this study considered the combined impact of geological-engineering factors on conductivity.Using reservoir production parameters and the discrete elementmethod,multispherical proppants were constructed.Additionally,a 3D fracture model,based on the specified conditions of the L block,employed coupled(Computational Fluid Dynamics)CFD-DEM(Discrete ElementMethod)for joint simulations to quantitatively analyze the transport and placement patterns of multispherical proppants in intersecting fractures.Results indicate that turbulent kinetic energy is an intrinsic factor affecting proppant transport.Moreover,the efficiency of placement and migration distance of low-sphericity quartz sand constructed by the DEM in the main fracture are significantly reduced compared to spherical ceramic proppants,with a 27.7%decrease in the volume fraction of the fracture surface,subsequently affecting the placement concentration and damaging fracture conductivity.Compared to small-angle fractures,controlling artificial and natural fractures to expand at angles of 45°to 60°increases the effective support length by approximately 20.6%.During hydraulic fracturing of gas wells,ensuring the fracture support area and post-closure conductivity can be achieved by controlling the sphericity of proppants and adjusting the perforation direction to control the direction of artificial fractures.
