- Email: [email protected]
Special issue of “fluid and melt inclusions”
Journal of Geochemical Exploration 171 (2016) 1–3
Contents lists available at ScienceDirect
Journal of Geochemical Exploration journal homepage: www.elsevier.com/locate/gexplo
Editorial
Special issue of “fluid and melt inclusions” The fifth biennial meeting of the Asian Current Research on Fluid Inclusions (ACROFI-V) was held at Chang'an University on May16-18th, 2014 at Xi'an, China. The conference was jointlyorganized by two Chinese universities,Nanjing University in Nanjing and Chang'an University in Xi’an. ACROFI-V was attended by 182 participants (Fig. 1)representing 12 countries and 4 continents.The ACROFI-V in Xi’an was preceded by a pre-conference short course on"Fluids in the Earth" from the 10th to the 14thof May in Nanjing University.This short course was attended by 93 students from 5 countries (Fig. 2). The present special volume of the Journal of Geochemical Exploration titled “Fluid and Melt Inclusions” contains 12 articles selected out of 24 manuscript based on topics that were presented at the ACROFI-V.Fluid and melt inclusion studies may be used to answer a variety of questions related to a range geologic environments. Thus, the articles contained in this special volume cover different topics. One of the most useful applications of fluid inclusions is to constrain the physical and chemical environment associated with ore-forming and oil/gas forming processes. As one of the fastest growing regions in the world, Asian countries have a continuous demand for mineral resources and oil and gas resources. In this Special issue, there are seven contributions characterizing the role of fluids in the origin and evolution of mineral deposits and two contributions characterizing the role of fluids in the oil and gas exploration field.The other three articles are focused on protocols for studying silicate melt inclusion, fluid inclusions formed in pegmatitic environments, and CH4 densometry. Below we give a brief introduction to all the articles contained in this special volume: Application of silicate melt inclusion analysis to the study magmatic processes has shown a rapid growth trend since the1980s. Acquisition of data on volatiles in magmas is a major concern. Cannatelli C. and coworkers provide a detailed and timely review of the technique of silicate melt inclusions in the study of magmatic volatiles. They introduce the history of research focused on silicate melt inclusions (SMI), the procedures to conduct a SMIs study and analytical techniques to determine the volatile contents of SMIs. This paper will be a useful guide for researchers interested in the melt inclusion technique.' Estimates of the internal pressure of fluid inclusions are an important part of fluid inclusion research.Zhang J-L. and coworkers provide new data on the shift of the Ramanband of the symmetric stretching of methane versus density/pressure at 25°C and give a unified equation to determine methane densities.The equation can be used to calculate the CH4-bearing fluid inclusion pressure and density up to 0.55g/cm3. Also, this CH4densimetrycan be successfully applied to natural methane inclusions in a MVT mineral deposit, China. Fluid inclusionscan be used to study the stability fields of minerals. Crystalline cristobalite commonly found in low-pressure environments in acid volcanic rocks, was thought to have difficulty to persist in H2O-
http://dx.doi.org/10.1016/j.gexplo.2016.10.013 0375-6742/© 2016 Published by Elsevier B.V.
rich environments. Li J-K. & Chou I-M observed coexistence of cristobalite with aqueous fluid in the crystal-rich inclusions in spodumene from Jiajika pegmatite deposit in China. They attribute the origin of cristobalite to the pressure decrease within crystal-rich inclusions since trapping and the extension of the cristobalite stability to low temperatures. Xu Y-F.and coworkers describe fluid inclusions from the Huangshan orogenic gold deposit that are hosted in the ductile shear zone of Precambrian Chencai Group in the Jiangshan-Shaoxing fault zone between the Yangtze and the Cathaysia blocks, China. The ore fluids are represented by the system H2O-CO2-NaCl, and immiscibility was observed only during the gold mineralization stage. H-O-S-Pb isotope data suggest a regional metamorphic source for the sulfur, water and, metals in the deposit. This work also shows that the Jiangshan-Shaoxing fault zone is a preferred target area for future Caledonian orogenicgold deposit exploration. Zhu X-T. and coworkers conducted a fluid inclusion study of the Yongping copper deposit, located at the Gandongbei metallogenic belt, South China. The ore fluids are characterized by H2O-CO2-NaCl. Fluid boiling induced metal precipitation. H–O isotope studies imply that the ore-forming fluids are derived from magmatic waters. Intensive skarn alteration took place during the Yongping copper mineralization and the Pb–Pb dating of pyrite from copper ore bodies suggests that the mineralization occurred in the Jurassic. All the data provided indicate a Jurassic skarn copper deposit rather than a Carboniferous Sedex deposit. Cai Y-T. and coworkers studied fluid inclusions in Dongxiang copper deposit thatis located in Northeastern Jiangxi Province, South China.This study shows that Dongxiang copper deposit was formed by H2O-NaCl fluids. The coexistence of gas-rich and daughter mineral-bearing fluid inclusions in the ore stage quartz indicates that boiling was the predominant mechanism of copper deposition. H–O isotopes demonstrate a primary magmatic origin for the ore-forming fluids. Sulfurisotope suggests a magmatic source for sulfide ore minerals. Lead isotope indicates that Pb in the sulfide minerals probably has originated from magma. Cai YT. and coworkerssuggest that the Dongxiang deposit is a Manto-type copper deposit. LiuX. and coworkers conducted a fluid inclusion study on the giant Dexing porphyry deposit, which is located adjacent to the Neoproterozoic suture of South China Block. The ore-forming fluids are characterized by H 2 O-CO 2 -NaCl. The new data show that this porphyry deposit was formed by unusual CO2 rich fluids at relatively deep levels of the crust, similar to Butte Cu-Mo porphyry deposit in Montana. From this study, the authors also note that the salinity uncertainties of fluid inclusions homogenized by halite disappearance could cause extremely large uncertainties for pressure calculations.
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Editorial
Fig. 1. Group photograph of participants at the ACROFI-V meeting at the University of Chang'an, Xi'an, China May 16-18th, 2014.
Wen B-J.and coworkers studied the Sanshandao gold deposit, located at the Jiaodong Peninsula, North China Craton using the fluid inclusion technique. The ore fluids are characterized by H2O-CO2-NaCl. The microthermometric analysis of fluid inclusions for each mineralization stage does not show any major variations with depth up to 4 km from the surface. H-O-S-He-Ar isotopic compositions indicate the oreforming fluids are of magmatic origin.Wen B-J. and coworkers suggested that gradual incorporation of shallower meteoric water occurred during/after mineralization, and that mantle-derived and crust-derived fluids were both responsiblefor the gold mineralization. Wang D. and coworkers comparedfluid and melt inclusions of mineralized and barren porphyry magmatic-hydrothermal systems from the Jinshajiang-Red River magmatic belt, which is an important CuAu- Mo mineralization belt and developed along the eastern IndoAsian collision zone in western China. The fluid and melt inclusion assemblages hosted in quartz phenocrysts are used to delineate barren from mineralized intrusions. Wang D. and coworkers proposed that fluid inclusion hosted in quartz phenocrysts containing halite, sylvite, calcite and an opaque phases as daughter mineral assemblages are associated toporphyry mineralization.The volatile contentsof these fluid inclusions can constrain thegrade of these ore deposits. Zheng Y. and coworkers studied fluid inclusion to constraints the metallic remobilization of the Ashele VMS Cu-Zn deposit, Altay, NW
China. Their work shows that the two ore-forming periods can be distinguished in the Ashele VMS Cu-Zn deposit: an early period VMS ores and a second period Cu-Pb-Zn polymetallic quartz veins. Fluid inclusion study revealed that ore-forming fluids in the Cu-Pb-Zn polymetallic quartz veins were characterized by NaCl-H2O-CO2implying a metamorphic origin of the fluids. This work supportsa two stage mineralization model. Pan L-Y. and coworkers investigated the sparry calcite cements in upper Permian Changxing reefal limestone of Sichuan Basin in which gas reservoirs formed. Based on the integration of petrography, fluid inclusions, carbon, oxygen and strontium isotopes, trace elements analysis Pan L-Y. and coworkers reconstructed the diagenetic environments in which these cements formed. They highlighted the existence of the thermal stretching of fluid inclusions happened in pre-bitumen calcite cements and only part of fluid inclusions in this stage documented precipitation temperature. The Th data of post-bitumen calcite cements are the valid records of precipitation temperatures. Mi J-Kand coworkers gathered a set of data of homogenization temperature of fluid inclusions, and conducted a systematic comparison on the components and Carbon isotopic ratio between fluid inclusion gases and reservoirs gases in upper Paleozoic formation and calcite veins in Ordos basin, China.The similar geochemistry in hydrocarbon components between reservoir gases and fluid inclusion
Fig. 2. Participants of theshort course "Fluids in the Earth" at the University of Nanjing, China, May 10-14th, 2014.
Editorial
gases indicate that upper Paleozoic gases had experienced a weak or no secondary alteration. We thank all the researchers for their cooperation in preparing the papers for this Special Issue. In addition, We expressour sincere thanks to the following reviewers and many other anonymous reviewers, without whoseassistance thework could not have been completed: Rainer Thomas, Maria-Luce Frezzotti, Thomas Ulrich, Jingwen Mao, Jonathan Naden, Jean Dubessy, Alfons Van den Kerkhof, John Parnell, Jacques Pironon, Zenqian Hou, Ronald J Bakker, Joanna Potter, Nigel Blamey, Hongrui Fan, Hecai Niu, Habil Peter Kodera, Huayong Chen, James Lambert-Smith, Daniel James Smith, Julian Menuge, JiuhuaXu, Ines Mulder, Matthew Steele-MacInnis, Stephen Becker, Mona Liza Sirbescu, Yilin Xiao, Ihsan Al-Aasm, Pilar Lecumberri-Sanchez, Brian Tattitch, Rongxi Li, Yanbo Cheng, Chunfang Cai and Zhirong Zhang.
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We offer special thanks to the Editor-in-Chief, De Vivo Benedetto, for his encouragement and support. Finally many thanks to Yanping Hou and Arnold Justus Stanly for their technical support for the publication of this Special issue. Pei Ni E-mail address: [email protected] Rosario Esposito E-mail address: [email protected] Andy H. Rankin E-mail address: [email protected]
Contents lists available at ScienceDirect
Journal of Geochemical Exploration journal homepage: www.elsevier.com/locate/gexplo
Editorial
Special issue of “fluid and melt inclusions” The fifth biennial meeting of the Asian Current Research on Fluid Inclusions (ACROFI-V) was held at Chang'an University on May16-18th, 2014 at Xi'an, China. The conference was jointlyorganized by two Chinese universities,Nanjing University in Nanjing and Chang'an University in Xi’an. ACROFI-V was attended by 182 participants (Fig. 1)representing 12 countries and 4 continents.The ACROFI-V in Xi’an was preceded by a pre-conference short course on"Fluids in the Earth" from the 10th to the 14thof May in Nanjing University.This short course was attended by 93 students from 5 countries (Fig. 2). The present special volume of the Journal of Geochemical Exploration titled “Fluid and Melt Inclusions” contains 12 articles selected out of 24 manuscript based on topics that were presented at the ACROFI-V.Fluid and melt inclusion studies may be used to answer a variety of questions related to a range geologic environments. Thus, the articles contained in this special volume cover different topics. One of the most useful applications of fluid inclusions is to constrain the physical and chemical environment associated with ore-forming and oil/gas forming processes. As one of the fastest growing regions in the world, Asian countries have a continuous demand for mineral resources and oil and gas resources. In this Special issue, there are seven contributions characterizing the role of fluids in the origin and evolution of mineral deposits and two contributions characterizing the role of fluids in the oil and gas exploration field.The other three articles are focused on protocols for studying silicate melt inclusion, fluid inclusions formed in pegmatitic environments, and CH4 densometry. Below we give a brief introduction to all the articles contained in this special volume: Application of silicate melt inclusion analysis to the study magmatic processes has shown a rapid growth trend since the1980s. Acquisition of data on volatiles in magmas is a major concern. Cannatelli C. and coworkers provide a detailed and timely review of the technique of silicate melt inclusions in the study of magmatic volatiles. They introduce the history of research focused on silicate melt inclusions (SMI), the procedures to conduct a SMIs study and analytical techniques to determine the volatile contents of SMIs. This paper will be a useful guide for researchers interested in the melt inclusion technique.' Estimates of the internal pressure of fluid inclusions are an important part of fluid inclusion research.Zhang J-L. and coworkers provide new data on the shift of the Ramanband of the symmetric stretching of methane versus density/pressure at 25°C and give a unified equation to determine methane densities.The equation can be used to calculate the CH4-bearing fluid inclusion pressure and density up to 0.55g/cm3. Also, this CH4densimetrycan be successfully applied to natural methane inclusions in a MVT mineral deposit, China. Fluid inclusionscan be used to study the stability fields of minerals. Crystalline cristobalite commonly found in low-pressure environments in acid volcanic rocks, was thought to have difficulty to persist in H2O-
http://dx.doi.org/10.1016/j.gexplo.2016.10.013 0375-6742/© 2016 Published by Elsevier B.V.
rich environments. Li J-K. & Chou I-M observed coexistence of cristobalite with aqueous fluid in the crystal-rich inclusions in spodumene from Jiajika pegmatite deposit in China. They attribute the origin of cristobalite to the pressure decrease within crystal-rich inclusions since trapping and the extension of the cristobalite stability to low temperatures. Xu Y-F.and coworkers describe fluid inclusions from the Huangshan orogenic gold deposit that are hosted in the ductile shear zone of Precambrian Chencai Group in the Jiangshan-Shaoxing fault zone between the Yangtze and the Cathaysia blocks, China. The ore fluids are represented by the system H2O-CO2-NaCl, and immiscibility was observed only during the gold mineralization stage. H-O-S-Pb isotope data suggest a regional metamorphic source for the sulfur, water and, metals in the deposit. This work also shows that the Jiangshan-Shaoxing fault zone is a preferred target area for future Caledonian orogenicgold deposit exploration. Zhu X-T. and coworkers conducted a fluid inclusion study of the Yongping copper deposit, located at the Gandongbei metallogenic belt, South China. The ore fluids are characterized by H2O-CO2-NaCl. Fluid boiling induced metal precipitation. H–O isotope studies imply that the ore-forming fluids are derived from magmatic waters. Intensive skarn alteration took place during the Yongping copper mineralization and the Pb–Pb dating of pyrite from copper ore bodies suggests that the mineralization occurred in the Jurassic. All the data provided indicate a Jurassic skarn copper deposit rather than a Carboniferous Sedex deposit. Cai Y-T. and coworkers studied fluid inclusions in Dongxiang copper deposit thatis located in Northeastern Jiangxi Province, South China.This study shows that Dongxiang copper deposit was formed by H2O-NaCl fluids. The coexistence of gas-rich and daughter mineral-bearing fluid inclusions in the ore stage quartz indicates that boiling was the predominant mechanism of copper deposition. H–O isotopes demonstrate a primary magmatic origin for the ore-forming fluids. Sulfurisotope suggests a magmatic source for sulfide ore minerals. Lead isotope indicates that Pb in the sulfide minerals probably has originated from magma. Cai YT. and coworkerssuggest that the Dongxiang deposit is a Manto-type copper deposit. LiuX. and coworkers conducted a fluid inclusion study on the giant Dexing porphyry deposit, which is located adjacent to the Neoproterozoic suture of South China Block. The ore-forming fluids are characterized by H 2 O-CO 2 -NaCl. The new data show that this porphyry deposit was formed by unusual CO2 rich fluids at relatively deep levels of the crust, similar to Butte Cu-Mo porphyry deposit in Montana. From this study, the authors also note that the salinity uncertainties of fluid inclusions homogenized by halite disappearance could cause extremely large uncertainties for pressure calculations.
2
Editorial
Fig. 1. Group photograph of participants at the ACROFI-V meeting at the University of Chang'an, Xi'an, China May 16-18th, 2014.
Wen B-J.and coworkers studied the Sanshandao gold deposit, located at the Jiaodong Peninsula, North China Craton using the fluid inclusion technique. The ore fluids are characterized by H2O-CO2-NaCl. The microthermometric analysis of fluid inclusions for each mineralization stage does not show any major variations with depth up to 4 km from the surface. H-O-S-He-Ar isotopic compositions indicate the oreforming fluids are of magmatic origin.Wen B-J. and coworkers suggested that gradual incorporation of shallower meteoric water occurred during/after mineralization, and that mantle-derived and crust-derived fluids were both responsiblefor the gold mineralization. Wang D. and coworkers comparedfluid and melt inclusions of mineralized and barren porphyry magmatic-hydrothermal systems from the Jinshajiang-Red River magmatic belt, which is an important CuAu- Mo mineralization belt and developed along the eastern IndoAsian collision zone in western China. The fluid and melt inclusion assemblages hosted in quartz phenocrysts are used to delineate barren from mineralized intrusions. Wang D. and coworkers proposed that fluid inclusion hosted in quartz phenocrysts containing halite, sylvite, calcite and an opaque phases as daughter mineral assemblages are associated toporphyry mineralization.The volatile contentsof these fluid inclusions can constrain thegrade of these ore deposits. Zheng Y. and coworkers studied fluid inclusion to constraints the metallic remobilization of the Ashele VMS Cu-Zn deposit, Altay, NW
China. Their work shows that the two ore-forming periods can be distinguished in the Ashele VMS Cu-Zn deposit: an early period VMS ores and a second period Cu-Pb-Zn polymetallic quartz veins. Fluid inclusion study revealed that ore-forming fluids in the Cu-Pb-Zn polymetallic quartz veins were characterized by NaCl-H2O-CO2implying a metamorphic origin of the fluids. This work supportsa two stage mineralization model. Pan L-Y. and coworkers investigated the sparry calcite cements in upper Permian Changxing reefal limestone of Sichuan Basin in which gas reservoirs formed. Based on the integration of petrography, fluid inclusions, carbon, oxygen and strontium isotopes, trace elements analysis Pan L-Y. and coworkers reconstructed the diagenetic environments in which these cements formed. They highlighted the existence of the thermal stretching of fluid inclusions happened in pre-bitumen calcite cements and only part of fluid inclusions in this stage documented precipitation temperature. The Th data of post-bitumen calcite cements are the valid records of precipitation temperatures. Mi J-Kand coworkers gathered a set of data of homogenization temperature of fluid inclusions, and conducted a systematic comparison on the components and Carbon isotopic ratio between fluid inclusion gases and reservoirs gases in upper Paleozoic formation and calcite veins in Ordos basin, China.The similar geochemistry in hydrocarbon components between reservoir gases and fluid inclusion
Fig. 2. Participants of theshort course "Fluids in the Earth" at the University of Nanjing, China, May 10-14th, 2014.
Editorial
gases indicate that upper Paleozoic gases had experienced a weak or no secondary alteration. We thank all the researchers for their cooperation in preparing the papers for this Special Issue. In addition, We expressour sincere thanks to the following reviewers and many other anonymous reviewers, without whoseassistance thework could not have been completed: Rainer Thomas, Maria-Luce Frezzotti, Thomas Ulrich, Jingwen Mao, Jonathan Naden, Jean Dubessy, Alfons Van den Kerkhof, John Parnell, Jacques Pironon, Zenqian Hou, Ronald J Bakker, Joanna Potter, Nigel Blamey, Hongrui Fan, Hecai Niu, Habil Peter Kodera, Huayong Chen, James Lambert-Smith, Daniel James Smith, Julian Menuge, JiuhuaXu, Ines Mulder, Matthew Steele-MacInnis, Stephen Becker, Mona Liza Sirbescu, Yilin Xiao, Ihsan Al-Aasm, Pilar Lecumberri-Sanchez, Brian Tattitch, Rongxi Li, Yanbo Cheng, Chunfang Cai and Zhirong Zhang.
3
We offer special thanks to the Editor-in-Chief, De Vivo Benedetto, for his encouragement and support. Finally many thanks to Yanping Hou and Arnold Justus Stanly for their technical support for the publication of this Special issue. Pei Ni E-mail address: [email protected] Rosario Esposito E-mail address: [email protected] Andy H. Rankin E-mail address: [email protected]