The Experts below are selected from a list of 200568 Experts worldwide ranked by ideXlab platform
Zhigang Zeng - One of the best experts on this subject based on the ideXlab platform.
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Understanding the Compositional Variability of the Major Components of Hydrothermal Plumes in the Okinawa Trough
Hindawi-Wiley, 2018Co-Authors: Zhigang Zeng, Xiaoyuan Wang, Chentung Arthur ChenAbstract:Studies of the major components of Hydrothermal plumes in seafloor Hydrothermal fields are critical for an improved understanding of biogeochemical cycles and the large-scale distribution of elements in the submarine environment. The composition of major components in Hydrothermal plume water column samples from 25 stations has been investigated in the middle and southern Okinawa Trough. The physical and chemical properties of Hydrothermal plume water in the Okinawa Trough have been affected by input of the Kuroshio current, and its influence on Hydrothermal plume water from the southern Okinawa Trough to the middle Okinawa Trough is reduced. The anomalous layers of seawater in the Hydrothermal plume water columns have higher K+, Ca2+, Mn2+, B3+, Ca2+/SO42-, and Mn2+/Mg2+ ratios and higher optical anomalies than other layers. The Mg2+, SO42-, Mg2+/Ca2+, and SO42-/Mn2+ ratios of the anomalous layers are lower than other layers in the Hydrothermal plume water columns and are consistent with concentrations in Hydrothermal vent fluids in the Okinawa Trough. This suggests that the chemical variations of Hydrothermal plumes in the Tangyin Hydrothermal field, like other Hydrothermal fields, result in the discharge of high K+, Ca2+, and B3+ and low Mg2+ and SO42- fluid. Furthermore, element ratios (e.g., Sr2+/Ca2+, Ca2+/Cl−) in Hydrothermal plume water columns were found to be similar to those in average seawater, indicating that Sr2+/Ca2+ and Ca2+/Cl− ratios of Hydrothermal plumes might be useful proxies for chemical properties of seawater. The Hydrothermal K+, Ca2+, Mn2+, and B3+ flux to seawater in the Okinawa Trough is about 2.62–873, 1.04–326, 1.30–76.4, and 0.293–34.7 × 106 kg per year, respectively. The heat flux is about 0.159–1,973 × 105 W, which means that roughly 0.0006% of ocean heat is supplied by seafloor Hydrothermal plumes in the Okinawa Trough
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rhenium osmium abundance and isotopic compositions of massive sulfides from modern deep sea Hydrothermal systems implications for vent associated ore forming processes
Earth and Planetary Science Letters, 2014Co-Authors: Zhigang Zeng, Xuebo Yin, Shuai Chen, David Selby, Xiaoyuan WangAbstract:Studies of rhenium (Re) and osmium (Os) concentrations and isotopic compositions in seafloor Hydrothermal sulfides are an important tool for understanding the evolution of Hydrothermal systems, allowing the determination of both metal sources and reconstructing the physicochemical conditions of their deposition. The Re-Os concentrations and isotopic compositions of 38 massive sulfide samples have been studied in different Hydrothermal fields from the East Pacific Rise (EPR), Mid-Atlantic Ridge (MAR), Central Indian Ridge (CIR), Southwest Indian Ridge (SWIR), and Back-Arc Basin (BAB). The majority of the sulfides possess Os-187/Os-188 that span a narrow range (1.004 to 1.209), which is most easily explained as a seawater-derived component. This may suggest that those initial Os-187/Os-188 isotope compositions of ancient seafloor Hydrothermal sulfide deposits which were formed by the mixing process between seawater and Hydrothermal fluid, are possible for analysing ancient seawater Os components. Only two of samples (MAR05-TVG1-10-2 and MAR05-TVG1-21 from the Logatchev Hydrothermal field (LHF), MAR) possess moderately less radiogenic Os-187/Os-188 (0.645 to 0.730), which may reflect the lesser extent of Hydrothermal fluid-seawater mixing during Hydrothermal ore-forming process.
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boron isotope compositions of fluids and plumes from the kueishantao Hydrothermal field off northeastern taiwan implications for fluid origin and Hydrothermal processes
Marine Chemistry, 2013Co-Authors: Zhigang Zeng, Xiaoyuan Wang, Chentung Arthur Chen, Xuebo Yin, Shuai Chen, Yingkai XiaoAbstract:Boron is a common element in vent fluids of seafloor Hydrothermal fields, and it has been used to understand the Hydrothermal flux and water-rock interaction in Hydrothermal systems. We have measured the boron concentration and isotope composition of seawater, andesite, Hydrothermal fluid and plume samples from the Kueishantao Hydrothermal field. The delta B-11 value of ambient seawater near the field is 40.05 +/- 0.01 parts per thousand, and the boron concentration is 3.81 mg/L Andesite rocks from the Hydrothermal field have an average boron content of 153 ppm. The Hydrothermal fluids from the yellow spring and white spring span a small range of delta B-11 values, from 3327 +/- 022 to 36.84 +/- 0.11 parts per thousand, and plumes from both springs also cover a small range, from 37.56 +/- 0.01 to 40.37 +/- 0.21 parts per thousand. Hydrothermal fluids from both springs in the Kueishantao Hydrothermal field have variable B enrichments relative to seawater between 7 and 21%. They have B concentrations (4.10-4.64 mg/L) that are slightly higher and delta B-11 values (3327-36.84 parts per thousand) that are lower than those of the Hydrothermal plumes (3.94-4.17 mg/L, 37.56-40.37 parts per thousand). Hydrothermal fluids and plumes display a very regular array of data points in a delta B-11-B diagram, suggesting that the boron of Hydrothermal fluids and plumes is mainly from seawater and that little of it is, from andesite. This implies that the interaction of subseafloor fluid and -andesite at the Kueishantao Hydrothermal field is of short duration. In all the fluids, from springs to Hydrothermal plumes, the pH values, B concentrations and B isotopic compositions show significant correlations with each other suggesting that the delta B-11/B and pH/B ratios of Hydrothermal plumes have stable values over the small distance form vent to plume (<15 m). Thus the B concentrations and B isotopic compositions of Hydrothermal plumes can be used to describe the diffusive processes governing the chemical compositions of Hydrothermal plumes in the seawater environment. The water/rock ratios, based on the B concentrations and delta B-11 values, are between 1.96 and 3.63. The Hydrothermal flux of boron from the yellow spring into the oceans is between 1.17 x 10(5) mol/yr and 132 x 10(5) mol/yr, and from the white spring it is between 6.69 x 10(4) mol/yr and 7.17 x 10(4) mol/yr, assuming that only andesites are present in the reaction zone. (C) 2013 Elsevier B.V. All rights reserved.
Takeshi Tsuji - One of the best experts on this subject based on the ideXlab platform.
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Hydrothermal fluid flow system around the iheya north knoll in the mid okinawa trough based on seismic reflection data
Journal of Volcanology and Geothermal Research, 2012Co-Authors: Yuka Masaki, Ken Takai, Takeshi Tsuji, Hisashi Oiwane, Yasuyuki Nakamura, Hidenori Kumagai, Masataka Kinoshita, Fujio YamamotoAbstract:Seismic reflection data around the Iheya North Knoll Hydrothermal field provide insights into geological structures that control subseafloor Hydrothermal fluid flow in the sediment-covered continental backarc basin of the mid-Okinawa Trough. We identified the seismic expression of widespread porous volcaniclastic pumiceous deposits and intrusions as a result of silicic arc volcanism. The porous and permeable volcanic deposits are distributed in an area extending updip from the thick succession of the deep trough to the seafloor at the Hydrothermal field. Their regional structure focuses the flow of Hydrothermal fluids derived from the surrounding trough-fill sediments and directs them to the vents of the Hydrothermal field. The high concentrations of CH4 and NH4 in the fluids of the Hydrothermal field are likely derived from the interaction of migrating fluids with trough-fill sediments.
Xiaoyuan Wang - One of the best experts on this subject based on the ideXlab platform.
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Understanding the Compositional Variability of the Major Components of Hydrothermal Plumes in the Okinawa Trough
Hindawi-Wiley, 2018Co-Authors: Zhigang Zeng, Xiaoyuan Wang, Chentung Arthur ChenAbstract:Studies of the major components of Hydrothermal plumes in seafloor Hydrothermal fields are critical for an improved understanding of biogeochemical cycles and the large-scale distribution of elements in the submarine environment. The composition of major components in Hydrothermal plume water column samples from 25 stations has been investigated in the middle and southern Okinawa Trough. The physical and chemical properties of Hydrothermal plume water in the Okinawa Trough have been affected by input of the Kuroshio current, and its influence on Hydrothermal plume water from the southern Okinawa Trough to the middle Okinawa Trough is reduced. The anomalous layers of seawater in the Hydrothermal plume water columns have higher K+, Ca2+, Mn2+, B3+, Ca2+/SO42-, and Mn2+/Mg2+ ratios and higher optical anomalies than other layers. The Mg2+, SO42-, Mg2+/Ca2+, and SO42-/Mn2+ ratios of the anomalous layers are lower than other layers in the Hydrothermal plume water columns and are consistent with concentrations in Hydrothermal vent fluids in the Okinawa Trough. This suggests that the chemical variations of Hydrothermal plumes in the Tangyin Hydrothermal field, like other Hydrothermal fields, result in the discharge of high K+, Ca2+, and B3+ and low Mg2+ and SO42- fluid. Furthermore, element ratios (e.g., Sr2+/Ca2+, Ca2+/Cl−) in Hydrothermal plume water columns were found to be similar to those in average seawater, indicating that Sr2+/Ca2+ and Ca2+/Cl− ratios of Hydrothermal plumes might be useful proxies for chemical properties of seawater. The Hydrothermal K+, Ca2+, Mn2+, and B3+ flux to seawater in the Okinawa Trough is about 2.62–873, 1.04–326, 1.30–76.4, and 0.293–34.7 × 106 kg per year, respectively. The heat flux is about 0.159–1,973 × 105 W, which means that roughly 0.0006% of ocean heat is supplied by seafloor Hydrothermal plumes in the Okinawa Trough
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rhenium osmium abundance and isotopic compositions of massive sulfides from modern deep sea Hydrothermal systems implications for vent associated ore forming processes
Earth and Planetary Science Letters, 2014Co-Authors: Zhigang Zeng, Xuebo Yin, Shuai Chen, David Selby, Xiaoyuan WangAbstract:Studies of rhenium (Re) and osmium (Os) concentrations and isotopic compositions in seafloor Hydrothermal sulfides are an important tool for understanding the evolution of Hydrothermal systems, allowing the determination of both metal sources and reconstructing the physicochemical conditions of their deposition. The Re-Os concentrations and isotopic compositions of 38 massive sulfide samples have been studied in different Hydrothermal fields from the East Pacific Rise (EPR), Mid-Atlantic Ridge (MAR), Central Indian Ridge (CIR), Southwest Indian Ridge (SWIR), and Back-Arc Basin (BAB). The majority of the sulfides possess Os-187/Os-188 that span a narrow range (1.004 to 1.209), which is most easily explained as a seawater-derived component. This may suggest that those initial Os-187/Os-188 isotope compositions of ancient seafloor Hydrothermal sulfide deposits which were formed by the mixing process between seawater and Hydrothermal fluid, are possible for analysing ancient seawater Os components. Only two of samples (MAR05-TVG1-10-2 and MAR05-TVG1-21 from the Logatchev Hydrothermal field (LHF), MAR) possess moderately less radiogenic Os-187/Os-188 (0.645 to 0.730), which may reflect the lesser extent of Hydrothermal fluid-seawater mixing during Hydrothermal ore-forming process.
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boron isotope compositions of fluids and plumes from the kueishantao Hydrothermal field off northeastern taiwan implications for fluid origin and Hydrothermal processes
Marine Chemistry, 2013Co-Authors: Zhigang Zeng, Xiaoyuan Wang, Chentung Arthur Chen, Xuebo Yin, Shuai Chen, Yingkai XiaoAbstract:Boron is a common element in vent fluids of seafloor Hydrothermal fields, and it has been used to understand the Hydrothermal flux and water-rock interaction in Hydrothermal systems. We have measured the boron concentration and isotope composition of seawater, andesite, Hydrothermal fluid and plume samples from the Kueishantao Hydrothermal field. The delta B-11 value of ambient seawater near the field is 40.05 +/- 0.01 parts per thousand, and the boron concentration is 3.81 mg/L Andesite rocks from the Hydrothermal field have an average boron content of 153 ppm. The Hydrothermal fluids from the yellow spring and white spring span a small range of delta B-11 values, from 3327 +/- 022 to 36.84 +/- 0.11 parts per thousand, and plumes from both springs also cover a small range, from 37.56 +/- 0.01 to 40.37 +/- 0.21 parts per thousand. Hydrothermal fluids from both springs in the Kueishantao Hydrothermal field have variable B enrichments relative to seawater between 7 and 21%. They have B concentrations (4.10-4.64 mg/L) that are slightly higher and delta B-11 values (3327-36.84 parts per thousand) that are lower than those of the Hydrothermal plumes (3.94-4.17 mg/L, 37.56-40.37 parts per thousand). Hydrothermal fluids and plumes display a very regular array of data points in a delta B-11-B diagram, suggesting that the boron of Hydrothermal fluids and plumes is mainly from seawater and that little of it is, from andesite. This implies that the interaction of subseafloor fluid and -andesite at the Kueishantao Hydrothermal field is of short duration. In all the fluids, from springs to Hydrothermal plumes, the pH values, B concentrations and B isotopic compositions show significant correlations with each other suggesting that the delta B-11/B and pH/B ratios of Hydrothermal plumes have stable values over the small distance form vent to plume (<15 m). Thus the B concentrations and B isotopic compositions of Hydrothermal plumes can be used to describe the diffusive processes governing the chemical compositions of Hydrothermal plumes in the seawater environment. The water/rock ratios, based on the B concentrations and delta B-11 values, are between 1.96 and 3.63. The Hydrothermal flux of boron from the yellow spring into the oceans is between 1.17 x 10(5) mol/yr and 132 x 10(5) mol/yr, and from the white spring it is between 6.69 x 10(4) mol/yr and 7.17 x 10(4) mol/yr, assuming that only andesites are present in the reaction zone. (C) 2013 Elsevier B.V. All rights reserved.
Thangavel Mathimani - One of the best experts on this subject based on the ideXlab platform.
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Effect of reaction temperature on the conversion of algal biomass to bio-oil and biochar through pyrolysis and Hydrothermal liquefaction
Fuel, 2021Co-Authors: Kathirvel Brindhadevi, Susaimanickam Anto, Eldon R. Rene, Manigandan Sekar, Thangavel Mathimani, Nguyen Thuy Lan Chi, Arivalagan PugazhendhiAbstract:Abstract Thermochemical methods namely pyrolysis, gasification/Hydrothermal gasification, combustion, Hydrothermal liquefaction and Hydrothermal carbonization are widely practiced to convert algal biomass into fuels. Among the methods, pyrolysis, and Hydrothermal liquefaction are most commonly practised to convert numerous algal biomasses into bio-oil and/or biochar to substitute crude oil in petroleum refinery. In this regard, this review is focused on the conversion of various microalgal; and cyanobacterial biomasses into bio-oil, and solid char products through pyrolysis and Hydrothermal liquefaction. Initially, pyrolysis and Hydrothermal liquefaction of algal biomass on bio-oil and biochar yield have been reviewed. As the composition and yield of bio-oil from algae depends on the reaction temperature, detailed account of the impact of temperature on the quantity and quality of bio-oil and solid char obtained from pyrolysis and Hydrothermal liquefaction were comprehensively presented in the review. Eventually, this article provides opportunities and scope in the pyrolysis and Hydrothermal liquefaction of algae for further research.
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A review on the Hydrothermal processing of microalgal biomass to bio-oil - Knowledge gaps and recent advances
Journal of Cleaner Production, 2019Co-Authors: Thangavel Mathimani, Nirupama MallickAbstract:Abstract This state of the art review had presented Hydrothermal processing techniques such as Hydrothermal gasification, Hydrothermal carbonization, and Hydrothermal liquefaction. Further, pros and cons of each Hydrothermal technique were compared concerning the yield and quality of bio-crude, other products yield, nutrients of an aqueous phase, energy consumption and overall economics. Based on the numerous research and review articles survey, this critical review article had ascertained Hydrothermal liquefaction as an ideal technique for microalgal bio-crude production and thus, recent research works undertaken on the Hydrothermal liquefaction of different microalgal species has been summarized and discussed. This article has evaluated and described the impact of various factors such as reaction temperature, residence time, pressure, catalyst dose, feedstock selection and its load on the Hydrothermal liquefaction efficiency. A separate section dealing with upgrading of bio-oil delivers options to produce maximal bio-crude with higher heating value, low nitrogen, and oxygen heteroatoms. The key contribution of this review is information and scope itemized in this manuscript on Hydrothermal liquefaction process can be useful in propelling the prospect research to standardize an intact and efficient Hydrothermal liquefaction system for microalgae.
Hidenori Kumagai - One of the best experts on this subject based on the ideXlab platform.
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Hydrothermal fluid flow system around the iheya north knoll in the mid okinawa trough based on seismic reflection data
Journal of Volcanology and Geothermal Research, 2012Co-Authors: Yuka Masaki, Ken Takai, Takeshi Tsuji, Hisashi Oiwane, Yasuyuki Nakamura, Hidenori Kumagai, Masataka Kinoshita, Fujio YamamotoAbstract:Seismic reflection data around the Iheya North Knoll Hydrothermal field provide insights into geological structures that control subseafloor Hydrothermal fluid flow in the sediment-covered continental backarc basin of the mid-Okinawa Trough. We identified the seismic expression of widespread porous volcaniclastic pumiceous deposits and intrusions as a result of silicic arc volcanism. The porous and permeable volcanic deposits are distributed in an area extending updip from the thick succession of the deep trough to the seafloor at the Hydrothermal field. Their regional structure focuses the flow of Hydrothermal fluids derived from the surrounding trough-fill sediments and directs them to the vents of the Hydrothermal field. The high concentrations of CH4 and NH4 in the fluids of the Hydrothermal field are likely derived from the interaction of migrating fluids with trough-fill sediments.
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geological background of the kairei and edmond Hydrothermal fields along the central indian ridge implications of their vent fluids distinct chemistry
Geofluids, 2008Co-Authors: Hidenori Kumagai, Shinsuke Kawagucci, Tomohiro Toki, Kentaro Nakamura, Tomoaki Morishita, Kyoko Okino, Junichiro Ishibashi, Urumu Tsunogai, Toshitaka GamoAbstract:Hydrogen-rich Hydrothermal areas, such as those in the Indian Ocean, may have had an influence on early evolution of life on Earth and thus have attracted interest because they may be a proxy for ancient ecosystems. The Kairei and Edmond Hydrothermal fields in the Indian Ocean are separated by 160 km, but exhibit distinct fluid chemistry: Kairei fluids are hydrogen-rich; Edmond fluids are hydrogen-poor. At this region, the Central Indian Ridge shows an intermediate spreading rate, 48 mm year−1 as full rate, where the hydrothemal fields occur. Kairei field vent fluids show persistently high concentrations of H2. The Kairei field seems to be unique among hydrogen-enriched Hydrothermal regions: most similar hydrogen-rich Hydrothermal activity occurs along slowly spreading ridge, <40 mm year−1. The geological and tectonic aspects of the Kairei and Edmond Hydrothermal fields were studied to try to elucidate geological constraints on hydrogen production. Visual observations of the seafloor near Kairei from a submersible revealed olivine-rich plutonic rocks with olivine gabbro-troctolite-dunite assemblages exposed within 15 km of the vent field, with serpentinized ultramafic mantle rocks on the Oceanic Core Complex (OCC). The OCC area might be a recharge zone of Kairei Hydrothermal activity producing H2-rich vent fluids. The chaotic seafloor within 30 km of the Kairei field reflects a magma-starved condition persisting there for 1 Myr. Asymmetric geomagnetic and gravity anomalies near the Kairei field can be used to infer that patchy olivine-rich intrusions are scattered within mantle ultramafics, where infiltrated seawater reacts with magma and ultramafic rocks or olivine-rich rocks. The heterogeneous uppermost lithosphere containing shallow olivine-rich rock facies surrounding the Kairei field provides abundant H2 into the vent fluid through serpentinization. The hydrogen-rich Kairei field is hosted by basalt, with mafic-ultramafic olivine-rich lithology; the ordinary, hydrogen-poor Edmond field is hosted by a normal basaltic lithology. The contrasting geochemical signatures of the two fields reported here can also be found in ancient rocks from a juvenile Earth. This suggests that lithology-controlled generation of hydrogen may have operated for a long time and be relevant to the origin of life on Earth.
