Vent-distal Sedimentary-Exhalative(SEDEX)ore deposits are the main source of lead-zinc minerals worldwide,however,their genesis and diagnostic marks are yet controversial. Recently,some important discoveries have been made in the study of typical vent-distal SEDEX ore deposits in the world, including: Submarine exhalative sedimentation is not the unique way of mineralization, and laminated mineralization is not an exclusive diagnostic signature of the genesis of such deposits; Contrary to the traditional view given that vent-distal SEDEX deposits are generally formed in a closed,reduced and down-warped submarine sedimentary environment,the host rocks of these deposits can be formed in an open and oxidized sedimentary environment; Methane anaerobic oxidation and submarine hydrothermal alteration may be the main mechanisms for the formation of laminated and layered mineralization of this type of deposits. These understandings not only challenge the traditional genetic model of SEDEX deposits but also lead to the change of traditional prospecting and exploration evaluation criteria. Therefore,it is one of the urgent tasks to strengthen metallogenic research of this type of deposits learnt from the existing research experiences.
SUN Huashan, YANG Hui. Advance and Trend of the Vent-Distal SEDEX Lead-Zinc Deposits. Advances in Earth Science[J], 2021, 36(7): 663-670 DOI:10.11867/j.issn.1001-8166.2021.067
Fig. 1
Genetic model comparison of SEDEX Pb-Zn deposits[7]
(a)Vent-proximal genetic model; (b)Vent-distal genetic model; Both of (a) and (b) are controlled by submarine sedimentary exhalative and enclosed and reduced sedimentary environment; (c)Hydrothermal altered genetic model of SEDEX Pb-Zn deposits. Notably, mineralization is controlled by hydrothermal alteration within the diagenetic strata and formed in the open and oxidation environments
Fig. 2
Schematic figures for submarine sulphate-methane transition zone (a) and anaerobic oxidation of methane (b)[29]
(a)Sulphate reduced zone in the upper level, methane forming zone in the lower level, sulphate methane transition zone between them; (b)Thicked black arrows denote that SO infiltrates downward, whereas CH4 transfers upward, and anaerobic oxidation of methane occurs in the sulphate methane transition zone. In addition, in the upward stratigraphic sequences, it is the characteristics of depletion in δ13C while enrichment in δ34S
Fig. 3
Correlation diagrams between organic carbon content,δ34S of pyrites, and δ13C of autogenetic carbonate minerals and strata sequence in the ore-hosted DLK formation of SEDEX Pb-Zn deposit in Selwyn basin, Canada[22]
Fig. 4
Thermodynamic modeling diagrams illustrate how the pH value change, which is caused by the alteration between hydrothermal fluids and rocks, to effect on the precipitation sequence of sulfides from the hydrothermal fluids[14]
(a)Stable area of pyrite ranges from 3 to 9 in pH; (b)Higher pH value of 5~11 for sphalerite. Which gives a reasonable explanation for the formation of pyrite before sphalerite, and the latter is the result of alteration triggering pH value increasing
Genetic models for Sullivan and other SEDEX deposits
[C]//MIHIR Deb, GOODFELLOW W D. Sediment-hosted lead-zinc sulphide deposits, attributes and models of some major deposits in India, Australia and Canada. New Delhi, India: Narosa Publishing House, 2004: 149-190.
The mineralogical evolution of the clastic dominant-type Zn-Pb±Ba deposits at Macmillan Pass (Yukon, Canada)—tracing subseafloor barite replacement in the layered mineralization
Spatial distribution patterns of sulfur isotopes, nodular carbonates, and ore textures in the McArthur River (HYC) Zn-Pb-Ag deposit, northern Territory, Australia
The worldclass Howard's Pass SEDEX Zn-Pb district, Selwyn Basin, Yukon. Part I: trace element compositions of pyrite record input of hydrothermal, diagenetic and metamorphic fluids to mineralization
Geochemistry of host rocks in the Howards Pass district, Yukon-Northwest Territories, Canada: implications for sedimentary environments of Zn-Pb and phosphate mineralization
[J]. , 2017, 52: 565-593.
JOHNSONC A, SLACKJ F, DUMOULINJ A, et al.
Sulfur isotopes of host strata for Howards Pass (Yukon-Northwest Territories) Zn-Pb deposits implicate anaerobic oxidation of methane, not basin stagnation
Sulfur isotope variability in sediment-hosted massive sulfide deposits as determined using the ion microprobe SHRIMP: II. a study of the H.Y.C. deposit at McArthur River, northern Territory, Australia
The world-class Howard's Pass SEDEX Zn-Pb district, Selwyn Basin, Yukon. Part II: the roles of thermochemical and bacterial sulfate reduction in metal fixation
Textural, compositional, and sulfur isotope variations of sulfide minerals in the Red Dog Zn-Pb-Ag deposits, Brooks Range, Alaska: implications for ore formation
How sulfate-driven anaerobic oxidation of methane affects the sulfur isotopic composition of pyrite: a SIMS study from the South China Sea
[J]. , 2016, 440: 26-41.
LINZ Y, SUNX M, STRAUSSH, et al.
Multiple sulfur isotope constraints on sulfate-driven anaerobic oxidation of methane: evidence from authigenic pyrite in seepage areas of the South China Sea
The mineralogical evolution of the clastic dominant-type Zn-Pb±Ba deposits at Macmillan Pass (Yukon, Canada)—tracing subseafloor barite replacement in the layered mineralization
... (a)近喷口型成因模式;(b)远喷口型成因模式;(a)和(b)成因模式中成矿均受海底喷流沉积作用及封闭、还原沉积环境控制;(c)热液交代成因模式,成矿受压实成岩地层热液交代作用控制,沉积环境为开放、氧化环境Genetic model comparison of SEDEX Pb-Zn deposits[7]
(a)Vent-proximal genetic model; (b)Vent-distal genetic model; Both of (a) and (b) are controlled by submarine sedimentary exhalative and enclosed and reduced sedimentary environment; (c)Hydrothermal altered genetic model of SEDEX Pb-Zn deposits. Notably, mineralization is controlled by hydrothermal alteration within the diagenetic strata and formed in the open and oxidation environments ...
Spatial distribution patterns of sulfur isotopes, nodular carbonates, and ore textures in the McArthur River (HYC) Zn-Pb-Ag deposit, northern Territory, Australia
... (a)黄铁矿稳定域pH值变化范围3~9;(b)闪锌矿稳定域pH值变化范围5~11; SEDEX型Pb-Zn矿床一般黄铁矿形成早于闪锌矿,闪锌矿形成与交代作用导致的溶液pH值升高有关Thermodynamic modeling diagrams illustrate how the pH value change, which is caused by the alteration between hydrothermal fluids and rocks, to effect on the precipitation sequence of sulfides from the hydrothermal fluids[14]
(a)Stable area of pyrite ranges from 3 to 9 in pH; (b)Higher pH value of 5~11 for sphalerite. Which gives a reasonable explanation for the formation of pyrite before sphalerite, and the latter is the result of alteration triggering pH value increasing ...
Sediment-hosted lead-zinc deposits in Earth history
... 如上所述,在以往构建的该类矿床海底喷流沉积成因模式中,为确保海底沉积物中金属物质的硫化还原及保存,一个封闭、还原的海底沉积环境是不可或缺的条件[图1(a)和(b)].但是,这一条件也正在受到新发现的挑战.如以往判断地层沉积环境氧化还原条件一般依据岩石总有机碳含量(Total Organic Carbon, TOC),TOC越高认为地层有机质含量越高、越还原、沉积环境越封闭[8,13,16,17].但是,当前地层中的TOC主要来自生物死亡后沉积,未必能够代表当时沉积水体的氧化还原环境.此外,它们也有可能来自后期成岩过程中的有机质带入(如油气运移所致).尤其是以往认为的封闭还原环境有利于该类矿床形成的认识,与统计表明的该类矿床绝大多数形成于被动大陆边缘浅海环境,以及地质历史上该类矿床出现在地球大氧化事件之后的事实相矛盾[2,15].因此,有人对利用TOC方法确定地层沉积环境的氧化还原状态提出质疑[18~20].近年来,利用地层的Ce和Eu异常及Mo和V元素含量等沉积环境氧化还原评价标志,对加拿大Yukon地区的Citronen Fjord、Howards Pass和Anvil Range 3个SEDEX型矿床研究表明,其赋矿地层(分别为晚奥陶世、早志留世和晚寒武世)沉积环境均为氧化环境[图1(c)],而非以往认为的封闭还原环境[20~22].此外,研究显示,很多远喷口型SEDEX矿床成矿流体明显具有氧化性质(近喷口型一般为还原性质[2,23]),当这种流体注入海底/海底之下沉积物时,至少短时间内提升了环境的氧化程度[2,8,23].因此,最近Sangster[20]认为,沉积水体是否还原与该类矿床的形成关系不大.但是,水体之下的沉积柱/成岩地层必须是还原的,以确保高密度的、氧化性质的成矿流体在向下渗滤过程中受到还原,继而与还原硫结合,形成硫化物沉淀. ...
Geology and geochemistry of the Dengjishan Zn-Pb SEDEX deposit, Qinling belt, China
1
2007
... 如上所述,在以往构建的该类矿床海底喷流沉积成因模式中,为确保海底沉积物中金属物质的硫化还原及保存,一个封闭、还原的海底沉积环境是不可或缺的条件[图1(a)和(b)].但是,这一条件也正在受到新发现的挑战.如以往判断地层沉积环境氧化还原条件一般依据岩石总有机碳含量(Total Organic Carbon, TOC),TOC越高认为地层有机质含量越高、越还原、沉积环境越封闭[8,13,16,17].但是,当前地层中的TOC主要来自生物死亡后沉积,未必能够代表当时沉积水体的氧化还原环境.此外,它们也有可能来自后期成岩过程中的有机质带入(如油气运移所致).尤其是以往认为的封闭还原环境有利于该类矿床形成的认识,与统计表明的该类矿床绝大多数形成于被动大陆边缘浅海环境,以及地质历史上该类矿床出现在地球大氧化事件之后的事实相矛盾[2,15].因此,有人对利用TOC方法确定地层沉积环境的氧化还原状态提出质疑[18~20].近年来,利用地层的Ce和Eu异常及Mo和V元素含量等沉积环境氧化还原评价标志,对加拿大Yukon地区的Citronen Fjord、Howards Pass和Anvil Range 3个SEDEX型矿床研究表明,其赋矿地层(分别为晚奥陶世、早志留世和晚寒武世)沉积环境均为氧化环境[图1(c)],而非以往认为的封闭还原环境[20~22].此外,研究显示,很多远喷口型SEDEX矿床成矿流体明显具有氧化性质(近喷口型一般为还原性质[2,23]),当这种流体注入海底/海底之下沉积物时,至少短时间内提升了环境的氧化程度[2,8,23].因此,最近Sangster[20]认为,沉积水体是否还原与该类矿床的形成关系不大.但是,水体之下的沉积柱/成岩地层必须是还原的,以确保高密度的、氧化性质的成矿流体在向下渗滤过程中受到还原,继而与还原硫结合,形成硫化物沉淀. ...
The worldclass Howard's Pass SEDEX Zn-Pb district, Selwyn Basin, Yukon. Part I: trace element compositions of pyrite record input of hydrothermal, diagenetic and metamorphic fluids to mineralization
2
2016
... 如上所述,在以往构建的该类矿床海底喷流沉积成因模式中,为确保海底沉积物中金属物质的硫化还原及保存,一个封闭、还原的海底沉积环境是不可或缺的条件[图1(a)和(b)].但是,这一条件也正在受到新发现的挑战.如以往判断地层沉积环境氧化还原条件一般依据岩石总有机碳含量(Total Organic Carbon, TOC),TOC越高认为地层有机质含量越高、越还原、沉积环境越封闭[8,13,16,17].但是,当前地层中的TOC主要来自生物死亡后沉积,未必能够代表当时沉积水体的氧化还原环境.此外,它们也有可能来自后期成岩过程中的有机质带入(如油气运移所致).尤其是以往认为的封闭还原环境有利于该类矿床形成的认识,与统计表明的该类矿床绝大多数形成于被动大陆边缘浅海环境,以及地质历史上该类矿床出现在地球大氧化事件之后的事实相矛盾[2,15].因此,有人对利用TOC方法确定地层沉积环境的氧化还原状态提出质疑[18~20].近年来,利用地层的Ce和Eu异常及Mo和V元素含量等沉积环境氧化还原评价标志,对加拿大Yukon地区的Citronen Fjord、Howards Pass和Anvil Range 3个SEDEX型矿床研究表明,其赋矿地层(分别为晚奥陶世、早志留世和晚寒武世)沉积环境均为氧化环境[图1(c)],而非以往认为的封闭还原环境[20~22].此外,研究显示,很多远喷口型SEDEX矿床成矿流体明显具有氧化性质(近喷口型一般为还原性质[2,23]),当这种流体注入海底/海底之下沉积物时,至少短时间内提升了环境的氧化程度[2,8,23].因此,最近Sangster[20]认为,沉积水体是否还原与该类矿床的形成关系不大.但是,水体之下的沉积柱/成岩地层必须是还原的,以确保高密度的、氧化性质的成矿流体在向下渗滤过程中受到还原,继而与还原硫结合,形成硫化物沉淀. ...
Geochemistry of host rocks in the Howards Pass district, Yukon-Northwest Territories, Canada: implications for sedimentary environments of Zn-Pb and phosphate mineralization
0
2017
Sulfur isotopes of host strata for Howards Pass (Yukon-Northwest Territories) Zn-Pb deposits implicate anaerobic oxidation of methane, not basin stagnation
5
2018
... 如上所述,在以往构建的该类矿床海底喷流沉积成因模式中,为确保海底沉积物中金属物质的硫化还原及保存,一个封闭、还原的海底沉积环境是不可或缺的条件[图1(a)和(b)].但是,这一条件也正在受到新发现的挑战.如以往判断地层沉积环境氧化还原条件一般依据岩石总有机碳含量(Total Organic Carbon, TOC),TOC越高认为地层有机质含量越高、越还原、沉积环境越封闭[8,13,16,17].但是,当前地层中的TOC主要来自生物死亡后沉积,未必能够代表当时沉积水体的氧化还原环境.此外,它们也有可能来自后期成岩过程中的有机质带入(如油气运移所致).尤其是以往认为的封闭还原环境有利于该类矿床形成的认识,与统计表明的该类矿床绝大多数形成于被动大陆边缘浅海环境,以及地质历史上该类矿床出现在地球大氧化事件之后的事实相矛盾[2,15].因此,有人对利用TOC方法确定地层沉积环境的氧化还原状态提出质疑[18~20].近年来,利用地层的Ce和Eu异常及Mo和V元素含量等沉积环境氧化还原评价标志,对加拿大Yukon地区的Citronen Fjord、Howards Pass和Anvil Range 3个SEDEX型矿床研究表明,其赋矿地层(分别为晚奥陶世、早志留世和晚寒武世)沉积环境均为氧化环境[图1(c)],而非以往认为的封闭还原环境[20~22].此外,研究显示,很多远喷口型SEDEX矿床成矿流体明显具有氧化性质(近喷口型一般为还原性质[2,23]),当这种流体注入海底/海底之下沉积物时,至少短时间内提升了环境的氧化程度[2,8,23].因此,最近Sangster[20]认为,沉积水体是否还原与该类矿床的形成关系不大.但是,水体之下的沉积柱/成岩地层必须是还原的,以确保高密度的、氧化性质的成矿流体在向下渗滤过程中受到还原,继而与还原硫结合,形成硫化物沉淀. ...
... 长期以来,BSR和TSR两种硫酸盐还原机制是解释该类矿床还原硫来源及硫同位素组成变化特征的理论基础.最近,针对该类矿床成矿沉积环境认识的改变(即成矿由海底沉积成矿→海底之下压实成岩—成岩后热液作用成矿,成矿沉积环境由封闭、还原→开放、氧化),其形成过程中的另一种新的硫酸盐还原机制被发现.如Johnson等[22]通过对加拿大Yukon地区Howards Pass SEDEX型铅锌矿床硫化物矿体及其上、下赋矿围岩地层中沉积作用和热液充填交代作用形成的硫化物和碳酸盐矿物硫、碳同位素组成及变化特征的系统研究,提出该矿床硫酸盐还原不是以往认为的BSR/TSR作用,而是发生在硫酸盐—甲烷过渡带(Sulfate-Methane Transition, SMT)的甲烷厌氧氧化作用(Anaerobic Oxidation of Methane,AOM).SMT被现代海底沉积研究证实广泛发育,它是处于海底沉积上部未固结带与下部成岩带之间的一个过渡带[28~31].该带中的海底沉积上部未固结带的海水硫酸根向下渗透,下部成岩带中生物有机体分解形成的甲烷向上渗透,在二者之间形成了硫酸盐—甲烷过渡带.在该带甲烷通过还原硫酸根被氧化为碳酸氢根,继而与周围环境中的钙离子结合形成碳酸盐矿物;同时,硫酸根被还原为硫氢根,与周围环境中的金属离子结合形成硫化物(图2). ...
... [22]Correlation diagrams between organic carbon content,δ34S of pyrites, and δ13C of autogenetic carbonate minerals and strata sequence in the ore-hosted DLK formation of SEDEX Pb-Zn deposit in Selwyn basin, Canada[22]Fig. 3
Sulfur isotope variability in sediment-hosted massive sulfide deposits as determined using the ion microprobe SHRIMP: II. a study of the H.Y.C. deposit at McArthur River, northern Territory, Australia
The world-class Howard's Pass SEDEX Zn-Pb district, Selwyn Basin, Yukon. Part II: the roles of thermochemical and bacterial sulfate reduction in metal fixation
Textural, compositional, and sulfur isotope variations of sulfide minerals in the Red Dog Zn-Pb-Ag deposits, Brooks Range, Alaska: implications for ore formation
... (a)上部硫酸盐还原带,下部甲烷带,二者之间为硫酸盐—甲烷过渡带;(b)粗黑色箭头代表上部SO向下渗透,下部CH4向上渗透,二者渗透过程中出现甲烷厌氧氧化作用(AOM)及主要化学反应.此外,深部有机质分解形成的甲烷越向上δ13C越亏损,相反,硫酸盐还原形成的硫化物越向上δ34S越富集Schematic figures for submarine sulphate-methane transition zone (a) and anaerobic oxidation of methane (b)[29]
(a)Sulphate reduced zone in the upper level, methane forming zone in the lower level, sulphate methane transition zone between them; (b)Thicked black arrows denote that SO infiltrates downward, whereas CH4 transfers upward, and anaerobic oxidation of methane occurs in the sulphate methane transition zone. In addition, in the upward stratigraphic sequences, it is the characteristics of depletion in δ13C while enrichment in δ34S ...
How sulfate-driven anaerobic oxidation of methane affects the sulfur isotopic composition of pyrite: a SIMS study from the South China Sea
0
2016
Multiple sulfur isotope constraints on sulfate-driven anaerobic oxidation of methane: evidence from authigenic pyrite in seepage areas of the South China Sea
1
2017
... 长期以来,BSR和TSR两种硫酸盐还原机制是解释该类矿床还原硫来源及硫同位素组成变化特征的理论基础.最近,针对该类矿床成矿沉积环境认识的改变(即成矿由海底沉积成矿→海底之下压实成岩—成岩后热液作用成矿,成矿沉积环境由封闭、还原→开放、氧化),其形成过程中的另一种新的硫酸盐还原机制被发现.如Johnson等[22]通过对加拿大Yukon地区Howards Pass SEDEX型铅锌矿床硫化物矿体及其上、下赋矿围岩地层中沉积作用和热液充填交代作用形成的硫化物和碳酸盐矿物硫、碳同位素组成及变化特征的系统研究,提出该矿床硫酸盐还原不是以往认为的BSR/TSR作用,而是发生在硫酸盐—甲烷过渡带(Sulfate-Methane Transition, SMT)的甲烷厌氧氧化作用(Anaerobic Oxidation of Methane,AOM).SMT被现代海底沉积研究证实广泛发育,它是处于海底沉积上部未固结带与下部成岩带之间的一个过渡带[28~31].该带中的海底沉积上部未固结带的海水硫酸根向下渗透,下部成岩带中生物有机体分解形成的甲烷向上渗透,在二者之间形成了硫酸盐—甲烷过渡带.在该带甲烷通过还原硫酸根被氧化为碳酸氢根,继而与周围环境中的钙离子结合形成碳酸盐矿物;同时,硫酸根被还原为硫氢根,与周围环境中的金属离子结合形成硫化物(图2). ...
Geology and origin of shale-hosted Zn-Pb-Ag mineralization at the Century deposit, northwest Queensland, Australia