Stratabound gold deposits in the western Qinling Mountains occur in Cambrian chert formation composed of carbonaceous chert and carbonaceous slate. The distinctive chert formation provides important grounds for the mi...Stratabound gold deposits in the western Qinling Mountains occur in Cambrian chert formation composed of carbonaceous chert and carbonaceous slate. The distinctive chert formation provides important grounds for the mineralization and controls on the formation of gold deposits. Study shows that Se is exceptionally higher in both host rocks and gold orebodies. It may be recovered as a valuable component in ores for total utilization, and in some localities even independent Se orebodies (which are mined exclusively for Se) may be delineated. In gold ore Se mainly occurs as independent minerals or in the isomorphous form in sulphides and there is a positive correlation between Se and Au.展开更多
The skarn and ore bodies of the stratabound skarn copper deposits of Tongling, Anhui Province, are both controlled by definite stratigraphic horizons, and they are concordant with the strata. They occur as layers and ...The skarn and ore bodies of the stratabound skarn copper deposits of Tongling, Anhui Province, are both controlled by definite stratigraphic horizons, and they are concordant with the strata. They occur as layers and layer-like bodies in permeable carbonate rocks of the Middle-Upper Carboniferous Huanglong and Chuanshan Formations which are underlain by impermeable shale or siliceous rocks of the Upper Devonian Wutong Formation. The authors study the dynamics of ore-forming processes of the ore deposits with the dynamic model of coupled transport and reaction, and the following results are obtained: The salinity gradient and flow rate of the ore-forming fluids can both promote the mixing and reaction of juvenile water and formation water, and the permeable strata are favourable sites for the intense transport-reaction of mixing and the formation of deposits. (2) As isothermal transport-reaction took place along the bedding of strata, the moving transport-reaction front formed at the contact between the ore-forming fluids and the rocks advanced slowly along the permeable strata, and then stratiform skarn and ore bodies concordant with the strata were formed. (3) The gradient transport-reaction taking place across the isotherms in the cross-bedding direction caused the mineralogical composition to alter gradually from magnesian skarn to sulphide ore bodies.展开更多
Over the recent three decades, exploration of a large-size Sn-Fe polymetallic ore deposit at the Huanggangliang, the Da Hinggan Mountains, Inner Mongolia, China, has been largely focused on the premise that the minera...Over the recent three decades, exploration of a large-size Sn-Fe polymetallic ore deposit at the Huanggangliang, the Da Hinggan Mountains, Inner Mongolia, China, has been largely focused on the premise that the mineralization represents epigenetic magmatic hydrothermal ore deposit in genetic connection with the Mesozoic magmatism. The Huanggangliang Sn-Fe polymetallic ore deposits occurred in Permian strata, with silt- stone/marble of the Zhesi Formation and spilite/andesite/tuff of the Dashizhai Formation. The characteristics of geological and geochemical data demonstrated that sedimentary hydrothermal mineralization occurred during the basin evolution at the Permian, rather than representing epigenetie magmatic hydrothermal genesis with the following evidences. The ore-bearing skarus are stratiform with underlying metasedimentary rocks and overlying volcanic sedimentary rocks. Sedimentary hydrothermal textures and structures are observed in the stratabound ore-bearing skarn such as bedded-laminated skarn and magnetite ores with small-size folding or soft deforma- tion, synsedimentary breccia of skarn and magnetite ores and concentric shell structure of magnetite ores. So the stratabound ore-bearing skarns associated with magnetite ore and micro-disseminated tin, are peculiar examples of exhalite. The REE contents of the stratabound ore-bearing skarns display ∑LREE-rich （36.91×10^-6） but EHREE-depletion （6. 42 ×10^-6） , with positive Eu anomaly （Eu/Eu ＊ 1.28） and negative Ce anomaly （Ce/ Ce ＊ 0.88 ） , which is totally different from REE pattern of the Huanggang magmatic rocks（ with ∑REE 277.73 ×10^-6, ELREE 220.24 ×10^-6, ∑HREE 57.49 ×10^-6, Eu/Eu＊ 0.06, Ce/Ce＊ 1.52） , which is comparable with modern sea-floor hydrothermal fluid,sedimentary hydrothermal ore deposit and associated hydrothermal sedimentary rocks. Calcite samples with δ13CPDB from -5. 400 ‰ to -4. 397 ‰ and δ18SOSMOW from 9. 095 ‰ to 9. 364 ‰ in the stratabound ore-bearing skarns show sedimentary hydrothermal genesis of the Huanggangliang deposit. This proposition is useful not only for interpretation of the genesis of the Huanggangliang large Sn-Fe polymetallic ore deposit but also significant for mineral exploration in the area especially for finding large deposits caused by sedimentary exhalative mineralization processes.展开更多
This paper, based on the geochemical study and comparison of the gold-bearing formations and stratabound gold deposits hosted by the formations in the belt, shows that the most outstanding geochemical characteristics ...This paper, based on the geochemical study and comparison of the gold-bearing formations and stratabound gold deposits hosted by the formations in the belt, shows that the most outstanding geochemical characteristics of the strata-bound gold deposits in the Proterozoic Jiangnan Metallogenic Belt, namely 'Jiangnan-type' gold deposits, are conjugated occurrence of gold-depleted strata associated with high frequency gold mineralization in regional scale and negative gold anomaly in the wall rock of gold orebodies in the local range, concentration of the low-abundance elements such as Au, Sb, W and As, and impoverishment of base metals in the ore. Their ore-forming solutions have a temperature range of 160—390℃, intermediate salinity mostly from 4 to 10 wt% NaC1 equiv., nearly neutral to weak alkaline, and are reduced, rich in HCO_3^-, ΣS and poor in C1. It is suggested that the ore-forming elements of the deposits mostly come from the gold-bearing formations and the metallogenic processes are majorly related to the joint effects of metamorphic fluid from the deep and thermal groundwater in the shallow. Therefore the Jiangnan-type gold deposits should be regarded as a genetic type of transition from deposits formed by metamorphic fluid to that by infiltrating hydrothermal solution of groundwater.展开更多
The organic matter of three different chronological major carbonaceous rock gold-bearing formations of South China (Middle Proterozoic Shangqiaoshan group of northeastern Jiangxi, Lower Cambrian Shuikou group of north...The organic matter of three different chronological major carbonaceous rock gold-bearing formations of South China (Middle Proterozoic Shangqiaoshan group of northeastern Jiangxi, Lower Cambrian Shuikou group of northern Guangxi and Devonian Shetianqiao group of eastern Hunan) and related carbonaceous stratabound gold deposits such as Jinshan, Longshui and Shixia deposits, respectively, has been characterized by organic geochemical techniques. These organic geochemical results show that the average total organic carbon (TOC) content of the three chronological carbonaceous rock gold-bearing formations of South China ranges from 0.15% to 1.56%. The thermal maturity of the organic matter of host rocks in the three gold-bearing formations is high. The micro-component of the organic matter of the host rocks consists primarily of solid bitumen and graphite. The organic carbon and gold of the host rocks appear to syndepositin situ during the formation of the gold-bearing formations. The organic carbon played a certain role in controlling the geochemical environment of the gold-bearing formations. The metallogenetic mechanism of the carbonaceous rock stratabound gold deposits of South China is closely associated in genesis with the sedimentation, diagenesis and thermal evolution history of the organic matter of host rocks in the gold-bearing formations.展开更多
The banded or laminated exhalative hydrothermal chemical tourmalinite and mineralized tourmaline-rich sedimentary rocks were recognised for the first time in the stratabound and stratiform copper deposits in ghongtiao...The banded or laminated exhalative hydrothermal chemical tourmalinite and mineralized tourmaline-rich sedimentary rocks were recognised for the first time in the stratabound and stratiform copper deposits in ghongtiaoshan District in 1986, and further confirmed by the intensive investigations. The discovery can help better understand the geological environments and the origin of the stratabound and stratiform copper deposits.展开更多
基金This study was supported by the National Natural Science Foundation of China (Grant Nos. 49503048 and 49773197), a Sino-Austrian cooperation project (No. 4880099) and the Postdoctoral Science Foundation of China
文摘Stratabound gold deposits in the western Qinling Mountains occur in Cambrian chert formation composed of carbonaceous chert and carbonaceous slate. The distinctive chert formation provides important grounds for the mineralization and controls on the formation of gold deposits. Study shows that Se is exceptionally higher in both host rocks and gold orebodies. It may be recovered as a valuable component in ores for total utilization, and in some localities even independent Se orebodies (which are mined exclusively for Se) may be delineated. In gold ore Se mainly occurs as independent minerals or in the isomorphous form in sulphides and there is a positive correlation between Se and Au.
基金MGMR Eighth Five- Year Plan Basic Geology Research Foundation Grant 8502216China National Natural Science Foundation Grant 49173169
文摘The skarn and ore bodies of the stratabound skarn copper deposits of Tongling, Anhui Province, are both controlled by definite stratigraphic horizons, and they are concordant with the strata. They occur as layers and layer-like bodies in permeable carbonate rocks of the Middle-Upper Carboniferous Huanglong and Chuanshan Formations which are underlain by impermeable shale or siliceous rocks of the Upper Devonian Wutong Formation. The authors study the dynamics of ore-forming processes of the ore deposits with the dynamic model of coupled transport and reaction, and the following results are obtained: The salinity gradient and flow rate of the ore-forming fluids can both promote the mixing and reaction of juvenile water and formation water, and the permeable strata are favourable sites for the intense transport-reaction of mixing and the formation of deposits. (2) As isothermal transport-reaction took place along the bedding of strata, the moving transport-reaction front formed at the contact between the ore-forming fluids and the rocks advanced slowly along the permeable strata, and then stratiform skarn and ore bodies concordant with the strata were formed. (3) The gradient transport-reaction taking place across the isotherms in the cross-bedding direction caused the mineralogical composition to alter gradually from magnesian skarn to sulphide ore bodies.
基金Project supported by the National Basic Research Program(2009CB421008)Program for Changjiang Scholars and Innovative Research Teamin University (IRT0755)+1 种基金the 111 Project (B07011)China Postdoctoral Science Foundation funded project (20090460400)
文摘Over the recent three decades, exploration of a large-size Sn-Fe polymetallic ore deposit at the Huanggangliang, the Da Hinggan Mountains, Inner Mongolia, China, has been largely focused on the premise that the mineralization represents epigenetic magmatic hydrothermal ore deposit in genetic connection with the Mesozoic magmatism. The Huanggangliang Sn-Fe polymetallic ore deposits occurred in Permian strata, with silt- stone/marble of the Zhesi Formation and spilite/andesite/tuff of the Dashizhai Formation. The characteristics of geological and geochemical data demonstrated that sedimentary hydrothermal mineralization occurred during the basin evolution at the Permian, rather than representing epigenetie magmatic hydrothermal genesis with the following evidences. The ore-bearing skarus are stratiform with underlying metasedimentary rocks and overlying volcanic sedimentary rocks. Sedimentary hydrothermal textures and structures are observed in the stratabound ore-bearing skarn such as bedded-laminated skarn and magnetite ores with small-size folding or soft deforma- tion, synsedimentary breccia of skarn and magnetite ores and concentric shell structure of magnetite ores. So the stratabound ore-bearing skarns associated with magnetite ore and micro-disseminated tin, are peculiar examples of exhalite. The REE contents of the stratabound ore-bearing skarns display ∑LREE-rich （36.91×10^-6） but EHREE-depletion （6. 42 ×10^-6） , with positive Eu anomaly （Eu/Eu ＊ 1.28） and negative Ce anomaly （Ce/ Ce ＊ 0.88 ） , which is totally different from REE pattern of the Huanggang magmatic rocks（ with ∑REE 277.73 ×10^-6, ELREE 220.24 ×10^-6, ∑HREE 57.49 ×10^-6, Eu/Eu＊ 0.06, Ce/Ce＊ 1.52） , which is comparable with modern sea-floor hydrothermal fluid,sedimentary hydrothermal ore deposit and associated hydrothermal sedimentary rocks. Calcite samples with δ13CPDB from -5. 400 ‰ to -4. 397 ‰ and δ18SOSMOW from 9. 095 ‰ to 9. 364 ‰ in the stratabound ore-bearing skarns show sedimentary hydrothermal genesis of the Huanggangliang deposit. This proposition is useful not only for interpretation of the genesis of the Huanggangliang large Sn-Fe polymetallic ore deposit but also significant for mineral exploration in the area especially for finding large deposits caused by sedimentary exhalative mineralization processes.
文摘This paper, based on the geochemical study and comparison of the gold-bearing formations and stratabound gold deposits hosted by the formations in the belt, shows that the most outstanding geochemical characteristics of the strata-bound gold deposits in the Proterozoic Jiangnan Metallogenic Belt, namely 'Jiangnan-type' gold deposits, are conjugated occurrence of gold-depleted strata associated with high frequency gold mineralization in regional scale and negative gold anomaly in the wall rock of gold orebodies in the local range, concentration of the low-abundance elements such as Au, Sb, W and As, and impoverishment of base metals in the ore. Their ore-forming solutions have a temperature range of 160—390℃, intermediate salinity mostly from 4 to 10 wt% NaC1 equiv., nearly neutral to weak alkaline, and are reduced, rich in HCO_3^-, ΣS and poor in C1. It is suggested that the ore-forming elements of the deposits mostly come from the gold-bearing formations and the metallogenic processes are majorly related to the joint effects of metamorphic fluid from the deep and thermal groundwater in the shallow. Therefore the Jiangnan-type gold deposits should be regarded as a genetic type of transition from deposits formed by metamorphic fluid to that by infiltrating hydrothermal solution of groundwater.
文摘The organic matter of three different chronological major carbonaceous rock gold-bearing formations of South China (Middle Proterozoic Shangqiaoshan group of northeastern Jiangxi, Lower Cambrian Shuikou group of northern Guangxi and Devonian Shetianqiao group of eastern Hunan) and related carbonaceous stratabound gold deposits such as Jinshan, Longshui and Shixia deposits, respectively, has been characterized by organic geochemical techniques. These organic geochemical results show that the average total organic carbon (TOC) content of the three chronological carbonaceous rock gold-bearing formations of South China ranges from 0.15% to 1.56%. The thermal maturity of the organic matter of host rocks in the three gold-bearing formations is high. The micro-component of the organic matter of the host rocks consists primarily of solid bitumen and graphite. The organic carbon and gold of the host rocks appear to syndepositin situ during the formation of the gold-bearing formations. The organic carbon played a certain role in controlling the geochemical environment of the gold-bearing formations. The metallogenetic mechanism of the carbonaceous rock stratabound gold deposits of South China is closely associated in genesis with the sedimentation, diagenesis and thermal evolution history of the organic matter of host rocks in the gold-bearing formations.
文摘The banded or laminated exhalative hydrothermal chemical tourmalinite and mineralized tourmaline-rich sedimentary rocks were recognised for the first time in the stratabound and stratiform copper deposits in ghongtiaoshan District in 1986, and further confirmed by the intensive investigations. The discovery can help better understand the geological environments and the origin of the stratabound and stratiform copper deposits.
