The Youjiang Basin is characterized by a wide distribution of Au and Sb deposits.These deposits are mainly hosted by sedimentary rocks from Cambrian to Triassic and are structurally controlled by faults and folds.Thre...The Youjiang Basin is characterized by a wide distribution of Au and Sb deposits.These deposits are mainly hosted by sedimentary rocks from Cambrian to Triassic and are structurally controlled by faults and folds.Three types of Sb mineralization can be distinguished based on geologic characteristics,economic metals,and mineral associations.The first type is dominated by Sb mineralization but contains minor or little Au,similar to the large Qinglong deposit.The second type has a spatial association with the gold deposit but formed independent Sb mineralization,reminiscent of the Badu deposit.In the third type,Sb generally formed as an accompanying element in the Carlin-type gold deposit,and stibnite occurred as euhedral crystals filling the open space and faults in the late stage of gold mineralization,analogous to the Yata deposit.Trace element concentrations and sulfur isotopic ratio of stibnite,and oxygen isotope of stibnite bearing quartz were analyzed to infer the ore source(s)for Sb mineralization and genesis.To distinguish the various types of stibnite mineralization between the deposits,Cu,Pb,and As have recognized most diagnostic,with an elevated concentration in Au and Au-Sb deposits and depleted in Sb deposit.Theδ34S isotopic composition of stibnite samples from three deposits show a wide variation,ranging from-6.6%to+17.45%.Such isotopic values may indicate the sedimentary sulfur source,introduced by fluid–rock interaction.On the other hand,fluid mixing of several end members cannot be excluded.The calculatedδ18O isotopic data of Sb-bearing quartz show the initial ore fluid in Au and Au-Sb deposits most likely have a magmatic or metamorphic origin that enriched during fluid–rock interaction,and Sb deposit characterized by initial meteoric water.From these data,we proposed that different lithologies,fluid–rock interaction,fluid pathways,and different ore fluids controlled the compositional evolution of fluids,which might be the main reason for the diversity of Au or Sb mineralization.展开更多
Low-temperature Sb(Au-Hg) deposits in South China account for more than 50% of the world’s Sb reserves,however,their genesis remains controversial.Here we report the first study that integrates U-Pb and Lu-Hf analysi...Low-temperature Sb(Au-Hg) deposits in South China account for more than 50% of the world’s Sb reserves,however,their genesis remains controversial.Here we report the first study that integrates U-Pb and Lu-Hf analysis by LA-(MC)-ICPMS and conventional(U-Th)/He analysis,all applied to single zircon crystals,in an attempt to constrain the origin and timing of world-class Sb(Au-Hg) deposits in Banxi(South China).Zircon separated from a quartz-stibnite ore and an altered country rock samples revealed similar U-Pb age spectra defining two major populations-Paleoproterozoic(~1900-2500 Ma) and Neoproterozoic(~770 Ma),which are characterized by variable εHf(t) values(-10.7 to 9.1 and-16.5 to 11.2,respectively) and Hf crustal model ages(TDMC)(2.48 to 3.24 Ga and 0.97 to 2.71 Ga,respectively).The U-Pb age and Hf isotopic features of the zircons are consistent with the Banxi Group in the region,indicating that the zircons involved in the low-temperature hydrothermal system were originally from the Banxi Group country rocks.Thirty-three mineralization-related zircon crystals yielded a mean(U-Th)/He age of 123.8±3.8 Ma,which is interpreted to represent the timing of the latest low-temperature mineralization stage of the Banxi Sb deposit.The combined U-Pb,Lu-Hf and(U-Th)/He data suggest that Precambrian basement rocks were the major contributors to the low-temperature mineralization,and that Early Cretaceous(130-120 Ma) could be the most important ore-forming epoch for the Sb deposits in South China.This study also demonstrates the analytical feasibility of integrated U-Pb-Lu-Hf-(U-Th)/He "triple-dating",all applied to single zircon crystals.This approach reveals the full evolution of zircon,from its origin of the magmatic source,through its crystallization and low-temperature cooling.Although this study demonstrates the usefulness of this integrated approach in dating low-temperature mineralization,it has great potential for zircon provenance and other studies that may benefit from the large amount of information that can be extracted from single zircon crystals.展开更多
1 Geology Extensively developed on the southwestern margin of the Yangtze massif are epithermal deposits suchas gold, silve r, antimony, mercury, arsenic, uranium, copper and lead-zinc ore deposits, as well asbarite, ...1 Geology Extensively developed on the southwestern margin of the Yangtze massif are epithermal deposits suchas gold, silve r, antimony, mercury, arsenic, uranium, copper and lead-zinc ore deposits, as well asbarite, fluorite, iceland spar and rock crystal deposits, which constitute a unique low-temperature metallogenic domain. Except for the Gongguan deposit, the important Sb deposits in China are concentrated inthis low-temperature metallogenic domain, constituting the Hunan-Guizhou-Guangxi-Yunnan Sb ore belt.In general this ore belt extends in the NNE direction, measuring 1 900 km or more in length and 200 kmin width. A total of 505 Sb deposits (or occurrences) are known, accounting for 85.5 % of the展开更多
基金the National 973 Program of China(2014CB440906)。
文摘The Youjiang Basin is characterized by a wide distribution of Au and Sb deposits.These deposits are mainly hosted by sedimentary rocks from Cambrian to Triassic and are structurally controlled by faults and folds.Three types of Sb mineralization can be distinguished based on geologic characteristics,economic metals,and mineral associations.The first type is dominated by Sb mineralization but contains minor or little Au,similar to the large Qinglong deposit.The second type has a spatial association with the gold deposit but formed independent Sb mineralization,reminiscent of the Badu deposit.In the third type,Sb generally formed as an accompanying element in the Carlin-type gold deposit,and stibnite occurred as euhedral crystals filling the open space and faults in the late stage of gold mineralization,analogous to the Yata deposit.Trace element concentrations and sulfur isotopic ratio of stibnite,and oxygen isotope of stibnite bearing quartz were analyzed to infer the ore source(s)for Sb mineralization and genesis.To distinguish the various types of stibnite mineralization between the deposits,Cu,Pb,and As have recognized most diagnostic,with an elevated concentration in Au and Au-Sb deposits and depleted in Sb deposit.Theδ34S isotopic composition of stibnite samples from three deposits show a wide variation,ranging from-6.6%to+17.45%.Such isotopic values may indicate the sedimentary sulfur source,introduced by fluid–rock interaction.On the other hand,fluid mixing of several end members cannot be excluded.The calculatedδ18O isotopic data of Sb-bearing quartz show the initial ore fluid in Au and Au-Sb deposits most likely have a magmatic or metamorphic origin that enriched during fluid–rock interaction,and Sb deposit characterized by initial meteoric water.From these data,we proposed that different lithologies,fluid–rock interaction,fluid pathways,and different ore fluids controlled the compositional evolution of fluids,which might be the main reason for the diversity of Au or Sb mineralization.
基金This work was co-financed by the National Natural Science Foundation of China(Grant No.41502067)the Fundamental Research Funds for the Central Universities,China University of Geosciences(Wuhan)(Grant No.CUG150612)+1 种基金supported by Australian Research Council Discovery funding scheme(DP160102427)a Curtin Research Fellowship
文摘Low-temperature Sb(Au-Hg) deposits in South China account for more than 50% of the world’s Sb reserves,however,their genesis remains controversial.Here we report the first study that integrates U-Pb and Lu-Hf analysis by LA-(MC)-ICPMS and conventional(U-Th)/He analysis,all applied to single zircon crystals,in an attempt to constrain the origin and timing of world-class Sb(Au-Hg) deposits in Banxi(South China).Zircon separated from a quartz-stibnite ore and an altered country rock samples revealed similar U-Pb age spectra defining two major populations-Paleoproterozoic(~1900-2500 Ma) and Neoproterozoic(~770 Ma),which are characterized by variable εHf(t) values(-10.7 to 9.1 and-16.5 to 11.2,respectively) and Hf crustal model ages(TDMC)(2.48 to 3.24 Ga and 0.97 to 2.71 Ga,respectively).The U-Pb age and Hf isotopic features of the zircons are consistent with the Banxi Group in the region,indicating that the zircons involved in the low-temperature hydrothermal system were originally from the Banxi Group country rocks.Thirty-three mineralization-related zircon crystals yielded a mean(U-Th)/He age of 123.8±3.8 Ma,which is interpreted to represent the timing of the latest low-temperature mineralization stage of the Banxi Sb deposit.The combined U-Pb,Lu-Hf and(U-Th)/He data suggest that Precambrian basement rocks were the major contributors to the low-temperature mineralization,and that Early Cretaceous(130-120 Ma) could be the most important ore-forming epoch for the Sb deposits in South China.This study also demonstrates the analytical feasibility of integrated U-Pb-Lu-Hf-(U-Th)/He "triple-dating",all applied to single zircon crystals.This approach reveals the full evolution of zircon,from its origin of the magmatic source,through its crystallization and low-temperature cooling.Although this study demonstrates the usefulness of this integrated approach in dating low-temperature mineralization,it has great potential for zircon provenance and other studies that may benefit from the large amount of information that can be extracted from single zircon crystals.
文摘1 Geology Extensively developed on the southwestern margin of the Yangtze massif are epithermal deposits suchas gold, silve r, antimony, mercury, arsenic, uranium, copper and lead-zinc ore deposits, as well asbarite, fluorite, iceland spar and rock crystal deposits, which constitute a unique low-temperature metallogenic domain. Except for the Gongguan deposit, the important Sb deposits in China are concentrated inthis low-temperature metallogenic domain, constituting the Hunan-Guizhou-Guangxi-Yunnan Sb ore belt.In general this ore belt extends in the NNE direction, measuring 1 900 km or more in length and 200 kmin width. A total of 505 Sb deposits (or occurrences) are known, accounting for 85.5 % of the
