The concentration of 39 trace elements in coal from the late Permian taken from the eastern Yunnan-western Guizhou region was determined using inductively coupled plasma mass spectrometry. It was found that the mean c...The concentration of 39 trace elements in coal from the late Permian taken from the eastern Yunnan-western Guizhou region was determined using inductively coupled plasma mass spectrometry. It was found that the mean content of Ti, V, Cr, Mo, Co, Ni, Y, and Zr is higher than the national average. The occurrence of Mn, Ni, and Co in the different coalfields is distinctly different. Most of the enriched transition metal elements exist mainly as inorganic minerals. In the Zhina coalfield, Co, Ni, and Nb are primarily associated with sulfur. Mn, Cs, and Mo are mostly sulfides. Almost all Co was organic and a significant part of the Ni is also organic in the Liupanshui coalfield. Cs, Co, and Ni are related to sulfur in the coal taken from eastern Yunnan. Carbonate is the main form of Mn in the coal from eastern Yunnan and the Liupanshui coalfield. Ti is the oxide in the coal samples where Ti is enriched. Zr is in the form of zircon in the samples where Zr is enriched. The situation for most of the transition metal elements is consistent with terrestrial genesis. Coal seams are universally influenced by the sea. The strongly seawater effected peat bog with a reductive and alkaline environment favors the relative enrichment of Mn. A reducing environment is conducive to transition metal element enrichment.展开更多
The evolution characteristics of Gejiu granites.Yunnan Province are described in terms of theirPetrology,especially their trace elements and REE geochemistry The three major types of Gejiu granites:porphyritic biotite...The evolution characteristics of Gejiu granites.Yunnan Province are described in terms of theirPetrology,especially their trace elements and REE geochemistry The three major types of Gejiu granites:porphyritic biotite monzonitic granite(stageⅠ),medium-coarse-grained biotite-K-feldspar granite(stage Ⅱ)and two-mica alkali-feldspar granite(stage Ⅲ)are thought to have been formed successively from the samegranite magma source through fractional crystallization(Rayliegh fractionation),because linear correlationsare found between log(Rb/Sr)-log Sn,log(Rb/Ba)-log Sn,log(Rb/Ba)-log(Rb/Sr),log La-log Sr,log Ce-log Sr,log Eu-log Sr,etc In addition.the characteristics of REE distribution patterns in these three major types ofgranites also reflect the magmatic differentiation features of Gejiu granites.Of the three major types,the twomica alkali-feldspar granite of stage Ⅲ nuderwent the strongest differentiation,and thus has the closestgenetic relationship with the Gejiu tin-polymetallic ore deposit Such tin-polymetal mineralized granites arecharacterized by high Rb/Sr and Rb/Ba ratios,low K/Rb and ∑Ce/∑Y ratios and remarkable Eu depletion.展开更多
Copper and tin in cassiterite-sulfide deposits of the Gejiu metallogenic province are intimately associatedand show peculiar primary metal zoning. The authors made use of computer techniques to simulatenumerically the...Copper and tin in cassiterite-sulfide deposits of the Gejiu metallogenic province are intimately associatedand show peculiar primary metal zoning. The authors made use of computer techniques to simulatenumerically the zoning of these ore deposits. The study shows that the regular spatial zoning probably resultedfrom the succession of multiple, intermittent and pulsatory mineralizations, The successive transports with di-verse velocities along channelways of the ore-forming solutions, taking place under conditions of definite dif-ference between metal concentrations, in solutions and wallrocks, followed by differential deposition, consti-tute possible dynamic mechanisms for the primary metal zoning.展开更多
Based on an analysis of the circulation in May associated with the interannual variation of the onset of Yunnan’s rainy season, this study examined the rela-tionship between Arctic Oscillation (AO) and the onset timi...Based on an analysis of the circulation in May associated with the interannual variation of the onset of Yunnan’s rainy season, this study examined the rela-tionship between Arctic Oscillation (AO) and the onset timing of the rainy sea-son by using the NCEP/NCAR reanalysis and observational precipitation data for 1961-2010. The results indicated that, on an interannual time scale, intense Asian summer monsoon and an active EU-pattern wave train circulation in its positive phase, associated with a cold cyclonic cell covering the western part of the East Asian subtropical westerly jet (EASWJ), jointly contributed to the onset of the rainy season in May. Otherwise, the onset might be suppressed. The cold cyclonic cell over East Asia likely led to the southward shift and enhancement of EASWJ as well as its secondary circulation around the jet entrance, which could provide a favorable dynamic and thermal condition for rainfalls in Yunnan as was revealed in previous studies on 10 - 30-day time scale. Further examination showed that the preceding wintertime AO played a significant role in the timing of the onset of the rainy season before the mid-1980s’ by mostly modulating the wave-train-like circulation over East Asia in May. During that time period, when the AO index of the previous winter was positive (negative), Yunnan’s rainy season tended to begin earlier (later) than normal. Correspond-ingly, the precipitation in May was also closely linked to wintertime AO.展开更多
The Silurian-Devonian interval is an essential period in Earth history for witnessing the rise of sarcopterygian fishes and terrestrial vascular plants.In addition to its implication in global stratigraphic correlatio...The Silurian-Devonian interval is an essential period in Earth history for witnessing the rise of sarcopterygian fishes and terrestrial vascular plants.In addition to its implication in global stratigraphic correlation,the precise location of the Silurian-Devonian boundary(SDB)in East Yunnan closely relates to the minimal and maximal estimated dates for the lungfish-tetrapod split.Several geochemical indicators including the values and curves ofδ^(13)C_(org),δ^(13)Ccarb and TOC are obtained from the continuous SDB sequence in Dahe,Yiliang County,East Yunnan.The results reveal the significant positiveδ^(13)C_(org) shifts in the upper part of the Yulungssu Formation and the lower part of the Xishancun Formation,and the peak value(−20.0‰)in the sample YD-25 from the lowermost of the Xishancun Formation,replicating theδ^(13)C_(org) variation trend from the uppermost Silurian to the lowermost Devonian worldwide.Theδ^(13)C_(org) variation across the SDB at the Dahe Section resembles the SDB curve from the borehole Klonk-1 drilled at the top of the Klonk GSSP in the Prague Basin,Czech Republic.As such,we place the SDB in the Dahe Area between the samples of YD-17 and YD-18 from the lowermost part of the Xishancun Formation.This SDB assignment is corroborated by new findings of Early Devonian thelodont Parathelodus from the lower part of the Xishancun Formation in Qujing Area.The resolution of the SDB in Dahe,coupled with available paleontological data and the biostratigraphic zonation in East Yunnan,has provided vital data for the geological ages of the fish-bearing strata in East Yunnan.The earliest rhipidistian Youngolepis from the Xishancun Formation(Lochkovian,Devonian)and earliest stem-sarcopterygian Psarolepis from the Kuanti Formation(Ludfordian,Silurian)in East Yunnan indicate that the split between lungfish and tetrapods occurred between 426.5 and 416.0 Ma.展开更多
No. 6 East tin deposit in the Songshujiao orefield, Gejiu, is characterized by one-stage hydrothermal activity and monotonous country rocks. The authors selected this deposit and used the multivariate statistical anal...No. 6 East tin deposit in the Songshujiao orefield, Gejiu, is characterized by one-stage hydrothermal activity and monotonous country rocks. The authors selected this deposit and used the multivariate statistical analysis to study the types of association of main ore-forming elements at different temperatures and pressures and their distribution in the deposit. On that basis combined with the structural analysis of the deposit, the recto-geochemical features of No.6 East tin deposit have been revealed and the direction and channel of migration of the ore solutions in faults and the deposit have been deduced. This research can appropriately elucidate the control of faults on the migration of ore solutions and the sites where ore solutions are dispersed and accumulated, thus providing the theoretical basis for the prediction of hydrothermal deposits in question.展开更多
By means of multivariance analysis and finite element on the basis of the analysis of generation andevolution of structural systems and structural system of syn-metallogenesis in the orefield,the authorsmade a researc...By means of multivariance analysis and finite element on the basis of the analysis of generation andevolution of structural systems and structural system of syn-metallogenesis in the orefield,the authorsmade a research into the interrelation between tecto-geochemistry and structural stress field,revealedthe mechanism of metallogenesis by magma and ore-forming fluids driven under dynamic forces,andproposed a tecto-geochemistry model for the formation of the ore deposits,so as to suggest a basis oftheory for the prognoses of location and magnitude of hidden deposits.展开更多
基金financially supported by the National Natural Science Foundation of China (No. 40730422)
文摘The concentration of 39 trace elements in coal from the late Permian taken from the eastern Yunnan-western Guizhou region was determined using inductively coupled plasma mass spectrometry. It was found that the mean content of Ti, V, Cr, Mo, Co, Ni, Y, and Zr is higher than the national average. The occurrence of Mn, Ni, and Co in the different coalfields is distinctly different. Most of the enriched transition metal elements exist mainly as inorganic minerals. In the Zhina coalfield, Co, Ni, and Nb are primarily associated with sulfur. Mn, Cs, and Mo are mostly sulfides. Almost all Co was organic and a significant part of the Ni is also organic in the Liupanshui coalfield. Cs, Co, and Ni are related to sulfur in the coal taken from eastern Yunnan. Carbonate is the main form of Mn in the coal from eastern Yunnan and the Liupanshui coalfield. Ti is the oxide in the coal samples where Ti is enriched. Zr is in the form of zircon in the samples where Zr is enriched. The situation for most of the transition metal elements is consistent with terrestrial genesis. Coal seams are universally influenced by the sea. The strongly seawater effected peat bog with a reductive and alkaline environment favors the relative enrichment of Mn. A reducing environment is conducive to transition metal element enrichment.
文摘The evolution characteristics of Gejiu granites.Yunnan Province are described in terms of theirPetrology,especially their trace elements and REE geochemistry The three major types of Gejiu granites:porphyritic biotite monzonitic granite(stageⅠ),medium-coarse-grained biotite-K-feldspar granite(stage Ⅱ)and two-mica alkali-feldspar granite(stage Ⅲ)are thought to have been formed successively from the samegranite magma source through fractional crystallization(Rayliegh fractionation),because linear correlationsare found between log(Rb/Sr)-log Sn,log(Rb/Ba)-log Sn,log(Rb/Ba)-log(Rb/Sr),log La-log Sr,log Ce-log Sr,log Eu-log Sr,etc In addition.the characteristics of REE distribution patterns in these three major types ofgranites also reflect the magmatic differentiation features of Gejiu granites.Of the three major types,the twomica alkali-feldspar granite of stage Ⅲ nuderwent the strongest differentiation,and thus has the closestgenetic relationship with the Gejiu tin-polymetallic ore deposit Such tin-polymetal mineralized granites arecharacterized by high Rb/Sr and Rb/Ba ratios,low K/Rb and ∑Ce/∑Y ratios and remarkable Eu depletion.
文摘Copper and tin in cassiterite-sulfide deposits of the Gejiu metallogenic province are intimately associatedand show peculiar primary metal zoning. The authors made use of computer techniques to simulatenumerically the zoning of these ore deposits. The study shows that the regular spatial zoning probably resultedfrom the succession of multiple, intermittent and pulsatory mineralizations, The successive transports with di-verse velocities along channelways of the ore-forming solutions, taking place under conditions of definite dif-ference between metal concentrations, in solutions and wallrocks, followed by differential deposition, consti-tute possible dynamic mechanisms for the primary metal zoning.
文摘Based on an analysis of the circulation in May associated with the interannual variation of the onset of Yunnan’s rainy season, this study examined the rela-tionship between Arctic Oscillation (AO) and the onset timing of the rainy sea-son by using the NCEP/NCAR reanalysis and observational precipitation data for 1961-2010. The results indicated that, on an interannual time scale, intense Asian summer monsoon and an active EU-pattern wave train circulation in its positive phase, associated with a cold cyclonic cell covering the western part of the East Asian subtropical westerly jet (EASWJ), jointly contributed to the onset of the rainy season in May. Otherwise, the onset might be suppressed. The cold cyclonic cell over East Asia likely led to the southward shift and enhancement of EASWJ as well as its secondary circulation around the jet entrance, which could provide a favorable dynamic and thermal condition for rainfalls in Yunnan as was revealed in previous studies on 10 - 30-day time scale. Further examination showed that the preceding wintertime AO played a significant role in the timing of the onset of the rainy season before the mid-1980s’ by mostly modulating the wave-train-like circulation over East Asia in May. During that time period, when the AO index of the previous winter was positive (negative), Yunnan’s rainy season tended to begin earlier (later) than normal. Correspond-ingly, the precipitation in May was also closely linked to wintertime AO.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(CAS)(Grant Nos.XDB26000000,XDA19050102)the National Natural Science Foundation of China(Grant Nos.42072026,41972006&41530102)the Key Research Program of Frontier Sciences of CAS(Grant No.QYZDJ-SSWDQC002).
文摘The Silurian-Devonian interval is an essential period in Earth history for witnessing the rise of sarcopterygian fishes and terrestrial vascular plants.In addition to its implication in global stratigraphic correlation,the precise location of the Silurian-Devonian boundary(SDB)in East Yunnan closely relates to the minimal and maximal estimated dates for the lungfish-tetrapod split.Several geochemical indicators including the values and curves ofδ^(13)C_(org),δ^(13)Ccarb and TOC are obtained from the continuous SDB sequence in Dahe,Yiliang County,East Yunnan.The results reveal the significant positiveδ^(13)C_(org) shifts in the upper part of the Yulungssu Formation and the lower part of the Xishancun Formation,and the peak value(−20.0‰)in the sample YD-25 from the lowermost of the Xishancun Formation,replicating theδ^(13)C_(org) variation trend from the uppermost Silurian to the lowermost Devonian worldwide.Theδ^(13)C_(org) variation across the SDB at the Dahe Section resembles the SDB curve from the borehole Klonk-1 drilled at the top of the Klonk GSSP in the Prague Basin,Czech Republic.As such,we place the SDB in the Dahe Area between the samples of YD-17 and YD-18 from the lowermost part of the Xishancun Formation.This SDB assignment is corroborated by new findings of Early Devonian thelodont Parathelodus from the lower part of the Xishancun Formation in Qujing Area.The resolution of the SDB in Dahe,coupled with available paleontological data and the biostratigraphic zonation in East Yunnan,has provided vital data for the geological ages of the fish-bearing strata in East Yunnan.The earliest rhipidistian Youngolepis from the Xishancun Formation(Lochkovian,Devonian)and earliest stem-sarcopterygian Psarolepis from the Kuanti Formation(Ludfordian,Silurian)in East Yunnan indicate that the split between lungfish and tetrapods occurred between 426.5 and 416.0 Ma.
文摘No. 6 East tin deposit in the Songshujiao orefield, Gejiu, is characterized by one-stage hydrothermal activity and monotonous country rocks. The authors selected this deposit and used the multivariate statistical analysis to study the types of association of main ore-forming elements at different temperatures and pressures and their distribution in the deposit. On that basis combined with the structural analysis of the deposit, the recto-geochemical features of No.6 East tin deposit have been revealed and the direction and channel of migration of the ore solutions in faults and the deposit have been deduced. This research can appropriately elucidate the control of faults on the migration of ore solutions and the sites where ore solutions are dispersed and accumulated, thus providing the theoretical basis for the prediction of hydrothermal deposits in question.
文摘By means of multivariance analysis and finite element on the basis of the analysis of generation andevolution of structural systems and structural system of syn-metallogenesis in the orefield,the authorsmade a research into the interrelation between tecto-geochemistry and structural stress field,revealedthe mechanism of metallogenesis by magma and ore-forming fluids driven under dynamic forces,andproposed a tecto-geochemistry model for the formation of the ore deposits,so as to suggest a basis oftheory for the prognoses of location and magnitude of hidden deposits.
