On the basis of a comprehensive study on the petrology, trace elements and isotopic geochemistry of the Xiangshan amphibolites, we suggest that the protoliths of the amphibolites were basalts formed in an island\|arc ...On the basis of a comprehensive study on the petrology, trace elements and isotopic geochemistry of the Xiangshan amphibolites, we suggest that the protoliths of the amphibolites were basalts formed in an island\|arc tectonic setting. The basaltic magma was derived from a slightly depleted mantle source with a small amount of crustal contamination. Assemblage of the rock\|forming minerals indicates that these amphibolites underwent a low\|grade metamorphism of amphibolite facies. According to the formation age (1113 Ma) and subsequent metamorphic age (726.6 Ma) of the basalts as well as the geological and geochemical features of these amphibolites, a tectonic model of Proterozoic oceanic island\|arc setting is proposed for central Jiangxi.展开更多
Detailed REE and trace elements geochemical studies of the Zhoutan Group metasedimentary rocks in central Jiangxi Province, China, and rock-forming minerals such as garnet were conducted and the results showed that th...Detailed REE and trace elements geochemical studies of the Zhoutan Group metasedimentary rocks in central Jiangxi Province, China, and rock-forming minerals such as garnet were conducted and the results showed that the REEs are partly present in the rock-forming minerals and are dominantly contained in the lattice of accessory minerals. In the process of metamorphism the REEs between garnet porphyroblast and rock and the partitioning of REEs between garnet and the host rock is obviously controlled by the chemical composition of the system. The REEs compositions of metamorphic veins and their minerals display remarked lanthanide tetrad effects and the element pairs Zr-Hf, Y-Ho, Pb-Nd and U-Th have also experienced a certain degree of fractionation with respect to the metasedimentary rocks and they can be used as discriminating indicators to some extent for the occurrence of fluid processes in the process of metamorphism of the Zhoutan Group.展开更多
The metamorphic belt in central Jiangxi, located in the compound terrain within the Cathaysia, Yangtze Block and Caledonian fold zone of South China, is composed dominantly of meta-argillo-arenaceous rocks, with minor...The metamorphic belt in central Jiangxi, located in the compound terrain within the Cathaysia, Yangtze Block and Caledonian fold zone of South China, is composed dominantly of meta-argillo-arenaceous rocks, with minor amphibolite. These rocks underwent amphibolite-facies metamorphism. The meta-argillo-arenaceous rocks show large variations in major element composition, but have similar REE patterns and trace element composition, incompatible element and LIE enrichments [high Th/Sc ({0.57}-{3.59}), La/Sc ({1.46}-{12.4}), La/Yb ({5.84}-{19.0})] and variable Th/U ratios, with ΣREE=129-296μg/g, δEu={0.51}-{0.86}, and (La/Yb)-N={3.95}-{12.9}. The Nd isotopic model ages t-{DM} of these rocks vary from 1597 to 2124 Ma. Their {}+{143}Nd/+{144}Nd values are low [ε-{Nd}(0)={-11.4} to {-15.8}]. Some conclusions have been drawn as follows: (1) The metamorphic rocks in central Jiangxi Province are likely formed in a tectonic environment at the passive continental margin of the Cathaysia massif. (2) The metamorphosed argillo-arenaceous rocks are composed dominantly of upper crustal-source rocks (Al- and K|rich granitic or/and sedimentary rocks of Early Proterozoic), which experienced good sorting, slow deposition and more intense chemical weathering. (3) According to the whole-rock Sm-Nd isochron ages (1113±49 to 1199±26 Ma) of plagioclase-amphibole (schist) and Nd isotopic model age t-{DM} (1597-2124 Ma) of meta-argillo-arenaceous rocks, the metamorphic belt in central Jiangxi Province was formed during the Middle Proterozoic (1100-1600 Ma).展开更多
The Xinyu iron deposit, located in central Jiangxi Province, is one of the most important BIF-type deposits in China. It is hosted in the Late Proterozoic volcanic- sedimentary rocks, which are composed of sericite- c...The Xinyu iron deposit, located in central Jiangxi Province, is one of the most important BIF-type deposits in China. It is hosted in the Late Proterozoic volcanic- sedimentary rocks, which are composed of sericite- chlorite pyhllite, magnetite-bearing chlorite phyllite or schist, magnetite quartzite, and schist （Yu et al., 1989; Zeng et al., 2011）.展开更多
The Middle Proterozoic Jiuling Group, one of the most important geologic unit in the Northwest Jiangxi Terrain, is a kind of An-bearing formation with a An-Ag-As associahon, and itsgeotectonic sethng belongs to the AC...The Middle Proterozoic Jiuling Group, one of the most important geologic unit in the Northwest Jiangxi Terrain, is a kind of An-bearing formation with a An-Ag-As associahon, and itsgeotectonic sethng belongs to the ACM area. Granihfication can supply An with favorable com-plexing agents. Later granitification is of much more significance in boneralizahon. Regional Anmineralisahon includes two types: metamorPhic hydrothermal solo-An mineralization in the northernpart and magma hydrothermal superimposed polymetallic mineralization with An, Ag, etc, beingdominant in the southern part. Regional exploration should center around the Jiuling Group, smallgranite bodies of later periods and fault structures, while paying attention to the anomalies of trace elements such as Au, Ag, As, Pb, Zn, etc.展开更多
The spread of northwest China’s folk tales in the Donggan region of central Asia mainly includes two aspects: First, Donggan folk tales transplanted to the northwest folk tales. As the Donggan people migrated from no...The spread of northwest China’s folk tales in the Donggan region of central Asia mainly includes two aspects: First, Donggan folk tales transplanted to the northwest folk tales. As the Donggan people migrated from northwest China, folk tales from northwest China were also transplanted to central Asia. In the absence of written records, these stories also mutate as they are passed down through the mouths and ears of foreign peoples. Secondly, Donggan folk tales borrowed from northwest folk tales. Some plot units in Donggan folktales are very similar to those in northwest China, but the specific characters and plot structure of the whole story are obviously different from those in northwest China. This kind of folk stories are new stories created by Donggan people who borrowed the parent story of folk stories in northwest China and recombined it with other plots. With comparative study of folk tales, the profound cultural ties between the two places can be revealed.展开更多
This paper reports the systematic study on petrology, geochemistry, LA ICPMS zircons U-Pb dating, and in situ Hf isotope geology of the four plutons in the central-southern Jiangxi Province, an important part of the S...This paper reports the systematic study on petrology, geochemistry, LA ICPMS zircons U-Pb dating, and in situ Hf isotope geology of the four plutons in the central-southern Jiangxi Province, an important part of the South China Block. In the outcrops, rocks are gradually changed from wall rock (slate or schist) to pluton (gneissic granite); some residual blocks of sandy rock occur in the margin of pluton, and the foliations of residual blocks are parallel to those of both wall rock and gneissic granite. The thin-section observations show that the four plutons contain peraluminous minerals such as muscovite and sillimanite. The flattened and elongated feldspar and quartz grains are often visible in the gneissic granite, parallel to direction of lineation, suggesting that the granitic rock were subjected to a strong ductile shearing. Geochemically, the A/CNK values from 13 granitic samples are between 1.03 and 1.37 with an average of 1.16, indicating that the granites are of strongly peraluminous plutons. The REE compositions of the 13 samples are similar, showing higher REE contents, with enrichment in LREEs, depletion in Eu and REE patterns with relative LREE-enrichment and negligible Eu anomalies. They show enrichment in Rb, Th, U and depletion in Ba, Sr, Nb, Ti, belonging to a low Ba-Sr type of granite. Thus, the four bodies should be derived from the same magmatic source. Zircons used as U-Pb dating mostly exhibit euhedral shape and high Th/U values from 0.52 to 1.54 with an average of 1.08, suggesting that most zircons are of magmatic genesis. The zircons from four plutons yielded rather similar 206 Pb/ 238 U vs. 207 Pb/ 235 U concordia ages: 436.1±5.7 Ma for the Tangwan granite, 440.6±4 Ma for the Jiekou gneissic granite, 435.9±6.2 Ma for the Dongbao gneissic granite, and 441.9±3.1 Ma for the Jinxi K-granite, respectively, corresponding to Silurian Llandovery. Several xenocrysts yielded U-Pb ages around 700 Ma, implying that a breakup event took place during Neoproterozoic in the South China Block. In situ Lu-Hf isotopic analysis shows that all Hf (t) values of zircons are negative and have two-stage Hf model ages (TDM2) from 1.4 to 3.6 Ga, indicating that the Silurian granitic magma came from the recycle of Meso-Paleoproterozoic basement and even partly Archean rocks, and had not been effected by mantle magma. Researches on regional geology suggest that an intracontinental tectono-magmatic event took place during the early Paleozoic in the study areas, which is characterized by folding and thrusting, leading to crustal shortening and thickening, up to 20 km thickness. The high geothermal temperature from thickening crust and accumulation of producing high-heat radioactive elements gradually softened crustal rocks and caused a partial melting, forming peraluminous granitic magma. Under the post-orogenic extensional and de-pressure condition, these granitic magma rose and was emplaced in the upper crust, leading to development of S-type展开更多
Based on the geological and geochemical studies on the Middle Proterozoic Jiuling Group in the Northwest Jiangxi Terrain, it is ascertained that this group is a kind of Au-bearing formation with Au-Ag-As association, ...Based on the geological and geochemical studies on the Middle Proterozoic Jiuling Group in the Northwest Jiangxi Terrain, it is ascertained that this group is a kind of Au-bearing formation with Au-Ag-As association, and the volcanism is the key to its foundation. The Jiuling Group can be divided into two geochemical groups: high-Au layers and low-Au layers, which is due to the inhomogeneous metamorphic reformation. The discriminant functions F<sub>1</sub>& F<sub>2</sub> can be established by means of Au, Ag, As, Ti, Cr, V, etc. eleven elements, and the diagram of F<sub>1</sub>-F<sub>2</sub> is the distinguishing sign of the Au-bearing formation. Based on the systematic studies on two types of gold mineralization, namely, solo gold with metamorphic fluid and Au, Ag, etc. polymetallic association with magmatic fluid, the authors establish the metallogenic model of gold deposits in the area.展开更多
文摘On the basis of a comprehensive study on the petrology, trace elements and isotopic geochemistry of the Xiangshan amphibolites, we suggest that the protoliths of the amphibolites were basalts formed in an island\|arc tectonic setting. The basaltic magma was derived from a slightly depleted mantle source with a small amount of crustal contamination. Assemblage of the rock\|forming minerals indicates that these amphibolites underwent a low\|grade metamorphism of amphibolite facies. According to the formation age (1113 Ma) and subsequent metamorphic age (726.6 Ma) of the basalts as well as the geological and geochemical features of these amphibolites, a tectonic model of Proterozoic oceanic island\|arc setting is proposed for central Jiangxi.
基金supported jointly by the National Natural Science Foundation of China (40673061)the Ministry of Science and Technology of China (95-Pre-39)the Foundation of State Key Laboratory for Mineral Deposits Research, Nanjing University
文摘Detailed REE and trace elements geochemical studies of the Zhoutan Group metasedimentary rocks in central Jiangxi Province, China, and rock-forming minerals such as garnet were conducted and the results showed that the REEs are partly present in the rock-forming minerals and are dominantly contained in the lattice of accessory minerals. In the process of metamorphism the REEs between garnet porphyroblast and rock and the partitioning of REEs between garnet and the host rock is obviously controlled by the chemical composition of the system. The REEs compositions of metamorphic veins and their minerals display remarked lanthanide tetrad effects and the element pairs Zr-Hf, Y-Ho, Pb-Nd and U-Th have also experienced a certain degree of fractionation with respect to the metasedimentary rocks and they can be used as discriminating indicators to some extent for the occurrence of fluid processes in the process of metamorphism of the Zhoutan Group.
文摘The metamorphic belt in central Jiangxi, located in the compound terrain within the Cathaysia, Yangtze Block and Caledonian fold zone of South China, is composed dominantly of meta-argillo-arenaceous rocks, with minor amphibolite. These rocks underwent amphibolite-facies metamorphism. The meta-argillo-arenaceous rocks show large variations in major element composition, but have similar REE patterns and trace element composition, incompatible element and LIE enrichments [high Th/Sc ({0.57}-{3.59}), La/Sc ({1.46}-{12.4}), La/Yb ({5.84}-{19.0})] and variable Th/U ratios, with ΣREE=129-296μg/g, δEu={0.51}-{0.86}, and (La/Yb)-N={3.95}-{12.9}. The Nd isotopic model ages t-{DM} of these rocks vary from 1597 to 2124 Ma. Their {}+{143}Nd/+{144}Nd values are low [ε-{Nd}(0)={-11.4} to {-15.8}]. Some conclusions have been drawn as follows: (1) The metamorphic rocks in central Jiangxi Province are likely formed in a tectonic environment at the passive continental margin of the Cathaysia massif. (2) The metamorphosed argillo-arenaceous rocks are composed dominantly of upper crustal-source rocks (Al- and K|rich granitic or/and sedimentary rocks of Early Proterozoic), which experienced good sorting, slow deposition and more intense chemical weathering. (3) According to the whole-rock Sm-Nd isochron ages (1113±49 to 1199±26 Ma) of plagioclase-amphibole (schist) and Nd isotopic model age t-{DM} (1597-2124 Ma) of meta-argillo-arenaceous rocks, the metamorphic belt in central Jiangxi Province was formed during the Middle Proterozoic (1100-1600 Ma).
基金the China State Mineral Resources Investigation Program (Grant No.1212011220936)National Science Foundation of China (Grant No.U1403292 41472196)
文摘The Xinyu iron deposit, located in central Jiangxi Province, is one of the most important BIF-type deposits in China. It is hosted in the Late Proterozoic volcanic- sedimentary rocks, which are composed of sericite- chlorite pyhllite, magnetite-bearing chlorite phyllite or schist, magnetite quartzite, and schist （Yu et al., 1989; Zeng et al., 2011）.
文摘The Middle Proterozoic Jiuling Group, one of the most important geologic unit in the Northwest Jiangxi Terrain, is a kind of An-bearing formation with a An-Ag-As associahon, and itsgeotectonic sethng belongs to the ACM area. Granihfication can supply An with favorable com-plexing agents. Later granitification is of much more significance in boneralizahon. Regional Anmineralisahon includes two types: metamorPhic hydrothermal solo-An mineralization in the northernpart and magma hydrothermal superimposed polymetallic mineralization with An, Ag, etc, beingdominant in the southern part. Regional exploration should center around the Jiuling Group, smallgranite bodies of later periods and fault structures, while paying attention to the anomalies of trace elements such as Au, Ag, As, Pb, Zn, etc.
文摘The spread of northwest China’s folk tales in the Donggan region of central Asia mainly includes two aspects: First, Donggan folk tales transplanted to the northwest folk tales. As the Donggan people migrated from northwest China, folk tales from northwest China were also transplanted to central Asia. In the absence of written records, these stories also mutate as they are passed down through the mouths and ears of foreign peoples. Secondly, Donggan folk tales borrowed from northwest folk tales. Some plot units in Donggan folktales are very similar to those in northwest China, but the specific characters and plot structure of the whole story are obviously different from those in northwest China. This kind of folk stories are new stories created by Donggan people who borrowed the parent story of folk stories in northwest China and recombined it with other plots. With comparative study of folk tales, the profound cultural ties between the two places can be revealed.
基金supported by National Natural Science Foundation of China (Grant Nos. 40634022, 40972132)State Key Laboratory for Mineral Deposits Research of Nanjing University (Grant No. 2008-I-01)
文摘This paper reports the systematic study on petrology, geochemistry, LA ICPMS zircons U-Pb dating, and in situ Hf isotope geology of the four plutons in the central-southern Jiangxi Province, an important part of the South China Block. In the outcrops, rocks are gradually changed from wall rock (slate or schist) to pluton (gneissic granite); some residual blocks of sandy rock occur in the margin of pluton, and the foliations of residual blocks are parallel to those of both wall rock and gneissic granite. The thin-section observations show that the four plutons contain peraluminous minerals such as muscovite and sillimanite. The flattened and elongated feldspar and quartz grains are often visible in the gneissic granite, parallel to direction of lineation, suggesting that the granitic rock were subjected to a strong ductile shearing. Geochemically, the A/CNK values from 13 granitic samples are between 1.03 and 1.37 with an average of 1.16, indicating that the granites are of strongly peraluminous plutons. The REE compositions of the 13 samples are similar, showing higher REE contents, with enrichment in LREEs, depletion in Eu and REE patterns with relative LREE-enrichment and negligible Eu anomalies. They show enrichment in Rb, Th, U and depletion in Ba, Sr, Nb, Ti, belonging to a low Ba-Sr type of granite. Thus, the four bodies should be derived from the same magmatic source. Zircons used as U-Pb dating mostly exhibit euhedral shape and high Th/U values from 0.52 to 1.54 with an average of 1.08, suggesting that most zircons are of magmatic genesis. The zircons from four plutons yielded rather similar 206 Pb/ 238 U vs. 207 Pb/ 235 U concordia ages: 436.1±5.7 Ma for the Tangwan granite, 440.6±4 Ma for the Jiekou gneissic granite, 435.9±6.2 Ma for the Dongbao gneissic granite, and 441.9±3.1 Ma for the Jinxi K-granite, respectively, corresponding to Silurian Llandovery. Several xenocrysts yielded U-Pb ages around 700 Ma, implying that a breakup event took place during Neoproterozoic in the South China Block. In situ Lu-Hf isotopic analysis shows that all Hf (t) values of zircons are negative and have two-stage Hf model ages (TDM2) from 1.4 to 3.6 Ga, indicating that the Silurian granitic magma came from the recycle of Meso-Paleoproterozoic basement and even partly Archean rocks, and had not been effected by mantle magma. Researches on regional geology suggest that an intracontinental tectono-magmatic event took place during the early Paleozoic in the study areas, which is characterized by folding and thrusting, leading to crustal shortening and thickening, up to 20 km thickness. The high geothermal temperature from thickening crust and accumulation of producing high-heat radioactive elements gradually softened crustal rocks and caused a partial melting, forming peraluminous granitic magma. Under the post-orogenic extensional and de-pressure condition, these granitic magma rose and was emplaced in the upper crust, leading to development of S-type
基金Project supported by the National Natural Science Foundation of China.
文摘Based on the geological and geochemical studies on the Middle Proterozoic Jiuling Group in the Northwest Jiangxi Terrain, it is ascertained that this group is a kind of Au-bearing formation with Au-Ag-As association, and the volcanism is the key to its foundation. The Jiuling Group can be divided into two geochemical groups: high-Au layers and low-Au layers, which is due to the inhomogeneous metamorphic reformation. The discriminant functions F<sub>1</sub>& F<sub>2</sub> can be established by means of Au, Ag, As, Ti, Cr, V, etc. eleven elements, and the diagram of F<sub>1</sub>-F<sub>2</sub> is the distinguishing sign of the Au-bearing formation. Based on the systematic studies on two types of gold mineralization, namely, solo gold with metamorphic fluid and Au, Ag, etc. polymetallic association with magmatic fluid, the authors establish the metallogenic model of gold deposits in the area.
