The sedimentary manganese deposits occurring in Gufeng formation of the Permian in Guichi area, south Anhui Province, include manganese carbonate deposit formed by sedimentation, and manganese oxide deposit made by la...The sedimentary manganese deposits occurring in Gufeng formation of the Permian in Guichi area, south Anhui Province, include manganese carbonate deposit formed by sedimentation, and manganese oxide deposit made by later oxidation. The total REE contents of these samples are relatively low （ 〈 250 × 10^- 6）, belonging to LREE-enriched type, showing LREE enrichment during the process of formation of Mn deposit, especially during Mn-oxidizing process. Three normalized REE patterns and SCNA-normalized trace elements spider diagrams of the Mn-bearing sequence rocks and ores in this area reflect their same origin of ore sources, which is similar to rock-forming and ore-forming conditions. The Mnforming materials primarily came from the continent with higher mature degree and single material source. The δEu and δCe negative anomaly and Ce anomaly （ 〈 - 0.1） manifest that Mn-bearing sequence of the Permian was mostly formed in marine basin and oxidative environment. The Sr and Ba anomaly, Sr/Ba and Co/Ni values reflect the Mn deposit environment was of deep water and high-salinity of marine facies. Although the Ce/La （mean 1.05）, Y/Ho （25 - 41.5） and trace metals show a variety of correlations with Mn in the ten rock samples, which show multiple sources for the manganese, the analysis of geochemical characteristics indicate that the material sources of Mn deposit have been primarily terrestriallyderived. Another source of the manganese probably comes from the seafloor volcanism in this area. Analysis of sedimentary features and geohistoric evolvement reveals that the maximum transgression of the Qixia Period, ore district is then in deep shelf-basin sedimentary setting and the Mn-bearing sequence is deposited.展开更多
A study of REE compositions of Sinian to Triassic sedimentary strata from Guichi stratigraphic region located in northern margin of the Yangtze block indicates that average total REE concentration is 127μg/g which is...A study of REE compositions of Sinian to Triassic sedimentary strata from Guichi stratigraphic region located in northern margin of the Yangtze block indicates that average total REE concentration is 127μg/g which is lower than that of sedimentary rocks from the whole world(230 μg/g) and approximately resembles to that of sedimentary rocks from the platforms(129 μg/g). Among different lithologies, average total REE concentration of shales is the highest(230 μg/g), that of limestones is the lowest(18 μg/g) and that of sandstones and siltstones is in between(213 μg/g) .REE concentrations of strata of different geologic ages are controlled by lithology.REE concentrations of Ordovician and Triasaic strata consisting mostly of carbonate rocks are the lowest(40 and 44 μg/g, respectively), and those of Silulian and Devonian strata consisting mainly of terrestrial detrital rocks are the highest (231 and 248 μg/g, respectively). Sedimentary rocks studied show very similar REE patterns with LREE enrichment and negative Eu anomaly regardless of lithology and stratigraphic age. Samples are plotted in a confined area in Σ(La～Nd)-Σ(Sm～Ho)-Σ(Er～Lu) ternary plot, suggesting homogeneity of REE composition and a stable environment for the studied region. Similarity between REE compositions of sedimentary rocks from the studied region and that from typical platforms of the world suggests the platform character of the studied region during Sinica to Triassic. Results of this study suggests that the provenance of the studied sedimentary rocks is not the Jiangnanian old land mass, but the old continent(s) from the north.展开更多
为了解安徽贵池地区富硒土壤特征与潜力,服务当地富硒土地资源开发,选择贵池西部开展土壤地球化学测量试验,探讨Se、I等有益元素的富集特征、成因及潜力,Cd、As等有害元素的超标特征及成因等,结合研究区土壤中有益、有害元素特征,讨论...为了解安徽贵池地区富硒土壤特征与潜力,服务当地富硒土地资源开发,选择贵池西部开展土壤地球化学测量试验,探讨Se、I等有益元素的富集特征、成因及潜力,Cd、As等有害元素的超标特征及成因等,结合研究区土壤中有益、有害元素特征,讨论富硒土地资源及其开发优势。发现表层和深层土壤中Se等有益元素含量总体较高,其中Se含量达到富硒土地标准的表层土壤点位占全部样品点位的76%;表层土壤中Cd含量超标的点位占48%,其他有害元素仅个别点位超标,Cd是制约该地区富硒土地资源开发的主要不利因素。在研究区圈定了61.4 km 2的富硒土地资源,认为研究区东部土壤富硒的物质来源是二叠系灰岩,可以利用当地灰岩提升富硒土地资源品质,降低生态风险。展开更多
文摘The sedimentary manganese deposits occurring in Gufeng formation of the Permian in Guichi area, south Anhui Province, include manganese carbonate deposit formed by sedimentation, and manganese oxide deposit made by later oxidation. The total REE contents of these samples are relatively low （ 〈 250 × 10^- 6）, belonging to LREE-enriched type, showing LREE enrichment during the process of formation of Mn deposit, especially during Mn-oxidizing process. Three normalized REE patterns and SCNA-normalized trace elements spider diagrams of the Mn-bearing sequence rocks and ores in this area reflect their same origin of ore sources, which is similar to rock-forming and ore-forming conditions. The Mnforming materials primarily came from the continent with higher mature degree and single material source. The δEu and δCe negative anomaly and Ce anomaly （ 〈 - 0.1） manifest that Mn-bearing sequence of the Permian was mostly formed in marine basin and oxidative environment. The Sr and Ba anomaly, Sr/Ba and Co/Ni values reflect the Mn deposit environment was of deep water and high-salinity of marine facies. Although the Ce/La （mean 1.05）, Y/Ho （25 - 41.5） and trace metals show a variety of correlations with Mn in the ten rock samples, which show multiple sources for the manganese, the analysis of geochemical characteristics indicate that the material sources of Mn deposit have been primarily terrestriallyderived. Another source of the manganese probably comes from the seafloor volcanism in this area. Analysis of sedimentary features and geohistoric evolvement reveals that the maximum transgression of the Qixia Period, ore district is then in deep shelf-basin sedimentary setting and the Mn-bearing sequence is deposited.
文摘A study of REE compositions of Sinian to Triassic sedimentary strata from Guichi stratigraphic region located in northern margin of the Yangtze block indicates that average total REE concentration is 127μg/g which is lower than that of sedimentary rocks from the whole world(230 μg/g) and approximately resembles to that of sedimentary rocks from the platforms(129 μg/g). Among different lithologies, average total REE concentration of shales is the highest(230 μg/g), that of limestones is the lowest(18 μg/g) and that of sandstones and siltstones is in between(213 μg/g) .REE concentrations of strata of different geologic ages are controlled by lithology.REE concentrations of Ordovician and Triasaic strata consisting mostly of carbonate rocks are the lowest(40 and 44 μg/g, respectively), and those of Silulian and Devonian strata consisting mainly of terrestrial detrital rocks are the highest (231 and 248 μg/g, respectively). Sedimentary rocks studied show very similar REE patterns with LREE enrichment and negative Eu anomaly regardless of lithology and stratigraphic age. Samples are plotted in a confined area in Σ(La～Nd)-Σ(Sm～Ho)-Σ(Er～Lu) ternary plot, suggesting homogeneity of REE composition and a stable environment for the studied region. Similarity between REE compositions of sedimentary rocks from the studied region and that from typical platforms of the world suggests the platform character of the studied region during Sinica to Triassic. Results of this study suggests that the provenance of the studied sedimentary rocks is not the Jiangnanian old land mass, but the old continent(s) from the north.
文摘为了解安徽贵池地区富硒土壤特征与潜力,服务当地富硒土地资源开发,选择贵池西部开展土壤地球化学测量试验,探讨Se、I等有益元素的富集特征、成因及潜力,Cd、As等有害元素的超标特征及成因等,结合研究区土壤中有益、有害元素特征,讨论富硒土地资源及其开发优势。发现表层和深层土壤中Se等有益元素含量总体较高,其中Se含量达到富硒土地标准的表层土壤点位占全部样品点位的76%;表层土壤中Cd含量超标的点位占48%,其他有害元素仅个别点位超标,Cd是制约该地区富硒土地资源开发的主要不利因素。在研究区圈定了61.4 km 2的富硒土地资源,认为研究区东部土壤富硒的物质来源是二叠系灰岩,可以利用当地灰岩提升富硒土地资源品质,降低生态风险。
