Wan X.,Beijing University of Chemical Technology |
Dong H.,Beijing University of Chemical Technology |
Feng L.,Beijing University of Chemical Technology |
Lin Z.,Hunan Institute of Geological Survey |
Luo Q.,Beijing University of Chemical Technology
Chemosphere | Year: 2017
Three sequential extraction procedures (SEPs) including Tessier, Rauret, and Shiowatana SEPs, were compared for arsenic fractionation using highly polluted soils. In the definition context of exchangeable, reducible, oxidizable and residual fractions, with similar arsenic recovery and reproducibility, Tessier and Rauret SEPs were comparable to each other, whereas Shiowatana SEP showed higher extraction efficiency in all the first three arsenic fractions, although it might overestimate the reducible arsenic. Pot experiment indicated three SEPs all could provide an estimation of the most bioavailable arsenic fraction, and the application of Shiowatana SEP should be preferred. Accordingly, a case study with Shiowatana SEP for a site near a realgar mine area is conducted. The results show that although arsenic in this area presents predominantly in the stable fractions, the sum of most bioavailable fractions was accounted around 11% of total arsenic, and moreover, about another 10% of the total arsenic, the fourth fraction in Shiowatana SEP is likely to be transferred into bioavailable species under suitable conditions, such as strong acid impact, revealing a real major risk source being formed. The study indicated that Shiowatana should be more suitable for arsenic fractionation to provide valuable information in the framework of risk assessment. © 2017 Elsevier Ltd
Luo Z.,China University of Geosciences |
Chen B.,China University of Geosciences |
Chen B.,Hunan Institute of Geological Survey |
Jiang X.,China University of Geosciences |
And 2 more authors.
Acta Petrologica Sinica | Year: 2012
This article is contributed to propose a new methodology for targeting prospecting districts of the endogenic ore deposits, using the Wide composition-Spectrum Dike Swarm(WSDS). A Permian dike swarm, which consists of the lamprophyric, the basaltic, the andesitic, the dacitic, and the rhyolitic dikes, is extensively exposed in the South Alatao Mountains, and can be felled to the WSDS. The WSDS intrudes the Permian granitic plutons and their country rocks, and is the products of the latest epoch of magmatism in this region. The WSDS generation is accompanied by violent activity of the ore-bearing fluids because(1) many dike's rocks have the fumarolic structure, and contain numerous water-bearing mafic minerals: (2) a part of the dike's rocks have poly-phenocryst porphyritic texture with a cryptocrystalline or glassy matrix: (3) a part of the dike's rocks contain disseminated sulphides: (4) all dikes have the similar pattern of the incompatible and the ore-forming elements: (5) all the strata and plutons have the similar pattern of the oreforming elements. Accordingly, we can conclude that the WSDS and their country rocks are infiltrated and chemically modified by the ore-bearing fluids, and can be considered as the deterministic targeting element. The spatial patterning of the dike swarm is controlled by both the regional and the local fracture system. This can be explained by emplacement of the dike magmas into both the pre-existing and the self-propagating fractures. Therefore, the WSDS is resulted from the melt-fluid flows through rapid ascending and emplacement, and has a stronger potentiality to produce ore deposits. The spatial patterning of the dike swarm may suggest transport of the ore-bearing fluids, and thus can be used to predict the localities where the ore-forming metals have extensively cumulated. Along the transport paths of ore-bearing fluids, the ore-forming metals are largely discharged at the places where the fluid flow encounters: (1) carbonate rocks: (2) massive igneous blocks, in which fractures are poorly developed: (3) moderately broken regions cross-cut by faults: (4) strata with a high permeability: (5) minor magma bodies in the fields where the dikes are clustered. Accordingly, six prospecting regions can be targeted from the South Alatao Mountains. They are: A. the Xiaeraola, B. the Mierqike intrusion, C. the Legenwusu-Keketashugenwusu, D. the Aerxiati, E. the southwest Butuhamaer intrusion, and F. the Noerte. The divided prospecting regions cover 8 of the 20 mineralized points discovered in previous regional investigations. When the prospecting regions are slightly enlarged, they can cover 15 of them. It is clear that the new methodology is effective.
Jiang X.M.,China University of Geosciences |
Luo Z.H.,China University of Geosciences |
Chen B.H.,China University of Geosciences |
Chen B.H.,Hunan Institute of Geological Survey |
And 2 more authors.
Acta Petrologica Sinica | Year: 2014
The identification of causing intrusions is an important part of the metallogenia study and resources exploration, which is also a difficulty for many other types of deposits. The case study, the Aerxiati iron-copper skarn deposit, Xinjiang province, puts forward the understanding that the Tuimuerte batholith is the shielding layer of ore-bearing fluids, through the identification methods that establishing five kinds of contacts and the geology, petrology, mineralogy, geochemistry and metallogeny signs. The close spatial contact between the Tuimuerte batholith and skarn would easily be mistaken-making the batholith as a causing intrusion. However, the diagenetic stage of the batholith is earlier than the mineralization, its enplacement causes the thermal contact metamorphism of the country rocks, resulting the forming of marble and hornfels, which cannot be the resource of the ore-bearing fluids. In contrast, the small intrusive body in the region (the diorite intrusion) and the kinds of dykes not only have close spatial contacts with the ore body and the skarn, but also themselves and the country rocks suffers the intense hydrothermal alteration, which make the role that the channel of the ore-bearing fluids and the real causing intrusions.
Qiu J.-T.,China University of Geosciences |
Yu X.-Q.,China University of Geosciences |
Santosh M.,China University of Geosciences |
Santosh M.,Kochi University |
And 3 more authors.
Mineralium Deposita | Year: 2013
The Tongcun Mo porphyry deposit in northwest Zhejiang is hosted in three porphyry units: Huangbaikeng, Songjiazhuang, and Tongcun, from southwest to northeast. U-Pb zircon ages of 162 ± 3.0 Ma for the Huangbaikeng porphyry, 159.9 ± 3.0 Ma for the Songjiazhuang porphyry, and 167.6-155.6 Ma for the Tongcun porphyry indicate that these intrusions formed during the Jurassic and are most likely associated with the northwestward subduction of the Izanagi Plate. Trace element compositions of zircons from the Tongcun deposit constrain the oxygen fugacity (fO2) of the magma using zircon Ce anomalies and Ti-in-zircon temperatures. The average magmatic fO2 for the porphyries in the Tongcun deposit is fayalite-magnetite-quartz (FMQ) + 2.7, which is similar to the Shapinggou (FMQ + 3.2) and Dabaoshan (FMQ + 3.5) Mo porphyry deposits, but much higher than that of the reduced Cretaceous ore-barren Shangjieshou porphyry (FMQ-1.1) around 8 km away from the Tongcun deposit. The distinct difference in magmatic oxygen fugacity between the Jurassic and Cretaceous porphyries may help to explain the absence of Mo porphyry mineralization in northwest Zhejiang during the Cretaceous. © 2013 Springer-Verlag Berlin Heidelberg.
Chai B.,Hubei University |
Tong J.,Hunan Institute of Geological Survey |
Jiang B.,Hubei University |
Yin K.,Hubei University
Environmental Earth Sciences | Year: 2014
Marly rock is a sensitive rock group of landslides in the Three Gorges reservoir area, China. It is composed predominantly of carbonate and clay minerals, water–rock interaction (WRI) of which could activate landslides in the reservoir area. To study the mechanism by which WRI affects the mechanical properties of marly rock, samples were collected from two boreholes (depth 301.78 and 307.14 m) and slope surface. Then, laboratory tests were designed to study the quantitative relationship between mineral contents and mechanical properties of intact rock, to analyze both change process of mineral composition and microstructure under short-term and long-term WRI. Finally, the change in mechanical properties and its effect on slope stability are suggested. This study indicates that the uniaxial compressive strength and Poisson ratio can be estimated by linear regression equations: (1) σc = 8.959 × (C/Q) − 0.744 × CM + 58.516; (2) μ = 0.014 × (C/Q) − 0.001 × CM + 0.234. The chemical reactions of WRI mainly included dissolution and ion exchange. On the slope surface, dissolution mainly acts on calcite, illite, dolomite, feldspar and other minerals dissolved in water. Underground, both chemical reactions of dissolution and ion exchange easily approach equilibrium with long-term seepage. Small-size minerals and micropores damage the stable microstructure of marly rock. These changes of minerals and microstructure can trigger shallow slope failure and develop deep creep deformation along some crash zones in the reservoir shoreline. © 2014, Springer-Verlag Berlin Heidelberg.
Chen Z.,Chinese Academy of Sciences |
Zhou C.,Chinese Academy of Sciences |
Meyer M.,Virginia Polytechnic Institute and State University |
Xiang K.,Hunan Institute of Geological Survey |
And 3 more authors.
Precambrian Research | Year: 2013
Distinguishing Ediacaran trace fossils from tubular body fossils can be a challenge, and several Ediacaran fossils previously interpreted as animal traces have been shown to be tubular body fossils. Nonetheless, true Ediacaran trace fossils are present, but they are relatively few and morphologically simple, dominated by horizontal trails and shallow burrows. Such simple morphologies have been taken as evidence for a modest behavioral complexity and limited geobiological impact of animal bioturbators before the Cambrian explosion. Here we report three types of trace fossils-horizontal tunnels, surface tracks/trails, and vertical traces-from the latest Ediacaran Dengying Formation (551-541Ma) in the Yangtze Gorges area of South China. Cross-cutting tunnels and the presence of scratch marks indicate that these traces are unlikely tubular body fossils; instead, these three types of traces likely represent animal activities related to under-mat feeding, epibenthic locomotion, and temporary dwelling, respectively. We show that these three types of traces were constructed by the same bilaterian animals that had moderately complex interactions with microbial mats to exploit nutrients and O2 resources. These animals heralded a new age in ecosystem engineering, animal-sediment interaction, and biogeochemical cycling. © 2012 Elsevier B.V.
Li X.,Chinese Academy of science |
Hu R.,Chinese Academy of science |
Rusk B.,Western Washington University |
Xiao R.,Hunan Institute of Geological Survey |
And 2 more authors.
Journal of Asian Earth Sciences | Year: 2013
The Fujiawu porphyry Cu-Mo deposit is one of several porphyry Cu-Mo deposits in the Dexing district, Jiangxi Province, Southeast China. New zircon SHRIMP U-Pb data yield a weighted mean 206Pb/238U age of 172.0±2.1 and 168.5±1.4Ma from weakly altered granodiorite porphyry and quartz diorite porphyry, respectively. Two hydrothermal biotites from granodiorite porphyry give an Ar-Ar step-heating plateau age of 169.9±1.8 and 168.7±1.8Ma. Hydrothermal apatite exsolved from altered biotite yields an isotope dilution thermal ionization mass spectrometry isochron age of 164.4±0.9Ma. The apatite age is similar to the ages obtained from hydrothermal rutile (165.0±1.1 and 164.8±1.6Ma) and indicates that the magmatism and hydrothermal activity in the Fujiawu deposit occurred in the Middle Jurassic. Hydrothermal fluid circulation related to multiple stages of magma emplacement resulted in Cu-Mo mineralization in the Fujiawu porphyry deposit. The zircon SHRIMP U-Pb ages and the published molybdenite Re-Os age (170.9±1.5Ma) represent the timing of magma crystallization and Mo mineralization, whereas the rutile and apatite U-Pb ages reflect the timing of Cu mineralization following quartz diorite emplacement. The data suggest slow cooling after emplacement of the quartz diorite porphyry. © 2013 Elsevier Ltd.
PubMed | Hunan Institute of Geological Survey and Beijing University of Chemical Technology
Type: | Journal: Chemosphere | Year: 2016
The distribution characteristics of mercury fractions at the site near a pesticide plant was investigated, with the total mercury concentrations ranging from 0.0250 to 44.3mgkg
Ma H.-Y.,Hunan Institute of Geological Survey |
Sun H.-Q.,Hunan Institute of Geological Survey |
Xie W.,Central South University
Zhongguo Youse Jinshu Xuebao/Chinese Journal of Nonferrous Metals | Year: 2013
The geological and geochemical characteristics of the volcanic intrusive basic-ultrabasic complex in the central section of the Jiangnan Orogen in Hunan-Guizhou-Guangxi region were studied. The results indicate that the basement volcanic rocks of sedimentary basin in Nanhuaian period of Proterozoic Era belongs to island arc type. The basement sedimentary formation is active continental margin or continental island arc basin sediments. The initial regional extension built a fault-step continental slope basin in the southeastern margin of Yangtze platform, accepting sub-stable plural clastic deposit from continental margin. This calc-alkaline volcanic rock is initial swifting volcanic rock. The basin's tectonic setting is passive continental margin. In middle Nanhuaian period, the basin further extended along northern Guangxi-western Hunan to form a large quantity of alkaline basaltic rock with low calcium aluminum, belonging to intraplate rift environment. So far, the basin transformation has finished from compressive orogeny to initial splitting to full expansion, and then the basin began to develop steadily until the wildly transgression in early Sinian Era and submerged carbonate platform formed.
Gao L.,Chinese Academy of Geological Sciences |
Ding X.,Chinese Academy of Geological Sciences |
Zhang C.,China University of science |
Chen J.,Hunan Institute of Geological Survey |
And 4 more authors.
Acta Geologica Sinica | Year: 2012
In a re-study of regional geology by the China Geological Survey (CGS), the key problem is in the stratigraphical division and correlation. According to the new isotopic dating of the Meso- and Neoproterozoic in China, there have been great changes in the strata correlation and tectonic explanation. The authors obtained four zircon sensitive high resolution ion micro-probe (SHRIMP) U-Pb datings from the bentonite of the Lengjiaxi Group (822±10 Ma, 823±12 Ma and 834±11 Ma) and Banxi Group (802.6±7.6 Ma) in north Hunan Province, which is considered to be the middle part of the Jiangnan Orogenic Belt. On the basis of the zircon dating mentioned above, the end of the Wuling orogen is first limited in the period from 822 Ma to 802 Ma in one continued outcrop (Lucheng section) in Linxiang city, Hunan Province. Combining a series of new zircon U-Pb datings in the Yangtze and Cathaysia blocks, several Neoproterozoic volcanic events and distribution of the metamorphic rocks in the Jiangnan Orogenic Belt have been distinguished. In the context of the global geodynamics, it is useful to set up a practical and high precision chronological framework and basic and unified late Precambrian section in South China.