Li K.,Hubei University |
Wu C.-X.,Hubei Institute of Geological Survey
Geology in China | Year: 2014
Great progress has been made in recent years in prospecting for Pb- Zn ore deposits in western Hunan and eastern Guizhou provinces. There are more than two hundred Pb-Zn ore deposits hosted in the Cambrian and Ordovician strata. The authors carried out a systematic analysis of the carbon and oxygen isotopic compositions of carbonate wall rocks and hydrothermal calcites formed at the ore-forming stage. The results show that carbonate wall rocks have relatively homogeneous δ 13CPDb values (ranging from-1.16‰ to 1.70‰, 0.51‰ on average) and δ 18OSMow values (ranging from 18.56‰ to 22.42‰, 21.04‰ on average); in contrast, hydrothermal calcite has lower δ 13CPDb value (ranging from-5.80‰ to 0.42‰, -1.18‰ on average), and significantly declined δ 18OSMow values (ranging from 12.96‰ to 23.05‰, 18.36‰ on average). In the δ 13Cpdb VS δ 18Osmow diagram, the wall rocks are plotted in the marine carbonate rock area, and hydrothermal calcites are between marine carbonate rock and upper mantle. In combination with previous results, it is concluded that C of the ore-forming fluids was mainly derived from carbonate wall rocks, sulfur from sulfates in the sedimentary strata, and Pb and Zn from the rocks of lower Cambrian Niutitang Formation. The ore-forming fluids were higher salinity and lower temperature basin brines. Precipitation of ore minerals and hydrothermal calcites probably resulted from extensive fluid-rock interaction between ore-forming fluids and carbonate wall rocks in combination with corresponding decreasing temperature.
Xi X.,China Geological Survey |
Li M.,China Geological Survey |
Zhang X.,Hebei Institute of Geological Survey |
Zhang Y.,Henan Institute of Geological Survey |
And 4 more authors.
Earth Science Frontiers | Year: 2013
Soil organic carbon in middle-east China can be studied by comparison based on the data obtained by multi-purpose regional geochemical survey. The middle-east plain covers the terrain of Hebei, Henan, Hubei, Hunan, Guangdong and Hainan provinces, ranging from relatively higher latitude to low latitude and crossing temperate zone, subtropical zone and tropical zone. More than 334000 km2 were covered in the multi-purpose regional geochemical survey. Top soil (0-0.2 m) carbon storage is 906.84 Mt and average carbon density is 2716.93 t/km2. Including the higher soil carbon density in the northeastern plain, the carbon density in middle-east regions of China exhibited the changing pattern of high low high low from the northeastern plain downward to Hainan Province, that is 3327.8 t/km2 (northeastern plain)→2207.39, 2421.02 t/km2 (Hebei and Henan)→3442.15, 3942.92 t/km2 (Hubei and Hunan)→2255.90, 2936.72 t/km2(Guangdong and Hainan). The soil carbon density in agricultural ecosystem and urban ecosystem presented different changing rule from higher latitude to lower latitude, i.e., in agricultural farmland it changes from low to high, and in urban soil from high to low. The soil organic carbon increased by 14.5% (totally increasing 115.18 Mt and annually averaging 5.76 Mt/a) during past 20 years compared to the value achieved by the second soil reconnaissance. However organic carbon did not increase evenly. The rising rate decreased from low latitude to high latitude, and organic carbon increased in agricultural and urban ecosystem but decreased in tideland, rivers, lakes, grassland, forest and swamp.
Jin S.,Wuhan University |
Jin S.,University of Vienna |
Wang H.,Wuhan University |
Cao H.,Wuhan University |
And 5 more authors.
Austrian Journal of Earth Sciences | Year: 2014
LThe sediments of the Liushagang Formation in the Fushan Sag (Paleogene of the South China Sea) are preserved in a variety of structural settings and are described in a sequence stratigraphic framework. This paper presents the control of the sedimentary infill by the tectonic evolution of the Fushan Sag based on the integration of available cores data, corresponding well-logs interpretation, seismic interpretations, sedimentary distribution and spatial evolution analysis, fault activity rate calculation and paleogeographic reconstructions. Three third order sequences SQEls3, SQEls2 and SQEls1 are identified within the Eocene Liushagang Formation by sequence boundaries and maximum flooding surfaces based on seismic interpretations. Three sedimentary systems are identified: (1) a fan delta system, (2) braided river delta system and (3) a lake system inclduing turbidite deposits. The sandstone proportion in the three delta areas decreased from SQEls3 to SQEls2, which indicates a continuously transgression, showing the transition from proximal to distal sites in most wells, and an obvious decrease of fan delta sizes. The northeast-southwest striking faults control the lakeward distributions of delta fronts and turbidite fans. Tectonism is the main controlling factor for the sedimentary infill of the Fushan Sag. Syn-rifting tectonic subsidence, controls the spatial-temporal sediment distribution. The more active western part of the Lingao Fault has an important influence on the northeastward migration of depocenters in the Liushagang Formation. Tectonic activity along the eastern boundary fault in the Fushan Sag increased first and then decreased, which influences the fan delta system in the Bailian sub-sag. The tectonic activity along the Meitai Fault obviously increased since Els2, which controls the turbidite system in Els2, the delta plain and delta front distributions in Els1. The topography developed continuously from Els3 to Els1, and the diminished subsidence indicates the dominant geological process varying from intense fault rifting in an early period to relatively gentle and overall subsidence in a later period during the Paleogene. © 2014 Austrian Geological Society. All rights reserved.
Cheng H.,Institute of Geophysical and Geochemical Exploration |
Cheng H.,Chinese Academy of Geological Sciences |
Li M.,China Geological Survey |
Zhao C.,Institute of Geophysical and Geochemical Exploration |
And 22 more authors.
Journal of Geochemical Exploration | Year: 2015
A systematic geochemical lake sediment survey has been carried out in major freshwater lakes in China. Surface lake sediment (0-20cm) at a density of 1sample/4km2 and deep lake sediment (150-180cm) at a density of 1sample/16km2 were collected and analyzed with standard procedures. This overview provides a current ecological risk assessment for toxic metal contamination (As, Cd, Cr, Cu. Hg, Ni, Pb, and Zn) in the surface sediments of major freshwater lakes in China. Lake sediment in China poses a moderate ecological risk on a nationwide basis using a potential ecological risk index (PERI). Mercury ranked as presenting the greatest ecological risk, followed by Cd, As, Pb, Cu, Ni, Cr, and Zn. Liangzi Lake was classified as having high ecological risk; Dalonghu Lake, Dianchi Lake, Dongting Lake, Fuxian Lake, and Qilu Lake as having moderate ecological risk; while the other surveyed lakes were classified as having low ecological risk. Uncertainties of risk assessment are also discussed by considering geochemical background, the eco-toxicity of metals and the sensitivities of local benthic communities. These comprehensive findings have provided valuable information for improvement of lake management and pollution prevention and control in China. © 2015 Elsevier B.V..
Zhang S.,CAS Guangzhou Institute of Geochemistry |
Zhang S.,Wuhan University |
Yang D.,China Southwest Geotechnical Investigation and Surveying Institute |
Li F.,Wuhan University |
And 5 more authors.
Applied Geochemistry | Year: 2014
The soil geochemical baseline is an important index in environmental assessment. Detailed baseline studies are necessary in large areas with complex geological settings, landforms and soil types. The Jianghan plain, a major industrial and agricultural region located in central China, has a soil geochemical baseline that has yet to be fully defined. The objective of this paper is to study the baseline of Cd, Pb and Zn in the topsoil of the Jianghan plain in a subarea using principal component regression (PCR). A total of 9030 samples were collected from the surface layer, and 2 soil profiles and 2 sedimentary columns were sampled near the Yangtze and Han rivers. Fifty-two elements and two parameters were analyzed. Data processing and the creation of spatial distribution maps of the elements were performed using MapGIS, R and SPSS software. The results show that the distributions of Cd, Pb and Zn are mainly controlled by parent material, drainage system and soil type. The study area is divided into 3 subareas, with factors reflecting the physico-chemical characteristics of the soil using factor analysis (FA). The geochemical baseline model is established in every subarea to predict the Cd, Pb and Zn values using principal component regression analysis (PCR); the exceptional values (as a result of anthropogenic input or mineralization) are distinguished by residuals (γ); and the natural background values and anthropogenic contributions are clearly distinguished. Therefore, the PCR method in these subareas is objective and reasonable, and the conclusion provides effective evidence of exceptional high values for further environmental assessment. © 2014.
You Y.,Huazhong University of Science and Technology |
You Y.,Wuhan University |
Zhou M.,Wuhan University |
Hou H.,Wuhan University |
And 2 more authors.
2011 2nd International Conference on Mechanic Automation and Control Engineering, MACE 2011 - Proceedings | Year: 2011
The instability of the sludge will cause odor and other environmental pollution in the process of disposal and reuse. HAS soil stabilizer, Lime and Portland cement are used in this paper to modify the sewage. The experimental results showed that added by a certain content of the HAS Soil Stabilizer in sludge would be a good modification effect on removing Ammonia and Hydrogen Sulfide. When the curing time was 14d and the content was 15%, the concentration of Ammonia was 5μg/L and the removal rate could reach 93.5%. When the curing time was 3d and the content was10% or more, the concentration of Hydrogen Sulfide can be reduced to below 0.06μg/L and the removal rate could reach 95%, conforming to the relative standards. The SEM photos of 15% HAS modified sludge showed that Ettringite and Calcium Silicate hydrate crystals were the mainly hydration products, they formed a kind of three-dimensional crystal network and completely changed the original sludge structure, which effectively prevented the organic matter to further decay, made the sludge stabilized and achieved the improvement of sludge odor. © 2011 IEEE.
Origin and geodynamic significance of fault-hosted massive sulfide gold deposits from the Guocheng-Liaoshang metallogenic belt, eastern Jiaodong Peninsula: Rb-Sr dating, and H-O-S-Pb isotopic constraints
Tan J.,Wuhan University |
Wei J.,Wuhan University |
Li Y.,Wuhan University |
Fu L.,Wuhan University |
And 3 more authors.
Ore Geology Reviews | Year: 2015
More recent explorations (from 2009 to 2013) indicate a minimum of 27tonnes Au of additional resources in the Guocheng-Liaoshang gold belt, northeastern Jiaolai basin, Jiaodong gold province. The ores are hosted in faults/fractures in Paleoproterozoic metamorphic and granitic rocks, and are marked by massive sulfide type with sulfides of up to 40 to 95vol.%. Rb-Sr isotopic dating of mineralized quartz yielded an isochron age of 116.2±2.4Ma (MSWD=0.36). The ore-related quartz samples have δD values of -86 to -69‰ (mean -78‰), with calculated δ18OH2O values of 0.6 to 7.7‰ (average 3.6‰). The δ34S values of ore sulfides vary from 8.5 to 12.7‰ with an average of 9.9‰. Lead isotope signatures recorded in sulfides are much less radiogenic (206Pb/204Pb=17.039-17.862) relative to that of Phanerozoic convecting mantle (206Pb/204Pb=18.179-18.384). These results show that the gold mineralization style in this belt is different from the traditionally identified three types of gold deposits in the Jiaodong Peninsula (namely, Linglong, Jiaojia and Pengjiakuang type). They also suggest deep-seated, most likely mafic dike magmatic and mantle-derived, sources for the ore fluids, sulfur and metals in the hydrothermal system, despite the fact that wall rocks might provide some sulfur to satisfy the enriched 34S signature. The inferred mantle reservoir was probably formed by subduction-related fluid metasomatism during the Paleoproterozoic (ca. 1.85Ga) Jiao-Liao-Ji mobile belt assembly (suture within Columbia supercontinent). Extensional tectonic inversion during early Cretaceous, caused by subduction of the Kula-Pacific plate rather than postcollisional process of the Qinling-Dabie-Sulu Orogen, triggered partial melting of this mantle domain, subsequent magma mixing and final exsolution of ore-forming fluids. © 2014 Elsevier B.V.
Zhang X.,Wuhan University |
Luo H.,Hubei Institute of Geological Survey |
Wu Z.,Bureau of Mineral Resources |
Fan X.,Wuhan University |
And 3 more authors.
Diqiu Kexue - Zhongguo Dizhi Daxue Xuebao/Earth Science - Journal of China University of Geosciences | Year: 2014
Dayishan ore field located in the north rim of the middle section of the Nanling metallogenic belt in South China fold zone, and at the intersection of Yangmingshan-Dayishan-Shangpu EW basement fault, Youxian-Ningyuan NE basement fault and Chenzhou-Shaoyang NW concealed deep fault, has been controlled by the Dayishan intrusive rock. The greisens-vein type tin deposit is one of the typical mineralization types in this ore field. The Rb-Sr geochronology of fluid inclusions in quartz of the ore veins is presented and its geological significance of the Baishaziling greisens-vein type tin deposit is discussed in this paper. The Rb-Sr isotopic dating of fluid inclusions of quartz is 160±1 Ma, which indicates that the tin deposit was likely formed in the peaks (160-150 Ma) of Mesozoic mineralization period of Nanling region, and the mineralization was closely related to the magmatic intrusion of the Middle Jurassic monzogranite of Dayishan intrusive rock, as a result of the post-magmatic hydrothermal mineralization. The initial 87Sr/86Sr value of the fluid inclusions is 0.706 79±0.003 66, which may indicate a mantle-derived fluid contribution to the ore-forming fluids.
Liu Z.-X.,Hubei Institute of Geological Survey |
Zhang Y.-L.,Hubei Institute of Geological Survey |
Chen T.-L.,Hubei Institute of Geological Survey |
Zhou X.-H.,Hubei Institute of Geological Survey
Geological Bulletin of China | Year: 2012
Sinian carbonate rocks are widely developed in the study area, and these rocks constitute one of the most hopeful oil-gas exploration target strata where a breakthrough is likely to be made in the lower marine combination. Through oil-gas geological survey along the profile and the stratigraphic section measurement of the outcrops, in combination with the previous achievements, the authors restudied the strata and sedimentary facies of Dengying Formation in Hupingshan-Zouma area. According to systematic identification and analysis of the rock slices, casting body slices and reservoir property samples of the outcrops, the authors hold that the Dengying Formation is mainly composed of carbonate rocks, which can be divided into three lithologic sections in upward succession. The strata are in conformable contact with the underlying Doushantuo Formation, and in parallel unconformable contact with the overlying Niutitang Formation, with the total thickness being 242~339 m, belonging to the sedimentary environment of tidal flat of the restricted platform-open platform-slope of the platform edge. In the strata, the reservoir thickness is 210.4 m, which possesses 72.7% of the total stratigraphic thickness; the reservoir rocks are composed mainly of granular dolomite, micrite dolomite, psammitic dolomite and oolitic limestone; the reservoir space comprises mainly intercrystalline pores, intergranular dissolved pores and fissures; the porosities are mainly 0.69%~2.66%, with the maximum value being 3.52% and the average value being 1.52%; the maximum value of the permeability is 6.2812×10-3 μm2. and the average value is 0.3000×10-3 μm2. The main pore types are small throats and micro throats. On the whole, the reservoir property of the Dengying Formation is rather poor, and it is comprehensively evaluated as a III-grade reservoir; nevertheless, structural fractures of the Dengying Formation are well developed, which can improve the reservoir property, and it is also hopeful for the reservoir to become a good reservoir. If there exist good caps and traps above the Dengying Formation, it is possible to find commercial gas reservoirs of certain sizes in the Dengying Formation.
Deng Q.,University of Chinese Academy of Sciences |
Deng Q.,Chengdu Center |
Wang J.,Chengdu Center |
Wang Z.-J.,Chengdu Center |
And 4 more authors.
Geological Bulletin of China | Year: 2013
The Macaoyuan Group is an important stratigraphic unit of the Precambrian strata in South China, so its sedimentary characteristics and ages are of great importance for the stratigraphic division and the correlation and reconstruction of the sedimentary facies and paleogeographic framework of the northern margin of the Yangtze block. It is generally accepted that the Maocaoyuan Group comprising the lower Baliya Formation and the upper Huoshaojian Formation on the northern margin of the Yangtze block consists of a succession of the Neoproterozoic molasse formation unconformably overlying the Mesoproterozoic Shennongjia Group. The SHRIMP U-Pb zircon age of the synsedimentary tuff from the upper part of the Baliya Formation is dated at 1165 Ma±14 Ma. This dating result shows that the Macaoyuan Group should be traced back to the Mesoproterozoic rather than previously-considered Neo-proterozoic strata. Field investigation and sedimentary facies analysis demonstrate that there are slump-convolute structures and normal graded bedding formed by the gravity flow in the Maocaoyuan Group, in which the strata are mainly made up of a succession of slope carbonate gravity flow deposits, instead of molasse formation. In combination with previous research results, the authors hold that the Macaoyuan Group is not comparable with the Neoproterozoic rift successions in South China both in sedimentary characteristics and in ages, and the Macaoyuan Group in the Shennongjia area should be assigned to one of the basement strata beneath the Neoproterozoic rift succession in South China.