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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.

Shen B.,CAS South China Sea Institute of Oceanology | Shen B.,East China Institute of Technology | Shen B.,University of Chinese Academy of Sciences | Liu B.,Hainan Institute of Geological Survey | And 6 more authors.
Diqiu Kexue - Zhongguo Dizhi Daxue Xuebao/Earth Science - Journal of China University of Geosciences | Year: 2016

The western Qiongnan suture zone, i.e., Jiusuo-Lingshui fault belt, at the northern margin of the South China Sea, is important in tectonics. To better understand the tectonic evidences and ductile shear belts, a study is done in this area. Three types of rocks are sampled from the Xiaomei ductile shear zone on Hainan island, including granite, garnet quartz schist and granitic gneiss. Their shear surfaces were observed and analyzed through scanning electron microscope (SEM) at nanoscale. The results show multiple nano-textures and nanostructures in all three kinds of rocks and a positive relationship between the development degree of nanoparticles and the stress of the rocks. The authors propose several possible formation machanism of nanoparticles on the shear surfaces in this area, which may be thermal decomposition of sheet silicates under shear stress, or brittle deformation of minerals (especially feldspar with mechanical twins) after ductile deformation, then followed by crushing and grinding of the particles to nanoscale under shear force. Samples from the Taroko ductile shear belt, a part of the Taroko fault zone in Taiwan show similar nano characteristics to the Xiaomei ductile shear zone, implying both may have been in the same tectonic setting of a deep fracture as the Jiusuo-Lingshui fault belt. This study can therefore provide important observational facts for determining the structural properties and spatial positions of the Jiusuo-Lingshui fault belt. © 2016, Editorial Department of Earth Science. All right reserved.

Wang X.,Curtin University Australia | Wang X.,CAS Institute of Geology and Geophysics | Wang X.,University of Western Australia | Li Z.,Curtin University Australia | And 6 more authors.
Journal of Petrology | Year: 2012

Basaltic lavas from Hainan Island near114415607 the northern edge of the South China Sea have an age range of between late Miocene (about 13 Ma) and Holocene, with a peak age of late Pliocene to middle Pleistocene. The basaltic province is dominated by tholeiites with subordinate alkali basalts. Most analysed samples display light rare earth element (LREE) enriched REE patterns and ocean island basalt (OIB)-like incompatible element distributions. The basalts contain abundant undeformed high-Mg olivine phenocrysts (up to Fo 90·7) that are high in CaO and MnO, indicating high-magnesian parental magmas. Independent barometers indicate that clinopyroxenes in the basalts crystallized over a wide range of pressures of 2-25 kbar (dominantly at 10-15 kbar) and that the melt cooled from about 1350°C to 1100°C during their crystallization. The compositional characteristics of the basalts indicate that their generation most probably involved both low-silica and high-silica melts, as represented by the alkali basalts and tholeiites, respectively. Our results show that the source region for the Hainan basalts is highly heterogeneous. The source for the tholeiites is mainly composed of peridotite and recycled oceanic crust, whereas the source for the bulk of the low-Th alkali basalts consists predominantly of peridotite and low-silica eclogite (garnet pyroxenite). Some high-Th (≥ 4 ppm) alkali basalts may have been produced by partial melting of low-silica garnet pyroxenite (eclogite). We estimated the primary melt compositions for the Hainan basalts using the most forsteritic olivine (Fo 90·7) composition and the most primitive bulk-rock samples (MgO > 9·0 wt % and CaO >8·0 wt %), assuming a constant Fe-Mg exchange partition coefficient of K D = 0·31 and Fe 3+/Fe T = 0·1. The effective melting pressure (P f) and melting temperature (T) of the primary melts are P f = 18-32 kbar (weighted average = 23·8 ± 1·8 kbar) and T = 1420-1520°C for the tholeiites, and P f = 25-32 (weighted average = 28·3 ± 1·4 kbar) and T = 1480-1530°C for the alkali basalts. The P f -T data form an array that plots systematically above the dry lherzolite solidus but below the base of the lithosphere (∼55 km) and intersects the dry peridotite solidus at a pressure of about 50 kbar. The mantle potential temperature beneath Hainan Island, based on the estimate primary melt compositions, varies from about 1500 to 1580°C with a weighted average of 1541 ± 10°C. The high-magnesian olivine phenocrysts, high mantle potential temperature, and the presence of recycled oceanic crust in the source region provide independent support for the Hainan plume model that has previously been proposed largely based on geophysical observations. The Hainan plume thus provides a rare example of a young mantle plume associated with deep slab subduction. © The Author 2011. Published by Oxford University Press. All rights reserved.

Jiang W.,China University of Geosciences | Hou Q.,China University of Geosciences | Yang Z.,China University of Geosciences | Yu T.,China University of Geosciences | And 3 more authors.
Environmental Science and Pollution Research | Year: 2014

The accumulation of heavy metals in farmland has become an important issue related to food security and environmental risk. The annual inputs of heavy metals (As, Cd, Hg, Pb, Cr, Cu, and Zn) to agricultural soil for a full year in Hainan Island have been studied. Three fluxes through the cultivated horizon were considered: (1) atmospheric depositions, (2) fertilization, and (3) irrigation water. The corresponding samples were collected and analyzed on a large regional scale. The total input fluxes show obvious spatial variability among different regions. The inventory of heavy metal inputs to agricultural land demonstrates that agricultural soil is potentially at risk of heavy metal accumulation from irrigation water. The potential at risk of heavy metal accumulation from atmospheric deposition and fertilizer is relatively low compared to irrigation. The results indicate that Hg is the element of prior concern for agricultural soil, followed by Cd and As, and other heavy metal elements represent little threat to the environment in the study area. This work provides baseline information to develop policies to control and reduce toxic elements accumulated in agricultural soil. © 2014 Springer-Verlag Berlin Heidelberg.

Fu J.,Petrochina | Ding W.,China University of Geosciences | Zeng W.,Hainan Institute of Geological Survey | He J.,China University of Geosciences | Wang Z.,China University of Geosciences
Xinan Shiyou Daxue Xuebao/Journal of Southwest Petroleum University | Year: 2016

Tectonic conditions of Northwest Guizhouare highly complex. The preservation conditions of shale gas reservoirs in Lower Cambrian Niutitang Formation are studied and the favorable preservation condition areas of the shale gas reservoirs are divided with reference to shale gas reservoirs' preservation condition evaluation index. Combined with the tectonic evolution, the development and distribution characteristics of folds and faults, the shale sedimentary environment and thickness, the organic carbon content and the organic matter maturity, etc. in Northwest, Guizhou. Preservation conditions of shale gas reservoirs have important reference values in other areas. The folds and faults are highly developed in Northwest, Guizhou. The folds are mainly trough-like folds, and the faults have four groups of fault systems at different stages and trends. The preservation conditions of shale gas reservoirs are destroyed at different degrees by the above reasons. The favorable preservation condition areas of the shale gas reservoirs are mainly distributed in most parts of the Dafang and Qianxi County in Central of Northwest Guizhou, and some parts of the Tongzi County and Renhuai City in the northeast of Northwest Guizhou. © 2016, Science Press. All right reserved.

Fu Y.,Wuhan University | Fu Y.,Hainan Institute of Geological Survey | Chen M.,Wuhan University | Chen M.,Hainan Institute of Geological Survey | And 8 more authors.
Environmental Pollution | Year: 2011

The acquaintance of arsenic concentrations in rice grain is vital in risk assessment. In this study, we determined the concentration of arsenic in 282 brown rice grains sampled from Hainan Island, China, and discussed its possible relationships to the considered soil properties. Arsenic concentrations in the rice grain from Hainan Island varied from 5 to 309 μg/kg, with a mean (92 μg/kg) lower than most published data from other countries/regions and the maximum contaminant level (MCL) for Asi in rice. The result of correlation analysis between grain and soil properties showed that grain As concentrations correlated significantly to soil arsenic speciation, organic matter and soil P contents and could be best predicted by humic acid bound and Fe-Mn oxides bound As fractions. Grain arsenic rises steeply at soil As concentrations lower than 3.6 mg/kg and gently at higher concentrations. © 2011 Elsevier Ltd. All rights reserved.

Guo R.,Water Resources University | Jin X.,Water Resources University | Wang X.,Hainan Institute of Geological Survey | Hu G.,CAS Institute of Remote Sensing
Earth Science Frontiers | Year: 2014

In an arid inland basin, evapotranspiration (ET) is the major loss related to the water balance and precise estimation of ET is essential for evaluation of available water resources in these areas. The study of actual evapotranspiration on a regional scale has great significance for environmental protection. Based on SEBS algorithm (Surface Energy Balance System), the ET was estimated using DEM data, MODIS data and GLDAS data over the Qaidam Basin from 2001 to 2011 at a spatial resolution of 500 m. What's more, the long-term change and spatial distribution of ET and its relationship with pan observed evaporation in the Qaidam Basin were studied. The result indicated that the annual actual ET of Qaidam Basin increased with time and the value varied from 72.73 mm in 2001 to 182.34 mm in 2011, and the maximum of the mean daily ET varied between 2.62 mm and 3.20 mm during the year 2001 to 2011. The evaporation coefficient is 0.14 in the Qaidam Basin. The analysis of NDVI and its corresponding ET presented that the NDVI threshold between bare soil and vegetation is 0.055 in the Qaidam Basin. The water bodies had highest mean daily ET (2.31 mm/d) though they only make up 1.92% of the study area. The mean daily ET of bare soil, sparse shrub, dense shrub, grassland, farmland and forest in the Qaidam Basin from June to September in the year 2010 were 0.24 mm/d, 0.42 mm/d, 1.21 mm/d, 1.12 mm/d and 1.18 mm/d, respectively.

Liao X.,Geological Bureau of Hainan Province | Fu Y.,Hainan Institute of Geological Survey | He Y.,Hainan Institute of Geological Survey | Yang Y.,Hainan Institute of Geological Survey
Catena | Year: 2014

Arsenic is a highly toxic element and its presence in foodstuffs will do harm to human health. In this study, the levels of arsenic in the fruits of three mango cultivars (Mangifera indica L.) from Hainan Island, China were investigated and their relationships to soil properties were discussed. The concentrations of arsenic in the mango fruits ranged from 0.6 to 50μgkg-1 (FW) with a mean value of 8.6μgkg-1. The transfer factors (TFs) of arsenic from soil to fruit varied between 0.0001 and 0.055 with a mean value of 0.0059. Both arsenic concentrations in the mango fruits and TFs were negatively correlated with soil Al2O3, Fe2O3, and MnO concentrations that could be described by a power model (y=axb), suggesting that soil Al-Fe-Mn oxides may play an important role in limiting the bioavailability and bioaccumulation of arsenic in the mango fruits. In addition, arsenic accumulations in the mango fruits were influenced by the soil pH. Mango fruits from the soils with pH between 4.8 and 5.5 had relatively high arsenic concentrations and TF values. © 2013 Elsevier B.V.

Li S.,Hainan Institute of Geological Survey | Wei C.,Hainan Institute of Geological Survey | Wang Y.,Hainan Institute of Geological Survey | Hu Z.,Hainan Institute of Geological Survey | Chen F.,Hainan Institute of Geological Survey
Geotectonica et Metallogenia | Year: 2016

The mesometamorphic rocks in the Diaoluoshan area are composed of granulite and gneiss occurring as discrete patches in the Permian granite. Based on lithological comparison, the metamorphic rocks were classified as the Mesoproterozoic Baoban Group in the previous literatures. Our LA-ICP-MS zircon U-Pb results of the granulite and gneiss yielded ages of 255±9 Ma and 247±8 Ma, respectively. The zircon U-Pb ages of the metamorphic rocks demonstrated that the metamorphism of the rocks took place in Hercynian-Indo-Chinese Epoch rather than the previously believed Mesoproterozoic Period. © 2016, Science Press. All right reserved.

He Y.-S.,Hainan Institute of Geological Survey
Chinese Journal of Ecology | Year: 2013

The concentration, distribution, and speciation of heavy metals in urban soils of Haikou City were investigated. The mean concentrations of heavy metals Hg, As, Cd, Cu, Cr, Ni, Pb and Zn were 0. 073, 3. 82, 0. 25, 26. 7, 92. 4, 52. 5, 29. 1 and 84. 1 mg·kg-1, respectively. In comparison with the background values, the enrichments of Hg, As, Cd, Cu, Cr, Ni, Pb and Zn in the soils of Haikou City were obvious, indicating a certain degree of heavy metal pollution. Cr, Ni, Cu, Cd and Zn were enriched in suburban areas, while Pb was enriched in roadside green belts and Hg was enriched in residential areas. Zn, As, Cr, Cu and Ni in the soils of Haikou were predominantly in residual fraction. Hg was mainly associated with strong organic-bound and residual fractions, while Pb was mainly presented as iron and/ or manganese oxide-bound fractions. On the contrary, Cd existed mainly in bio-available fractions. The results of multiple-metals ecological risk assessment indicate that the heavy metal pollution in the soils of Haikou is at a relatively low level. However, Cd and Hg pollution deserves much more attention.

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