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Publisher: Springer-Verlag   (Total: 2341 journals)

 Acta Geochimica   [3 followers]  Follow         Hybrid journal (It can contain Open Access articles)    ISSN (Print) 2096-0956 - ISSN (Online) 2365-7499    Published by Springer-Verlag  [2341 journals]
• The formation of porphyry copper deposits
• Authors: Weidong Sun; Jin-tuan Wang; Li-peng Zhang; Chan-chan Zhang; He Li; Ming-xing Ling; Xing Ding; Cong-ying Li; Hua-ying Liang
Pages: 9 - 15
Abstract: Abstract Copper is a moderately incompatible chalcophile element. Its behavior is strongly controlled by sulfides. The speciation of sulfur is controlled by oxygen fugacity. Therefore, porphyry Cu deposits are usually oxidized (with oxygen fugacities > ΔFMQ +2) (Mungall 2002; Sun et al. 2015). The problem is that while most of the magmas at convergent margins are highly oxidized, porphyry Cu deposits are very rare, suggesting that high oxygen fugacity alone is not sufficient. Partial melting of mantle peridotite even at very high oxygen fugacities forms arc magmas with initial Cu contents too low to form porphyry Cu deposits directly (Lee et al. 2012; Wilkinson 2013). Here we show that partial melting of subducted young oceanic slabs at high oxygen fugacity (>ΔFMQ +2) may form magmas with initial Cu contents up to >500 ppm, favorable for porphyry mineralization. Pre-enrichment of Cu through sulfide saturation and accumulation is not necessarily beneficial to porphyry Cu mineralization. In contrast, re-melting of porphyritic hydrothermal sulfide associated with iron oxides may have major contributions to porphyry deposits. Thick overriding continental crust reduces the “leakage” of hydrothermal fluids, thereby promoting porphyry mineralization. Nevertheless, it is also more difficult for ore forming fluids to penetrate the thick continental crust to reach the depths of 2–4 km where porphyry deposits form.
PubDate: 2017-03-01
DOI: 10.1007/s11631-016-0132-4
Issue No: Vol. 36, No. 1 (2017)

• Analyzing crude oils from the Junggar Basin (NW China) using
comprehensive two-dimensional gas chromatography coupled with
time-of-flight mass spectrometry (GC×GC-TOFMS)
• Authors: Yuce Wang; Wanyun Ma; Ni Zhou; Jiangling Ren; Jian Cao
Pages: 66 - 73
Abstract: Abstract As a new technology of analyzing crude oils, comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC-TOFMS) has received much research attention. Here we present a case study in the Junggar Basin of NW China. Results show that the hydrocarbons, including saturates and aromatics, were all well-separated without large co-elution, which cannot be realized by conventional one-dimensional GC–MS. The GC×GC technique is especially effective for analyzing aromatics and low-to-middle-molecular-weight hydrocarbons, such as diamondoids. The geochemical characteristics of crude oils in the study area were investigated through geochemical parameters extracted by GC×GC-TOFMS, improving upon the understanding obtained by GC–MS. Thus, the work here represents a new successful application of GC×GC-TOFMS, showing its broad usefulness in petroleum geochemistry.
PubDate: 2017-03-01
DOI: 10.1007/s11631-016-0115-5
Issue No: Vol. 36, No. 1 (2017)

• Spatial analysis of carbon storage density of mid-subtropical forests
using geostatistics: a case study in Jiangle County, southeast China
• Abstract: Abstract The mid-subtropical forest is one of the biggest sections of subtropical forest in China and plays a vital role in mitigating climate change by sequestering carbon. Studies have examined carbon storage density (CSD) distribution in temperate forests. However, our knowledge of CSD in subtropical forests is limited. In this study, Jiangle County was selected as a study case to explore geographic variation in CSD. A spatial heterogeneity analysis by semi-variogram revealed that CSD varied at less than the mesoscale (approximately 2000–3000 m). CSD distribution mapped using Kriging regression revealed an increasing trend in CSD from west to east of the study area. Global spatial autocorrelation analysis indicated that CSD was clustered at the village level (at 5% significance). Some areas with local spatial autocorrelation were detected by Anselin Local Moran’s I and Getis-Ord G*. A geographically weighted regression model showed different impacts on the different areas for each determinant. Generally, diameter at breast height, tree height, and stand density had positive correlation with CSD in Jiangle County, but varied substantially in magnitude by location. In contrast, coefficients of elevation and slope ranged from negative to positive. Based on these results, we propose certain measures to increase forest carbon storage, including increasing forested area, improving the quality of the current forests, and promoting reasonable forest management decisions and harvesting strategies. The established CSD model emphasizes the important role of mid-subtropical forest in carbon sequestration and provides useful information for quantifying mid-subtropical forest carbon storage.
PubDate: 2017-04-20

• Seasonal changes in TC and WSOC and their 13 C isotope ratios in Northeast
Asian aerosols: land surface–biosphere–atmosphere interactions
• Authors: Chandra Mouli Pavuluri; Kimitaka Kawamura
Abstract: Abstract In order to understand the relative importance of anthropogenic and biological sources of carbonaceous aerosols in Northeast Asia, we measured total carbon (TC) and water-soluble organic carbon (WSOC) and their stable carbon isotope ratios (δ13C) in total suspended particulates collected from Sapporo, northern Japan (43.07°N, 141.36°E) over a 1-year period (during 2 September 2009 and 5 October 2010). Temporal variations of TC showed a gradual decrease from mid-autumn to winter followed by a gradual increase to growing season with a peak in early summer. Both δ13CTC and δ13CWSOC showed very similar temporal trends with a gradual enrichment of 13C from mid-autumn to winter followed by a depletion in the 13C to early summer and thereafter it remained stable, except for few cases. Based on the results obtained together with the air mass trajectories, we found that biogenic emissions including biological particles (e.g., pollen) and secondary organic aerosol formation from biogenic volatile organic compounds are the important sources of carbonaceous aerosols in spring/summer whereas fungal spores from soil and biomass burning and enhanced fossil fuel combustion contribute significantly in autumn/winter and in winter, respectively, in Northeast Asia.
PubDate: 2017-04-11
DOI: 10.1007/s11631-017-0157-3

• Effect on greenhouse gas balance of converting rice paddies to vegetable
production
• Authors: Lei Wu; Xian Wu; Ronggui Hu
Abstract: Abstract Rice paddies are increasingly being converted to vegetable production due to economic benefits related, in part, to changes in demand during recent decades. Here, we implemented a parallel field experiment to simultaneously measure annual emissions of CH4 and N2O, and soil organic carbon (SOC) stock changes, in rice paddies (RP), rice paddy–converted conventional vegetable fields (CV), and rice paddy–converted greenhouse vegetable fields (GV). Changing from rice to vegetable production reduced CH4 emissions by nearly 100%, and also triggered substantial N2O emissions. Furthermore, annual N2O emissions from GV significantly exceeded those from CV due to lower soil pH and higher soil temperature. Marginal SOC losses occurred after one year of cultivation of RP, CV, and GV, contributing an important share (3.4%, 32.2%, and 10.3%, respectively) of the overall global warming potential (GWP) balance. The decline in CH4 emissions outweighed the increased N2O emissions and SOC losses in CV and GV, leading to a 13%–30% reduction in annual GWP as compared to RP. These results suggest that large-scale expansion of vegetable production at the expense of rice paddies is beneficial for mitigating climate change in terms of the overall GWP.
PubDate: 2017-04-11
DOI: 10.1007/s11631-017-0152-8

• Timing of mineralization at the Shihu gold deposit in the middle segment
of the Taihang Mountain, China
• Authors: Chao Chen; Shuyin Niu; Fang Wang; Fuxiang Zhang; Qinglian Zhang; Baojun Ma; Aiqun Sun; Jianzhen Zhang; Yaqi Cao; Xiaoqing Zhang
Abstract: Abstract The Shihu gold deposit, located in the middle-south section of the core of the Fuping mantle branch structure, is hosted in the Archean Fuping Group and adjacent to the quartz diorite porphyrite. The gold deposit is the only large gold deposit with reserves of more than 30 tons gold discovered in western Hebei Province so far. In order to constrain the timing of mineralization of this ore deposit, this paper focuses on the isotopic dating of zircon and pyrite. Zircons in gold-bearing quartz veins are magmatic in origin and no hydrothermal zircon has been found in such quartz veins, indicating that zircons were derived from the wall rocks. U–Pb ages of zircons fall mainly in the two domains: 2492 ± 82 and 136 ± 4 Ma, respectively, indicative of the contribution of the Fuping-Group TTG gneiss and Yanshanian igneous rocks, respectively. The Re–Os isotopic compositions of pyrites in the gold-bearing quartz veins yield an isochron age of 127 ± 31 Ma. Combined with other dating results, we suggest that the main metallogenic age of the Shihu gold deposit is 120–127 Ma.
PubDate: 2017-04-11
DOI: 10.1007/s11631-017-0158-2

• The δ 15 N response and nitrate assimilation of Orychophragmus violaceus
and Brassica napus plantlets in vitro during the multiplication stage
cultured under different nitrate concentrations
• Authors: Kaiyan Zhang; Yanyou Wu
Abstract: Abstract Natural nitrogen isotope composition (δ15N) is an indicator of nitrogen sources and is useful in the investigation of nitrogen cycling in organisms and ecosystems. δ15N is also used to study assimilation of inorganic nitrogen. However, the foliar δ15N of intact plants, which is a consequence of nitrate assimilation occurring in the roots and shoots, is not suited for studying nitrate assimilation in cases where nitrate is the sole nitrogen source. In this study, Orychophragmus violaceus (Ov) and Brassica napus (Bn) plantlets, in which nitrate assimilation occurred in the leaves, were used to study the relationship between foliar δ15N and nitrate assimilation. The plantlets were grown in vitro in culture media with different nitrate concentrations, and no root formation occurred for the plantlets during the multiplication stage. Nitrogen isotope fractionation occurred in both the Ov and the Bn plantlets under all treatments. Furthermore, the foliar nitrogen content of both the Ov and Bn plantlets increased with increasing nitrate concentration. Foliar nitrogen isotope fractionation was negatively correlated with foliar nitrogen content for both the Ov and Bn plantlets. Our results suggest that the foliar nitrogen isotope fractionation value could be employed to evaluate nitrate assimilation ability and leaf nitrate reductase activity. Moreover, high external nitrate concentrations could contribute to improved foliar nitrogen content and enhanced nitrate assimilation ability.
PubDate: 2017-04-10
DOI: 10.1007/s11631-017-0156-4

• Damming effects on dissolved inorganic carbon in different kinds of
reservoirs in Jialing River, Southwest China
• Authors: Gaoyang Cui; Xiaodong Li; Qinkai Li; Jun Huang; Yuele Tao; Siqi Li; Jun Zhang
Abstract: Abstract To assess the effects of river damming on dissolved inorganic carbon in the Jialing River, a total of 40 water samples, including inflow, outflow, and stratified water in four cascade reservoirs (Tingzikou, Xinzheng, Dongxiguan, Caojie) were collected in January and July, 2016. The major cations, anions, and δ13CDIC values were analyzed. It was found that the dissolved compositions are dominated by carbonate weathering, while sulfuric acids may play a relatively important role during carbonate weathering and increasing DIC concentration. Different reservoirs had variable characteristics of water physiochemical stratification. The DIC concentrations of reservoir water were lower in summer than those in winter due to the dilute effects and intensive aquatic photosynthesis, as well as imported tributaries. The δ13CDIC values in Tingzikou Reservoir were higher during summer than those in winter, which indicated that intensive photosynthesis increased the δ13CDIC values in residual water, but a similar trend was not obvious in other reservoirs. Except for in Xinzheng Reservoir, the δ13CDIC values in inflow and outflow reservoir water were lower than those in the surface water of stratified sampling in summer. For stratified sampling, it could be found that, in summer, the Tingzikou Reservoir δ13CDIC values significantly decreased with water depth due to the anaerobic breakdown of organic matter. The significant correlation (p < 0.01 or 0.05) between the DIC concentrations, the δ13CDIC values and anthropogenic species (Na++K+, Cl–, $${\text{SO}}_{4}^{2 - }$$ and $${\text{NO}}_{3}^{ - }$$ ) showed that the isotope composition of DIC can be a useful tracer of contaminants. In total, Tingzikou Reservoir showed lacustrine features, Xinzheng Reservoir and Dongxiguan Reservoir had “transitional” features, and Caojie Reservoir had a total of “fluvial” features. Generally, cascade reservoirs in the Jialing River exhibited natural river features rather than typical lake features due to characteristics of reservoir water in physiochemical stratification, spatiotemporal variations of DIC concentrations and isotopic compositions. It is evident that the dissolved inorganic carbon dynamics of natural rivers had been partly remolded by dam building.
PubDate: 2017-04-09
DOI: 10.1007/s11631-017-0155-5

• Carbon dioxide emissions from the Three Gorges Reservoir, China
• Authors: Shuang Li; Fushun Wang; Wenyun Luo; Yuchun Wang; Bing Deng
Abstract: Abstract Carbon dioxide (CO2) emission from the river-type reservoir is an hotspot of carbon cycle within inland waters. However, related studies on the different types of reservoirs are still inadequate. Therefore, we sampled the Three Gorges Reservoir (TGR), a typical river-type reservoir having both river and lake characteristics, using an online system (HydroCTM/CO2) and YSI-6600v2 meter to determine the partial pressure of carbon dioxide (pCO2) and physical chemical parameters in 2013. The results showed that the CO2 flux from the mainstream ranged from 26.1 to 92.2 mg CO2/m2 h with average CO2 fluxes of 50.0 mg/m2 h. The CO2 fluxes from the tributary ranged from −10.91 to 53.95 mg CO2/m2 h with area-weighted average CO2 fluxes of 11.4 mg/m2 h. The main stream emits CO2 to the atmosphere the whole year; however, the surface water of the tributary can sometimes act as a sink of CO2 for the atmosphere. As the operation of the TGR, the tributary became more favorable to photosynthetic uptake of CO2 especially in summer. The total CO2 flux was estimated to be 0.34 and 0.03 Tg CO2/year from the mainstream and the tributaries, respectively. Our emission rates are lower than previous estimates, but they are in agreement with the average CO2 flux from temperate reservoirs estimated by Barros et al. (Nat Geosci 4(9):593–596, 2011).
PubDate: 2017-03-31
DOI: 10.1007/s11631-017-0154-6

• The influence of atmospheric Hg on Hg contaminations in rice and paddy
soil in the Xunyang Hg mining district, China
• Authors: Ming Ao; Bo Meng; Atindra Sapkota; Yonggui Wu; Xiaoli Qian; Guangle Qiu; Shunqing Zhong; Lihai Shang
Abstract: Abstract To date, the Xunyang mercury (Hg) mining district is the only ongoing large-scale Hg mining district in China. To understand the influence of Hg contamination mode from the Hg mining and smelting activities, 27 sampling sites in the Xunyang Hg mining district were chosen in this study. Total gaseous mercury (TGM) in ambient air was measured using a Lumex-RA915 automatic Hg analyzer in 2011. Rice samples and soil samples from rhizosphere were collected systematically and simultaneously. Total Hg (THg) and methylmercury (MeHg) concentrations in rice grain and soil samples and Hg speciation with modified sequential selective extractions were measured. The local environment was seriously polluted with Hg. The TGM (302 ± 376 ng·m−3, ranging from 24 to 2220 ng·m−3) in the local ambient air, THg (28 ± 30 mg·kg−1, ranging from 0.31 to 121 mg·kg−1) and MeHg (2.3 ± 1.9 μg·kg−1, ranging from 0.24 to 8.9 μg·kg−1) in soil samples were at the sample level with Hg contaminated area. The THg concentration (26 ± 16 μg·kg−1 ranging from 4.5 to 71 μg·kg−1) in most of the rice grain samples clearly exceeds the threshold level (20 μg·kg−1) in the Chinese national guidelines for cereals (NY 861-2004). The inorganic mercury (IHg) (9.1 ± 5.6 μg·kg−1, ranging from 1.2 to 24 μg·kg−1) and MeHg (14 ± 9.8 μg·kg−1, ranging from 2.1 to 59 μg·kg−1) concentration in rice grain samples were at the same level with Hg contaminated area. The main species of Hg in paddy soils reveal strong complex Hg and residue Hg. According to the correlation analysis, a Hg pollution mode from local Hg mining and smelting was hypothesized, including Hg emission, transportation, methylation, and uptake process.
PubDate: 2017-03-30
DOI: 10.1007/s11631-017-0142-x

• Effects of river damming on biogenic silica turnover: implications for
biogeochemical carbon and nutrient cycles
• Authors: Nan Ma; Zhaoliang Song; Baoli Wang; Fushun Wang; Xiaomin Yang; Xiaodong Zhang; Qian Hao; Yuntao Wu
Abstract: Abstract Rivers link terrestrial ecosystems and marine ecosystems, and they transport large amounts of substances into oceans each year, including several forms of silicon (Si), carbon (C), and other nutrients. However, river damming affects the water flow and biogeochemical cycles of Si, C, and other nutrients through biogeochemical interacting processes. In this review, we first summarize the current understanding of the effects of river damming on the processes of biogeochemical Si cycle, especially the source, composition, and recycling process of biogenic silica (BSi). Then, we introduce dam impacts on the cycles of C and some other nutrients. Dissolved silicon in rivers is mainly released from phytolith dissolution and silicate weathering. BSi in suspended matter or sediments in most rivers mainly consists of phytoliths and mainly originates from soil erosion. However, diatom growth and deposition in many reservoirs formed by river interception may significantly increase the contribution of diatom Si to total BSi, and thus significantly influence the biogeochemical Si, C, and nutrient cycles. Yet the turnover of phytoliths and diatoms in different rivers formed by river damming is still poorly quantified. Thus, they should be further investigated to enhance our understanding about the effects of river damming on global biogeochemical Si, C and nutrient cycles.
PubDate: 2017-03-30
DOI: 10.1007/s11631-017-0153-7

• Mineralogy, sulfur isotopes and infrared microthermometric study of the
Leishan-Rongjiang antimony ore field, SW China
• Authors: Jun Chen; Ruidong Yang; Junbo Gao; Lulin Zheng; Lijuan Du; Minggang Yuan; Huairui Wei
Abstract: Abstract The Leishan-Rongjiang antimony ore field (LAOF) is in a unique geotectonic location in the uplift between the Youjiang and Xiangzhong basins. This paper focuses on two representative deposits in the LAOF: the Bameng and Peize antimony (Sb) deposits. We analyzed fluid inclusions (FIs) in stibnite and coexisting quartz, as well as the sulfur isotopic composition of stibnite, to better understand the nature of the ore-forming fluid and the metallogenic process. The FIs data from samples of the stibnite and coexisting quartz indicate that the ore-forming fluids were characterized by low-temperature (150–210 °C), low-salinity (1.5 wt%–6.0 wt% NaCl equiv.), and low-density (0.872–0.961 g/cm3). The δ34S values of stibnite (−8.21‰ to 3.76‰, average = −6.30‰) fall in between the sulfur isotopic compositions of the mantle and of biogenic sulfur in sedimentary rocks. However, the δ34S∑S values (−4.41‰ to +0.04‰, average = −2.49‰) of the ore-forming fluids are generally closer to the sulfur isotopic composition of the mantle source, indicating that the sulfur in the LAOF was mainly sourced from the mantle, but with possible involvement of biogenic sulfur. In addition, FIs petrography and ore deposit geology show that fluid boiling resulted from an abrupt decrease in pressure, which may have triggered the precipitation of stibnite. We conclude that low-temperature, dilute hydrothermal fluids with mixed origins migrated along the regional fault and interacted with the wall rock, extracting the ore-forming materials. Then, the ore-forming fluids were injected into the fault fracture zones.
PubDate: 2017-03-24
DOI: 10.1007/s11631-017-0151-9

• Geochemistry, petrogenesis and tectonic significance of the late Triassic
A-type granite in Fujian, South China
• Authors: Dawei Cai; Jingyu Zhao; Yong Tang; Hui Zhang; Yunlong Liu; Zhenghang Lv
Abstract: Abstract The late Permian–Triassic granites in southeastern China have important tectonic significance for the evolution of South China. Here, we present the detailed geochronological, geochemical and petrological analyses for the Jinlongyan (JLY) granite in northwest Fujian Province, southeast China. LA–ICP–MS zircon U–Pb dating yielded a weighted average 206Pb/238U age of 224.1 ± 3.3 Ma. The granite is mainly comprised of K-feldspar, plagioclase, quartz, biotite and minor amphibole. It is characterized by enrichments in Rb, Th, REEs (total REE = 295.1–694.3 ppm), and HFSEs (e.g., Zr = 289–520 ppm, Hf = 9.3–15.0 ppm, Y = 36.2–68.2 ppm) but depletions in Ba, Sr, Eu and Ti. The granite is metaluminous to weakly peraluminous and show a clear A-type granite geochemical signature with high SiO2 (70.89 wt%–75.76 wt%), total alkalis (Na2O + K2O = 7.51 wt% –8.72 wt%), Ga/Al ratios (10000 Ga/Al = 2.72–3.43). In-situ zircon Hf isotope analysis shows their εHf(t) values ranging from −7.2 to −3.2, with Mesoproterozoic T2DM ages (1308–1525 Ma). Whole-rock Nd isotope data show their εNd(t) values in the range of −9.5 to −9.1 and yield paleoproterozoic TDM ages (1606–1985 Ma). These characteristics indicate that the JLY A-type granite magma was formed by the partial melting of Meso-Paleoproterozoic crust rocks in the Cathaysia Block. Our study of the JLY A-type granite, together with other Triassic A-type granites in South China, defines an extensional environment in the late Triassic which probably was caused by the collision of the South China Block with Indochina Block.
PubDate: 2017-03-24
DOI: 10.1007/s11631-017-0143-9

• Geochemistry and Zircon U–Pb age of the Yao’an pseudoleucite porphyry,
Yunnan Province, China
• Authors: Chundi Sun; Peng Wu; Die Wang; Shenjin Guan; Xiaojun Jiang; Longyan Jiang; Longyan Wang
Abstract: Abstract The Yao’an Pb–Ag deposit, located in the Chuxiong Basin, western Yangtze Block, is an important component of the Jinshajiang–Ailaoshan alkaline porphyry–related polymetallic intrusive belt. This complex suite of rock bodies includes a vein of pseudoleucite porphyry within deposits of syenite porphyry and trachyte. The pseudoleucite is characterized by a variable greyish, greyish-white, and greyish-green porphyritic texture. Phenocrysts are mainly pseudoleucite with small amounts of alkali feldspar and biotite. In an intense event, leucite phenocrysts altered to orthoclase, kaolinite, and quartz. Both the pseudoleucite porphyry and the syenite porphyry samples were typical alkali-rich, K-rich, al-rich rocks with high LaN/YbN ratios; enriched in light rare earth elements and large-ion lithophile elements, and depleted in high field strength elements; and with strongly negative Ta, Nb, and Ti (TNT) anomalies and slightly negative Eu anomalies—all characteristics of subduction-zone mantle-derived rock. We obtained a LA-ICP-MS zircon U–Pb age of 34.1 ± 0.3 Ma (MSWD = 2.4), which is younger than the established age of the Indian and Eurasian Plate collision. The magma derived from a Type-II enriched mantle formed in a post-collisional plate tectonic setting. The geochemical characteristics of the Yao’an pseudoleucite porphyry are powerful evidence that the porphyry’s development was closely linked to the Jinshajiang–Ailaoshan fault and to the Indian-Eurasian collision.
PubDate: 2017-03-22
DOI: 10.1007/s11631-017-0149-3

• Integration of SEM/WDX elemental mapping and micromorphology to determine
mineralogical traits of peat soils (case study: Northern Iran)
• Authors: Milad Kurdi; Taymor Eslamkish
Abstract: We explored the potential use of combining wavelength-dispersive X-ray spectroscopy (WDX) and micromorphology of thin sections to identify minerals in peat soils. Peat soil minerals from three peats and swamps across Golestan Province in northern Iran were first characterized by micromorphological studies. Soils were composed mainly of quartz, muscovite, biotite, pyroxene, sericitized Fe-nodules, and iron-rich garnet. In addition, micromorphological results indicated that Galougah Coastal Swamp sections contained some inorganic residue with biological origin including oyster and limpet, which may be related to the swamp’s location near Gorgan Gulf. In order to determine mineralogical properties of samples, twelve unknown grains were chosen for elemental concentration map studies. Quartz, garnet, ilmenite, calcite, and pyroxene in Suteh samples; epidote and Fe-nodule in Ghaleh-Ghafeh Peat Swamp; and barite, phyllosilicates, and calcite in Galougah were identified by WDX mapping of Si, Al, Fe, Ca, Mg, C, Ba, S, and Ti. Composition of the oysters’ body was also analyzed by WDX for Si, Ca, Fe, and C. The results indicated that most of the minerals in all sections likely formed through weathering, inheriting their composition from the parent rock. This research suggests that merging micromorphology and SEM/WDX image techniques can be useful in confirming the presence of mineral particles in soil science. Graphical
PubDate: 2017-03-17
DOI: 10.1007/s11631-017-0148-4

• Speciation and spatial distribution of Cr in chromite ore processing
residue site, Yunnan, China
• Authors: Guangzhu Zhou; Xin Yin; Jing Zhou; Weiyu Cheng
Abstract: Abstract Remediation of COPR sites requires the key information including chromium oxidation, speciation and spatial distribution. Samples were gathered from a COPR site in Luliang County in Qujing, Yunnan Province of China. The total Cr, Cr(VI) and chromium species were investigated. Results indicated the concentration of total Cr was between 110.5 and 21,774 mg/kg, and the concentration of Cr(VI) was between 0.1 and 1075 mg/kg. The map of total-Cr and ratio of Cr(VI)/total-Cr (%) showed that the maximum of total-Cr and Cr(VI) appeared in the layers near the surface. In the horizontal direction, the pollution was more serious in the middle and southeast part than that in the west. Additionally, acid extractable chromium increased in the layers at depth from −0.3 to −2.0 m, and it decreased in the deeper layers. There was a trend that the movable Cr(VI) migrated to the deeper layers, and then it turned into Cr(III). Water played an important role for the Cr distribution. Cr(VI) in COPR released to the soil solution after rainfall, and then gravity led the solution down to the deeper layers. After repeated rainfall and leaching, Cr(VI) moved to the deeper soil layers. Due to capillarity and evaporation, Cr(VI) migrated and was enriched at the surface layer. Therefore, measures on controlling water movement should be taken in the remediation of the COPR site.
PubDate: 2017-03-13
DOI: 10.1007/s11631-017-0147-5

• Adsorption of 133 Cs and 87 Sr on pumice tuff: A comparative study between
powder and intact solid phase
• Authors: Mohammad Rajib; Chiaki T. Oguchi
Abstract: Abstract This study examines the use of intact samples as an alternative to powder in conventional batch sorption studies to determine the distribution coefficient (K d). Stable cesium (133Cs) and strontium (87Sr) were used under specified geochemical conditions to compare the K d values of powder and block pumice tuff samples. The aim of the study was to infer any K d difference under laboratory and field conditions. K d values for block samples were found to be less than one order of magnitude lower than powder materials for both Cs and Sr on fresh tuff, and more than one order of magnitude lower in oxidized tuff. Destruction of micropores in oxidized tuff was estimated to be mainly responsible for reducing K d values in oxidized tuff. However, approximately one order of magnitude difference in K d values indicates that homogenously prepared intact samples can be used for sorption coefficient measurement at closer to in situ conditions. Pore size distribution analysis using mercury intrusion porosimetry revealed that lower K d values on block samples result from lower surface area available as sorption sites due to inaccessible closed pores in the intact solid.
PubDate: 2017-03-02
DOI: 10.1007/s11631-016-0133-3

• Temporary fluoride concentration changes in groundwater in the context of
impact assessment in the Vaniyar sub-basin, South India
• Authors: S. Satheeshkumar; S. Venkateswaran; R. Kannan
Abstract: Abstract India’s surface water and groundwater distribution is temporally variable due to the monsoon. Agriculture is one of the dominant economic sectors in India. Groundwater quality is regularly assessed to determine usability for drinking and irrigation. In this study, World Health Organization and Bureau of Indian Standards guidelines were used to determine suitability of groundwater near artificial recharge structures (ARS) with a focus on the structures´ impact on groundwater quality. Groundwater resources were evaluated for irrigation suitability using electrical conductivity (EC), sodium adsorption ratio, the US Salinity Laboratory diagram, sodium concentration, Wilcox’s diagram, Kelly’s index, and Doneen’s permeability index. EC and major ions were tested in recharge areas at different distances from the ARS. The construction of ARS at optimal distances along major streams has improved groundwater quantity and quality in the sub-basin. Before construction of ARS, fluoride concentrations were higher; after construction, fluoride was reduced in most locations. Water stored in the check dam and groundwater in the wells closer to the structure were suitable for both drinking and irrigation purposes. Impact of ARS on nearby groundwater quality was observed at Pallipatti, Mulayanur, Venkadasamuthram, Pudupatti, Poyyappatti, Harur1, and Sekkampatti. More distant sites included Pappiredipatti, Nambiyappati, Menasi, Harur, Todampatti, and Adikarapatti. Data demonstrated improved groundwater quality in the area of the ARS. Through recharge, the non-potable fluoride in the region is reduced to the permissible limit for human consumption.
PubDate: 2017-01-04
DOI: 10.1007/s11631-016-0137-z

• Evaluation of hydrogeochemical characteristics and the impact of
weathering in seepage water collected within the sedimentary formation
• Authors: M. V. Prasanna; R. Nagarajan; S. Chidambaram; A. Anand Kumar; C. Thivya
Abstract: Abstract A study was conducted by collecting eight seepage water samples that drain through the sedimentary rocks, mainly sandstone and shale, to evaluate the hydrogeochemical characteristics. The collected samples were analyzed for physico-chemical parameters using standard procedures. Three water types were identified in the Piper plot and the hydrogeochemical evolution starts from a Ca–Cl facies (type 1) via mixed Ca–Mg–Cl and Ca–Na–HCO3 facies (type 2) to Na–Cl facies (type 3). Increasing trend of electrical conductivity (EC) values were observed from type 1 water to type 3 water. Lower ionic concentrations with an average EC value of 35.7 µs/cm in Ca–Cl facies indicate the recharge water by monsoonal rainfall, and ion exchange/weathering process is reflected in the mixing zone. Higher ionic concentration with an average EC value of 399 µs/cm is noted in Na–Cl facies, which indicates the ion exchange during water–rock interaction. Higher log pCO2 values are also found in this facies, revealing the longer residence time of seepage water in the rock matrix, which release more ions into the water. The relative mobility of elements during weathering suggest that the order of mobility in both sandstone and shale is Na > Ca > Mg > K. It was observed that the hydrogeochemistry of seepage water is mainly controlled by the bedrock geology.
PubDate: 2016-12-18
DOI: 10.1007/s11631-016-0125-3

• Carbon isotopic composition and genetic types of natural gas in the
Sichuan Basin, China
• Authors: Jin-ning Peng; Dong-yan Wang; Guang-xiang Liu; Min Zhang; Feng-li Li
Abstract: Abstract The origin and genetic types of natural gas in the Sichuan Basin are still disputed. To classify the origin and genetic types in different areas, the paper analyzes the carbon isotopic composition of gases and geologic features in the Sichuan Basin. The results showed that the gas sourced from terrestrial layers is typically characterized by terrestrial origin and was mainly accumulated nearby to form reservoir. The carbon isotopic composition of gas showed a normal combination sequence distribution, suggesting that natural gas in continental strata is not affected by secondary alteration or that this deformation is very weak. The gas source is singular, and only gas from the southern and northern Sichuan Basin shows the characteristic of mixed sources. However, marine gas presents the characteristics of an oil-formed gas. The carbon isotopic composition of natural gas in the western and central part of the basin mostly distributes in a normal combination sequence, and few of them showed an inversion, indicating that the gas perhaps had not experienced secondary alteration. The carbon isotopic composition of marine-origin gas in the southern, northern and eastern Sichuan Basin displays a completely different distribution pattern, which is probably caused by different mixing ratio of gas with multi-source and multi-period.
PubDate: 2016-11-16
DOI: 10.1007/s11631-016-0134-2

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