Research on the stabilization treatment of clay slope topsoil by organic polymer soil stabilizer     

Jin Liu  Bin Shi  Hongtao Jiang  He Huang  Gonghui Wang  Toshitaka Kamai 《Engineering Geology》2011,117(1-2):114-120

The topsoil of clayey slope is easy to erosion because it is weak in its strength, water stability and erosion resistance. A new organic polymer soil stabilizer, which was developed for the stabilization treatment of clay slope topsoil and was named as STW, was introduced in this study. In order to understand the effect of STW on the stabilization of clayey soil, laboratory tests on the unconfined compressive strength, shear strength, water stability and erosion resistance of untreated and treated soil specimens are performed, The results indicated that STW soil stabilizer can significantly increased the unconfined compression strength, shear strength, water stability and erosion resistance of clayey soil. The unconfined compression strength increased with the increasing of curing time and the variation mainly occurs in the first 24-hour. With the addition amounts of STW increasing, the strength, water stability and erosion resistance increased at the curing time being 48 h, but in the case of friction angle, no major change was observed. Based on the scanning electron microscopy (SEM) analysis of the stabilized soil, the stabilization mechanisms of STW soil stabilizer in the clayey soil were discussed. Finally, a field test of the stabilization treatment of clay slope topsoil with STW was carried out, and the results indicated that the STW soil stabilizer on the stabilization treatment of clay slope topsoil is effective for improving the erosion resistance of slope topsoil, reducing the soil loss and protecting the vegetation growth. Therefore, this technique is worth popularizing for the topsoil protection of clay slope.  相似文献   

Age of the MGS5 segment of the Milanggouwan stratigraphical section and evolution of the desert environment on a kiloyear scale during the Last Interglacial in China's Salawusu River Valley: Evidence from Rb and Sr contents and ratios     

Shuhuan Du  Baosheng Li  Dongfeng Niu  David Dian Zhang  Xiaohao Wen  Deniu Chen  Yi Yang  Fengnian Wang 《Chemie der Erde / Geochemistry》2011,(1):87-95

The MGS5 segment of the Milanggouwan stratigraphical section in China's Salawusu River Valley records 8.5 sedimentary cycles consisting of dune sands alternating with fluviolacustrine facies or/and paleosols. Based on a comprehensive analysis of the distribution of Rb and Sr within the segment and paleoecological evidence (fossils), it appears that the observed sedimentation cycles mainly resulted from fluctuations between dry-cold and warm-humid climates, which indicates that the MGS5 segment experienced at least eight cold-dry and nine warm-humid climatic fluctuations. Of these, 12 cold–warm climate fluctuations correspond to DO20–DO25 and stadia 21–26 recorded by the NGRIP ice cores. Another five cold–warm climatic fluctuations that occurred during MGS5e correspond to five substages (5e1–5e5) recorded by the GRIP ice cores from Greenland. This kind of high-frequency climatic fluctuation on a kiloyear scale was mainly subject to variations in the strength of the East Asian winter and summer monsoons.  相似文献   

Activation of cloud droplets in bin-microphysics simulation of shallow convection     

Andrzej A. Wyszogrodzki  Wojciech W. Grabowski  Lian-Ping Wang 《Acta Geophysica》2011,59(6):1168-1183

This paper describes implementation of the warm-rain bin microphysics in a LES model based on the EULAG fluid flow solver. The binmicrophysics EULAG is applied to the case of shallow nonprecipitating tropical convection to investigate the impact of the secondary activation of cloud droplets above the cloud base. In a previous study applying the EULAG model with the double-moment bulk warm-rain microphysics scheme, the in-cloud activation was shown to have significant implications for the mean microphysical and optical characteristics of the cloud field. By contrasting the simulations with and without in-cloud activation as in the previous study, we show that the in-cloud activation has qualitatively similar but quantitatively smaller effect. In particular, the concentration of cloud droplets in the bin simulation without in-cloud activation decreases with height not as strongly as in corresponding simulations applying the double-moment bulk scheme.  相似文献   

Silicon isotopic composition of dissolved silicon and suspended particulate matter in the Yellow River, China, with implications for the global silicon cycle   总被引：2，自引：0，他引：2  

T.P. Ding  J.F. Gao  S.H. Tian  H.B. Wang 《Geochimica et cosmochimica acta》2011,75(21):6672-6689

The silicon isotopic composition of dissolved silicon and suspended particulate matter (SPM) were systematically investigated in water samples from the mainstem of the Yellow River and 4 major tributaries. The SPM content of the Yellow River varied from 1.4 to 38,560 mg/L, averaging 3568 mg/L, and the δ³⁰Si of suspended particulate matter (δ³⁰Si_SPM) varied from 0.3‰ to −0.4‰, averaging −0.02‰. The major factors affecting the SPM content and the δ³⁰Si_SPM values in the Yellow River were inferred to be the mineralogical, chemical and isotopic characteristics of the sediments from the Loess Plateau and a combination of the climate and the flow discharge of the river.The major ions in the Yellow River water were Na⁺, Ca²⁺, Mg²⁺, HCO₃⁻, SO₄²⁻ and Cl⁻. High salt concentration was observed in samples from the middle and lower reaches, likely reflecting the effects of evaporation and irrigation because the Na⁺, Mg²⁺, SO₄²⁻ and K⁺ concentrations were correlated with the Cl⁻ concentration. The dissolved Si concentration (D_Si) increased downstream, varying from 0.016 to 0.323 mM. The δ³⁰Si of dissolved Si (δ³⁰Si_Diss) varied from 0.4‰ to 2.5‰, averaging 1.28‰. The major processes controlling the D_Si and δ³⁰Si_Diss of the Yellow River are (a) the weathering of silicate rocks, (b) the formation of phytoliths in plants, (c) the evaporation of water from and the addition of meteoric water to the river system, which only affects concentrations, (d) the adsorption and desorption of aqueous monosilicic acid on iron oxide, and (e) the dissolution of phytoliths in soils.The D_Si and δ³⁰Si_Diss values of global rivers vary spatially and temporally in response to changes in climate, chemical weathering intensity and biological activity. The moderately positive δ³⁰Si_Diss values observed in the Yellow River may be attributed to the higher rates of chemical weathering and biological activities that have been observed in this catchment in comparison with those of other previously studied catchments, excluding the Yangtze River. Human activities may also potentially influence chemical weathering and biological activities and affect the D_Si and δ³⁰Si_Diss values of the major rivers of the world. Further river studies should be performed to gain a better understanding of the global Si isotope budget.  相似文献   

Determination of Ni(II) uptake mechanisms on mordenite surfaces: A combined macroscopic and microscopic approach   总被引：2，自引：0，他引：2  

Shitong Yang  Xiaoli Tan  Jinzhou Du  Xiangke Wang 《Geochimica et cosmochimica acta》2011,75(21):6520-6534

  相似文献   

遥感地质勘查技术与应用研究   总被引：14，自引：0，他引：14  

王润生  陈微  杨苏明  张瑞江  葛大庆  张晓坤  张振华  王品清  郭小方  李丽  熊盛青  聂洪峰  梁树能  齐泽荣  杨金中  闫柏琨  赵福岳  范景辉  童立强  林键  甘甫平 《地质学报》2011,85(11):1699-1743

遥感的发展极大地拓宽了人类的视野和视觉能力,以其宏观性、综合性、多尺度、多层次的特点,已成为地质研究和地质勘查不可缺少的技术手段,在地质调查、矿产勘查、地质环境评价、地质灾害监测和基础地质研究等方面都发挥了越来越大的作用.随着传感器分辨率(空间、光谱、时间、辐射)的不断提高,特别是高光谱和干涉雷达技术的发展,不仅极大地...  相似文献   

Geochemistry of Palaeozoic marine petroleum from the Tarim Basin, NW China: Part 3. Thermal cracking of liquid hydrocarbons and gas washing as the major mechanisms for deep gas condensate accumulations   总被引：2，自引：0，他引：2  

Shuichang Zhang  Jin Su  Xiaomei Wang  Guangyou Zhu  Haijun YangKeyu Liu  Zhenxi Li 《Organic Geochemistry》2011,42(11):1394-1410

The Lunnan Lower Uplift in the Tarim Basin, NW China contains a composite petroleum system with mainly biodegraded heavy oil in the west, normal oil in the center and gas condensate in the east. Twenty-three gas samples and 37 oil samples taken from three major hydrocarbon bearing intervals in the Lunnan lower bulge were analyzed for their stable carbon isotopes and molecular biomarkers. On the basis of their isotopic compositions, biomarkers, especially diamondoids, and integrating the physical properties of the hydrocarbons including densities, GOR and PVT relationships, it has been concluded that the recently discovered deep (6500 m) eastern Lungu giant Ordovician gas condensate pool with an estimated reserve of 723 million bbl oil equivalent is a secondary hydrocarbon accumulation derived from the mixing of an early formed oil and a late formed gas. The extremely dry gases with a gas dryness of >0.98 were derived from thermal cracking of crude oils and charged to an existing oil reservoir causing extensive gas washing and secondary alteration. Compared with most of the hydrocarbons in the Lunnan area, the gas from the eastern Lungu gas condensate pool has a heavier carbon isotopic composition, higher dryness and a higher maturity level. The unique physical, chemical and isotopic compositions of the gas condensate are believed to be a direct result of gas flushing of an early formed eastern Lungu oil pool by a late formed dry gas from oil cracking. The eastern Lungu gas condensate pool is presently characterized by containing “dry gas, heavy oil, abundant aromatics and high wax”.  相似文献   

U–Pb and Re–Os geochronology and geodynamic setting of the Dabaoshan polymetallic deposit, northern Guangdong Province, South China     

Lei Wang  Mingan Hu  Zhen Yang  Wenjun Qu  Jinlong Xia  Kaixu Chen 《Ore Geology Reviews》2011,43(1):40-49

The Dabaoshan polymetallic deposit in northern Guangdong Province contains iron, copper, lead, zinc, molybdenum, tungsten and sulfur mineral resources. Porphyry-type Mo(W) and skarn-type Mo-W mineralization occurs along the internal and external contact zones of the granodioritic porphyry, respectively. LA-ICP-MS U–Pb dating of zircons from two granodioritic porphyry samples yielded a weighted mean ²⁰⁶Pb/²³⁸U age of 175.8 ± 1.5 Ma (MSWD = 0.037) and 175.0 ± 1.7 Ma (MSWD = 0.41). They can be pooled together to yield a combined weighted age of 175.4 ± 1.6 Ma (MSWD = 0.26), which is interpreted as the emplacement age of the granodioritic porphyry. Re–Os dating of three molybdenite samples from porphyry and skarn ores yielded consistent model ages of 163.2 ± 2.3 Ma to 165.2 ± 2.4 Ma, with a weighted mean of 163.9 ± 1.3 Ma (MSWD = 0.81), which is the age of Mo–W mineralization. These ages are consistent with the molybdenite Re–Os model age (164.7 ± 3 Ma) measured by Mao et al. (2004a) for the stratiform Cu–Pb–Zn orebody, and they can yield a weighted mean of 164.0 ± 2.5 Ma (MSWD = 0.16). This implies that Mo–W and Cu–Pb–Zn mineralization in the Dabaoshan polymetallic deposit are the products of one mineralization event. The mineralization in the deposit coincides closely with that of Mo-polymetallic mineralization (164–149 Ma) elsewhere in the Nanling region, comprising an important polymetallic metallogenic belt of south China, and corresponds to the second episode of Mesozoic metallogenesis in South China. Combined with previous studies, we suggest that the Dabaoshan polymetallic deposit is related to post-collisional lithosphere extension in the Nanling region of South China. Geological data and Pb isotopic evolution diagrams, together with stable isotopic data of fluid inclusions (δ¹⁸O = − 3.75–7.0‰, δD = − 50.7 to − 56.1‰) and ore sulfides (δ³⁴S = − 2–3‰), suggest a genetic relationship between the Dabaoshan polymetallic deposit, the granodioritic porphyry and the dacitic porphyry. These data, combined with the Re content (64.7 to 102.4 ppm) of molybdenite, indicate that the ore-forming components were derived from mixed crustal and mantle sources.  相似文献   

Holocene monsoon climate documented by oxygen and carbon isotopes from lake sediments and peat bogs in China: a review and synthesis   总被引：1，自引：0，他引：1  

Jiawu Zhang  Fahu Chen  Jonathan A. Holmes  Hui Li  Xiaoyan Guo  Junlan Wang  Shuang Li  Yanbin Lü  Yan Zhao  Mingrui Qiang 《Quaternary Science Reviews》2011,30(15-16):1973-1987

There has been much recent debate about Holocene climate variation in the monsoon region of China, especially the temporal pattern of variations in precipitation, the time-transgressive nature of the Holocene precipitation maximum, and the extent to which variations in regions influenced by the Indian Summer Monsoon (ISM) and the East Asian Summer Monsoon (EASM) have been synchronous. We summarize and compare carbonate oxygen-isotope records (δ¹⁸O_carb) from ten lakes within the present-day ISM region. We discuss their paleoclimate significance considering the present-day moisture source, isotopic composition of precipitation and the hydrological setting. The δ¹⁸O_carb records are controlled mainly by the isotopic composition of lake water, which in turn is a function of regional Precipitation/Evaporation (P/E) balance and the proportion of precipitation that is monsoon-derived. We normalized the δ¹⁸O_carb data and used these records to generate an integrated moisture index. This index, along with oxygen-isotope records from speleothems and carbon-isotope records (δ¹³C_org) from peats within the monsoon region, suggests that Holocene climate was broadly synchronous across the monsoon region and, within the limits of accuracy of the existing age models, provides no strong evidence for previously-proposed anti-phasing of the ISM and the EASM. Stable-isotope records from lake sediments and peat bogs have excellent potential for providing high-quality paleoclimate data for monsoon Asia, and complement high-resolution speleothem sequences, which are only found in certain localities.  相似文献   

Mercury fluxes from air/surface interfaces in paddy field and dry land   总被引：3，自引：0，他引：3  

Jinshan ZhuDingyong Wang  Xiao LiuYutong Zhang 《Applied Geochemistry》2011,26(2):249-255

In order to provide insight into the characteristics of Hg exchange in soil/water-air surface from cropland (including paddy field and dry land), Hg fluxes were measured in Chengjiang. Mercury fluxes were measured using the dynamic flux chamber method, coupled with a Lumex® multifunctional Hg analyzer RA-915⁺ (Lumex Ltd., Russia). The Hg fluxes from paddy field and dry land were alternatively measured every 30 min. Data were collected for 24-48 h once per month for 5 months. Mercury fluxes in both fields were synchronously measured under the same conditions to compare Hg emissions between paddy field and dry land over diurnal and seasonal periods and find out what factors affect Hg emission on each surface. These results indicated that air Hg concentrations at the monitoring site was double the value observed at the global background sites in Europe and North America. The Hg release fluxes were 46.5 ± 22.8 ng m⁻² h⁻¹ in the warm season, 15.5 ± 18.8 ng m⁻² h⁻¹ in the cold season for dry land, and 23.8 ± 15.6 ng m⁻² h⁻¹ in the warm season, 6.3 ± 11.9 ng m⁻² h⁻¹ in the cold season for paddy field. Solar radiation is important in the emission of Hg over both sites. Hg exchange at the soil/air and water/air interfaces showed temporal variations. The amount of Hg emission from dry land was higher than that from the paddy field, and the emission in daytime was higher than that at night. Moreover, Hg emissions from land covered by crops, was lower than that for bare land.  相似文献