Elemental characteristics of lacustrine oil shale and its controlling factors of palaeo-sedimentary environment on oil yield: a case from Chang 7 oil layer of Triassic Yanchang Formation in southern Ordos Basin

As an important unconventional resource, oil shale has received widespread attention. The oil shale of the Chang 7 oil layer from Triassic Yanchang Formation in Ordos Basin represents the typical lacustrine oil shale in China. Based on analyzing trace elements and oil yield from boreholes samples, characteristics and paleo-sedimentary environments of oil shale and relationship between paleo-sedimentary environment and oil yield were studied. With favorable quality, oil yield of oil shale varies from 1.4% to 9.1%. Geochemical data indicate that the paleo-redox condition of oil shale’s reducing condition from analyses of V/Cr, V/(V + Ni), U/Th, δU, and authigenic uranium. Equivalent Boron, Sp, and Sr/Ba illustrate that paleosalinity of oil shale is dominated by fresh water. The paleoclimate of oil shale is warm and humid by calculating the chemical index of alteration and Sr/Cu. Fe/Ti and (Fe + Mn)/Ti all explain that there were hot water activities during the sedimentary period of oil shale. In terms of Zr/Rb, paleohydrodynamics of oil shale is weak. By means of Co abundance and U/Th, paleo-water-depth of oil shale is from 17.30 to 157.26 m, reflecting sedimentary environment which is mainly in semi deep–deep lake facies. Correlation analyses between oil yield and six paleoenvironmental factors show that the oil yield of oil shale is mainly controlled by paleo-redox conditions, paleoclimate, hot water activities, and depth of water. Paleosalinity and paleohydrodynamics have an inconspicuous influence on oil yield.     

Precipitation rate climatology related to different cloud types using satellite imagery over Iran

Cloud types have a substantial influence on precipitation. This paper presents a study of the monthly variations of daytime different cloud types over Iran using data collected from Moderate-resolution Imaging Spectroradiometer (MODIS) aboard Terra during 2001–2015, MODIS aboard Aqua during 2002–2015, International Satellite Cloud Climatology Project (ISCCP) H-series cloud type data during 2001–2009 and precipitation rate associated with different cloud types using Tropical Rainfall Measuring Mission (TRMM) satellite products during 2001–2009. Different cloud types were determined using MODIS cloud optical thickness and cloud top pressure data based on ISCCP algorithm. The results showed that stratocumulus and cumulus clouds have maximum occurrence frequency over marine areas especially southern seas. The maximum frequency of nimbostratus and deep convective occurrence occurred over mountainous regions particularly at the time of Aqua overpass and cirrus and cirrostratus are observed over southeast of Iran during warm months due to monsoon system. Altostratus cloud is extended in each month except January, at the time of Terra overpass while nimbostratus is seen at the time of Aqua overpass during warm months in the study area. Cumulus and altocumulus clouds have shown remarkable frequency in all months especially over marine regions during warm and fall months. The higher value of precipitation rate is related to altostratus with a rate approximately 7 mm/h at the time of Terra overpass during April. Altostratus has the maximum recorded precipitation rate except in Nov., Dec., Sep., and Jan. at the time of Terra overpass, whereas the maximum precipitation rate is linked to nimbostratus cloud activity (up to 5 mm/h) except for March, April, and Sep. at the time of Aqua overpass. Deep convective (up to 1.32 mm/h), cirrostratus (up to 1.11 mm/h), and cirrus (0.02 mm/h) are observed only in warm months. The results were compared with ISCCP cloud types so that precipitation rate classified from low to high and Spearman rank correlation was calculated. The results showed good agreement between these two cloud type data; however, there were few notable difference between them.     

Effect of Lime Stabilized Soil Cushion on Strength Behaviour of Expansive Soil

An experimental investigation was undertaken to study the effects of lime-stabilized soil-cushion on the strength behavior of expansive soil. In the present investigation, a series of laboratory tests (Unconfined compression tests and CBR tests) were conducted on both expansive soil alone and expansive soil cushioned with lime-stabilized non-expansive cohesive soil. Lime contents of 2, 4, 6, 8 and 10% by dry weight of cohesive non-swelling soil was used in the stabilized soil cushion. Both expansive soil and lime stabilized soil cushion were compacted to Standard Proctor’s optimum condition with thickness ratio 2:1. Tests on cushioned expansive soils were conducted at different curing and soaking periods i.e., 7, 14, 28 and 56 days. The test results revealed that maximum increase in strength was achieved after 14 days of curing or soaking period with 8% of lime content.     

Isotopic Characteristics and Key Factors Favoring the Formation of Fuwan Super-large Silver Deposit in Guangdong Province

Rb-Sr isochron age of fluid inclusions in quartz from the Fuwan super-large silver deposit is 68 - 6 Ma, the silver deposit is characterized by high μ values (10.67 - 10.95 ), which are much higher than those of the ore-hosted Paleozoic strata and are close to those of ores hosted in the Proterozoic metamorphic basement in western Guangdong Province. Based on the Pb isotopic characteristics, coupled with much high background silver contents (200-1000ng/g) in the Proterozoic basement and relatively low silver contents in the Paleozoic strata in the region of the Sanshui Basin, it is concluded that the ore-forming material of the super-large silver deposit came mainly from the old basement. The super-large silver deposit related genetically to the intense volcanic activities during the Upper Cretaceous to Eogene. The formation of the Fuwan super-large silver deposit is controlled by the following favorable geological conditions : ( 1 ) The intersection of deep faults and contemporaneous faults at the margin of the Sanshui Basin led to the formation of an excellent structure as passageway for ore fluids; (2) The special ore-hosted rock association forms a ore gathering-trap structure that favors the precipitation of ore; (3) The silver-rich old basement, multi-stage mineralization and multi-episode volcanic activities which constitute a geothermal convection system.     

东南沿海地震活动特征量

1970年以来,东南沿海地区经历了上世纪末以来明显的第Ⅴ活跃幕(或轮回)平静和活跃时段,本文通过分析研究这两个时段地震活动在时空强上的差异性,定量提取其活动演化过程参量,为该区未来地震活动期判定提供相对定量的参考依据。     

Quantitative assessment of gas washing of oils in the Tazhong area of the Tarim Basin,Northwest China

Gas washing has been known in the Tazhong area of the Tarim Basin, but its quantitative assessment has not yet been reported. Here the influence of gas washing fractionation in the area was discussed based on the gas chromatogram data of 68 oils and the results of the mixing experiments of a black oil and a condensate. The results show that the intensity of gas washing fractionation decreased generally from northern to southern part and vertically from deep reservoirs to shallow reservoirs. The gas washing fractionation was mainly controlled by fault systems in this area, with the increase of n-alkane mass depletion positively correlated to the number and scale of faults. Gas washing fractionation appears to have affected the hydrocarbon property, and as a result the diversity of the crude oils is markedly controlled by gas washing. In addition, the occurrence of waxy oil in this area may be resulted from multiple factors including gas washing, mixed filling and migration fractionation. Supported by National Basic Research Program of China (Grant No. 2006CB202303) and the National Natural Science Foundation of China (Grant No. 40672091)     

Evaluation of an automated EA-IRMS method for total carbon analysis of atmospheric aerosol at HEKAL

Comprehensive atmospheric studies have demonstrated that carbonaceous particles are one of the main components of atmospheric aerosols over Europe. The aim of our study was to establish an automated elemental analyser interfaced to a stable isotope mass spectrometer (EA-IRMS) method at the Hertelendi Laboratory of Environmental Studies (HEKAL), as a suitable method of quantification of total carbon mass in individual PM_2.5 aerosol samples. Total carbon (TC) mass and simultaneous stable isotopic ratios were determined for both test standard and genuine aerosol samples. Finally, the results were compared to the ones obtained independently by an alternative sealed tube combustion method developed previously at HEKAL. The TC recovery tests of standard material prepared by the sealed tube method confirmed at least a carbon recovery yield of 92% for a broad range of carbon mass (100–2000 μg). The stable isotopic results confirmed that sealed tube method is reproducible and suitable to be used as a reference to verify our new EA-IRMS method. The EA-IRMS TC measurements of genuine aerosols gave on average 3% higher carbon recovery yield, relative to the uncorrected results of the sealed tube method. The comparison of the stable isotopic results by the two methods for aerosols also showed minimal differences. Consequently, the possibility of simultaneous TC and stable isotopic analyses makes the EA-IRMS method a very attractive alternative for continuous measurement of aerosols, with an accuracy and reliability similar to other commercial devices.     

Summer distribution and geochemical composition of suspended-particulate matter in the east china sea

The distribution and geochemical composition of suspended-particulate matter (SPM) in the East China Sea (ECS) were investigated during the summer period of high continental runoff to elucidate SPM sources, distribution and cross-shelf transport. The spatial variability of SPM distribution (0.3–6.5 mg l⁻¹) and geochemical composition (POC, Al, Si, Fe, Mn, Ca, Mg and K) in the ECS was pronounced during summer when the continental fluxes of freshwater and terrestrial materials were highest during the year. Under the influences of Changjiang runoff, Kuroshio intrusion, surface production and bottom resuspension, the distribution generally showed strong gradients decreasing seaward for both biogenic and lithogenic materials. Particulate organic carbon was enriched in surface water (mean ∼18%) due to the influence of biological productivity, and was diluted by resuspended and/or laterally-transported materials in bottom water (mean 9.4%). The abundance of lithogenic elements (Al, Si, Fe, Mn) increased toward the bottom, and the distribution correlations were highly significant. Particulate CaCO₃ distribution provided evidence that the SPM of the bottom water in the northern part of the study area was likely mixed with sediments originally derived from Huanghe. A distinct benthic nepheloid layer (BNL) was present in all seaward transects of the ECS shelf. Sediment resuspension may be caused by tidal fluctuation and other forcing and be regarded as the principal agent in the formation of BNL. This BNL was likely responsible for the transport of biogenic and lithogenic particles across or along the ECS shelf. Total inventories of SPM, POC and PN are 46, 2.8 and 0.4 Tg, respectively, measured over the total area of 0.45 × 10⁶ km² of the ECS shelf. Their mean residence times are about 27, 13 and 11 days, respectively. The inventory of SPM in the water column was higher in the northernmost and southernmost transects and lower in the middle transects, reflecting the influences of terrestrial inputs from Changjiang and/or resuspended materials from Huanghe deposits in the north and perhaps from Minjiang and/or Taiwan’s rivers in the south. The distribution and transport patterns of SPM and geochemical elements strongly indicate that continental sources and cross-shelf transport modulate ECS particulate matter in summer.     

Vertical distributions of aerosol optical properties during haze and floating dust weather in Shanghai

A comparative study on the vertical distributions of aerosol optical properties during haze and floating dust weather in Shanghai was conducted based on the data obtained from a micro pulse lidar.There was a distinct difference in layer thickness and extinction coefficient under the two types of weather conditions.Aerosols were concentrated below 1 km and the aerosol extinction coefficients ranged from 0.25 to 1.50km^-1 on haze days.In contrast,aerosols with smaller extinction coefficients(0.20 0.35 km^-1) accumulated mainly from the surface to 2 km on floating dust days.The seasonal variations of extinction and aerosol optical depth（AOD） for both haze and floating dust cases were similar greatest in winter,smaller in spring,and smallest in autumn.More than 85%of the aerosols appeared in the atmosphere below 1 km during severe haze and floating dust weather.The diurnal variation of the extinction coefficient of haze exhibited a bimodal shape with two peaks in the morning or at noon,and at nightfall,respectively.The aerosol extinction coefficient gradually increased throughout the day during floating dust weather.Case studies showed that haze aerosols were generated from the surface and then lifted up,but floating dust aerosols were transported vertically from higher altitude to the surface.The AOD during floating dust weather was higher than that during haze.The boundary layer was more stable during haze than during floating dust weather.     

综合物探方法在地质灾害调查中的应用研究

介绍了在地质灾害调查中常用的几种物探方法的适用条件和应用范围,并通过实例展示了各种方法的应用效果.结果表明浅层物探方法应用效果显著,在地质灾害调查中具有较好的应用前景.