论晋北石炭二叠系紫色高岭石粘土的成因   总被引：3，自引：0，他引：3  

刘长龄  王双彬 《岩石学报》1987,3(2)

晋北地区石炭二叠系煤层中与四号及九号煤伴生的含有机质的软质耐火粘土,即高岭石粘上,俗称紫矸或紫木节。对紫矸的成因过去有两种看法:(1)原生沉积的;(2)后期风化残积“由煤变来的”。笔者认为除这两个因素同时存在外,还与成岩后生作用中有机酸的淋滤和高岭石的重结晶、有序化等有关,尤其是后期风化表生作用使有机质氧化淋滤去SiO_2形成一水软铝石、褪色、溶蚀多孔、质地疏松,形成今日所见紫色高岭石粘土。  相似文献   

Vulnerability of groundwater in Quaternary aquifers to organic contaminants: a case study in Wuhan City,China   总被引：5，自引：0，他引：5  

Yanxin Wang  Broder J. Merkel  Yilian Li  Hui Ye  Surong Fu  Dana Ihm 《Environmental Geology》2007,53(3):479-484

More than 30 organic contaminants were detected in shallow groundwaters at Wuhan, the largest city in central China. Seriously contaminated groundwaters were from densely populated, industrial and commercial areas. Abnormal concentrations were found in groundwater from Hankou, downtown Wuhan: trimethylbenzene up to 29 μg/L, tetramethylbenzene up to 866 μg/L, and trichloroethene up to 9.5 μg/L. Benzene, Toluene, Ethylene and Xylene (BTEX) contamination of groundwater is serious and widespread at Wuhan, ranging between 0.14 and 25.0 μg/L. Considering the hydrogeological conditions of most Chinese cities, DRAMIC, a modified version of the widely used DRASTIC model, was proposed by the authors for assessing vulnerability of groundwater to contamination. The factors D, R, A and I in DRAMIC model are the same as in DRASTIC. The factor topography is ignored. The factor soil media is substituted by a new factor aquifer thickness (M) and the factor hydraulic conductivity of the aquifer by a new factor impact of contaminant (C). The equation for determining the DRAMIC Index is: DRAMIC = 5D _R + 3R _R + 4A _R + 2M _R + 5I _R + 1C _R. The calculated DRAMIC Index can be used to identify areas that are more likely to be susceptible to groundwater contamination relative to each other. The higher the DRAMIC Index is, the greater the groundwater pollution potential. Applying DRAMIC, a GIS-based vulnerability map for Wuhan city was prepared. Interestingly, places such as downtown Hankou, where enhanced concentrations of BTEX have been detected, correspond quite well with those with higher DRAMIC ratings.  相似文献   

Effect of system variables and particle size on physical characteristics of air sparging plumes     

Daniel M. Baker  Craig H. Benson 《Geotechnical and Geological Engineering》2007,25(5):543-558

Air was injected through a well in a thin transparent tank filled with saturated glass beads to study how the size and air saturation of air sparging plumes are affected by particle size and gradation; operational parameters such as injection pressure, well depth, injection pressure pulsing; and well outlet configuration. V-shaped air plumes with an apex between 40° and 60° were obtained for all tests. The air pressure required to initiate sparging agreed closely with the sum of the air entry pressure and the hydrostatic pressure, with higher initiation pressures required in the fine and well-graded beads. Higher air flow rates and air saturations were obtained in coarser beads at a given pressure, and the variation in flow rate was consistent with estimated air permeabilities. Peak average air saturations were 28–56% for the coarse-medium beads, 10% for the well-graded beads, and 8% for the fine beads. Air saturation and the radius of influence increased modestly (<40%) as the normalized injection pressure exceeded 0.1. Radius of influence increased by approximately a factor of two as the well depth increased, but leveled off once the ratio of radius of influence to well depth reached 0.60–1.05. Pulsing of injection pressure had no effect on the initiation pressure, air flow rate, or air saturation, but increased the size of the air plume and the radius of influence slightly (<15%). Well outlet configuration had only a slight affect the radius of influence (<10%), air saturation (<10%), or air flow rate (<12%). Dye testing showed that water surrounding the air plume circulated during continuous and pulsed sparging. However, pulsed sparging resulted in greater and more defined circulation of water within and adjacent to the air plume, which should reduce mass transfer limitations during sparging.  相似文献   

Response of littoral chironomid communities and organic matter to late glacial lake—level,vegetation and climate changes at Lago dell’Accesa (Tuscany,Italy)     

Laurent Millet  Boris Vannière  Valérie Verneaux  Michel Magny  Jean Robert Disnar  Fatima Laggoun-Défarge  Anne Véronique Walter-Simonnet  Gilles Bossuet  Elena Ortu  Jacques-Louis de Beaulieu 《Journal of Paleolimnology》2007,38(4):525-539

This study focuses on the response of lacustrine littoral chironomid communities to late glacial changes in limnological, environmental and climate conditions in the Mediterranean context. Late glacial chironomid (Diptera: Chironomidae) assemblages, organic petrography and geochemistry were analysed in a sediment core from the littoral zone of Lago dell’Accesa (Tuscany, Italy), where the lake-level fluctuations and the vegetation history have been previously reconstructed. Comparison of the chironomid stratigraphy to other proxies (pollen assemblages, organic petrography and geochemistry, lake-level) and regional climate reconstruction suggested the predominant influence of lake-level changes on the littoral chironomid fauna. The main lowering events that occurred during the Oldest and the Younger Dryas were followed by higher proportions of taxa typical of littoral habitats. A complementary study of organic matter suggested the indirect impact of lake-level on the chironomids through changes in humic status and habitat characteristics, such as the type of substrate and aquatic macrophyte development. Several chironomid taxa, such as Glyptotendipes, Microtendipes and Cricotopus type patens, were identified as possible indicators of low lake-level in the late glacial records. Nevertheless, this study suggested that parallel analyses of organic matter and chironomid assemblages may be needed to circumvent misinterpretation of littoral chironomid assemblage stratigraphy. There was a weak response of the chironomid assemblages to small lake-level lowerings that corresponded to the Older Dryas and Preboreal oscillations. A higher level of determination, e.g. to the species group level, may be necessary to increase the sensibility of the indicators to lake-level changes.  相似文献   

我国砷中毒病区的环境特征研究   总被引：18，自引：0，他引：18  

林年丰  汤洁 《地理科学》1999,19(2):135-139

我国饮水型砷中毒的流行屡见报道,台湾嘉南,新疆奎屯,内蒙古河套及山西大同等地是我国几个有代表性的病区。病区多为河湖相和滨海相沉积,粘土,粘土质淤泥和有机淤泥层发育,为富含有要质的还原环境,地下水中的含量一般为０．２－０．６ｍｇ／Ｌ。有时还有氟,腐殖酸,甲基胂酸和某些烷烃类等的有害有机化合物。  相似文献   

塔里木盆地库鲁克塔格奥陶系牙形石色变指标与有机质成熟度的关系     

李金龙  王璞珺  孙少波  贾军涛  张艳 《新疆地质》2006,24(4):373-376,I0013

应用牙形石色变指标(CAI)对塔里木盆地孔雀河斜坡东北段南雅尔当山剖面奥陶系有机质成熟度进行了研究,得出的结果是南雅尔当山却尔却克组产出的牙形石色变指标CAI值为2~2.5,有机质处于成熟阶段.综合研究认为,本区奥陶系烃源岩在中奥陶世逐渐进入生烃门限并快速成熟;在奥陶纪末达到经历的最大古地温,顶部为80℃,底部为180℃,之后遭受抬升剥蚀,区域剥蚀量在2 300 m左右.本区奥陶系烃源岩存在3种生烃类型:第Ⅰ种为南雅尔当山型,为非有效烃源岩;第Ⅱ种为群克1井部分生烃型,奥陶纪末抬升剥蚀后埋深在2 500 m以上的烃源岩(Ⅱ-1型)停止生烃,埋深在2 500 m以下的烃源岩(Ⅱ-2型)持续生烃;第Ⅲ种为二次生烃型,当中新生代的快速沉积使Ⅱ-1型烃源岩顶部埋深达到3 200 m时,相同层位的烃源岩达到经历的最大古地温,开始二次生烃,生烃潜力最大.  相似文献   

初论塔里木盆地砂岩储层中SiO₂的溶蚀类型及其机理   总被引：8，自引：2，他引：8       下载免费PDF全文

钟大康  朱筱敏  周新源  王招明 《地质科学》2007,42(2):403-414

根据显微镜观察,塔里木盆地砂岩储层中SiO₂溶蚀分为石英颗粒边缘溶蚀、次生加大边溶蚀和交代溶蚀。通过对石英颗粒和加大边溶蚀特征及其与粘土矿物组合、与碳酸盐胶结、与古油藏破坏以及现今油田水中Si离子含量等关系的综合研究,这些SiO₂溶蚀可能存在两种机理:碱性环境下的SiO₂溶蚀和有机酸(烃类微生物降解产生的有机酸以及有机质成熟产生的有机酸)引起的SiO₂溶蚀。第一种溶蚀类型较普遍,但程度微弱;第二种溶蚀类型主要发生在古油藏破坏和有机质成熟过程中,这种溶蚀较强烈但很局限。SiO₂的溶蚀作用可以为油气提供一定量的储集空间,这对于深埋的时代较老的志留-泥盆系储层具有重要意义。在古油藏中尽管烃类已经充注储层孔隙,但只要孔隙中存在有机酸或碱性孔隙水,SiO₂的溶蚀和石英次生加大的胶结等作用仍可进行。  相似文献   

Organic geochemistry and petrology of barren and Mo–Ni–PGE mineralized marine black shales of the Lower Cambrian Niutitang Formation (South China)     

Bohdan K&#x;íbek  Ivana Sýkorov  Jan Pa&#x;ava  Vladimír Machovi 《International Journal of Coal Geology》2007,72(3-4):240-256

Marine black shales of the Lower Cambrian Niutitang Formation in southern China host Mo–Ni–platinum group elements (PGE) mineralization confined to a phosphate- and pyrite-rich stratiform body (max. 20-cm thick). The H/C atomic ratio, carbon isotopic composition, FTIR spectra of bulk organic matter, and spectra of extractable part of organic matter indicate similar sources and thermal evolution of organic matter in barren and mineralized black shales.The morphology and relative abundance of organic particles in barren and mineralized shales are different. In barren black shales, organic particles comprise only elongated bodies and laminae 2–10 μm across or elongated larger bodies (> 10 μm) with R_max = 2.96–5.21% (Type I particles). Mineralized black shales contain Type I particles in rock matrix (90–95 vol%), small veinlets or irregular organic accumulations (Type II particles, 1–5 vol%) that display weak to well developed mosaic texture and a variable reflectance (R_max = 3.55–8.65%), and small (< 1 to 5 μm) rounded or irregular Type III organic particles (1–4 vol%) distributed within phosphate nodules and sulphide rip-up clasts. Type III particles show similar reflectance as particles of Type I in rock matrix. Type I particles are interpreted as remnants of in situ bacterially reworked organic matter of cyanobacteria/algal type, Type II as solidified products or oil-derived material (migrabitumen), and Type III particles as remnants of original organic matter in phosphatized or sulphidized algal/microbial oncolite-like bodies. Equivalent vitrinite reflectances of Type I and III particles in barren and mineralized rocks are similar and correspond to semi-anthracite and anthracite. Micro-Raman spectra of organic particles in rocks display a wide belt in the area of 1600 cm^− 1 (G belt) and approximately the same belt in the area of 1350 cm^− 1 (D belt). The ratio of integrated areas of the two belts correlate with R_max values.The Mo–Ni–PGE mineralized body is interpreted as to represent a remnant of phosphate- and sulphide-rich subaquatic hardground supplied with organic material derived from plankton and benthic communities as well as with algal/microbial oncolite-like bodies that originated in wave-agitated, shallow-water, nearshore environment.  相似文献   

铀矿地质样品中有机碳的测定     

孔玉清 《铀矿地质》1998,14(2):115-118

用盐酸预处理岩矿样品以驱除样品中的碳酸盐碳;滤出酸不溶物并洗净,待干燥后置入900-1000℃的管式炉中,在富氧气流中灼烧,有机碳被氧化成CO2由烧碱石棉吸收后称重,根据烧碱石棉管的增重计算有机碳的含量。对含有机碳为0．23％的样品进行10次测定,标准偏差为0．0116％,变异系数为5．04％。  相似文献   

The influence of organic debris on channel morphology and bedload transport in a New Zealand forest stream     

M. Paul Mosley 《地球表面变化过程与地形》1981,6(6):571-579

The behaviour and form of, and bedload sediment transport through, a 3.5 m wide forest stream have been monitored for nearly three years. Bedload transport is highly episodic and spatially variable, and is controlled less by water discharge than by sediment availability. Organic debris in the channel creates temporary base levels and sites at which coarse sediment may remain stored for long periods; collapse or disruption of log and debris jams makes sediment available for transport in only a small proportion of the runoff events that are actually competent to move the material. Even then, sediment travels only a short distance before being redeposited, frequently behind debris accumulations further downstream. Rates of sediment transport during a given runoff event can vary markedly over short distances along the stream, again depending on whether sediment was made available for transport by log jam collapse upstream. Organic debris is therefore a major constraint on the application of physical laws and theories to explaining sediment movement in, and the morphology of, this stream.  相似文献