Analysis of resistivity data obtained from cone penetrometer in contaminated soil layers

In horizontally layered soils of different electrical properties, electrical potential distribution becomes complex and the obtained resistivity data may be limited in reflecting the actual soil profile. Thus the objective of this study was to identify the factors that affect resistivity measurement on the cone penetrometer and further investigate the sensitivity of measured resistivity to different types and concentrations of contaminants at the subsurface level. First, a theoretical resistivity equation was derived to provide a means of computing the geometric factor. The effective volume of measurement on the cone penetrometer was investigated and laboratory soil box tests verified the dominance of partially high resistivity regions within the effective volume of measurement over the apparent resistivity. Such effect was found to lead to possible discrepancies between the recorded resistivity data and the actual depth of measurement. Measurements on contaminated soil layers indicated that resistivity cones are efffective in delineating inorganic contaminants in soils of high water contents, and detecting NAPLs floating above the groundwater table provided that soils adjacent to the plume are not dry of water. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

广西刁江沿岸农田受矿山重金属污染现状与治理对策

刁江流域的源头区域是我国名的矿区，长期以来不合理的矿产资源开发利用行为导致了刁江沿岸农田严重的重金属污染。本选择污染最严重的金洞村农田进行典型调查与分析，根据两个剖面不同深度的重金属含量和形态分析结果，认为该农田受到了严重的As、Pb、Cd、Zn复合污染。由于土壤污染十分严重，建议采取工程治理措施，或改变污染农田利用模式，即根据新的土壤资源特点，设计土地利用模式。     

超临界流体萃取技术在地质样品分析中的应用

综述了分析型超临界流体萃取（ＳＦＥ）技术替代有机溶剂,在地质样品分析中萃取总石油烃,多环芳烃、多氯苯、生物标志物、有机金属化合物的应用,展望了ＣＯ２－ＳＦＥ方法用于地质样品中金属离子测定的前景。     

The first finds of cretaceous belemnites from the Magellan Rise, Pacific Ocean

The occurrence of belemnites in Mesozoic sediments of the Pacific guyots is established for the first time (rostra Dimitobelidae gen. et sp. indet. from the late Campanian-Maastrichtian detrital limestone of the DVGI Guyot, Belemnitella? sp. from oolitic limestone of the Gelendzhik Guyot, which are presumably of the Santonian-Maastrichtian age, and Belemnitidae? gen. et sp. indet. from the Maastrichtian oolitic limestone of the Butakov Guyot, the Magellan Rise). In recent years, fossil cephalopods important in stratigraphic and paleobiogeographic aspects have been found at five guyots of that rise. New data on fossil invertebrates from the study region suggest breaks in the sedimentation here at the terminal Maastrichtian, Paleogene, and initial Neogene time. Possible limits of vertical migration in the tropical Pacific are estimated for the Late Cretaceous belemnites based on preliminary results of the oxygen isotope analysis.     

河流沿岸土壤对上游矿山及矿山开发的环境地球化学响应——以广西刁江流域为例

刁江流域上游的矿山和矿山开发引发了显著的土壤环境地球化学变化,突出表现是沿岸形成了严重的土壤重金属污染带。污染带的分布与近20多年来的洪水淹没区和引水灌溉区呈现高度的一致性。上游地带的土壤污染区有明显的尾砂沉积,污染呈显性状态,而下游地带的尾砂沉积现象不明显,污染表现为隐性。无论是上游还是下游,土壤中的As、Pb、Zn、Cd含量均异常高。水田的犁底层对污染物质具有明显的隔断作用,而旱地淀积层中的污染物含量比较高,对污染物质的隔断作用不明显。污染耕地上生产的玉米中的Cd、Pb、Zn含量和大米中的Cd、Pb含量超过国家食品卫生标准。     

The Potential Endangers of the Tectonic Lake Water Leakage from Dianchi and Water Security

Dianchi or Lake Dian is the largest shallow water lake on the Yunnan-Guizhou Plateau, which is not only crucial to maintain the ecological environments of Kunming, the famous city with four springs, but also contains almost 1.5×10⁹ m³ highly polluted water. The management of the lake pollution and eutrophication will be a long-lasting hard work and the sudden diffusion of such highly polluted water can lead to catastrophic eco-environmental problems. Based on the historical documents, underwater topographic features, regional geological tectonics and the chronology of the sediments, it can be concluded that at one time the water leaked out in Dianchi, which is in consistent with the historical record of 1764 AD. This water leak event resulted in two funnels in the center of Dianchi. The sedimentary feature and the deformation properties indicated that the slope of one funnel collapsed, which means it was blocked, but the other one was under development or in dormancy. When the pressure induced from the water level changed or the earthquakes occurred, the underwater channel could be open or connected, a catastrophic water leakage might be induced. The highly polluted lake water would possibly flow to Lake Fuxian and pollute almost 9% national strategic fresh water resource, resulting in an eco-environmental event and endangering the national water security. Therefore, to monitor the water flowing situation, detect the position and direction of the channel, block the channel and prevent possible lake water leakage are the priority and urgent measurements at present.     

河北开滦矿区晚古生代煤对CO2 和CH4 气体吸附模型探讨

对河北开滦矿区不同变质程度的煤进行了纯CO2和纯CH4气体等温吸附实验,并用Langmuir模型、三参数BET模型和吸附势理论模型（DR,DA）对煤的吸附实验数据进行了拟合,检验了各模型的拟合程度。结果表明：中煤阶烟煤的马家沟矿9号煤（Ro, ran = 1.21%）对CH4和CO2吸附能力比低煤阶烟煤的林南仓矿11号煤（Ro, ran = 0.58%）的吸附能力大;在相同压力下,同一煤样对CO2的吸附能力明显大于对CH4的吸附能力。马家沟矿9号煤对CO2和CH4的等温吸附线具有典型的I型特征,各模型对其吸附行为拟合误差相差很小,可用Langmuir方程描述;林南仓矿煤等温吸附线较复杂,因用Langmuir描述误差较大,应优先选择误差较小的吸附势理论DA模型来描述其吸附行为。9号煤对CH4和11号煤对CO2和CH4的吸附均以单分子层吸附为主。     

羌塘盆地雁石坪地区中-晚侏罗世碳、氧同位素特征与沉积环境分析

通过对雁石坪地区中-上侏罗统碳酸盐岩的碳、氧同位素组成特征分析,认为其原始组分保存良好.在垂向上,碳、氧同位素的变化与沉积相演化和海平面曲线相吻合,说明它们与沉积环境的演化密切相关.结合碳、氧同位素的环境效应分析,认为中侏罗世雀莫错期沉积水体主要以陆源淡水作用为主,沉积环境属陆缘近海湖;布曲期为广海碳酸盐台地环境;夏里期为三角洲-淡化泻湖-潮坪环境.晚侏罗世索瓦早期为高盐度、高水温,相对局限浅海碳酸盐台地环境.中侏罗世至晚侏罗世早期经历了一次完整的海侵-海退旋回和一次海侵过程.     

运用地球化学分析研究潜江凹陷潜江组沉积环境

运用同位素及粘土矿物的沉积地球化学特征在沉积环境方面的指示意义分析了潜江凹陷潜江组硫、碳、氧同位素及粘土矿物,结合层序地层学分析,对其演化规律与沉积环境的关系进行了探讨.认为硫、碳、氧同位素值及粘土矿物的高低变化与气候的变化和沉积环境的变化具有很好的相关性;潜江凹陷潜江组的沉积环境是一个封闭的较高盐度的陆相咸化湖泊沉积环境.     

Implications for Neoarchaean ocean chemistry from primary carbonate mineralogy of the Campbellrand-Malmani Platform, South Africa

The precipitation of calcite and aragonite as encrustations directly on the seafloor was an important platform‐building process during deposition of the 2560–2520 Ma Campbellrand‐Malmani carbonate platform, South Africa. Aragonite fans and fibrous coatings are common in unrestricted, shallow subtidal to intertidal facies. They are also present in restricted facies, but are absent from deep subtidal facies. Decimetre‐thick fibrous calcite encrustations are present to abundant in all depositional environments except the deepest slope and basinal facies. The proportion of the rock composed of carbonate that precipitated as encrustations or in primary voids ranges from 0% to > 65% depending on the facies. Subtidal facies commonly contain 20–35%in situ precipitated carbonate, demonstrating that Neoarchaean sea water was supersaturated with respect to aragonite, carbonate crystal growth rates were rapid compared with sediment influx rates, and the dynamics of carbonate precipitation were different from those in younger carbonate platforms. The abundance of aragonite pseudomorphs suggests that sea‐water pH was neutral to alkaline, whereas the paucity of micrite suggests the presence of inhibitors to calcite and aragonite nucleation in the mixed zone of the oceans.     

渔塘坝富硒硅质岩成因及沉积环境探讨：硅、氧、碳和硫同位素证据

鄂西渔塘坝含碳硅质岩段(P³₁m)为硒矿床的主要赋硒层位,其硅、氧同位素组成δ³⁰Si变化范围为0.5‰~1.8‰（平均1.25‰）;δ¹⁸O为22.7‰~27.1‰ （平均25.3‰）;硅质岩中黄铁矿 δ³⁴S的值变化范围为-27.7‰~-5.65‰,幅度大于20‰;硅质岩层位中方解石样品的δ¹³C值范围为4.19‰~0.52‰。综合研究表明,渔塘坝硅质岩在成因上主要表现为热水沉积特征,成岩温度为45℃,形成于半封闭的浅海至滨浅海（滞留的盆地）缺氧沉积环境。     

墕则村铝土矿沉积特征分析

从铝土矿的矿物成分、化学成分、结构构造、共伴生矿产等方面,阐明了竭则村铝土矿沉积特征,并分析了其形成古地理环境。     

A study of Holocene floodplain particle size characteristics with special reference to palaeochannel infills from the upper Severn basin,Wales, UK

Multiple sedimentary units from floodplain reaches at Welshpool on the upper River Severn and at the confluence of the Afon Tanat and Afon Vyrnwy (mid‐Wales, UK) were examined to ascertain if they have distinctive particle size characteristics. Changes in particle size characteristics and their possible relationship to known human and climatic impacts are also discussed. Ellipse plots of particle size characteristics from the River Severn floodplain at Welshpool show that coarse‐grained outwash deposits can be clearly discriminated from channel margin or palaeochannel sediments. In contrast, at the Afon Tanat–Vyrnwy study reach, this discrimination is not seen so clearly. The relationships between age and particle size characteristics from the most sampled sedimentary environment, palaeochannel infills, were also examined. The data from the River Severn floodplain at Welshpool show that palaeochannel sediments reveal a gradual but clear increase in particle size from the mid‐ to late Holocene towards the present day. Sediments deposited in the period 90–160 years BP are markedly coarser. It is suggested that these changes may be related to the combined effect of land‐use changes, metal mining impacts and changes in flood frequency and magnitude that occurred at this time within the upper Severn basin. In contrast, the particle size characteristics of post Late Devensian/Early Holocene units from Tanat–Vyrnwy palaeochannels were random with no discernible age–size patterns. It is suggested that the non‐systematic grain size distribution may be due to the steeper valley gradients of the Tanat–Vyrnwy system (and by inference higher stream powers) and its relatively narrow valley form enabling more effective coupling between coarser outwash deposits found on and at the edges of hillslopes and the valley floor. Although the two study reaches have undergone comparable environmental change during the Holocene and lie in the piedmont zone of their catchments, palaeochannel units of the same age possess distinctly different characteristics. Intrinsic reach‐scale geomorphic factors would appear to preclude the uniform application of particle size characteristics to determine alluvial response to environmental change. Consequently, care needs to be applied to the use of such data for environmental discrimination because the phenomenon of equifinality means that a specific set of sediment characteristics is not necessarily exclusive to specific fluvial environments in either space or time. Copyright © 2001 John Wiley & Sons, Ltd.     

新疆阿克苏地区早寒武世碳酸盐岩沉积环境:微量元素和碳同位素证据

对出露于塔里木盆地北缘阿克苏地区寒武系纽芬兰统玉尔吐斯组上部和寒武系第二统肖尔布拉克组下部海相沉积碳酸盐岩进行了氧化-还原敏感元素(Mo、V、Cd和U)及稳定C、O同位素的地球化学剖面研究,以探讨早寒武世沉积碳酸盐岩的沉积环境.研究揭示,尤尔美那克剖面肖尔布拉克组底部和下部含有两个δ13C负异常,谷值分别为-2.1‰和...     

贵州草海近21 ka以来有机地球化学记录反映的古环境变化*

草海位于黔滇交界,主要受印度夏季风的影响,其湖沼沉积物记录了中—晚第四纪的环境变化历史,是研究第四纪环境和季风演变的良好载体。本研究选取的南屯NT03钻孔,岩心长405 cm,在放射性碳同位素(AMS¹⁴C)测年基础上建立了年代序列,并进行了沉积物的色差值(L^*)、烧失量(LOI550)、总有机碳(TOC)、碳氮比(C/N)和有机稳定碳同位素(δ13Corg)等古环境替代指标的测试。实验结果显示,L^*、LOI550和TOC等3个有机碳含量指标同步变化,共同指示该钻孔序列经历了3个沉积环境演变阶段,即末次盛冰期晚期(21—15 cal ka BP)河流—冲积相沉积阶段、冰消期至早中全新世(15—4 cal ka BP)高湖面湖泊—沼泽相沉积阶段和晚全新世(4 cal ka BP以来)洪冲积相沉积阶段。近2万年以来草海湖沼面积经历的收缩→扩张→收缩演变过程与石笋氧同位素变化基本吻合,表明季风降雨是引起草海湖泊水体和周边生态系统变化的主要因素。δ13Corg指标变化范围为-29.28‰~-24.19‰,表明草海盆地周围植被组成在末次盛冰期以来C4草本虽然略有增加,但均以C3植物为主。同时,TOC和δ13Corg指标证明了B/A冰消期暖事件对盆地边缘区的湿地泥炭富集起到关键作用,而多指标揭示了近4 ka以来水域变浅并发展成为冲积环境的过程,也可能与石笋记录的夏季风减弱所带来的降水量减少有关。     

辽西下白垩统义县组湖相碳酸盐岩碳氧稳定同位素组成及其沉积环境

通过辽西义县盆地上白垩统义县组湖相碳酸盐岩碳氧稳定同位素组成,分析了赋存热河生物群的义县盆地湖湘沉积环境.该地层序列中碳酸盐岩的δ13C值在-4.825‰～6.870‰之间;δ18O值在-16.190‰～-7.143‰之间,均呈负值,这表明当时水文特征趋于封闭,气候炎热干燥,湖水温度和盐度均较高,火山活动可能是影响义县...     

滇西新近纪植物气孔、碳同位素组成与古环境分析

对滇西腾冲新近纪两种被子植物叶片及其现存对应种的气孔参数和碳同位素组成的综合分析表明:当时的大气CO2浓度略高于现在水平;化石种的碳同位素分馏值高于现存对应种,但水分利用效率低于现存对应种;这证明当时的气候条件比当前更为温暖湿润。受新生代全球气候变冷和喜马拉雅运动的影响,该盆地一方面受印度洋季风的影响增强,干湿季节交替明显;另一方面受地形地貌影响,沿袭了温暖湿润的气候条件。      

Palynofacies and organic geochemistry studies of organic matter from a wetland system of southern Brazil influenced by different hydrological regimes in the Quaternary

The main goal of this study was to quantitatively and qualitatively characterize the sedimentary organic matter (OM) and demonstrate the usefulness of geochemistry and palynofacies analysis for obtaining paleoenvironmental data for the Holocene in southernmost Brazil. The results indicate that during the time interval from 10,586 cal yr BP to the present, the study area housed a wetland characterized by different hydrologic regimes. The basal peaty deposits correspond to a phase influenced mainly by the groundwater table, whereas the upper deposits composed of silty organic mud indicate fluvial influence related to river overflow events. In a similar manner, the TOC (total organic carbon) and TS (total sulfur) contents are higher in the basal portion of the profile, decreasing toward the top. These findings could be related to granulometry alterations that are linked to hydrologic regimes or anthropogenic interference in the landscape dynamics. Anomalous TS content observed in one of the samples might be due to an external source and perhaps related to the presence of thermal springs in the region. These types of areas have potential as a modern reference that can be applied in the reconstruction of past analogous environments such as coal deposits associated with fluvial paleoenvironments.     

咸化湖盆沉积物有序分布及其控制因素——以渤南洼陷沙四上亚段为例

咸化湖盆存在碎屑岩、化学岩及混积岩共生的沉积现象,但多类型沉积物有序分布的机制尚不明确。本文以渤南洼陷沙四上亚段为例,开展了咸化湖盆多类型沉积物有序分布及控制因素的分析,结果表明：渤南洼陷沙四上亚段低位域沉积期以碎屑岩沉积为主,湖侵域和高位域则出现化学岩与混积岩,由近岸到远岸呈扇体、砂岩滩坝、混积岩滩坝、碳酸盐岩滩坝、盐湖、半深湖及深湖有序分布;化学岩主要受水体环境控制,水体古盐度大于10‰是化学岩形成的基础,盐度和深度共同控制碳酸盐岩、膏岩以及盐岩分布,同时水体深度对不同成因类型的碳酸盐岩及碎屑岩分布也产生影响;碎屑岩主要受物源地貌控制,物源区位置及物源供应强度决定着碎屑岩的沉积位置和规模大小,同时古碳酸盐岩的发育影响着现今碳酸盐岩的发育位置;古地貌位置的高低及坡度的陡缓决定着砂体成因类型,同时古地貌还影响着生物礁生长及碳酸盐沉淀;咸化湖盆多类型沉积物有序分布受古水深、古盐度、古物源、古地貌的共同作用。     

Structure of the crust and uppermost mantle of the Yanshan Belt and adjacent regions at the northeastern boundary of the North China Craton from Rayleigh Wave Dispersion Analysis

We have used Rayleigh wave dispersion analysis and inversion to produce a high resolution S-wave velocity imaging profile of the crust and uppermost mantle structure beneath the northeastern boundary regions of the North China Craton (NCC). Using waveform data from 45 broadband NCISP stations, Rayleigh wave phase velocities were measured at periods from 10 to 48 s and utilized in subsequent inversions to solve for the S-wave velocity structure from 15 km down to 120 km depth. The inverted lower crust and uppermost mantle velocities, about 3.75 km/s and 4.3 km/s on average, are low compared with the global average. The Moho was constrained in the depth range of 30–40 km, indicating a typical crustal thickness along the profile. However, a thin lithosphere of no more than 100 km was imaged under a large part of the profile, decreasing to only ~ 60 km under the Inner Mongolian Axis (IMA) where an abnormally slow anomaly was observed below 60 km depth. The overall structural features of the study region resemble those of typical continental rift zones and are probably associated with the lithospheric reactivation and tectonic extension widespread in the eastern NCC during Mesozoic–Cenozoic time. Distinctly high velocities, up to ~ 4.6 km/s, were found immediately to the south of the IMA beneath the northern Yanshan Belt (YSB), extending down to > 100-km depth. The anomalous velocities are interpreted as the cratonic lithospheric lid of the region, which may have not been affected by the Mesozoic–Cenozoic deformation process as strongly as other regions in the eastern NCC. Based on our S-wave velocity structural image and other geophysical observations, we propose a possible lithosphere–asthenosphere interaction scenario at the northeastern boundary of the NCC. We speculate that significant undulations of the base of the lithosphere, which might have resulted from the uneven Mesozoic–Cenozoic lithospheric thinning, may induce mantle flows concentrating beneath the weak IMA zone. The relatively thick lithospheric lid in the northern YSB may serve as a tectonic barrier separating the on-craton and off-craton regions into different upper mantle convection systems at the present time.