共查询到20条相似文献，搜索用时 62 毫秒
1.
G. T. Skublov Yu. B. Marin V. M. Semikolennykh S. G. Skublov Yu. N. Tarasenko 《Geology of Ore Deposits》2007,49(8):681-696
Volkhovites are tektite-like glasses of mafic and ultramafic composition discovered in the fluvioglacial drift of the Valdai glaciation (10–60 ka ago) along the right bank of the Volkhov River (59°27′ N, 32°01′ E). Volkhovite particles are small in size (0.1–3.0 mm) and irregular in shape, with various microtektite aerodynamics (globular, droplike, and dumbbell-like forms). They are perfectly preserved, and, thus, postglacial in age. Sporadic volkhovite grains (up to 20 items per 1 kg of loam) were detected over an area 1.0 × 1.5 km2. Some samples from local spots 20 × 30 m2 in size are anomalously enriched, up to 1700 volkhovite grains per 1 kg of loam. Tiny Ti-Fe, Fe, and Cu-Au spherules, particles of quenched glass and cinder, and fragments of the Precambrian and Paleozoic rocks are spatially associated with volkhovites. The suggested cryptomagmatic model assumes that the glass and cinder are pre-Holocene in age, whereas volkhovites were formed in the post-glacial time as a result of the outburst of the slag-stone-melt-mud-gas mixture that ascended from the asthenosphere to the surface. Drops of the melt solidified in the air instantaneously to form tectite-like glasses, and the tuffisite-like agglomerate mixed with the fluvioglacial drift. 相似文献
2.
在吉林东部花岗岩区地下水化学成分和化学类型研究的基础上,以Na作为参比元素,确定了花岗岩风化过程中22种主量元素和微量元素的相对活动顺序。花岗岩区地下水的地球化学类型属低矿化度(变化范围为69.51×10-6~386.49×10-6,平均值为199.48×10-6)的HCO3-Ca和HCO3-Na-Ca型。花岗岩风化过程中元素的活动性顺序(RM)从大到小依次为:B、Ca、Mo、Zn、Sr、Na、Mg、Cr、Cu、Ni、K、Co、Li、V、As、Ba、Si、Y、Fe、Ti、Al、Mn。风化产物中的粘土矿物主要为高岭土、蒙脱石,反映出本区花岗岩的风化淋滤程度较弱的特点。 相似文献
3.
G. T. Skublov Yu. B. Marin S. G. Skublov E. V. Vasil’ev I. M. Gembitskaya E. S. Nechaeva Yu. N. Tarasenko 《Geology of Ore Deposits》2009,51(8):698-711
Kirishites are highly carbonaceous hairlike fibers 30–100 μm in thickness and 3–30 mm long, which jut out as bunches on the
surface of cinder and shungite fragments associated with volkhovites (Holocene tectitelike glasses corresponding to the rocks
of kimberlite-lamproite-carbonatite series in composition). Kirishite fibers are zonal. Their inner (axial) zone is composed
of high-nitrogen proteinlike compounds, whereas the outer zone is essentially carbonaceous, with a high content of organoelemental
complexes (Si, Fe) and numerous micrometer-sized anomalies of major, volatile, trace, and ore elements. Longitudinal zoning
is established in aposhungite kirishites: the consecutive change of maximum concentrations—K, Na, Cl, C, Mn → C, S, V, Ni,
Cu, Zn → S, N, Ba, Te, Pb, Bi, Nd—is traced from the roots of fibers to their ends. It is suggested that as volkhovites were
forming, fragments of cinder and shungite underwent partial melting. The highly carbonaceous compounds released due decompression
and explosion were squeezed out from fragments and solidified as fibers during fall of fragments on the Earth’s surface. 相似文献
4.
《Journal of Geochemical Exploration》1997,60(2):139-155
Soil samples were collected at 420 locations in a 5-km grid pattern in the Istria and Gorski Kotar areas of Croatia, and on the Croatian islands of Cres, Rab and Krk, in order to relate geochemical variation in the soils to underlying differences in geology, bedrock lithology, soil type, environment and natural versus anthropogenic influences. Specific objectives included assessment of possible agricultural and industrial sources of contamination, especially from airborne effluent emitted by a local power plant. The study also tested the adequacy of a fixed-depth soil sampling procedure developed for meager karstic soils. Although 40 geochemical variables were analyzed, only 15 elements and 5 radionuclides are common to all the sample locations. These elements can be divided into three groups: (1) those of mostly anthropogenic origin — Pb, V, Cu and Cr; (2) those of mixed origin — radionuclides and Zn; and (3) those of mostly geogene origin — Ba, Sr, Ti, Al, Na, Ca, Mg, Fe, Mn, Ni and Co. Variation in Pb shows a strong correlation with the pattern of road traffic in Istria. The distributions of Ca, Na and Mg in the flysch basins of southern Istria and Slovenia are clearly distinguishable from the distributions of these elements in the surrounding carbonate terrains, a consequence of differences in bedrock permeability, type of drainage and pH. The spatial pattern of 137Cs from the Chernobyl nuclear power plant accident reflects almost exclusively the precipitation in Istria during the days immediately after the explosion. 相似文献
5.
为了解黑龙江东宁金厂金矿体土壤离子的电导率异常特征,查明金矿体中土壤离子电导率成分的离子组成以及不同种类离子的含量变化关系对电导率的贡献大小,初步探讨矿区土壤离子电导率异常的形成机理,本文对金厂金矿开展了土壤离子电导率测量,取得以下认识:(1)发现多个具有成矿远景的离子电导率异常区,经深部工程验证具有隐伏的金矿体;(2)组成土壤离子电导率异常的离子成分主要是HCO-3、SO2-4、Ca2+、Cl-、K+、Na+、F-、Mg2+、Mn2+等一套水可溶性离子,经过相关分析得出金矿电导率异常与各离子的相关系数为HCO-3>Ca2+>SO2-4>Cl->K+>Na+>F->Mg2+>Mn2+。 相似文献
6.
《Quaternary International》2006,142(1):162-171
A geochemical study of oligotrophic Lake Sanabria (NW Iberian Peninsula) allows us to distinguish the geochemical response of a lacustrine system to catastrophic events and climatic events. The main major elements analysed were: K, Na, Mg, Ca, Ti, Al, Fe, Mn, P and S. The organic matter content in the sediment of Lake Sanabria is determined by the rainfall regime of the region. Periods when sediments were enriched in Ti, Mg, K, and Al are indicative of relatively wet paleoenvironmental conditions, whereas intervals when sediments were enriched in S and P (associated with organic matter) are indicative of dry conditions. A factor analysis of the geochemical data shows a progressive temporal displacements from organic rich conditions (relatively high values of S and P) to inorganic rich conditions (relatively high values of Ti, Mg, K, Al, and Na). Maximal inorganic content occurred at the beginning of two discrete sedimentary levels: the LOL2 (cal. 1160–1230 yr AD) and the LOL1 (cal. 1510–1680 yr AD) horizons. The LOL2 and LOL1 horizons constitute two discrete events related to climatic changes during the beginning and end of the Little Ice Age, respectively. In contrast, the geochemical analysis provides evidence that the samples associated with the 1959 catastrophic event that occurred in the catchment area of Lake Sanabria do not follow the long-term geochemical evolution paths of the climate driven system. 相似文献
7.
S. Venkatramanan S. Y. Chung S. Selvam J. H. Son Y. J. Kim 《Environmental Earth Sciences》2017,76(13):456
This research was conducted at Samrak Park Delta of Nakdong River Basin in Busan Metropolitan City, Korea. The main objective of this study was to evaluate the interrelationship of geochemical elements in sediments and groundwater through multivariate statistical analyses and a multilayer perceptron artificial neural network model. The mean concentrations of chemical elements were Si (46%), Fe (16.9%), Al (15.7%), K (7.5%) and Ca (4.5%) in sediments, and Na (8650 mg/L), Mg (999 mg/L), Ca (432 mg/L), K (293 mg/L) and Cl (17,640 mg/L) in groundwater, respectively. The principal component analysis produced 3 kinds of factors with the variances of 63.37, 27.02 and 9.62%, respectively. It is suggested that the chemical components of sediments and groundwater were mainly originated from source rocks and seawater intrusion, with the minor impacts of irrigation and industry. Cluster analysis also showed that chemical elements were mainly controlled by the natural geogenic sources and seawater intrusion. Multilayer perceptron of artificial neural network (ANN) presented the good interrelationship between sediment and groundwater. The determination coefficients (R 2) between ANN predicted values and observed values in groundwater showed the high values of 0.61–0.97 except Mg, Mn and Sr. It is revealed that the chemical components of sediment and groundwater were derived from local geological origin and from the minor impact of anthropogenic sources. Multivariate analyses and ANN contributed to the identification of the mutual relationship between the geochemical elements of sediment and those of groundwater. 相似文献
8.
铁岭市东部山区野生经济植物榛子营养元素地球化学特征 总被引：1，自引：1，他引：0
对辽宁省铁岭市东部山区野生经济植物榛子样品中的常量营养元素P、K、Ca、Na、Mg、S,14种营养微量元素和稀土元素含量进行了分析.结果表明,本区的榛子样品其主量元素化学特征属K > P > Ca型,其中Na元素含量变异系数最大,为44.27.微量元素含量水平均在植物元素含量正常值变化范围内,由高到低,元素含量排列顺序为;Mn > Si > Fe > Zn > B > Cu > Ni > F > Cr > Mo > Co > Se > I > V.其中,V元素变异系数最大,为93.18.稀土元素总量∑REE（平均值）为29.66×10-9,属低含量.元素相关性分析表明,元素K与Na、Mg,S与Mg、Ca,P与K、Na、Mg、Ca,Fe与Mn,Co与Mn,Cu与Zn之间,在0.01水平都表现出极显著的正相关,反映这些元素之间的吸收积累有很好的协同作用. 相似文献
9.
《Applied Geochemistry》2002,17(8):1003-1016
Concentrations of major and trace elements in soils and grass are determined at Shimba Hills National Reserve in Kenya using geochemical mapping techniques. The study investigates the influence of soil and vegetation type on the concentrations of Na, K, Mg, Ca, Mn, P, Co, Cu, Zn, Mo, Ni and Se in soils and grass. The implications are assessed for the nutrition of the sable antelope, of which the Reserve supports the last remaining viable population in Kenya. Low concentrations in surface soils of a number of major and minor elements are attributed to the geochemical nature of the underlying parent materials of sands, sandstone and grits. Within the Reserve, variations in the element status of surface soils are related to the vegetation and soil types. Elevated element concentrations in surface soils in natural forest areas are attributed to the influence of litterfall whilst in grassland areas, soil element status is controlled by soil type and decreases in the order ferralsols > acrisols > arenosols. The general depletion of major and minor elements in soils at Shimba Hills is not reflected as fully in grasses in which nutrient concentrations were of similar magnitude to those reported from other Kenyan conservation areas. Burning of grassland areas leads to elevated concentrations of K, P, Co, Cu and Mo in grasses, elevated soil-plant uptake ratios for P and K and elevated soil pH. It is suggested that increased availability of P in soils at elevated soil pH levels contributes to its enhanced uptake into grass. A tentative assessment of the mineral status of grass at the Reserve using guidelines developed for domestic ruminants indicates deficiencies of Na, K, P and Zn and that the Ca:P ratio exceeds the tolerable range for animals. In addition, the low concentrations of Cu, Co and Zn in surface soils in the Reserve indicate that the potential supply of these elements to plants is limited. 相似文献
10.
On the right-hand bank of the Volkhov River, in the natural area of tektite-like glasses (Volkhovites), fragments of shungites
and slags with bunches of hairlike dark brownish enclosures were found. The filament thickness ranged from 20 to 100 μm, and
separate “hairlines” were 3 cm in length. The composition of shungites and “hairlines” was found to be identical, which allowed
us to consider the latter as aposhungite carbon formations. The high-carbon hairline structures associated with volkhovites
are called kirishites. Kirishites are a new type of high-carbon structures that formed simultaneously with volkhovites in
the case of explosion-type delivery of carbon slag and shungite fragments to the daylight surface during Holocene explosive
activity. Under sharply reductive conditions, the slags partially melted, the melts were segregated, and carbonaceous-silicate
and carbonaceous-ferriferous glasses formed with subsequent decompression-explosive liberation of carbon-supersaturated structures,
which were extruded from shungite and slag fragments in the form of a resinoid mass. The “hairlines” were found to be zonal
in structure: the central axial zones are composed of high-nitrogen hydrocarbon compounds, and peripheral regions are essentially
carbonaceous with a high content of organic-mineral compounds and numerous microanomalies of petrogenic, volatile, rare, and
ore elements. Infrared spectroscopy identified in kirishites proteinlike compounds, diagnosed in absorption bands (in cm−1) 600–720 (Amid V), 1200–1300 (Amid III), 1480–1590 (Amid II), 1600–1700 (Amid I), 3000–3800 (vibrations in NH2 and II groups). Gas chromatography, with the possibility of differentiation of left- and right-handed forms, revealed a broad
spectrum of amino acids in kirishites, with their total content found to be the absolutely highest record for natural bitumens,
an order of magnitude higher than the largest amino acid concentrations ever revealed in fibrous high-structured kerite crystals
from Volyn pegmatites and in Transbaikalia phyto fulgurates. Like in phytofulgurites and fibrous kerites, in kirishites the
amino acids are abiogenic, and they are predominately left-handed in configuration, contrary to the commonly accepted view
about the exclusively biological nature of left-handed amino acids and their natural abiological thermofusion. Kirishites
can be considered as models of prebiotic systems, predecessors of the simplest living organisms. This process could be favored
by extreme conditions with rapid variations of temperature and pressure. Further study of kirishites and construction of a
kirishite formation model will also be useful for development of the conception of endogenous ore-naphtobiogenesis. 相似文献
11.
The chemistry of suspended matter in Esthwaite Water,a biologically productive lake with seasonally anoxic hypolimnion 总被引：1，自引：0，他引：1
Ten detailed vertical water column profiles were taken between April and November, 1979, in Esthwaite Water (English Lake district), a lake with high biological productivity and a seasonally anoxic hypolimnion. Measurements of the major-element particle composition (organic C, P, S, Si, Al, Ti, K, Mg, Ca, Fe, Mn, and Ba) and hydrochemical constituents (temperature, pH, dissolved oxygen, total suspended load, dissolved Fe, Mn, P, and Ba) were carried out. These have revealed new information about the mechanisms and kinetics of biogeochemical cycles in a lake.Pronounced seasonal cycles exist in which large excess concentrations (those unsupported by detrital components) of particulate organic C, Fe, Mn, P, S, Mg, K, Ba, and Ca are being generated and lost in situ in the water column (15m deep). In the epilimnion these elements (excepting Fe and Mn) are incorporated into the organic components of growing phytoplankton during the spring and summer. Simultaneously, in the hypolimnion there is a build-up and then a decrease in the excess concentrations of particulate C, P, S, Mg, K, Ba and Ca; this cycle is due to the indirect involvement of these elements with the iron redox cycle. As the hypolimnion becomes anoxic, dissolved ferrous Fe is released from the sediments and large concentrations of excess particulate iron (III) oxides accumulate; these oxides act as adsorbing substrates for the above mentioned elements. As conditions become more reducing, these same elements are solubilized as the iron (III) oxide particles are reduced to dissolved ferrous iron.Adsorption equations are derived from the field data which relate the concentration of excess particulate Fe to those of POC, P, S, Ca, Mg, Ba, and K. At the last stages of anoxia (before the lake overturns) large populations of bacteria and the formation of iron sulfide particles control the concentrations of excess particulate C, S, P, Mg, K, and Ca. 相似文献
12.
Hyun-Ju Cha Man Sik Choi Chang-Bok Lee Dong-Hyeok Shin 《Journal of Asian Earth Sciences》2007,29(5-6):685-697
We analyzed 77 surface sediment samples collected in the southwestern East/Japan Sea from the Korea Strait through the Ulleung Basin and the Korea Plateau for grain size, calcium carbonate, organic carbon, and major (Na, Mg, Al, Fe, K, Ca, and Ti) and trace elements (P, Mn, Sr, Li, Sc, V, Cr, Co, Ni, Zn, Cu, and Pb).The chemical composition of the surface sediments was found to be highly variable spatially. Cluster analysis of surface sediment chemical compositions indicated five major geochemical sedimentary environments: basin, lower slope, coast and upper slope, inner shelf, and outer shelf. Continental-shelf sediments were rich in shell fragments and had relict and coarse-grained characteristics. Recent fine-grained sediments were only distributed in coastal, slope, and basin areas. Concentrations of Al, K, Ca, Ti, Cr, and Sc were highest in the coastal and upper slope areas and decreased with water depth. Elemental ratios using major and trace elements indicated that coastal and upper slope detrital sediments were mixtures of sediments derived from the Changjiang (Yangtze) and Nakdong Rivers. Although the concentrations of organic carbon, P, Mn, V, Co, Ni, Cu, and Pb increased with water depth, their distribution patterns indicated authigenic (V, Cu, and Pb) and diagenetic (Fe, P, Mn, Co, and Ni) origins. The distribution pattern with water depth suggested that the chemical composition of surface sediment was determined by sedimentologic and geochemical processes, such as the supply of detrital and biogenic materials, and authigenic and post-depositional diagenetic processes in sediments. 相似文献
13.
In support of IGCP Project 259 (International Geochemical Mapping), a pilot survey designed to test the effectiveness of analysing dried humus collected at an extremely low sampling density (one composite sample per 23 000 km2) for geochemical mapping was carried out in 49 large catchment basins in Fennoscandia. The samples were analysed for their aqua-regia leachable contents of 30 elements by ICP-ES. The results were compared with those of till sampled at the same sites and with moss from previous surveys. The correlation with underlying bedrock was also studied.Geological features exert only a weak influence on the regional distribution of elements in humus. Exceptions are high levels of Ca and Sr in areas of carbonate bedrock and low contents of K in areas of Archean rocks. The distribution patterns of Co, Cr, Cu, Mg, Ni and Zn in humus coincide partly, and the levels correlate positively with those in till. The contents of Ni, Cr and Cu are lower in humus overlying acid magmatic rocks and arkose than other rock types.Pollution is the obvious source of high concentrations of Pb, Cd and Zn in southern Sweden and southern Norway. Acid fallout seems to cause leaching of Al, P and La from the humus horizon. The contents of these elements are low in the south where deposition of S and N is high and pH of rainwater is below 4.5. Deposition of sea salts gives high levels of Na, Mg, K and B along the coast of Norway and southern Sweden.The contents of several elements in humus correlate positively with the amount of organic matter (LOI). Comparison between four types of forest shows that the contents of Ca, Mg and Na in birch forest and of Cd, Mn, Pb and Zn in spruce forest are significantly higher than in other forest types. These features, however, are considered false and are due to sources such as atmospheric deposition of anthropogenic metals and sea salt.The results of the relatively strong chemical attack used for analyses of humus samples are less informative than those from till and overbank sediments. A weaker attack may have given more useful information. The humus horizon could be suited for environmental monitoring if used in global geochemical mapping. 相似文献
14.
依据2003-2008年松辽平原中南部地区多目标区域地球化学调查成果,选择黑土类型土壤样本6553件,研究典型黑土中有机质及养分元素碳、氮、硫、磷、钙、钾、铁、镁、锌、铜、钼、锰、硼的变化特征.发现典型黑土中有机质结构性元素碳、氮、硫、磷以及铜、镁、铁、钙元素的含量变化与有机质的变化具有正相关性.养分元素含量的变化与成土母质和土壤类型关系密切,如锰在黑土中含量普遍偏高.中国土壤以及松辽平原土壤的宏观背景是典型黑土中钾偏高和钼、硼偏低.生物气候带是影响有机质和某些养分元素变化的重要因素.温带-寒温带的气候条件影响着土壤的物理性质和化学性质,如粒级、黏粒性、酸碱性,进而影响元素含量的变化. 相似文献
15.
沉积物的元素地球化学特征是对沉积盆地水体环境以及古气候条件变化的响应。本文根据元素（Al、Fe、Mg、Ca、K、Na、P、V、Ni、Co、Cr、Cu、Zn、Sr、Ba、Cd、Li、Mn、Pb、Ti）的含量及其比值（Al/Ti、Fe/Mn、Sr/Ba、Mg/Ca、Sr/Ca、Na/Ca、V/Cr、Ni/Co、Ni/V）的变化，对三水盆地古近系心组红岗段生油层的沉积条件进行了系统分析。心组红岗段下部（亚段A）表现为较稳定的地球化学特征。各元素丰度及其比值指示这一时期陆源输入持续较高、且物源组成变化不大。由于海水入侵的影响，湖盆水体盐度相对较高，底部水体以弱氧化条件为主，O2-H2S界面位于水/沉积物界面附近。红岗段中上部（亚段B、C）的元素地球化学特征变化较为频繁且幅度很大，反映古气候和湖盆沉积条件的迅速变迁。在潮湿气候条件下，沉积物的地球化学特征表现为以Al、Ti为代表的外源元素含量及其比值较高，而Mg、Ca等盆内化学沉积元素含量较低。古氧气指标指示底部水体为还原环境，有利于有机质保存。因而，相应于较高的有机碳含量。在间歇性干旱时期，陆源输入减少，外源元素含量及其比值显著降低。随着蒸发作用的加强，水体盐度加大，内源元素丰度以及Mg/Ca、Sr/Ba、Sr/Ca和Na/Ca比值大幅度上升。底部水体为氧化环境，O2-H2S界面多位于水/沉积物界面或沉积物中。上述两种气候条件在红岗段中上部沉积时期交替出现。红岗段沉积后期由于淡水的长期输入，湖水出现逐渐淡化趋势。 相似文献
16.
The authors have studied an Albian glauconite—phosphate—carbonate ore in the Sierra de Espuña (Murcia), situated in the betic Cordilleras, nappe of Malaga. The geochemical data concern 76 samples from which the following elements were titrated by spectro-photometric methods: P, Fe, Ti, Al, Mg, Mn, Ca, Na, K, Zn, Li, Ni, Cr and Sr.The percentages of SiO2, P2O5, Al2O3, K2O and total Fe with respect to the insoluble fraction and the CaCO3, Mn, P2O5 amounts permit of partly explaining the phosphate—glauconite bond. The pH and Eh conditions, deduced from vertical variations in the chemistry, are associated with the mineralogic evolution of the glauconites.The authors define the paleoenvironment of this glauconite—phosphate ore deposit. They clearly separate the environment of the genesis from that of sedimentation of the grains. The sedimentation of carbonate—phosphate—glauconitic particles occurred in a confined environment without continental debris. These grains were formed in proximity of the shelf edge.The phosphate and carbonate supplies are attributed to upwelling of deep waters. 相似文献
17.
黔北白云岩红色风化壳元素地球化学特征 总被引：5，自引：3，他引：2
选取贵州高原喀斯特地区典型白云岩风化剖面作为研究对象,探讨了红土剖面元素迁移特征及其影响因素,为进一步认识红色风化壳元素地球化学特征提供依据。结果表明:（1）红土剖面中土壤样品（XPS-4~XPS-25）Fe、K、Mn常量元素及Co、Pb、Zn微量元素的分布曲线相对于其他元素靠近 UCC,元素Mg、Ca、Na、Ti和 Li、Cr、Ba、V 的数据点则显著偏离了上部陆壳的平均组成。（2）元素对协变分析得出Ti与Fe、Ba和V的积累特征一致,呈增加趋势;Ti与Mg呈反向变化特征。（3）以Ti为参比元素的剖面迁移特征表明,绝大部分元素的地球化学行为表现为迁移淋失,仅 Fe 、Cr和V 富集。K、Ba总体上呈迁出趋势,个别层段有轻微富集;Na和Co在风化原岩处有一个富集端点。元素在风化过程中的迁移聚集与土壤剖面的pH值和剖面结构变化、粘土矿物和有机质等的吸附有关。 相似文献
18.
沧东凹陷孔二段页岩层系广泛发育混合细粒沉积岩.混合细粒沉积岩的岩石类型划分和沉积环境分析是其成因研究的重要组成部分,有助于总结混合细粒沉积岩的沉积规律,寻找有利勘探目标.通过岩心与薄片观察、二维XRF（X射线荧光光谱）扫描,结合XRD（X射线衍射）、元素地球化学测试等资料,以矿物成分和沉积构造为主要依据,将孔二段混合细粒沉积岩划分为21种岩相;通过Sr/Cu、Mg/Ca、Sr/Ba、V/（V+Ni）、Al、Ti含量、Fe/Mn和（Fe+Al）/（Ca+Mg）等地球化学指标的垂向变化及岩相分析沉积环境演化.沧东凹陷孔二段混合细粒沉积岩主要发育在气候干旱、微咸水-咸水相、水体贫氧、陆源输入较强的半深湖-深湖环境中;岩相类型的发育同时受到水体的高盐度和陆源输入的影响,均一细粒沉积岩分布最广,其次为灰云细粒沉积岩,黏土细粒沉积岩不发育. 相似文献
19.
为研究砂岩型铀矿与古层间氧化带之间的关系,本文通过对鄂尔多斯盆地苏台庙地区直罗组下段上亚段砂岩的地球化学环境和常量元素进行规律总结与讨论。将古层间氧化带进一步细分为古氧化残留带、二次还原带、叠置带和原生带等4个亚带,总结了各亚带地球化学环境指标特征,揭示了各亚带常量元素的演化规律,其中Si、Al、Fe和Ca活动性较强,Na、Mg和Ti活动性其次,而K、Mn和P较稳定。研究认为,该地区砂岩依次经历了成岩作用、古氧化作用、主成矿期铀成矿作用、二次还原作用和叠加铀成矿作用等,且未曾经历大幅沉降和显著构造热事件。研究区铀成矿作用与还原介质和Ca含量关系最密切,其次是Si、Fe、Ti,铀矿勘查应以叠置亚带为重点,兼顾二次还原亚带。 相似文献
20.
《Applied Geochemistry》2006,21(2):352-376
Chemical weathering rates for a mudstone obtained from a mining environment were investigated using a combination of batch reactors and hydrologically unsaturated column experiments. Results of tracer tests were combined with relationships between solute concentrations, mass fluxes, flow rates and residence times, and used to calculate element release rates and infer rate-controlling mechanisms for the two different experimental environments.Elements that eluted from column experiments exhibited either:
- (1)concentrations independent of flow rate and column length coupled with mass flux increasing with flow rate, or
- (2)an inverse relationship between concentration and flow rate coupled with mass flux increasing with both column length and flow rate.