Geochemische Untersuchungen an Sedimenten des Persischen Golfes

The data obtained can be summed up in 6 points:

1. The sediment consists of varying amounts of quartz (14–23 weight percent, mean value 18%), aragonite, dolomite, Mg-rich calcite, Mg-poor calcite, Na-rich plagioclase (7–10%, m.v. 8%), chlorite (18–32%, m.v. 22%), kaolinite (4–29%, m.v. 13%), illite and mixedlayered illite-montmorillonite (20–42%, m.v. 34%) and organic matter (0.7–2.5%, m.v. 1.1%).
2. The composition of the carbonate fraction suggests a detrital origin for the carbonates deposited along the Persian Coast.
3. The clay mineral distribution follows gradients perpendicular to the long half-axis of the Persian Gulf. This favours detrital origin. The kaolinite distribution suggests an additional detritus from Euphrates and Tigris,
4. Enrichments of trace elements with regard to mean values in clays (Turekian and Wedepohl, 1961) are estimated for Fe, Co, Mo, Ni, V, Zr and Br; impoverishments are recorded for Cu, Mn, K. The contents of Rb, Ti and Zn comply with mean values of clays. The enrichments distribute as follows: chlorite concentrates Mn and Fe, kaolinite Ti and Zr, illite and mixedlayered illite-montmorillonite Rb, V, M, Zn, Mo and Co.
5. The high Br-contents (up to 420 ppm) in the sediment give positive correlations with the concentrations of organic carbon. The X-ray analysis of isolated kerogen confirms an enrichment of Br in this fraction of the organic matter.
6. The distribution of elements in the sediment to a large extent is controlled by a) detritus of Euphrates and Tigris, b) influence of organic matter.

     

Geo-environmental appraisal of the Meda creek,Saurashtra, Gujarat

Water chemistry, sediment texture, clay mineralogy and foraminiferal contents from the bottom of Meda creek were studied to assess the geo-environmental status of the creek. Water quality data for three seasons suggests domination of marine environment as pH remained above 8 and salinity above 35‰ throughout. Clay dominate the bottom sediments, except near mouth. Montmorillonite, illite and kaolinite are the major clay minerals in the sediments. In absence of any source rock in the catchment of the Meda creek, the presence of illite and kaolinite indicates their transportation and depositions from near coastal waters during high tides. Ammonia sp. is the most dominating foraminifera. Reworked forms as well as angular asymmetric forms of foraminifera were dominant in clay rich areas of the creek.     

东海东北部海域表层沉积物黏土矿物来源及输运

利用X射线衍射,对东海东北部海域80个表层沉积物样品进行黏土矿物的相对含量分析.结果表明:东海东北部海域表层沉积物黏土矿物中伊利石（65.1%）含量最高,其次为绿泥石（26.6%）、高岭石（8.9%）和蒙皂石（4.3%）;矿物组合中伊利石-绿泥石-高岭石-蒙皂石型占绝对优势,伊利石-绿泥石-高岭石型较少.由外陆架至冲绳海槽,伊利石含量分布呈低-高-低-高;绿泥石呈低-高-低;高岭石分布趋势明显异于伊利石和绿泥石,含量值分布出现由高到低的趋势;蒙皂石在个别区域缺失,高值区呈斑块状分布在水深小于100 m的外陆架.快速聚类分析显示,黏土矿物可分为“类长江”、“类黄河”和“类台湾”3种类型,呈4个区域相间展布.“类黄河”型黏土矿物主要由黄海沿岸流将黄河、废黄河等物质再悬浮搬运而来,分布于29.5°N以北、127°E以西的外陆架区,并未越过东海外陆架进入冲绳海槽.外陆架区“类长江”型黏土矿物主要为低海平面时期古长江物质,并混有少量现代长江源悬浮物质;冲绳海槽区“类长江”型黏土矿物主要来自低海平面时期古长江物质.“类台湾”型黏土矿物主要由黑潮控制,由台湾经冲绳海槽南部搬运而来,沿陆坡附近沉积.      

Clay mineralogy, grain size distribution and their correlations with trace metals in the salt marsh sediments of the Skallingen barrier spit, Danish Wadden Sea

To understand the behavior of trace metals in the salt marsh at Skallingen, Danish Wadden Sea, we investigated a profile from surface to 25?cm depth of the salt marsh sediment, focusing primarily on clay mineralogy and grain size distribution of the sediments and their relationship with trace metals. The clay assembly of the sediment consists of illite, kaolinite and much less chlorite and smectite. The major clay minerals of illite, kaolinite as well as chlorite correlate very poorly with all the trace metals investigated, due probably to the weak competing strength of these clays compared with the other adsorbents and to low availability of the mobile trace metals in the system. Correlation between trace metals and clay minerals may therefore be used as an indicator in environmental assessment. Fine grain fractions of the sediment increased markedly after salt marsh invasion in about 1931 but decreased after 1964. This increase was contributed mainly by the grains finer than 20???m while the fraction of 40?C63???m actually decreased soon after the invasion. The relation between most of the trace metals and grain size distributions is close in general but far from linear. The drastic turning point is observed at about 30???m, around where the correlation coefficient r drops from 0.8 to 0.1. Adsorption is the controlling mechanism for the behavior of trace metals in the salt marsh. Fe/Mn (hydr)oxides and organic matter play the key role.     

Formation mechanisms of illite,chlorite and mixed-layer illite-chlorite in Triassic volcanogenic sediments from the Southland Syncline,New Zealand

Clay minerals from the three principal kinds of zeolitic sediments from the type area for zeolite facies alteration, the Triassic Murihiku Supergroup, Southland, New Zealand, have been studied by TEM. Bentonitic tuff consists largely of smectite and heulandite with minor illite; they occur as replacements of glass shards and are inferred to be direct alteration products of tuff alteration. Both analcime- and laumontite-rich tuffs contain chlorite, illite and mixed-layer illite-chlorite, including 11 mixed-layer sequences. Subhedral to euhedral phyllosilicate crystal shapes and other textural features imply that phyllosilicates crystallized from solution derived in part by dissolution of precursor smectite. Intralayer transitions involving illite and chlorite are inferred to be products of crystallization rather than direct alteration and replacement. Petrographically similar bentonitic and analcimized tuffs overlap each other in the stratigraphic section, supporting earlier observations that there is no systematic change in smectite relative to the illite plus chlorite derived from smectite in sections up to 8.5 km thick. The data imply that smectite may be metastable relative to illite plus chlorite. Permeability and fluid chemistry are inferred to be as significant as temperature in promoting reactions in clay minerals as well as zeolites during burial metamorphism.Contribution No. 436, from The Mineralogical Laboratory, Department of Geological Sciences, The University of Michigan, Ann Arbor, Michigan 48109     

The sedimentation of copper-bearing shales (Kupferschiefer) in the sudetic foreland

The profile of the copper-bearing shales (Kupferschiefer) displays 3 types of lithological developments of the Sudetic Foreland:

in reduction facies: with the notably diminishing of participation of clay minerals and organic substance from bottom to top.

Many horizons of concentration of copper, lead and zinc are present.

in oxidation facies: where marley shales are forming, the metals decrease to trace contents.

in intermediate zones, from reduction facies to oxidation facies shales, the lithological formation is changing and the greatest variability is encountered in the intensity of metal contents.

The concentrations of copper sulphides occur in lagoonal areas in which an oxigen deficiency was associated with a great amount of organic matter. The beds formed in the oxidation facies represent the coastal zones of an open sea basin where the influence of inflow and outflow were considerable.     

青海湖沉积物中的粘土矿物

本文对青海湖沉积物中的粘土矿物和沉积环境进行了初步研究。沉积物的粒度成分一般以粉砂级为主,湖周沉积物较粗,湖内沉积物较细。湖中粘土矿物以伊利石-绿泥石为主,含少量蒙脱石和高岭石等。沉积物表层未见蒙脱石,粘土中Al₂O₃、K₂O和MgO的相对百分含量的特征与海粘土的化学成分特征相似。     

Tonminerale in normalsedimenten,hydrothermal beeinflu\ten sedimenten und Erzschlämmen des Roten Meeres

From 14 deeps and other regions of the Red Sea totally 226 samples from 28 cores recovered during the VALDIVIA cruises (1971, 1972) were investigated according to their clay mineral content (<2μm resp. < 6.3 μm) after carbonate dissolution. Three facies groups are to distinguish:

1. normal sediments: dominance of chlorite, kaolinite, illite, small amounts of smectite and sepiolite. Two palygorskite types are present only in a few samples.
2. normal sediments with hydrothermal influence: clay mineral paragenesis similar like that of normal sediments; but increase of smectite and presence of goethite in each sample; partly small contents of talc.
3. heavy metal deposits: dominance of iron-bearing smectite, partly with amorphous components resp. pure ore mineral assemblages with authigenic silicates (talc, quartz, opal, chrysotile, sepiolite, palygorskite, chlorite).

Crystallinity of the clay and ore minerals is independent from sedimentary overburden. Sepiolite shows in small amounts a wide distribution; palygorskite₂ (d₁₁₀=11.3 Å) yields locally an increased concentration in the range of pteropod layers cemented by aragonite. The environment of ore deposits is characterized by iron-bearing smectite besides the ore minerals.     

Sulfide oxidation in brown coal overburden and chemical modeling of reactions in aquifers influenced by sulfide oxidation

With a mean annual flow of 5.9×10¹¹m³yr^–1 and sediment load of 1600x10¹²gyr^–1 the Ganges river ranks second and third, respectively, in terms of water flow and sediment load among the world's rivers. Considering the enormous sediment transport by Ganges to the Bay of Bengal, a study was conducted on the size distribution and mineral characteristics of the suspended sediments of the Ganges river and is reported here. Most of the sediment load has a size range between <4–5.75 ). The sediments are mostly medium to coarse silt and are poorly sorted. Mica dominates among the clay minerals, followed by chlorite, vermiculite, kaolinite, and smectite. Due to differences in geology, smectite becomes a major clay mineral in downstream rivers. At Calcutta, the clay mineral transport in millions of tons per year is 18,464, 8000, and 2147, for mica, smectite, and chlorite, respectively.     

Diagenesis of clay minerals and K-bentonites in Late Permian/Early Triassic sediments of the Sichuan Basin (Chaotian section,Central China)

Detailed clay mineralogical analyses were carried out on Late Permian/Early Triassic carbonate sediments exposed on the Chaotian section (Sichuan Basin, Central China). The clay assemblages are dominantly composed of illite in platform carbonates and clay seams, and illite–smectite mixed-layers (I/S) in tuff layers (K-bentonites) intercalated in the carbonate succession. Detrital and authigenic volcanogenic clay minerals have been partially replaced through illitisation processes during burial, raising questions about diagenetic effects. The precise determination of I/S occurring in K-bentonites shows that the sediments reached a temperature of about 180 °C, which is consistent with (1) previous estimates based on fluid-inclusion homogenisation temperature analysis, (2) the burial depth of the sedimentary series deduced from the post-Palaeozoic geological history of the Sichuan Basin and (3) the new data (T_max) obtained on organic matter indicating the transition between oil and gas windows. The Wangpo Bed, located close to the Guadalupian–Lopingian Boundary, is interpreted either as a volcanic acidic tuff or as a clastic horizon. This controversial origin probably results from mixed volcanogenic and detrital influences. The Wangpo Bed is therefore interpreted as a reworked bentonite as revealed by the occurrence of I/S similar to those found in tuff layers, together with preserved detrital kaolinite.     

Time series analyses of suspended sediment concentrations at North Inlet,South Carolina

Daily water samples have been collected at three stations in the North Inlet (South Carolina) marshestuary system since February 1981 as part of the NSF Long-Term Ecological Research (LTER) project. As a result of this sampling regime, nearly continuous time series of inorganic and organic suspended sediment, particulate organic carbon (POC), Secchi disk, salinity, and water temperature are now available. Power spectrum analysis of these data reveals that most of the explainable variance in the inorganic suspended sediment, POC, and Secchi disk data is related to a yearly cycle that is strongly coherent with water temperature such that high turbidity is associated with high water temperature. Only a small fraction of the explainable variance is associated with frequencies that can be related to the semidiurnal tide. Simple correlation analysis also indicates that turbidity is more closely associated with water temperature than with tide height or salinity. The ratio of POC to inorganic suspended sediment shows no discernible power spectra peaks and is weakly, but inversely, correlated with temperature. From these results we hypothesize that temperature-regulated bioturbation is the main factor controlling turbidity variations in the system. The lack of a strong inverse correlation between turbidity and salinity suggests that river runoff has little immediate impact on the suspended sediment of nearshore coastal waters in systems similar to North Inlet.     

Characteristics and distribution of clay minerals and their effects on reservoir quality: Huagang Formation in the Xihu Sag,East China Sea Basin

Abstract

The characteristics and distribution of clay minerals and their effects on reservoir quality in the Huagang sandstones in the Xihu Sag, East China Sea Basin were studied by using X-ray diffraction, casting thin-sections, scanning electron microscopy, electron microprobe analysis, fluid inclusion analysis, constant-rate mercury injection and nuclear magnetic resonance. Clay minerals consist of kaolinite, chlorite, illite and illite–smectite mixed layer (I/S); kaolinite forms from dissolved feldspars, chlorite occurs as clay coatings that are transformed from clay precursors owing to the flocculation of suspended detrital clays or the crystallisation of pore fluids, and illite forms from the illitisation of detrital smectite, authigenic kaolinite and K-feldspars. Clay distribution is controlled by sedimentary environments, burial history and lithologies. Typical reservoirs in the western sub-sag are thin and developed in braided river facies at relatively shallow burial depths with clays dominated by kaolinite. However, typical reservoirs in the central inversion tectonic zone are thicker and developed in a braided delta front facies at deeper burial depths with clays mainly consisting of chlorite, illite and I/S. High-quality reservoirs are characterised by coarse granularity, high quartz content and low clay content with widespread development of chlorite coatings that inhibit quartz cements at low temperatures. At higher temperatures, the high-quality reservoirs develop more pores providing growth space for quartz cements and result in the coexistence of chlorite coatings and quartz cements. The high-quality reservoirs are controlled by their lithological characteristics rather than chlorite coatings. Illite and I/S clays create severe damage to reservoirs by reducing the size and connectivity of pore-throats.     

Occurrence of Li,B, Cu and Zn in some Egyptian Nile sediments

Lithium, boron, copper and zinc have been determined on cored and surface sediments from the delta and the drainage valley of the Nile River. The clay size fraction separated from the samples consists of montmorillonite and kaolinite as the predominant clay components, followed by illite and chlorite. Quartz and calcite are the non-clay admixtures.Lithium content varies between 7 and 48 ppm in the bulk sediments and between 28 and 61 ppm in the clay fractions, being clearly enriched in the clay material. In the clay fractions, concentration of lithium in kaolinite is indicated by a close relation between the lithium and kaolinite contents and is further supported by a close correlation with A1₂O₃.Boron in the clay fraction (62–112 ppm) appears to be concentrated in detrital illite.The concentrations of copper (26–900 ppm) and zinc (65–333 ppm) in the clay fractions correlate positively with the CO₂ percentage. Both elements tend to occur in or on the claysized grains of caleite.     

Clay mineralogy of archaeological soil: an approach to paleoclimatic and environmental reconstruction of the archaeological sites of the Paharpur area,Badalgacchi upazila,Naogaon district,Bangladesh

A geo-archaeological examination was carried out in and around the Paharpur area, Badalgacchi upazila of Naogaon District in the north-western part of Bangladesh. Clay mineralogy and global paleo-temperature curves were used to determine the paleoclimatic and depositional environmental conditions of the Holocene archaeological soils (Barind clay residuum) of the Paharpur archaeological spot. Clay mineralogical data show that the dominant clay mineral is illite with subordinate amounts of kaolinite and chlorite. The high illite and low kaolinite content implies a marine or estuarine deposit. The clay mineral ratio log diagram, constructed by plotting the 7–10°Å integrated intensity ratios versus depth, supports this assumption. The presence of illite, together with quartz and feldspar, suggests high detrital input under generally cool to temperate and dry climates. Chlorite is another common by-product of weathering reactions with low hydrolysis, which is typical for cool to temperate and dry climates. The results suggest the existence of a marine–estuarine influence under a generally cool to temperate and dry climates around Paharpur and the surrounding region throughout the Pala dynasty around mid-century 700 a.d. to early 1100 a.d. Furthermore, this observation is consistent with the global paleo-temperature curves.     

Some factors affecting TDS and pH values in groundwater of the Beihai coastal area in southern Guangxi,China

Groundwater of low total dissolved solids (TDS) of 10 mg/L and low pH ranging commonly from 4.0 to 7.0 occurs in the unconsolidated unconfined and confined aquifers in the coastal plain near Beihai, Guangxi, China. Minerals in the unconsolidated sediment of Quaternary are predominated by quartz (more than 50%) with small amount of clay minerals, such as kaolinite, illite and chlorite. SiO₂ accounts for most (more than 70%) of the chemical compositions of the sediments. The sediments contain low concentrations of soluble constituents (below 300 μg/g) and are predominated by SO₄. Abundant recharge from low-TDS precipitation and a long time’s dissolution of the unconsolidated sediments containing small amount of soluble compositions lead to low TDS of the groundwater in the area.     

南海北部陆架海域表层沉积物黏土矿物分布特征及物源分析

应用X射线衍射(XRD)对南海北部陆架海域225个站位表层沉积物黏土组分进行分析,结果表明,研究区黏土矿物总体以伊利石和绿泥石为主,高岭石和蒙脱石质量分数少,绿泥石、高岭石与蒙脱石质量分数呈明显的负相关关系。根据南海北部陆架海域表层沉积物中黏土矿物空间分布特征,结合邻近河流的黏土矿物组分以及洋流搬运作用,雷州半岛东部海域伊利石主要来源于广东沿海河流和珠江,绿泥石来自台湾岛,蒙脱石主要由吕宋河流提供,高岭石则由广东沿海河流和海南岛入海河流提供;雷州半岛西部海域伊利石来源于珠江,绿泥石和高岭石由红河提供,蒙脱石可能受广西入海河流携带的沉积物影响。     

Freshwater sediment quality in Spain

This study was carried out to evaluate sediment pollution related to trace elements such as Cd, Cu, Ni, Pb, Zn, Hg, As and Cr and eight polycyclic aromatic hydrocarbons (PAHs) in 127 sites located in 85 rivers in Spain. Sediment samples were classified according to similar chemical characteristics by means of statistical multivariate techniques (principal component analysis, PCA) and artificial neural networks such as self-organizing maps (SOM). Sediment sample classification provided by PCA was not as useful as the one provided by the SOM, revealing itself as a powerful tool to be incorporated in the first steps of sediment quality assessments. The use of sediment quality guidelines such as the mean-probable effects concentration quotient (m-PECQ) predicted sediment quality and gave an overall view of sediment pollution throughout Spain. Most of the samples (118 out of 127) showed m-PECQ values below 0.5 highlighting their relative low potential risk to cause adverse effects on the benthic fauna. However, some samples presented m-PECQ values higher than 0.5 suggesting a clear potential risk to these fauna. Besides, unusual high concentrations of trace elements and PAHs were related to the human activities carried out near each sampling point.     

Provenance of Clay Minerals in the Amami Sankaku Basin and Their Paleoclimate Implications Since Late Pleistocene

We analyzed the clay mineral assemblages, content and mineralogical characteristics of Hole U1438A sediment recovered from Amami Sankaku Basin during International Ocean Discovery Program (IODP) expedition 351. The results show that the clay minerals are mainly composed of illite (average 57%), smectite (average 26%), chlorite (average 14%) and minor kaolinite(average 3%). The crystallinity of illite in all samples are good (<0.4 Δ° 2θ), and the chemical indexes of illite in all samples are low (<0.4). Both indicate that illite in Hole U1438A formed in cold and dry climate. By comparing clay mineral assemblages of hole U1438A and the potential sediment sources, we suggest that smectite be mainly derived from the volcanic materials around Amami Sankaku Basin. Illite, chlorite and kaolinite are mainly derived from the Asian dust. The ratios of (illite+chlorite)/smectite show a phased increase over the last 350 ka, which is consistent with the cold and drying trend of the Asian continent since late Pleistocene. The high ratios of (illite+chlorite)/smectite and (illite+chlorite)/kaolinite during glacial period indicate that much more Asian dust was input into the Amami Sankaku Basin, which are responded to the aridity of Asian continent and strengthened east Asian Monsoon during glacial period.     

Trace metals in suspended particulate matter and in sediment trap material from a permanently anoxic fjord — Framvaren, South Norway

Geochemical studies of the trace metal concentrations in suspended particulate matter (SPM) and sediment trap material from a permanently anoxic fjord, Framvaren, South Norway in 1989 and 1993 indicate that extremely high concentrations of zinc (max = 183920 mg/kg), copper (max = 4130 mg/kg), lead (max = 2752 mg/kg), and cadmium (max= 8.1 mg/kg) sometimes (1993) occur in the SPM collected in the anoxic water layer. The highest concentrations of Zn occur just below the redoxcline at 22 m water depth (in 1993), and copper, lead and cadmium have maximum concentrations between 30 and 80 m depth, where the amount of total SPM is at a minimum (about 0.3 mg/L). On a mass per volume (g/L) basis, the maximum concentrations of Cd, Cu and Fe occur at the interface (21m) and those of Zn occur just below the redoxcline (22 m depth). The SPM and sediment trap data suggest that the metals are precipitated as sulfide minerals in the anoxic water. The presence of particulate sulfides was confirmed by SEM studies that show the occurrence of discrete metal (Cu, Fe, Pb, and Zn) sulfide particles in size from 10–20 m as well as framboidal pyrites (1–5 m in size). Higher levels of metal sulfides at intermediate depths rather than in the deep water of Framvaren (> 100 m), may be due to input of trace metals by water exchange over the sill in the upper part of the water column. In the deep water, less metal sulfide precipitation takes place due to depletion of trace metals, and the dilution of particulate metal concentrations by organic matter and by the chemogenic formation of calcite.     

Selected elements in major minerals from bituminous coal as determined by INAA: implications for removing environmentally sensitive elements from coal

The four most abundant minerals generally found in Euramerican bituminous coals are quartz, kaolinite, illite and pyrite. These four minerals were isolated by density separation and handpicking from bituminous coal samples collected in the Ruhr Basin, Germany and the Appalachian basin, U.S.A. Trace-element concentrations of relatively pure ( 99⁺%) separates of major minerals from these coals were determined directly by using instrumental neutron activation analysis (INAA). As expected, quartz contributes little to the trace-element mass balance. Illite generally has higher trace-element concentrations than kaolinite, but, for the concentrates analyzed in this study, Hf, Ta, W, Th and U are in lower concentrations in illite than in kaolinite. Pyrite has higher concentrations of chalcophile elements (e.g., As and Se) and is considerably lower in lithophile elements as compared to kaolinite and illite. Our study provides a direct and sensitive method of determining trace-element relationships with minerals in coal.Mass-balance calculations suggest that the trace-element content of coal can be explained mainly by three major minerals: pyrite, kaolinite and illite. This conclusion indicates that the size and textural relationships of these major coal minerals may be a more important consideration as to whether coal cleaning can effectively remove the most environmentally sensitive trace elements in coal than what trace minerals are present.