Clastic Fragments Research Articles

FEATURES OF THE FORMATION, INTAKE AND DISTRIBUTION OF THE IRON-CONTAINING COMPONENT IN THE WATER SUSPENSION OF THE DNIEPER RIVER WITHIN ZAPORIZHZHIA CITY

The article presents the results of research devoted to one of the aspects of environmental issues, namely: the determination of the distribution features of the solid component of the river suspension containing iron oxide; investigation of the morphological characteristics of iron-containing particles; and the discovering of their genetic affiliation to various technological processes of metallurgical production. The results of many years of continuous comprehensive research on the distribution of iron in the suspended matter of the Dnieper water within Zaporizhzhia city are presented. Field observations were carried out by scientists of the Institute of Geological Sciences of the National Academy of Sciences of Ukraine (IGS) in cooperation with specialists from the State Institution “Scientific Hydrophysical Center of the National Academy of Sciences of Ukraine” (SHC). Analytical studies of the solid phase of the suspended matter were done in the Center for Collective Use of Scientific Equipment of the National Academy of Sciences of Ukraine and the Educational and Scientific Institute “Institute of Geology” of Taras Shevchenko Kyiv National University. The publication considers the seasonal features of the distribution of the total iron content in suspension and the relationship of its monthly changes with the distribution of concentrations of such heavy metals as copper, chromium, nickel, zinc. Considerable attention is paid to the examination of iron-containing particles present in suspension, their chemical and trace element composition and the allocation of their individual categories in accordance with the technogenic processes during which they were formed. Comprehensive analysis of suspension samples made it possible to identify and classify a group of typical iron-bearing formations that are inherent in the territory of Zaporizhzhia city. Based on a set of characteristics, three main genetic categories have been identified: spherical mineral aggregates represented by iron oxide; clastic fragments of Fe2O3, and aluminosilicate spherules (formation, the main or essential component of which is aluminum oxide with an admixture of iron). The obtained data showed a significant influence of the metallurgical industry on the chemical composition of the Dnieper suspension within Zaporizhzhia. Comparison of iron-containing particles observed in the Dnieper suspended matter with the substance filtered out by gas purification systems of various parts of metallurgical production and slag deposits showed that the most active emission to the environment occurs during the preparation and smelting of iron ore.

Mobilization pilot test of PCE sources in the transition zone to aquitards by combining mZVI and biostimulation with lactic acid

The potential toxic and carcinogenic effects of chlorinated solvents in groundwater on human health and aquatic ecosystems require very effective remediation strategies of contaminated groundwater to achieve the low legal cleanup targets required. The transition zones between aquifers and bottom aquitards occur mainly in prograding alluvial fan geological contexts. Hence, they are very frequent from a hydrogeological point of view. The transition zone consists of numerous thin layers of fine to coarse-grained clastic fragments (e.g., medium sands and gravels), which alternate with fine-grained materials (clays and silts). When the transition zones are affected by DNAPL spills, free-phase pools accumulate on the less conductive layers. Owing to the low overall conductivity of this zone, the pools are very recalcitrant. Little field research has been done on transition zone remediation techniques. Injection of iron microparticles has the disadvantage of the limited accessibility of this reagent to reach the entire source of contamination. Biostimulation of indigenous microorganisms in the medium has the disadvantage that few of the microorganisms are capable of complete biodegradation to total mineralization of the parent contaminant and metabolites. A field pilot test was conducted at a site where a transition zone existed in which DNAPL pools of PCE had accumulated. In particular, the interface with the bottom aquitard was where PCE concentrations were the highest. In this pilot test, a combined strategy using ZVI in microparticles and biostimulation with lactate in the form of lactic acid was conducted. Throughout the test it was found that the interdependence of the coupled biotic and abiotic processes generated synergies between these processes. This resulted in a greater degradation of the PCE and its transformation products. With the combination of the two techniques, the mobilization of the contaminant source of PCE was extremely effective.

Carbon, oxygen, and strontium isotopic fingerprint in Neoproterozoic to early Cambrian limestones in an active margin setting: A record of local environment or global changes?

The Ediacaran to early Cambrian limestones preserved within the Blovice accretionary wedge, Bohemian Massif, are part of Ocean Plate Stratigraphy (OPS) and provide an intriguing example of how paleooceanographic and palaeoenvironmental conditions at active plate margins may be recorded by isotopic composition. Field relations, petrography and geochemical data elucidate the complex interplay of oceanic, diagenetic and volcanic processes. Rare calcite-dominated primary oolitic/pisolitic limestones were deposited on the slopes of seamount volcanoes in shallow-water lagoons and their formation was simultaneous with volcanic activity. In contrast, volumetrically more abundant re-deposited limestones occurring as layers within siliciclastic, graywacke-dominated successions consist of clastic fragments derived from previously formed carbonate ramps, which were disrupted during subduction and subsequently incorporated in deep-water turbidity currents. In both limestone types, the major/trace element as well as C, O and Sr isotope signatures are well preserved and provide a fingerprint of various limestone depositional conditions that can be directly linked with paleooceanic and paleogeographic interpretations. The observed spatial distribution of carbonate-bearing silicate rocks with elemental and isotopic compositions that differ from primary limestones suggest their common origin at active margins and indicate that some of these rocks have been formed by hydrothermal activity. Finally, we demonstrate that the carbonate member of OPS may provide important insights into the polarity and dynamics of subduction zones.

Oil shale of the Middle Volga region: composition, structure, energy properties

The article presents the results of the Volga oil shale study in the territory of Tatarstan and the Ulyanovsk region. It is shown that shales are polymineral rocks of complex composition. The main valuable component is organic matter (kerogen), formed from the products of aquabionts fossilization. Ash components are represented by clay minerals, clastic fragments of mineral grains, calcareous fragments of organic residues, and diagenetic pyrite. Organic matter has a complex structure. The predominant fractions are light and medium hydrocarbons boiling out in the temperature range 150-560°C. In smaller amounts, heavy fractions are present, which are released at temperatures of 560-620°C. The heat capacitance of oil shale ranges from 1607 to 9052 J/g. Loss of shale mass can range from 18.0 to 25.0% of the original sample. According to the summary valuable and genetic indicators, the Volga oil shale belongs to the humus-sapropel type; low-calorie in heat of combustion terms; polysulphide in terms of sulfur content; aluminosilicate-carbonate in terms of the prevalence of oxides in ash.

Establishment of occupation chronicles in Grotte Mandrin using sooted concretions: Rethinking the Middle to Upper Paleolithic transition

Soot marks, witnesses of past human activities, can sometimes be noticed in concretions (speleothem, travertine, carbonated crust, etc.) formed in cavities. We demonstrate here that these deposits, generally ignored in archaeological studies, turned out to be a perfectly suitable material for micro-chronological study of hominin activities in a site. At the Grotte Mandrin (Mediterranean France), thousands of clastic fragments from the rock walls were found in every archaeological level of the shelter. Calcareous crusts containing soot deposits are recorded on some of their surfaces. They appear in thin section as thin black laminae. Microscopic observation of these crusts revealed that they kept track of many occupations. We show that is possible to link them with the archaeological units identified during the excavation. Minimum Number of Occupations (MNO) can be built out of these sooted crusts. MNO are usually high and attest to the cumulative nature of each archaeological unit. They are witnesses of each occupation of hominin groups in each archaeological level of the cave. This study also shows that, in Grotte Mandrin, a very short time separates the first Middle/Upper Paleolithic transitional groups' occupations from those of the last Mousterians. The research perspectives on soot deposits are diversified and raise the possibility of studying multiple aspects of past human life, and in this case, to rethink the Middle/Upper Paleolithic transition, with an unmatched temporal resolution. Sooted concretion analysis provides high temporal resolution archaeology. There is a real possibility of extending this study with chronological implications to cavities of all ages and areas.

Paleo-Tsunami deposits on the Red Sea beach, Egypt

The characteristics of the recent tsunami deposits threw light on some sources of deposition on the beach of the Red Sea. The studied area is delineated by latitudes 25°6′ N and 25°9′ N and longitudes 34°50′ E and 34°53′ E; it covers an elongate area of about 12 km2 along the Red Sea coast, North Marsa Alam City (4 km). The area is bounded by Wadi Asalay to the north and Wadi Sifayn from the south. For evaluation of the area, a lot of information allows us to interpret the conditions prevailing during deposition of the sediments especially at the coast. To achieve the target, five wells were drilled to study core samples, well logging measurements, and 69 vertical electrical sounding stations were carried out. The studied area and adjacent areas were geologically surveyed to note geological features related to Paleo-earthquakes. From geological and geophysical studies, the dominant rock types at the western portions of the studied area are sandstone, sandy clay, clay, clayey sandstone, and gravels; at the middle portion of the studied area, the rocks are hard, but the eastern side of the area, especially at the beach of the Red Sea, several cycles of depositions of coral reefs occurred with intercalations of clastic deposits such as clay, sand, sandstone, conglomerate, gravels, pebbles, and a lot of fossils and shell fragments. The rocks are characterized by heterogeneous properties and ill-sorted. The area includes large numbers of faults due to highly tectonism of the area. The results indicated that the area has lateral variation of sediments. The carbonate rocks at the beach contain clastic fragments, and carbonate blocks are included within clastic rocks. With increasing the distance from the beach to the west, the sediments are less heterogeneous. The beach of the Red Sea was subjected to Paleo-tsunami waves due to highly Paleo-seismic activity inside the Red Sea and left their signature in geological column especially at the beach. The observation of some geological features such as Paleo-liquefaction and landslides indicate that the area subjected to strong earthquakes related to rifting of the Red Sea.

A NOTE ON CARBONATE-FILLED NEPTUNEAN DYKES IN THE OX MOUNTAINS GRANODIORITE, NW IRELAND

This paper documents the first record of carbonate-filled neptunean dykes within the Ox Mountains Granodiorite. A post-Carboniferous age for the formation of the dykes is rejected and a Visean age favoured. Differential uplift and tilting of segments of the Ox Mountains inlier could have contributed to a complex sub-Visean unconformity and Visean deposition. Field relationships and petrology of the neptunean dykes Neptunean dykes within the Ox Mountains Grano diorite crop out on a peninsula of the isthmus near Pontoon (G 209 005) between Lough Conn and Lough Cullin, Co. Mayo (Fig. 1) at a height of 15m above sea level. They are formed mainly of horizon tally laminated micritic limestones. Seven neptunean dykes occupy eroded vertical joints with a mean ori entation of 098? (Taylor 1966, Figs 32A and 32D; Crane 1984. Fig. 32), extend to a depth of less than a metre, and are less than 2cm in width (Figs 2a and 2b). No evidence of movement along the contact walls has been observed. The dyke infills have sharp contacts with the granodiorite (Figs 2a-2c) and con sist of alternating clean light grey (N7, Geological Society of America 1970) and silty dark grey (N3) sub-parallel bands that are usually less than 3mm in thickness (Fig. 2b). Some bands exhibit small-scale load/erosional structures (Fig. 2b). Since the bands are approximately horizontal they are probably in their formation position. The mineralogy of the infills is predominately micro crystalline calcite (>96%) with clastic fragments of main ly silt-sized sub-angular quartz (rarely exceeding 0.5mm in diameter) and rare altered feldspar and micas (Fig. 2c). Most likely the clastic fragments have been derived from the adjacent granodiorite. Palaeontological material has not been observed and attempts to isolate microfos sils from the infill have proved unsuccessful. Hence, the age of formation for the neptunean dykes has not been resolved with any certainty.

A contribution to geochemical prospecting for fluorite

With fluorine as indicator, eight different extraction methods were tested for their suitability in geochemical prospecting for fluorite in stream sediments. Since this material can be regarded as coarse-grained, clastic fragments derived from the bedrock - i.e. granites, gneisses, and fluorite veins as well - it was concluded that the fluorine content of the stream sediments comes mostly from fluorine-bearing bedrock minerals. Anomalous samples contain fluorine predominantly as fluorite from fluorspar mineralization. Five of the commonest fluorine-bearing minerals - fluorite, mica, apatite, amphibole and tourmaline - were treated with the different extractants and with various times of reaction and mineral grain size. Fluorine analysis was by ion-selective electrode. The ratio cx-F (fluorite) vs. cx-F (mica, apatite) was found to be a useful measure of the applicability of the respective method. In order to test this conclusion 41 stream sediment samples ( −177 microns ≜ −80 mesh ) from the area under investigation were treated with eight different extractants. The most suitable extraction solution - boric acid solution - was used for the reconnaissance stream sediment survey in an area of 400 km 2 in the southeastern part of the Black Forest (F.R. Germany).

On the nature and origin of isolated olivine grains in carbonaceous chondrites

Many carbonaceous chondrites contain discrete olivine fragments that have been considered to be primitive material, i.e. direct condensates from the solar nebula or pre-solar system material. Olivine occurring in chondrules and as isolated grains in C3(0) chondrites has been characterized chemically and petrographically. Type I chondrules contain homogeneous forsterite grains that exhibit a negative correlation between FeO and CaO. Type II chondrules contain zoned fayalite olivines in which FeO is positively correlated with CaO and MnO. The isolated olivines in C3(0) chondrites form two compositional populations identical to olivines in the two types of porphyritic olivine chondrules in the same meteorites. Isolated olivines contain trapped melt inclusions similar in composition to glassy mesostasis between olivines in chondrules. Such glasses can be produced by fractional crystallization of olivine and minor spinel in the parent chondrule melts if plagioclase does not nucleate. The isolated olivine grains are apparently clastic fragments of chondrules. Some similarities between olivines in C3(0), C2, and Cl chondrites may suggest that olivine grains in all these meteorites crystallized from chondrule melts.

Chromian spinels from Apollo 14 rocks

Electron microprobe analysis of 13 pink, isotropic, high-relief grains from Apollo 14 clastic rock 14063,14 and a lithic fragment from the 1–2 mm fines, 14002,7, identifies them as spinel minerals dominated by the spinel component MgAl 2O 4 associated with a moderate content of chromite and hercynite. The spinel is thought to have crystallized from a magma high in aluminum and low in iron, with possible crystal separation, followed by incorporation in clastic rocks by impacts. Many bulk compositions of the clastic fragments fall near the field of primary spinel in the model system An-Fo-SiO 2. Experimental syntheses of Apollo 14 rocks are needed to test the suggested primary origin.

Interpreting Detrital Modes of Graywacke and Arkose

ABSTRACT The determination of detrital modes in graywackes and arkoses, here grouped as subquartzose sandstones, requires special attention to the identification of detrital grain types, as defined operationally, and to the recognition of detrital textures, as opposed to textural elements of diagenetic origin. Accurate detrital modes can yield specific information on provenance that can be gained in no other way. Reserving the terms graywacke and arkose for imprecise field descriptions and abandoning the proportion of matrix as a prime means of classification, subquartzose sandstones can be described adequately using six numerical grain parameters. Three primary parameters summing to 100 permit quantitative serial designation of rock types in the form QxFyLz, w ere Q is total quartzose grains, F is total feldspar grains, and L is total unstable lithic fragments in the framework. Three secondary parameters in the form of ratios permit desirable refinement within each primary parameter: C/Q where C is total polycrystalline quartzose grains, P/F where P is total plagioclase grains, and V/L where V is total volcanic lithic grains. Stable grains, whose sum is the parameter Q, are essentially pure silica in mineralogy, and include both monacrystalline quartz and polycrystalline lithic fragments. The latter are gradational to less quartzose types and difficult to distinguish from felsite grains, which display relict textures of volcanic origin and internal relief owing to their polyminerallic nature. Lithic fragments are subdivided at two levels into our main categories within which are various subcategories: (a) volcanic fragments include felsitic, microlitic, lathwork, and vitric types; (b) clastic fragments include silty-sandy and argillaceous types; (c) tectonite fragments include metasedimentary quartzose types and metavolcanic feldspathic or ferromagnesian types; and (d) microgranular fragments include hypabyssal, hornfelsic, and indurated sedimentary types. Interstitial materials include (a) exotic cements like calcite or zeolite; (b) homogeneous, monominerallic phyllosilicate cement displaying textures indicative of porefilling; (c) clayey detrital lutum called protomatrix; (d) recrystallized lutum or protomatrix called orthomatrix with relict detrital texture| (e) murky, polyminerallic, diagenetic pore-filling called epimatr x, whose growth is accompanied by alteration of framework grains; and (f) deformed and recrystallized lithic fragments called pseudomatrix. Extensive albitization and other alterations complicate the interpretation of detrital modes in many rocks, but potential errors commonly can be avoided by close attention to mineralogy and relict texture except where tectonite fabrics disrupt or transpose the original detrital framework. Most subquartzose sandstones were derived from one. or a mixture, of three salient provenance types: (a) volcanic terranes, yielding feldspatholithic rocks nearly free of quartz, (b) plutonic terranes, yielding feldspathic rocks with few lithic fragments, and (c) uplifted sedimentary and metasedimentary tectonic terranes, yielding chert-grain lithic rocks with f w quartz and feldspar grains except where recycled volcanic or plutonic detritus is abundant. Many voluminous accumulations of subquartzose sandstones near continental margins had as their provenance complex volcano-plutonic orogens representing ancient magmatic arcs analogous to modern arcs associated with trenches.

Grains of Detrital, Secondary, and Primary Dolomite from Cretaceous Strata of the Western Interior

Three genetic types of dolomite grains occur in Cretaceous sandstones of the Western Interior and Alaska. They are: (1) Detrital—clastic fragments eroded from dolomite rocks in the sediment-source terrain. These are well-rounded polycrystalline aggregates with relict internal textures inherited from the source rocks. (2) Secondary—formed after deposition of the enclosing sediment. These are small euhedral rhombs that replaced calcite cement in lenticular marine sandstones. (3) Primary—formed within the depositional basin prior to final settling-down and burial of the sediment. These are single rhombic crystals abraded to various degrees of roundness and sorted to the size of associated clastic sand grains. The fabric relationships are of the depositional type, with no evidence of relict internal structures. This ––––eliminates a possible secondary origin. A detrital origin is eliminated by the absence of inherited textures and by the distribution patterns, for primary-dolomite grains are restricted to marine sandstones. Within these sandstones, the primary-dolomite grains are most abundant in the basinward portions. The grains are widely distributed in marine Cretaceous sandstones throughout the Western Interior, regardless of variations in lithology of sediment-source terrains. The recognition and interpretation of primary-dolomite grains is the major contribution of this paper.

Some Grits and Associated Rocks in the Etruria Marls of North Staffordshire

The grits and conglomerates in the Etruria Marls of North Staffordshire include types with a chamosite-rhombohedral carbonate cement containing interesting spherulitic and concentric structures. Manganese appears in this cement and in certain calcareous bands in the argillaceous fades of the Marls. The clastic fragments suggest derivation from Pre-Cambrian and Cambrian rocks. The heavy mineral suite resembles that listed by Fleet for similar horizons in the Midlands, but staurolite is recorded also.There is no new evidence bearing on Robertson’s hypothesis that basic igneous rocks of Carboniferous age have contributed to the formation of the Etruria Marls.

Radioactivity and Organic Content of Some Paleozoic Shales

By measurement of the total beta activity, the total alpha activity and the radium content, a new method has been developed for the routine determination of radioactive substances in sedimentary rocks. The important radioactive elements in these rocks are uranium, thorium, and potassium. Earlier work by Beers and Goodman has shown that these radioactive elements may be found largely in three principal loci: (1) in association with the heavy minerals of sands and sandstones, (2) in K40, the active isotope of potassium which is found in evaporites, oil-field brines, clastic fragments of micas and other potassium-bearing minerals, and in clays and shales which may contain up to 6.5 per cent potassium, (3) in the uranium and thorium content of shales and clays, imp re limestones and marls, shaly sandstones, and organic sediments. Pure limestones and pure quartz sands are found to exhibit practically no measurable radioactivity. Black shales containing up to 16 per cent organic matter have been found to contain high concentrations of the three principal radioactive elements. Excellent correlations are shown to exist between the uranium content, the thorium-uranium ratio and carbon content in individual shale formations. These studies throw new light on three important problems: (1) the sedimentation environment of Paleozoic black shales, (2) the evolution of petroleum source beds, (13) the relationship of radioactive and organic matter in these beds.

Radioactivity and Organic Content of Some Paleozoic Shales

By measurement of the total beta activity, the total alpha activity and the radium content, a new method has been developed for the routine determination of radioactive substances in sedimentary rocks. The important radioactive elements in these rocks are uranium, thorium, and potassium. Earlier work by Beers and Goodman has shown that these radioactive elements may be found largely in three principal loci: (1) in association with the heavy minerals of sands and sandstones, (2) in K40, the active isotope of potassium which is found in evaporites, oil-field brines, clastic fragments of micas and other potassium-bearing minerals, and in clays and shales which may contain up to 6.5 per cent potassium, (3) in the uranium and thorium content of shales and clays, imp re limestones and marls, shaly sandstones, and organic sediments. Pure limestones and pure quartz sands are found to exhibit practically no measurable radioactivity. Black shales containing up to 16 per cent organic matter have been found to contain high concentrations of the three principal radioactive elements. Excellent correlations are shown to exist between the uranium content, the thorium-uranium ratio and carbon content in individual shale formations. These studies throw new light on three important problems: (1) the sedimentation environment of Paleozoic black shales, (2) the evolution of petroleum source beds, (13) the relationship of radioactive and organic matter in these beds.