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Wyszukujesz frazę "Sandstone" wg kryterium: Temat


Tytuł:
Assessment of the quantitative and chemical groundwater status of the Łukowica river catchment area
Autorzy:
Pietrzak, D.
Powiązania:
https://bibliotekanauki.pl/articles/184155.pdf
Data publikacji:
2016
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
sandstone
shale
catchment area
Opis:
The main objective of this thesis is the assessment of the quantitative and chemical groundwater and surface water status of the Łukowica river catchment area. This area is located within the Magura Nappe of Outer Carpathians that are built of flysch, which is a series of alternating layers of sandstone and shale (Oszczypko & Wójcik 1989a, 1989b). The reason for making hydrological characteristics of the catchment area is i.e. to determine the status and causes of hydrological changes occurring within it, using the surface and groundwater, management, the degree of anthropogenic impact on the water, quantitative and chemical balance of water and the size of disposable and renewable resources of analyzed area. Hydrological investigations are necessary to know the process of water circulation in the catchment area. Then these investigations were the basis for further works focused on the factors affecting features of the river regime. The work is based on my own field researches carried out in September 2015. In order to assess the quantitative and chemical waters status, hydrogeological mappings of the field were performed, including measurements of the depth of groundwater table in dug wells by hydrogeological whistle. The discharge of sources and the volume flow of the river in the upper, middle and lower section, and two inflows was also examined. Flow measurements for the river were made on the 10 meter-section by float method. For the inflows, the volumetric method was applied (Banach 2005). At the end, the literature and cartographic elaborations were collected. Prepared materials enabled to make the hydrogeological map of the quaternary multiaquifer formation and to illustrate the circulation of groundwater. On these basis the groundwater’s renewable and disposable resources of the catchment basin were calculated (Chełmicki 2001) and they are 3086 m 3 /d and 1543 m 3 /d respectively. To determine the amount of reserves of groundwater resources it is necessary to compare obtained results with an average annual extraction from groundwater intakes ( Rozporządzenie..., 2008). For the purpose of the work the water samples were collected in 7 dug wells and in 4 points alongside the river – in the upper, middle and lower section. The samples were analyzed in the Accredited Hydrogeochemical Laboratory of the Hydrogeology and Engineering Geology Department AGH (Accreditation Certificate AB 1050). The test results were the basis for assessing the chemical status of water. They are developed in accordance with applicable laws, which are based on the Water Framework Directive of the European Parliament ( Commission Directive..., 2009) and Regulation of the Minister of the Environment for the criteria and method of evaluation of groundwater status ( Rozporządzenie..., 2015). The mineralization of the surface water of Łukowica River is more or less constant at the entire length and it is 430–450 mg/dm 3, whereas the mineralization of groundwater for the catchment is more diverse and ranges from 325 mg/dm 3 to 553 mg/dm 3. According to the Shchukarev–Priklonskiy classification, both surface water and groundwater are HCO 3 -Ca-Mg type. On the basis of the results of chemical analyzes, the chemical status of groundwater was considered as good, since they were classified as class II of groundwater quality ( Rozporządzenie..., 2015). The limit values for class I have been exceeded for the following cations: Zn 2+, Cu 2+, Mo 6+, Ag +, Ca 2+ and anions: NO 2 − and HCO 3 −. The chemical status of surface water was considered as good, since it was classified as class II of surface water quality ( Rozporządzenie..., 2011). The limit values for I class have been exceeded only for anion HCO 3 −. All European Union countries, including Poland, are obliged to respect the Water Framework Directive, established by the European Parliament in 2000 and updated in 2009 ( Commission Directive..., 2009). It obliges member states to perform i.e. assessment of quantitative and chemical status in an area of separated bodies of groundwater. Result of the assessment of the quantitative and chemical groundwater status is the basis for the development of action programs. These programs lead to protection of groundwater bodies and to achieve good groundwater status at the latest by 2015. Many catchments of small streams have not been covered by such tests so far, hence the appropriateness of conducting the studies mentioned above. Summing up, both surface water and groundwater of the Łukowica River catchment area were classified into class II of water quality, what means that they are characterized by a good chemical status. Mineralization of surface water is similar on the entire length of the river and is 430–450 mg/dm 3. In contrast, mineralization of groundwater is in the range from 325 mg/dm 3 to 553 mg/dm 3. The amount of renewable resources for this catchment is 3086 m 3 /d and the value of disposable resources is 1543 m 3 /d.
Źródło:
Geology, Geophysics and Environment; 2016, 42, 1; 118-119
2299-8004
2353-0790
Pojawia się w:
Geology, Geophysics and Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Physicochemical Properties of Soils derived from Sandstone Parent Materials under Selected Land use types at Agoi-Ibami in Central Cross River State, Nigeria
Autorzy:
Eyong, M. O.
Akpa, E. A.
Powiązania:
https://bibliotekanauki.pl/articles/1076791.pdf
Data publikacji:
2019
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Physicochemical properties
Sandstone
land use types
Opis:
Three profiles were sited on the major landscape elements of crest, middle slope and lower slope on three land uses; Forest (FS), Rubber (RS) and arable cropping (AS) at Agoi-Ibami in Central Cross River State, Nigeria. For study purposes, soil samples were collected from the morphogenetic horizons for the analysis of physical and chemical properties. Results showed that the surface horizon textures were mostly sandy loams with little sandy clay loam, while subsurface textures were mostly sandy clay loams with few silt clay loams and clays. The bulk densities were below the ranges of 1.46 to 1.63 g cm-3 for silts and clays and 1.75 g cm-3 for sands. This imposes stresses such as mechanical resistance to root penetration, decrease in cultivation and organic matter. The surface and subsurface pH values vary from 4.9–4.5 in FS, 4.9-4.6 in RS and 4.9 in AS, indicating that the soils are very strongly acidic. The Organic carbon contents was low with mean values of 4.33 and 0.6 % in surface and subsurface for FS, 2.10 and 0.50 % for surface and subsurface for RS, while surface and subsurface values proved to be 0.57 and 0.31 % for AS. The nitrogen contents was also low, mean values of 0.16 and 0.06 % for surface and subsurface for FS, 0.23 and 0.08 % for surface and subsurface for RS, and 0.19 and 0.10 % for surface and subsurface for AS. The content and available phosphorus are equally low, except for AS, with surface mean values ranging from 11.52 mg kg-1 to 13.87 mg kg-1. The exchangeable cations, Ca, Mg, K, and Na were very low, while exchangeable H+ and Al3+ were high. Base saturation was also low in FS and AS (< 50%) in surface soils, but higher in AS in the surface and in RS in the subsurface soils. The mean values of organic matter were 4.33 and 0.16 %. The land use should, therefore, be adjusted by application of recommended inorganic fertilizers and organic matter so as to support growth of crops such as maize, yams, cassava etc.
Źródło:
World News of Natural Sciences; 2019, 23; 1-12
2543-5426
Pojawia się w:
World News of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sedimentary record comparison of the Piwniczna and Poprad sandstones (Magura Unit, Outer Carpathians) : a study from the border area of eastern Slovakia and Poland
Autorzy:
Dirnerová, D.
Farkašovský, R.
Powiązania:
https://bibliotekanauki.pl/articles/2060081.pdf
Data publikacji:
2018
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Outer Carpathians
Magura Unit
Piwniczna Sandstone Member
Poprad Sandstone Member
facies analysis
thin-section analysis
Opis:
Thick deep-water sandstone successions are known from many localities in the Outer Western Carpathians. The present study is focused on comparison of deposits of the Piwniczna (PwSM) and Poprad (PpSM) Sandstone members belonging to the Magura Formation of the Magura Unit, outcropping in the eastern Slovakia and Poland border area. At the general level, a close similarity of the sandstone successions was confirmed by this study. However, in more detail, facies analysis shows differences in the thickness of the sandstone successions, in grain size and in the character of intervals between the thick sandstones. Thin-section study, though, showed almost the same modal composition in the sandstones analysed. The sandstone successions studied are interpreted as sandy debrites, the PwSM showing transitional facies to turbidites. These deposits rep resent channelized depositional lobes in the proximal part of a submarine fan with the PpSM closer to the source. The sediment source area was common to both lithostratigraphic units, and was most likely the South-Magura Ridge.
Źródło:
Geological Quarterly; 2018, 62, 4; 881--895
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Removal of iron from sandstone by magnetic separation and leaching: case of El-Aouana deposit (Algeria)
Autorzy:
Bouabdallah, S.
Bounouala, M.
Chaib, A. S.
Powiązania:
https://bibliotekanauki.pl/articles/89037.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Wydział Geoinżynierii, Górnictwa i Geologii. Instytut Górnictwa
Tematy:
leaching
magnetic separation
sandstone
mineral processing
Opis:
To improve the quality of raw materials from North East Algeria and their application in the field of flat glass manufacturing, the sandstone of El-Aouana (Jijel) was subjected to a physicochemical characterization. Analysis techniques such as X-ray diffraction, atomic absorption spectrophotometry and a chemical analysis of size fractions by sieving were used. According to this characterization it is noticed that sandstone feedstock contains primarily quartz (SiO2), as well as ferriferous minerals considered as impurities during glass manufacturing. This work concerns the removal of iron oxide from silica sandstone to obtain a material acceptable for flat glass manufacturing. For this, we have studied the silica enrichment process using a magnetic separation. Moreover, a leaching process by using hydrochloric acid has been studied under various experimental conditions; the parameters studied were: hydrochloric concentration, temperature, and time of contact. The results obtained show that the leaching studied presents a better removal of iron oxide after 150 min of treatment at temperature 90°C with a 3 mol/L, a concentrate obtained final of 99.16% SiO2 with a content of 0.01% Fe2O3.
Źródło:
Mining Science; 2015, 22; 33-44
2300-9586
2353-5423
Pojawia się w:
Mining Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical approach in recognition of selected features of rock structure from hybrid hydrocarbon reservoir samples based on microtomography
Autorzy:
Kaczmarek, Ł. D.
Zhao, Y.
Konietzky, H.
Wejrzanowski, T.
Maksimczuk, M.
Powiązania:
https://bibliotekanauki.pl/articles/178817.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
compression test
flow paths
porosity
sandstone
Opis:
The study employs numerical calculations in the characterization of reservoir sandstone samples based on high-resolution X-ray computed microtomography. The major goals were to determine porosity through pore size distribution, permeability characterization through pressure field, and structure impact on rock strength by simulation of a uniaxial compression test. Two Miocene samples were taken from well S-3, located in the eastern part of the Carpathian Foredeep. Due to the relation between sample size and image resolution, two X-ray irradiation series with two different sample sizes were performed. In the first approach, the voxel side was 27 µm and in the second it was up to 2 µm. Two samples from different depths have been studied here. Sample 1 has petrophysical features of conventional reservoir deposits, in contrast to sample 2. The approximate grain size of sample 1 is in the range 0.1–1.0 mm, whereas for sample 2 it is 0.01–0.1 mm with clear sedimentation lamination and heterogenic structure. The porosity, as determined by µCT, of sample 1 is twice (10.3%) that of sample 2 (5.3%). The equivalent diameter of a majority of pores is less than 0.027 mm and their pore size distribution is unimodal right-hand asymmetrical in the case of both samples. In relations to numerical permeability tests, the flow paths are in the few privileged directions where the pressure is uniformly decreasing. Nevertheless, there are visible connections in sample 1, as is confirmed by the homogenous distribution of particles in the pore space of the sample and demonstrated in the particle flow simulations. The estimated permeability of the first sample is approximately four times higher than that of the second one. The uniaxial compression test demonstrated the huge impact of even minimal heterogeneity of samples in terms of micropores: 4–5 times loss of strength compared to the undisturbed sample. The procedure presented shows the promising combination of microstructural analysis and numerical simulations. More specific calculations of lab tests with analysis of variable boundary conditions should be performed in the future.
Źródło:
Studia Geotechnica et Mechanica; 2017, 39, 1; 13-26
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Provenance of the Malužiná Formation sandstones (Western Carpathians, Slovakia): constraints from standard petrography, cathodoluminescence imaging, and mineral chemistry of feldspars
Autorzy:
Vdacny, M.
Powiązania:
https://bibliotekanauki.pl/articles/2060008.pdf
Data publikacji:
2013
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Sandstone Petrography
Cathodoluminescence
Mineral Chemistry
provenance
Opis:
Petrographic, cathodoluminescence, and phase chemistry studies of detrital grains were carried out on sandstones from the Permian Malužiná Formation in the Malé Karpaty Mts. (Hronic Unit, Western Carpathians, Slovakia) to determine their provenance and tectonic setting during the Permian. The results of the present study suggest derivation of the Malužiná Formation sandstones from multiple source areas. Major source lithologies were acid (felsic) plutonic rocks and low- to high-grade metamorphic rocks (probably metamorphosed igneous rocks and metasedimentary rocks), but notable amounts of detritus were also derived from felsic and mafic volcanic rocks. There was only a minor contribution from sedimentary rocks. Detritus was stripped rapidly from broken, high-relief source areas before weathering processes could destroy unstable framework constituents, as documented by the relatively high content of unstable rock fragments and the high feldspar content in the sandstones investigated. The provenance characteristics indicate that deposition of the sandstones of the Malužiná Formation occurred in a rifted continental margin environment supplied from an uplifted area on a thick continental crust composed of rocks of older fold belts.
Źródło:
Geological Quarterly; 2013, 57, 1; 61--72
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Laboratory measurement of wettability for Ciężkowice sandstone
Autorzy:
Czarnota, R.
Janiga, D.
Stopa, J.
Wojnarowski, P.
Powiązania:
https://bibliotekanauki.pl/articles/298866.pdf
Data publikacji:
2016
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
Ciężkowice sandstone
rock wettability
oil fields
Opis:
The type of reservoir rock wettability is one of the most important factors affecting flow of formation fluids in rock pores. It impacts on the characteristics of capillary pressure curves and residual oil saturation, what result in final recovery factor. There are generally, four differ states of wettability for hydrocarbon fields. These are: water wet, oil wet, mixed and fractional. For determination of wettability both quantitative and qualitative methods are implemented. In presented work, the results of wettability laboratory measurement for Ciężkowice sandstone by Amott–Harvey has been shown. Obtained outcomes underline the influence of wettability phenomena on the recovery factor for Carpathian hydrocarbon fields, where Ciężkowice sandstone is the oil bearing formation. The proper understanding of the wettability of reservoir is essential for determining the most efficient way of oil production.
Źródło:
AGH Drilling, Oil, Gas; 2016, 33, 1; 167-172
2299-4157
2300-7052
Pojawia się w:
AGH Drilling, Oil, Gas
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Distinct Element Simulation of a Landslide Process
Autorzy:
Zabuski, Lesław
Mierczyński, Jacek
Powiązania:
https://bibliotekanauki.pl/articles/1837764.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
Distinct Element Method
sandstone quarry
landslide
Opis:
The paper presents a numerical simulation of the development of a catastrophic landslide in a sandstone quarry and methods of reconstructing the quarry to its previous condition from before the landslide. The important objective of the paper is to present the capabilities of the numerical method used in the analysis of the landslide process, namely the Distinct Element Method (DEM). This method is poorly known, though it is capable of solving important geotechnical problems in which massive displacements are modelled. The features of the method are presented on the basis of a case study. Therefore a numerical analysis is carried out to show the performance of DEM in generating a displacement of several dozen meters in the example of a catastrophic landslide that occurred some years ago in a sandstone quarry. This engineering problem makes it possible to describe and analyse the mechanisms, causes and consequences of the landslide.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2020, 67, 1-4; 3-16
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Detritus from Variscan lower crust in Rotliegend sandstones of the Intra-Sudetic Basin, SW Poland, revealed by detrital high-pyrope garnet
Autorzy:
Biernacka, J.
Powiązania:
https://bibliotekanauki.pl/articles/191532.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Geologiczne
Tematy:
Permian
Sudetes
sandstone
provenance
detrital garnet
granulite
Opis:
It is well established that pebbles in the Sudetic Permian conglomerates were derived from the nearby Variscan massifs of upper-crustal composition. However, the provenance of the sand-size grains remains enigmatic. Electron microprobe analyses (EMPAs) of detrital garnet from upper Rotliegend conglomerates and sandstones exposed at Golińsk, the Intra-Sudetic Basin, showed a distinct assemblage dominated by high-pyrope (high-grossular) almandine, typical of high-grade metamorphic rocks, such as high-pressure granulites. These results, coupled with a previously reported population of similar detrital garnet in the stratigraphically equivalent conglomerates and sandstones of the Karkonosze Piedmont Basin, suggest regional input of detrital lower-crustal material. This detritus was derived ultimately either from the Moldanubian Zone of the Bohemian Massif, or from high-grade rocks of the Orlica-Śnieżnik Massif that were exposed in the Carboniferous–Permian. Permian siliciclastic rocks might have covered a large part of the Sudetes. During the Mesozoic and Palaeogene, these rocks might have been recycled further, contributing high-pyrope garnet, as an accessory mineral, into siliciclastic rocks of the Sudetes and their foreland.
Źródło:
Annales Societatis Geologorum Poloniae; 2012, 82, 1; 127--138
0208-9068
Pojawia się w:
Annales Societatis Geologorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Detritus from Variscan lower crust in Rotliegend sand stones of the Intra-Sudetic Basin, SW Poland, revealed by detrital high-pyrope garnet
Autorzy:
Biernacka, J.
Powiązania:
https://bibliotekanauki.pl/articles/191747.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Geologiczne
Tematy:
Permian
Sudetes
sandstone
provenance
detrital garnet
granulite
Opis:
It is well established that pebbles in the Sudetic Permian conglomerates were derived from the nearby Variscan massifs of upper-crustal composition. However, the provenance of the sand-size grains remains enigmatic. Electron microprobe analyses (EMPAs) of detrital garnet from upper Rotliegend conglomerates and sandstones exposed at Golińsk, the Intra-Sudetic Basin, showed a distinct assemblage dominated by high-pyrope (high-grossular) almandine, typical of high-grade metamorphic rocks, such as high-pressure granulites. These results, coupled with a previously reported population of similar detrital garnet in the stratigraphically equivalent conglomerates and sandstones of the Karkonosze Piedmont Basin, suggest regional input of detrital lower-crustal material. This detritus was derived ultimately either from the Moldanubian Zone of the Bohemian Massif, or from high-grade rocks of the Orlica-Śnieżnik Massif that were exposed in the Carboniferous–Permian. Permian siliciclastic rocks might have covered a large part of the Sudetes. During the Mesozoic and Palaeogene, these rocks might have been recycled further, contributing high-pyrope garnet, as an accessory mineral, into siliciclastic rocks of the Sudetes and their foreland.
Źródło:
Annales Societatis Geologorum Poloniae; 2012, 82, 2; 127--138
0208-9068
Pojawia się w:
Annales Societatis Geologorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental research on energy release characteristics of water-bearing sandstone alongshore wharf
Autorzy:
Wang, S.
Zhao, Y.
Zou, Z.
Jia, H.
Powiązania:
https://bibliotekanauki.pl/articles/258604.pdf
Data publikacji:
2017
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
sandstone
energy release
water content
confining pressure
Opis:
It is important to evaluate the deformation and failure of sandstone in the foundation engineering of coast, river bank and lake shore. While the deformation and failure of sandstone is a comprehensive result of energy release and dissipation, and energy release is the internal reason which leads to global failure of the sandstone. The experimental analysis is conducted on the character of energy revolution of the sandstone specimen by rating loading and unloading, and the catastrophe model is followed in analyzing elastic strain energy accumulation and release in rock deformation and failure. The index based on elastic energy release is proposed to assess the rock brittleness. It is found that increasing water content is to relieve energy release and catastrophe failure of the rock specimen, and weakening the capacity of elastic energy storage. The peak and residual values of elastic energy are raised as the confining pressure increases, and the post-peak released energy decreases progressively. The confining pressure strengthens energy storage and inhibits energy release of the rock specimen, and saturation of rock will weaken this inhibit effect. The brittleness index decreases with increasing confining pressure as the rock specimen transforming from brittle to ductile.
Źródło:
Polish Maritime Research; 2017, S 2; 147-153
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Age of Lower Jurassic Springdale Sandstone of Southwestern Utah from its Magnetic Polarity Sequence
Autorzy:
Steiner, M.
Powiązania:
https://bibliotekanauki.pl/articles/2077337.pdf
Data publikacji:
2014
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
sinemurian magnetostratigraphy
Springdale Sandstone
paleopole
piaskowiec Springdale
Opis:
The Springdale Sandstone records a large number of reversals of the geomagnetic field. Forty-three percent of the 60 m section investigated showed 25 polarity intervals. These frequent reversals follow the nearly constant normal polarity of the underlying Whitmore Point strata. Comparison of the reversal sequence of the Springdale Sandstone with a core from the Paris Basin suggests that the Springdale Sandstone spans an interval extending possibly from as early as late Hettangian to early-mid Sinemurian time. The paleomagnetic pole calculated from Springdale paleomagnetic directions is statistically identical to that of the underlying Whitmore Point Member of the Moenave Formation, and considerably different from that of the overlying Kayenta Formation. This similarity suggests that the Springdale Sandstone should be retained as a member of the Moenave Formation, not considered part of the Kayenta Formation.
Źródło:
Volumina Jurassica; 2014, 12, 2; 23--30
1896-7876
1731-3708
Pojawia się w:
Volumina Jurassica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Coprolite of a durophagous carnivore from the Upper Cretaceous Godula Beds, Outer Western Carpathians, Poland
Autorzy:
Bajdek, P.
Powiązania:
https://bibliotekanauki.pl/articles/2059732.pdf
Data publikacji:
2013
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
coprolite
feces content
taphonomy
turbidite sandstone
Cretaceous
Opis:
The Upper Cretaceous turbidite sandstones of the Godula Beds at Międzybrodzie Bialskie, Outer Western Carpathians, Poland, yielded a specimen here interpreted as a coprolite due to its elongated morphology and a high content of fragmented inoceramid shells. The coprolite was produced by a durophagous carnivore, which was most likely a teleost fish, or possibly a reptile. Coprolites are therefore confirmed to have a potential utility as aggregations of body fossils in macrofossil-poor sedimentary rocks, exemplified by the Godula Beds.
Źródło:
Geological Quarterly; 2013, 57, 2; 361--364
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Petrographic and geochemical study of the Maastrichtian Ajali Sandstone, North Central Nigeria
Autorzy:
Ogala, J. E.
Olobaniyi, S. B.
Omo-Irabor, O. O.
Adaikpoh, E. O.
Powiązania:
https://bibliotekanauki.pl/articles/2059843.pdf
Data publikacji:
2015
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
petrography
geochemistry
Ajali Sandstone
provenance
tectonic setting
Opis:
he Upper Cretaceous Ajali Sandstone is an extensive stratigraphic unit of the Anambra Basin in southern Nigeria. It consists of friable, white cross-bedded sandstones exhibiting a fining upward sequence. Structures such as bioturbation, planar and herringbone cross beds indicate variability in depositional environment ranging from fluviatile to deltaic. Petrographic and geochemical compositions (major and trace elements) of these sandstones have been investigated to determine their provenance, tectonic setting and weathering conditions. Fifteen sandstone samples examined are rich in quartz but poor in feldspar and lithic fragments. Texturally, the framework grains of the sandstones are fine- to medium-grained, sub-angular to sub-rounded, moderately sorted to poorly sorted, positively skewed and leptokurtic. The sandstones are texturally immature as depicted by their sub-angular edges of grains, but mineralogically mature in terms of high percentage of quartz. The high chemical index of alteration (CIA) values (71.0–99.2%) for these sandstones suggests that they were derived from highly weathered rocks in the source area. The composition of the major oxides in the sandstones revealed that SiO2 (49.1–99.7%), Al2O3 (0.2–30.3%), Fe2O3 (0.4–1.8%) and TiO2 (0.06–3.2%) were the most abundant elements in all sandstone samples indicating a high detrital quartz and clay mineral content. The Al2O3/TiO2 ratios (1.47 to 12.48), Ti/Zr (6.48–18.63) and Zr/Cr (2.24–22.36) suggest that the sandstones were derived from variable basement complex rocks, including some contribution from mafic or ultramafic components. Inferences from the plots of K2O/Na2O versus SiO2 indicated a passive margin tectonic setting for the sandstones. The high loading of CaO and Na2O in more than 50% of the samples is indicative of terrigenous input, mainly in the form of carbonates and silicates. These results are generally consistent with a derivation of the sandstones from adjacent igneous and metamorphic basement complexes (Cameroon–Adamawa highlands and Oban Massif) while the extensive and blanket-like geometry of the Ajali Sandstone is indicative of an excellent reservoir for groundwater in the Anambra Basin.
Źródło:
Geological Quarterly; 2015, 59, 1; 79--90
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
What do the K-Ar ages of illite tell us about the diagenesis of Rotliegend sandstones of the Fore-Sudetic Monocline, SW Poland?
Autorzy:
Biernacka, J.
Powiązania:
https://bibliotekanauki.pl/articles/2060296.pdf
Data publikacji:
2015
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
K-Ar dating
illite
sandstone
Permian
Polska
Opis:
The all available K-Ar data of authigenic illite from Rotliegend aeolian sandstones of the Fore-Sudetic Monocline, including the results from six samples examined in the present study, are reviewed in terms of their geological meaning, relation to diagenetic processes occurring in the sandstones, and implications for a petroleum system. The majority of ages fall in the range between 195 and 150 Ma, i.e. they correspond to Jurassic times. The results may be grouped in several time intervals, which are almost identical to those identified for Rotliegend sandstones of central and western Europe, and which are interpreted as pulses of intensive illite growth. The K-Ar data corroborate the long-held assumption that throughout the entire Southern Permian Basin Jurassic illite growth was triggered by the same, large-scale underlying processes, which manifested themselves in enhanced heat flow. These processes may also have caused the expulsion of hydrocarbons from source rocks.
Źródło:
Geological Quarterly; 2015, 59, 2; 257--270
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł

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