Articles de revues : « Sand Petrography »

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Ownby, Mary F., James M. Heidke et Henry D. Wallace. « New Insights into Hohokam Buff Ware Production and Distribution ». American Antiquity 80, n^o 2 (avril 2015) : 387–96. http://dx.doi.org/10.7183/0002-7316.80.2.387.

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Hohokam buff ware pottery produced in Arizona has been much studied over the last few decades. However, petrographic analysis has been less frequently applied, due in part to mistaken assumptions regarding the raw materials utilized. The current study reexamined the use of petrography for locating the provenance of buff ware pottery from two sites, La Villa in the Phoenix area and Honey Bee Village in the Tucson area. The petrographic results suggest that production occurred in one primary area along the middle Gila River with minor production in a few other locations. The potters in this area supplied both the Tucson and Phoenix basins. Significantly, it was determined that, after the Early Gila Butte phase, potters switched from crushed schist to sand with natural schist. Such a phenomenon is likely related to increased demand developing from a rapidly evolving sociopolitical system and buff ware pottery becoming a socially valued commodity. This study indicates that petrographic analysis focused on relating sand to known sand composition zones, called petrofacies, can be a key tool for identifying production sources for Hohokam buff ware.

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Guo, Yan Hua, Rui Jun Cao et Li Hua Zhu. « Research on Similar Material in Physical Specimen Petrography of Rock ». Advanced Materials Research 616-618 (décembre 2012) : 346–49. http://dx.doi.org/10.4028/www.scientific.net/amr.616-618.346.

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The similar material composed of quartz sand, gypsum, colophony and alcohol solution, model test and similarity theory were depended on in the test, and standard cylinder specimens were made in different proportions. The physical and mechanical properties of blocks were studied through uniaxial compressive experiments. The researches show that the ratio of elastic modulus and down modulus of the specimens increase linearly with the increase of the ratio of sand and cement; while the elastic modulus, the down modulus and the uniaxial compressive strength decrease in shah model of index function with the increase of it. All parameters mentioned above reduce rapidly with the increase of the ratio of sand and cement when the ratio of sand and cement less than 4, if not, the parameters increase slowly.

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Gravesen, Peter. « Petrography of the quartz sand deposits of the Lower Cretaceous of Bornholm, Denmark ». Danmarks Geologiske Undersøgelse Serie A 10 (1 juin 1986) : 1–24. http://dx.doi.org/10.34194/seriea.v10.7029.

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The quartz sand of the Lower Cretaceous Robbedale Formation and lowermost part of the Jydegard Formation in the Arnager-Sose fault block of Bornholm has been investigated with respect to mineralogy, grain-size, grain rounding and grain shape. Analyses of both light and heavy minerals have been carried out for 18 samples from different localities and facies. The purpose of the investigation was to try to recognize the possible types of source rocks and provenance areas. The Precambrian basement rocks of Bornholm are not the main sources of the sand, especially not the heavy minerals, but parts of the sand may have originated from the basement. The Palaeozoic sandstones and siltstones have delivered only a small amount of material. Parts of the older Mesozoic sediments of the Bornholm Group and Homandshald Member may have been redeposited in the Lower Cretaceous as they contain the same kinds of heavy minerals as the Robbedale and Jydegard Formations, although in differing amounts. It seems very possible, however, that most of the Mesozoic sediments of Bornholm have had a source area outside Bornholm, and this source area has been nearly the same during the whole span of time. The Fenno-Scandian Shield seems to be the most obvious provenance area, but eastern and southern areas are possibilities too. It is concluded that most of the Lower Cretaceous sands are first deposition cycle sediments of both local and distant origin combined with minor amounts of polycyclic sediments of mainly local origin.

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Chmil, L. V. « THE RESULTS AND PERSPECTIVES OF STUDYING CERAMIC WARE PRODUCTION TECHNOLOGY IN THE MIDDLE DNIEPER REGION IN THE 16th — 18th CENTURIES ». Archaeology and Early History of Ukraine 29, n^o 4 (22 décembre 2018) : 323–41. http://dx.doi.org/10.37445/adiu.2018.04.19.

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The paper focuses on studying ceramic ware production technology in the 16th—18th centuries. The main perspective methods for each production stage, such as chemical, petrographic and trajectory have been considered, as well as archaeological, sphragistic and ethnographic sources have been analysed. The ware was made of kaolin clay with the addition of sand. Glaze consisted of lead, sand and metallic oxide for color. Clay with the addition of metallic oxide, such as iron, copper etc. was colorant for painting. The ware was formed with foot potter fast wheel by drawing from a piece of clay. Decor represented relief or painting without or with glaze. The glaze was colored or colorless. The ware was roasted in bicameral kilns with vertical movement of hot gases in oxidizing or reductive medium. Perspective directions of the further study of pottery production technology can be physical and chemical methods, petrography and experiment to verify results of the research.

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Broekmans, Maarten A. T. M., Isabel Fernandes, Ola Fredin et Annina Margreth. « Polarization-fluorescence Microscopy in the Study of Aggregates and Concrete ». Elements 18, n^o 5 (1 octobre 2022) : 321–26. http://dx.doi.org/10.2138/gselements.18.5.321.

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Concrete structures may develop deleterious damage, which significantly reduces service life, structural integrity, and safety, posing serious issues in large or otherwise critical infrastructure. Routine petrographic assessments, including microstructure, texture, and fabric, of concrete and its (gravel and sand) aggregate and binder constituents in thin section using polarization-fluorescence microscopy (PFM) enables the unequivocal identification of features that would otherwise remain hidden in conventional petrography. Rigorous preparation procedures preserve original microstructural details, make preparation artefacts recognizable, and ensure that the fluorescent emission can be quantified. This contribution outlines the preparation of fluorescence-impregnated thin sections and elaborates on the application of PFM to damaged concrete, with further examples from selected rock types commonly used for concrete aggregate.

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Le Pera, Emilia, Consuele Morrone, José Arribas, M. Eugenia Arribas, Eumenio Ancochea et M. José Huertas. « Petrography and provenance of beach sands from volcanic oceanic islands : Cabo Verde, Atlantic Ocean ». Journal of Sedimentary Research 91, n^o 1 (31 janvier 2021) : 92–115. http://dx.doi.org/10.2110/jsr.2020.096.

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ABSTRACT Volcaniclastic deposits have been extensively analyzed in several settings in the Pacific and circum-Pacific area. Recent volcaniclastic products from Atlantic oceanic islands offer another opportunity to add new data and be an important key to a better understanding of volcanic imprints on the sedimentary record. The Cabo Verde archipelago is an Atlantic Oceanic plateau with late Oligocene to Holocene volcanism. Outcrops consist mainly of mafic and strongly alkaline and ultra-alkaline volcanic (pyroclastic and lava flows) and less abundant intrusive rocks with minor carbonatites and carbonate sedimentary rocks, constituting a multiple-provenance assemblage for the sandy beaches surrounding the islands. Currently, climate is semiarid to hyperarid with ephemeral and intermittent streams. Thirty-six samples of beach sand from six principal Cabo Verde Islands were selected for petrographic inspection. On average, beach sands constitute a volcanolithic petrofacies. A relative increase in carbonate limeclasts and bioclasts dilutes the pure volcaniclastic contribution mainly on the older island beaches (Sao Vicente, Sal, and Boa Vista). The major components of Cabo Verde beach sands are highly variable; in general, composition is a function of island morphological evolution and age. Thus, beaches of the younger islands (Sao Nicolau, Santiago, and Fogo) consist mainly of volcanic lithic fragments, and monomineralic grains of dense minerals such as olivine, pyroxene, and amphibole, and single grains of plagioclase and anorthoclase. By contrast, beaches of older eastern islands (Sal, Boa Vista, and Sao Vicente) contain more calcareous bioclasts, micritic and/or sparitic sedimentary lithic grains. The presence of carbonate grains suggests provenance from shallow carbonate platforms developed during periods of volcanic quiescence. Cabo Verde volcanic sandy fractions are composed mostly of black, brown, and orange glassy volcanic particles exhibiting microlitic, lathwork, and vitric textures. Volcanic particles with lathwork textures are linked to mafic provenance assemblages (nephelinites, basanites, and tephrites). The content of glassy particles is nearly constant in all beaches, and both hydroclastic and epiclastic processes are reflected in these populations of glassy grains. Boa Vista, Sao Vicente, and Santiago beaches contain higher proportions of sideromelane, linked to recent coastal volcanism, and lower proportions of orange and black glassy particles. The concentration of orange glass particles in the beaches of Santiago Island is higher than in the other island beaches. These orange glassy textures have been preserved even if they were sourced from the intensely altered Ancient Eruptive Complex, representing the pre-Miocene seamount stage of Santiago Island. A very small percentage of altered labile monocrystalline grains such as olivine and the paucity of altered volcanic components reflect the weathering-limited erosion regime of the islands. The exposed phonolitic lava flows that occupy only a minor surface part of the inland source produce particles with microlitic texture in sand beaches. Thus, this texture is not exclusive to andesitic, basaltic, and basaltic andesites sources, suggesting the need for a review of these particles as source-sensitive provenance signals.

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Lupin, Janifar H., et Gary J. Hampson. « Sediment-routing controls on sandstone bulk petrographic composition and texture across an ancient shelf : Example from Cretaceous Western Interior Basin, Utah and Colorado, U.S.A. » Journal of Sedimentary Research 90, n^o 10 (1 octobre 2020) : 1389–409. http://dx.doi.org/10.2110/jsr.2020.044.

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ABSTRACT Sediment-routing controls on sandstone texture and bulk petrography have been evaluated in linked alluvial–coastal–shelfal deposits of the Upper Cretaceous Castlegate Sandstone, Blackhawk Formation, Star Point Sandstone, and Mancos Shale (Western Interior Basin, Utah and Colorado, USA) using thin-section analysis of representative outcrop samples in the context of a high-resolution sequence stratigraphic and paleogeographic framework. The studied strata record deposition from two styles of sediment-routing system within an overfilled foredeep and contiguous intra-continental seaway. First, multiple transverse drainages supplied sand to fluvial, shoreline, and shelf segments of sediment-routing systems characterized by down-dip transport distances of 150–450 km and significant strike-oriented sediment transport along the shoreline. Second, the distal shoreline–shelf segment of an axially supplied sediment-routing system was characterized by sand transport for a distance of c. 300 km. Bulk petrographic composition indicates that transverse sediment-routing systems were sourced from catchments that supplied quartz-rich sand with a subordinate lithic component, while the large axial sediment-routing system was sourced from a catchment(s) supplying slightly more feldspathic sand. Thin-section measurements of mean grain size, sorting, skewness, and ratio of minimum-to-maximum diameter (a proxy for sphericity) are similar for sandstones deposited in fluvial, shoreline, and shelf segments of the transverse sediment-routing systems and in the shoreline–shelf segment of the axial sediment-routing systems, although hydrodynamic sorting is important in locally segregating grain-size populations within each segment. Further, textural analysis of detrital quartz, feldspar, and lithic sand-grain populations shows little evidence of relative change in mean grain size or apparent grain sphericity with downsystem distance, implying that sand-grain populations of different petrographic composition did not undergo significant differential mechanical breakdown during transport. Instead, the textural characteristics of these sand-grain populations are inferred to have been controlled mainly by bedrock lithology and recycling in source catchments. The textural signal of sediment-source areas then propagated downsystem in the sand fraction of detrital sediment supply. This inference is supported by the fine- to medium-grained, well- to very well-sorted character of all sandstone samples, consistent with recycling of sandstones and quartzites from the Sevier fold-and-thrust belt.

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De Rosa, R., G. G. Zuffa, A. Taira et J. K. Leggett. « Petrography of trench sands from the Nankai Trough, southwest Japan : implications for long-distance turbidite transportation ». Geological Magazine 123, n^o 5 (septembre 1986) : 477–86. http://dx.doi.org/10.1017/s0016756800035068.

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AbstractTwenty-three samples of Quaternary sands from Deep Sea Drilling Project (DSDP) Leg 87 Sites 582 (trench axis) and 583 (lowermost terrace of uplifted trench sediments in the accretionary prism) off Shikoku show a 70–80% volcanic component in the terrigenous grain population. This component comprises 30–40% neovolcanic grains, among which basic and intermediate types are present in roughly equal proportions, and 60–70% palaeovolcanic grains, which are predominantly of acidic composition. No volcanic terrane occurs, in the hinterland of the Shikoku portion of the Nankai Trough, and the first such rocks to the east (up the very slight depositional slope of the Nankai Trough axis) are not encountered for more than 500 km. These, occupying the Izu Peninsula and the majority of the Tokai drainage basin to the north, are Neogene and Recent volcanics which are of comparable variability to the volcanic grains in the sands off Shikoku.The minor component of sedimentary, metamorphic and plutonic grains in the Leg 87 sand samples can be matched with the basinal clastic ophiolitic Shimanto and Chichibu terranes and the high-pressure metamorphic Sambagawa terrane which border the Nankai Trough fore-arc along southwest Japan. This detritus also most likely derives from the Tokai drainage basin, where the easternmost outcrops of the above-mentioned terranes occur, because most sediments deriving from Shikoku and the Kii regions are ponded in terraced fore-arc basins or in basins on the lower slope. Only three major submarine canyons debouch into the floor of the Nankai Trough. The easternmost of these, the Suruga Trough, taps the volcanic Izu/Tokai hinterland, and is therefore the conduit for most sand fed to the trench off Shikoku.

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Stoltman, James B. « A Quantitative Approach to the Petrographic Analysis of Ceramic Thin Sections ». American Antiquity 54, n^o 1 (janvier 1989) : 147–60. http://dx.doi.org/10.2307/281336.

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This paper introduces a new technique for the quantitative analysis of ceramic thin sections through petrography. The technique is a version of point counting that estimates with considerable precision the amounts of human additives (temper) and natural inclusions (silt and sand) in ceramic pastes. In concert with traditional qualitative identification of mineral inclusions, this technique expands the capacity of petrography to shed meaningful light on such topics in ceramic analysis as technology, production, trade, and classification. To demonstrate the utility of the technique it is used to reassess the taxonomic status of the type Spring Hollow Incised. The results conclusively show that Spring Hollow Incised is much more closely related to a newly defined Early Woodland ceramic assemblage in the Upper Mississippi Valley region than to the Middle Woodland Linn ware to which it originally was assigned.

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Reedy, Chandra L., Jenifer Anderson, Terry J. Reedy et Yimeng Liu. « Image Analysis in Quantitative Particle Studies of Archaeological Ceramic Thin Sections ». Advances in Archaeological Practice 2, n^o 4 (novembre 2014) : 252–68. http://dx.doi.org/10.7183/2326-3768.2.4.252.

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AbstractThin-section petrography is a crucial tool for the study of archaeological ceramics, and in recent years, image analysis has emerged as a powerful quantitative enhancement of that tool. Exploratory applications of image analysis to archaeological ceramic thin sections, and related work by sedimentary geologists, have indicated its usefulness to the field. In this paper, we first present the results of experimental work testing the consistency and reproducibility of image analysis. We identify procedures for fast and reliable analysis of thin sections using laboratory-prepared ceramic specimens of simple clay-sand systems. We then show how those procedures can be slightly modified to accommodate more complex archaeological specimens. We conclude with a discussion of the role of image analysis within the overall context of thin-section petrography of ceramic materials, as one among a repertoire of techniques, adding quantitative data and increasing the usefulness of ceramic thin sections for addressing archaeological research questions.

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Pirrie, Duncan. « Petrography and provenance of the Marambio Group, Vega Island, Antarctica ». Antarctic Science 6, n^o 4 (décembre 1994) : 517–27. http://dx.doi.org/10.1017/s0954102094000775.

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Late Cretaceous sedimentary rocks assigned to the Santa Marta (Herbert Sound Member) and López de Bertodano (Cape Lamb and Sandwich Bluff members) formations of the Marambio Group, crop out on Cape Lamb, Vega Island. Although previous studies have recognized that these sedimentary rocks were derived from the northern Antarctic Peninsula region, the work presented here allows the provenance and palaeogeographical evolution of the region to be described in detail. On the basis of both sandstone petrography and clay mineralogy, the Herbert Sound and Cape Lamb members reflect sediment input from a low relief source area, with sand grade sediment sourced from low grade metasediments, and clay grade sediment ultimately derived from the weathering of an andesitic source area. In contrast, the Sandwich Bluff Member reflects a switch to a predominantly andesitic volcaniclastic source. However, this sediment was largely derived from older volcanic suites due to renewed source area uplift, with only a minor component from coeval volcanism. Regional uplift of both the arc terrane and the western margin of the James Ross Basin was likely during the Maastrichtian.

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Pavia, Jennifer A., Kathleen M. Marsaglia et Scott M. Fitzpatrick. « Petrography and Provenance of Sand Temper Within Ceramic Sherds from Carriacou, Southern Grenadines, West Indies ». Geoarchaeology 28, n^o 5 (16 juillet 2013) : 450–77. http://dx.doi.org/10.1002/gea.21449.

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Gerth, Andreas, et Raimo Becker-Haumann. « Sedimentuntersuchungen an unterpleistozänen Schmelzwasserablagerungen und Periglazialschottern im Riß-Iller-Gebiet, deutsches Alpenvorland ». E&G Quaternary Science Journal 56, n^o 3 (1 septembre 2007) : 186–211. http://dx.doi.org/10.3285/eg.56.3.04.

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Abstract. The Lower Pleistocene meltwater deposits at the contact of the Rhine- and Illergalcier (Baden-Württemberg, Bavaria) and the periglacial sediments occurring below them are described. The research is focused on the analysis of the petrography of the pebble-size fraction and of the sand-size heavy mineral assemblages of the Biber-, Donau- and Günz-age deposits. The results confirm that the periglacial sediments can be distinguished clearly from the glaciofluvial material by arguments of the petrography. However, a systematic change of the lithology also within the glaciofluvial material can be inferred from the high number of the investigated samples. Within the gravel fraction the amount of crystalline rocks, radiolarite and hornstone increases towards the younger accumulation units, whereas the content of calcareous components decreases. Concerning the heavy minerals the amount of instable minerals as Garnet and Hornblende decreases, while the portion of Staurolite increases remarkably towards the younger deposits. In the paper at hand these results are interpreted with respect to the paleogeography, in order to figure out the river development of the Riß-Iller-tract.

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Kulkova, Marianna Altkseevna. « PETROGRAPHY FOR ASSESSMENT OF MOULDING COMPOUND OF ANCIENT POTTERY ». Samara Journal of Science 4, n^o 3 (1 septembre 2015) : 100–107. http://dx.doi.org/10.17816/snv20153208.

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Ancient ceramics are the valuable artifacts which saves the information about ancient people and their traditions. The process of making pottery is begun with the choosing and preparation of raw clay and temper material and further applying of different techniques (moulding of vessel, decoration etc.) and finally firing. Petrographical analysis of ancient pottery allows to determine the mineralogical composition of ceramic matrix, the features of their technology and to identify the raw mineral sources (Feliu et al. 2004, Papadopoulou et al. 2006, Bastie et al. 2006). Such kind investigations expand the frames of our knowledge about ancient technological traditions in pottery making. The following characteristics could be determined in thin-sections of ceramic shards: nature and features of plastic and aplastic inclusions; textural and optical characteristics of clay matrix; shape, amount and orientation of pores; features of surface treatment, decoration. This information is animportant for understanding of principles of ancient technologies. The different temper materials inside clay matrix such as sand, crushed rocks, organic materials, shells, grog can be identified accurately using petrography. The ceramic structure and characteristics of mineral changes during the firing are indicators of firing temperatures and atmosphere. A distribution of clay particles and porous inside of ceramic matrix is useful for reconstruction of moulding methods. The study of ceramic collection of the same cultural tradition and from the same region using petrography gives the possibility for differentiation of the natural and cultural factors influenced on the choose of raw materials, variations in the ceramic composition and techniques. This method is one the most precise for identification of an import pottery.

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Underwood, Michael B., et Christopher L. Fergusson. « Late Cenozoic evolution of the Nankai trench-slope system : evidence from sand petrography and clay mineralogy ». Geological Society, London, Special Publications 244, n^o 1 (2005) : 113–29. http://dx.doi.org/10.1144/gsl.sp.2005.244.01.07.

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Dickinson, William R. « Petrography and geologic provenance of sand tempers in prehistoric potsherds from Fiji and Vanuatu, South Pacific ». Geoarchaeology 16, n^o 3 (2001) : 275–322. http://dx.doi.org/10.1002/1520-6548(200103)16:3<275 ::aid-gea1005>3.0.co;2-e.

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Makongoro, Mohamed Zengo, Maheswara Rao Vegi, Said Ali Hamad Vuai et Michael Mwita Msabi. « Geochemical, Mineralogical, and Geomorphological Characterization of Ash Materials as a Tracer for the Origin of Shifting Sands near Oldupai Gorge, Ngorongoro, Tanzania ». Scientific World Journal 2022 (28 octobre 2022) : 1–16. http://dx.doi.org/10.1155/2022/2593944.

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Shifting sand (SS) is a single dune-shaped mass of black ash material moving across western Ngorongoro in northern Tanzania. The moving sand has become an important tourist destination for several decades. Despite being part of the important geosites at the Ngorongoro Conservation Area, the nature, origin, and behaviors demonstrated by SS remain poorly understood. This work contributes toward understanding the nature and identification of the possible origin of the SS through the correlation of geochemical, mineralogical, and geomorphological data of ash material from four selected locations in the study area. To achieve this goal, elemental, mineralogical, and morphological characterization of ash samples was performed by energy-dispersive X-ray fluorescence, polarized petrographic microscopy, automated sieve shaker, and binocular microscopy techniques, respectively. Correlation studies were based on magnesian-ferriferous associations, similarities in mineralogy, particle size, shape, and distribution patterns of ash materials, and weather data. There are close similarities in the chemical compositions among ash samples of SS, Ootun area, and Oldoinyo Lengai. Augite and magnetite minerals appear only in samples of SS, Ootun area, and Oldoinyo Lengai, while hornblende appears only in the samples from the Ngorongoro crater. Oldoinyo Lengai rock petrography revealed significant amounts of augite minerals. Blocky and elongated-shaped ash particles dominate the samples from SS, Ootun area, and Oldoinyo Lengai. The particle size of ash materials decreases westwards across the study site. The distribution patterns of ash material align with the west-south-west wind direction. Based on these findings, the study concludes that SS and Ootun ash could be tephra depositions resulting from past volcanic eruptions of Oldoinyo Lengai.

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Abi Tiyana, Rasis, Supriyanto, Tri Rani Puji Astuti, Gamma Abdul Jabbar et Muhammad Rizqy Septyandy. « Mineralogy, geochemistry, and genesis of glauconite mineral from paleotsunami deposit in Lebak, Banten, Indonesia ». E3S Web of Conferences 340 (2022) : 01004. http://dx.doi.org/10.1051/e3sconf/202234001004.

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Bagedur coast in Lebak regency, Banten province, Indonesia is part of lowland-swampy swale area that consist of various sediment deposit. Based on its sediment characteristics and geomorphology profile, Bagedur coast is assumed as depositional environment of paleotsunami deposit. Hand Auger drilling method is used to collecting loose sediment sample from eight observation stations. The depth of hand drilling in BG 01 station to BG 08 station is consecutively as follows: 115 cm, 100 cm, 80 cm, 700 cm, 400 cm, 450 cm, 160 cm, and 143 cm. This research is carried out to understand the diagenetic process of glauconite mineral in presumption paleotsunami deposit. The diagenetic process of glauconite mineral is identified based on its mineralogical and geochemical characteristics by petrography and X-Ray Fluorescence (XRF) methods. Observation samples is taken from green sand sediment bed in hand drilling core. Petrographic analysis under polarized microscope shows various glauconite mineral which recognized as matrix, oval pellets, replacement of precursor mineral, and bioclastic shell infillings. XRF analysis result show that glauconite in observation site are classified as glauconitic-illite type. The diagenetic stage is interpreted as early stage of diagenetic (nascent) which characterized by low Fe2O3 and K2O content relative to Al2O3 content.

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Virolle, Maxime, Benjamin Brigaud, Hugues Féniès, Raphaël Bourillot, Eric Portier, Patricia Patrier, Hervé Derriennic et Daniel Beaufort. « Preservation and distribution of detrital clay coats in a modern estuarine heterolithic point bar in the Gironde estuary (Bordeaux, France) ». Journal of Sedimentary Research 91, n^o 8 (9 août 2021) : 812–32. http://dx.doi.org/10.2110/jsr.2020.146.

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ABSTRACT Estuaries provide an excellent depositional environment to study the interaction between minerals (clays, quartz sands…) and biofilms. The estuary bottom is largely covered by biofilms that impact sediment stability, the mud and clay-coat content in sands, and sedimentary-structure stability, thus influencing sandstone properties during burial. Although numerous oil, gas, and geothermal reservoirs are exploited in estuarine heterolithic point bars, many questions remain about the origin of reservoir properties and heterogeneities in these sedimentary bodies. In order to better understand the sedimentary and microbiologic processes in estuarine systems and to better predict the reservoir quality of estuarine sandstones, this study characterizes a modern heterolithic point bar located in the Garonne estuarine channel at various scales, ranging from the microscopic (thin section) to the macroscopic (core) scale. Three piston cores 4.5 to 6.8 m long were drilled in the Bordeaux North Point Bar. Three main facies were identified in these cores: 1) sandy gravel, 2) heterolithic, medium-grained sand dunes, and 3) thin heterolithic, fine-grained sand beds with mud drapes. The sands are classified as lithic arkoses to feldspathic litharenites. Detrital clay grain coats, which at deep burial depths are transformed to permeability preserving authigenic chlorite coatings, are observed from the base to the top of the point bar. These detrital clay grain coats are mainly composed of smectite, illite, kaolinite, and chlorite, intermixed with other components, such as diatoms or pyrite. Biofilms of exopolymeric substances (EPSs), mostly produced by diatoms, are believed to control the adhesion of the clay coats to the surface of sand grains. Quantification by thin section shows that on average about 30% of the sands are coated in the point bar. The proportion of clay-coated grains appears to be independent of facies. Radiocarbon age dating measured on organic matter points to significant vertical mixing, highlighting the significance of erosion and redeposition. The activities of 137Cs and 210Pb indicate a vertical sedimentation rate of ca. 0.02 m.yr–1 in the muddy chute channel. These ages, coupled to historical maps, suggest that the present-day point bar has developed over the last 300 years with a vertical sedimentation rate ranging from 0.015 to 0.036 m.y–1 and a lateral migration rate of about 1 m.y–1. The combination of sedimentary geology, thin-section petrography, and mineralogy at high spatial and temporal resolutions highlights the potential of this study area as a modern analogue for ancient tidally influenced point-bar deposits associated with clay coatings.

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Khan, Zuhi, et A. H. M. Ahmad. « Provenance, tectonic setting and palaeoclimate of the Ridge Sandstone of Jumara Dome, Kachchh, Gujarat ». Journal of Palaeosciences 65, n^o (1-2) (31 décembre 2016) : 189–201. http://dx.doi.org/10.54991/jop.2016.310.

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This study deals with petrography, provenance, tectonic setting and palaeoclimate of the Ridge Sandstone Member encountered in the Jumara Dome, Kachchh, Gujarat. The sandstones in this member are medium to coarse grained, poorly to moderately sorted and sub angular to sub rounded. Framework grains are sand–sized to silt–sized particles of mainly detrital origin. Among the main detrital framework grains, quartz constitutes 55.42–96.09%, feldspar 4.9–27.76%, and lithic fragments 0–3.73%. These sandstones have been classified as sub–arkose to arkose in composition and were deposited in continental block provenance with stable craton in rifted continental margin basin setting in a humid climate with the source material from either the Aravalli or Nagar Parker massif.

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Dewez, Véronique, et Marie-Anne Geurts. « Analyses minéralogiques multivariées de sédiments du Wisconsinien supérieur au sud-ouest du Yukon ». Canadian Journal of Earth Sciences 33, n^o 1 (1 janvier 1996) : 42–51. http://dx.doi.org/10.1139/e96-005.

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For this study, 84 samples of glacial and juxtaglacial sediments were collected in valleys of the Ruby Range and Aishihik Basin (southwestern Yukon). Analyses were conducted to quantify the heavy minerals in the sand fraction and to assess the petrography of the gravel fraction. A cluster analysis performed on the heavy mineral results showed five groups of deposits, three of which are related to local glaciers inside the Ruby Range, the other two being related to regional ice lobes of Kluane and Aishihik, respectively. The three groups of local sediments correspond to the three lithologies of the Ruby Range, i.e., the granitic batholith, the schists, and the alaskite. The sediments from the regional ice lobes are characterized by highly diversified mineralogy and petrography and the relative abundance of minerals from the Saint Elias Mountains, the main source of the ice lobes. A correspondance factor analysis performed on the heavy mineral results organizes samples and minerals into a triangular cloud, the three vertices corresponding to biotite, carbonate, and titanite–garnet. These are the key elements of local glaciers, Kluane ice lobe, and Aishihik ice lobe, respectively. Finally, the study shows the extension of Kluane lobe in one valley of the Ruby Range, the ice flow pattern in another valley, as well as a transfluence from Kluane lobe inside the Range.

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Arribas, José, Meaza Tsige, Guillermina Garzón et Rosa Tejero. « Transport-Limited Denudation Regime Inferred from Sand Petrography and Chemical Composition : Cenozoic Sediments from the Guadiana Basin (SW Spain) ». International Journal of Geosciences 05, n^o 05 (2014) : 478–96. http://dx.doi.org/10.4236/ijg.2014.55046.

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Xia, Mei, Chao Sun, Xiaoyong Yang et Jian Chen. « Assessment of Gold-Bearing Quartz Vein as a Potential High-Purity Quartz Resource : Evidence from Mineralogy, Geochemistry, and Technological Purification ». Minerals 13, n^o 2 (13 février 2023) : 261. http://dx.doi.org/10.3390/min13020261.

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High-purity quartz (HPQ) is an important material widely used in many high-tech industries. It is a product processed from pure natural quartz raw materials, so selecting suitable quartz raw material is the key to successfully processing HPQ. Hydrothermal quartz vein is one of the most likely raw materials to be purified into HPQ because of its high SiO2 content. This study focuses on the evaluation of HPQ raw material potential of the two gold-bearing quartz vein tailing resources in Chibougamau (CBG) and Tianjingshan (TJS). Petrography and the contents of impurity elements in the two vein quartz samples before and after processing were studied by optical microscope, SEM, Raman spectrometry, XRD, LA-ICP-MS, and bulk solution ICP-OES. Petrographic results reveal that major impurities in quartz are feldspar, mica, iron compounds, ankerite, rutile, silicate melt, and fluid inclusions. LA-ICP-MS analysis result shows that the SiO2 contents are between 99.953–99.971 wt.% in CBG raw quartz and 99.969–99.976 wt.% in TJS raw quartz, respectively, with very low contents of impurity elements, except for Ca. Bulk solution ICP-OES analysis demonstrates that the CBG processed quartz sand has total impurity contents of 56.8 µg·g−1, with 13.1 µg·g−1 Al and 6.6 µg·g−1 Ti, and the TJS processed quartz sand has the total impurity contents of 85.2 µg·g−1 with 29.4 µg·g−1 Al and 6.1 µg·g−1 Ti. Both the contents of Al and Ti fit with the lattice-bound criteria for HPQ. These results, for most of the impurities, are likely hosted by silicate melt, fluid, and mineral inclusions, indicating that these two hydrothermal raw vein quartz samples can be upgraded to HPQ after processing by more advanced methods. Therefore, the CBG and TJS quartz vein deposits would be considered as potential future resources for HPQ to realize efficient recovery and utilization of tailings resources and to improve mine economic benefits.

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Szilágyi, V., B. Péterdi, Gy Szakmány, S. Józsa, D. G. Miklós et Gy Gyuricza. « Application of heavy mineral analysis for ceramic provenance research by the micromineralogical collection of the Mining and Geological Survey of Hungary – a case study ». Archeometriai Műhely 18, n^o 2 (2021) : 109–22. http://dx.doi.org/10.55023/issn.1786-271x.2021-009.

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This study introduces a possible archaeometric application of the micromineralogical collection belonging to the Mining and Geological Survey of Hungary. Micromineralogical (heavy mineral) assemblage of natural clastic sediments (clay, silt, sand) can characterize the plastic ceramic raw materials typical for a delimited region (i.e. a river catchment area or a geological subunit). Heavy mineral investigation is a useful method which can complete conventional ceramic provenance studies applying microscopic petrography and instrumental chemical analyses, especially in cases of very fine-grained pottery or mature, less characteristic ceramic compositions. Using the 10th c. pottery of Edelény-Borsod (NE Hungary) as an example, we present the application of the micromineralogical collection. The study points out the difficulties with the evaluation, i.e. different sample preparation and data collecting strategy for archaeological and geological samples. Finally, the benefits of the results are formulated as conclusions on the ceramic provenance.

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Kamiludin, Udaya, et Udaya Kamiludin. « KANDUNGAN MINERAL DI PERAIRAN BINUANGEUN, LEBAK-BANTEN ». JURNAL GEOLOGI KELAUTAN 12, n^o 2 (16 février 2016) : 79. http://dx.doi.org/10.32693/jgk.12.2.2014.248.

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Data dan informasi sumberdaya mineral terkait dengan batuan penyusunnya di daerah pantai dan lepas pantai masih terbatas. Untuk keberadaan sumberdaya mineral ini maka dilakukan identifikasi kandungan mineral dalam sedimen sebagai objek penelitian guna mengetahui jenis, persentase, distribusi dan perkiraan sumber batuannya. Metode penelitan meliputi pengambilan sampel sedimen, pemisahan konsentrat dulang, analisis mineragrafi butir, dan petrografi batuan. Ragam mineral di dalam endapan sedimennya terdiri dari kuarsa, magnetit, amfibol, ilmenit, felspar, glaukonit, apatit, piroksen, limonit, zirkon, fragmen batuan dan pecahan cangkang. Fraksi mineral yang dominan adalah fraksi pasir sangat halus dan lanau kasar. Secara lateral distribusi kuarsa, felspar dan piroksen relatif membesar ke arah endapan sedimen gisik pasir, tanggul gisik dan sedimen sungai dengan persentase tertinggi, masing-masing mencapai 49 %, 21 % dan 13 %. Sedangkan distribusi limonit dan zirkon membesar ke arah endapan sedimen gisik pasir dengan persentase tertinggi, masing-masing mencapai 5 % dan 2 %. Persentase tertinggi magnetit 17 %, ilmenit 23 %, apatit 3 %, fragmen batuan 51% dan pecahan cangkang 90 % umumnya terdapat dalam endapan sedimen permukaan dasar laut. Keterdapatan mineral utama dan tambahan ini diduga bersumber dari Batuan Gunungapi andesiti-basaltik, dan Formasi Batuan Sedimen berbahan volkanik. Sedangkan klastika biogeniknya bersumber dari batugamping terumbu. Hasil analisis petrogafi menunjukan bahwa fragmen batuannya memiliki kesesuaian dengan penyusun litologinya. Kata Kunci : Kandungan mineral, distribusi mineral, sumber batuan, Perairan Binuangeun. Data and information mineral resources related to rock forming mineral on shore and offshore area is still limited. For the existence of mineral resources is then to identify the content of the sediment as the object study in order to determine the type, percentage, distribution and estimation of rocks origin. The method includes sedimentary sampler, pan concentrates separation, grain mineragraphy analysis, and petrography rock. The mineral in the sediment consist of quartz, magnetite, amphibole, ilmenite, feldspar, glauconite, apatite, pyroxene, limonite, zircon, rock fragments and shell fragments. The minerals fractions are dominant in very fine sand and coarse silt. Laterally, the distribution of quartz, feldspar and pyroxene relatively increasing towards sand beach, berm and river sediments with the highest percentage, respectively reach 49 %, 21 % and 13 %. While, distribution of limonite and zircon are increasing toward sand beach with the highest percentage, respectively 5 % and 2 %. The highest percentage of magnetite (17 %), ilmenite (23 %), apatite (3 %), and rock fragments (51 %) and shell fragments of surfacially sediments (90 %). The occurrence of these main and accessory minerals is thought to be originated from andesitic-basaltic volcanic rocks and from volcanoclastic sediments whereas bioclastic sediments are from reefs limestone. The petrography analysis shows that their rock fragments are compatible with their rocks forming minerals. Keywords: The minerals content, mineral distribution, source rocks, and Binuangeun Waters.

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Dill, Harald G., Jolanta Kus, Abdulkader M. Abed, Reinhard F. Sachsenhofer et Hani Abul Khair. « Diagenetic and epigenetic alteration of Cretaceous to Paleogene organic-rich sedimentary successions in northwestern Jordan, typical of the western margin of the Arabian Plate ». GeoArabia 14, n^o 2 (1 avril 2009) : 101–40. http://dx.doi.org/10.2113/geoarabia1402101.

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ABSTRACT Four reference sections through the calcareous-siliciclastic rocks of the Lower Cretaceous Kurnub Group and the Amman and Muwaqqar formations of the Upper Cretaceous to Paleogene Belqa Group in Jordan document the various processes of accumulation and alteration of organic matter (OM). Sections at Jerash, Sultani, Wadi Isal, and in the Kharazeh area were investigated by means of sedimentary petrography/mineralogy, organic petrography, and organic chemistry, and correlated with equivalent deposits in Syria and Egypt. The impacts of oxidation potential (Eh), acidity/basicity (pH) and temperature variations during the post-depositional alteration of these organic concentrations were assessed using x-y plots. Syngenetic Aptian-Albian coaly and organic-rich amber beds near Jerash developed in a tide-dominated delta under marginally alkaline conditions and were altered under slightly acidic conditions at temperatures of less than 100°C. Environmental analysis focused on Maastrichtian-Paleocene (?), oil shales in the Sultani area that were deposited in a small restricted basin on the continental shelf of the Neo-Tethys Ocean. Abnormally high contents of vanadium (V), phosphorus (P), zinc (Zn), and uranium (U) gave rise to yellow uranium ore minerals, phosphates and zinc sulfides and so bridge the gap between OM concentrations and those of uranium. The western part of the Arabian Peninsula is known for its uraniferous phosphorites and U-bearing calcretes. Reducing conditions during deposition of syngenetic OM in the oil shales may have shifted, in places, toward more oxidizing conditions in the course of post-depositional alteration at temperatures well below 200°C. Epigenetic fault-related concentration of OM was responsible for the Wadi Isal Aptian-Albian tar sand deposit and the oil seepage system in calcareous wall rocks of the Kharazeh Fault. The alteration of the tar sands (fluvial sandstones) is designated a high-sulfidation type (introduced aluminum sulfate minerals), whereas the oil seepage in Campanian shallow-marine carbonates is a low-sulfidation type (removal of aluminum sulfate minerals). Both alteration patterns may have implications for structure-bound base- and precious-metal deposits whose emplacement involves hydrocarbons as a carrier of metals in the mineralizing fluids. The Jordanian oil shales, tar sands, and uranium mineralization are possible sources of energy. Recent economic deals on the recovery and use of oil shales and uranium in Jordan are reviewed.

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Musu, Junita Trivianty. « RESERVOIR QUALITY REDUCTION CAUSED BY CLAY INDUCED DUCTILITY ». Scientific Contributions Oil and Gas 33, n^o 1 (15 février 2022) : 10–34. http://dx.doi.org/10.29017/scog.33.1.659.

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Ductile components including rock fragments, clay, and matrix material are often consideredas the most important factors that control quality of shaly sandstones, which areusually characterized by low porosity and permeability. In presence of ductile components,the degree of quality reduction is affected mainly by distribution, occurences, andamounts of the ductile components. Therefore, the presence of ductile components affectsrock petrophysics, and consequently has effect on fluid movements in reservoir duringproduction.This paper presents results of the study on plug samples taken from five wells fromvarious fields in Cooper Basin (Tirrawarra Sand), South Australia. The samples were studiedpetrographically using x-ray diffraction, optical petrography, and scanning electronemicroscope. The results were integrated with routine and special core analysis data. Theoverall results show that the distribution and the amount of ductile components have significantlyreduced porosity, hence the quality of the reservoir. However, the effect isdifferent for different types of porosity, and this certainly is valuable addition to our understandingover permeability behavior of shaly sandstones.

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Proidak, Andrii, Mykhailo Gasyk et Yurii Proidak. « Research into phosphate mineral composition and waste phosphorite ore ». Mining of Mineral Deposits 15, n^o 1 (2021) : 96–102. http://dx.doi.org/10.33271/mining15.01.096.

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Purpose. Theoretical and experimental studies of chemical and mineral composition and the structure peculiarities of phosphorites from Ukrainian deposits to define the degree of their suitability for other industries. Methods. The ore chemical composition was determined by conventional (wet) analysis using standard certified chemical reagents. The mineral composition was studied on the scanning electron microscope equipped with the attachment for the energy-dispersive electron microprobe analysis (EMPA) with the software for calculating the chemical composition of the studied sample microvolume. The petrographic analysis was carried out by the traditional methods of microscopic section preparation with subsequent identification and description of the minerals. The microscopic study of the original ore samples aimed at their mineral composition determination was conducted on the Nu optical microscope (Germany) both in transmitted and reflected light. The thin and polished sections prepared using the standard technology were used as samples. In the laboratory environment, the phosphorites were subjected to magnetic dressing in magnetic fields with different intensity. The experiments in the weak field were modelled with the help of the magnetic analyzer while the experiments in the strong magnetic field were modelled on the rotor separator. The flotation dressing method was studied on the laboratory mechanical flotation machine. Findings. It was found that phosphate nodules are rounded mineral formations of irregular shape; they consist of sand bound with the yellow-brown phosphate cement. Ore useful substance is a phosphorus-bearing mineral that by the element chemical composition corresponds to fluorocarbon-hydroxyl-apatite with the dominant content of Ca (45.23%), P (15.67%), and B (27.87%). The results of the integrated petrographic study of the phosphorite samples from the ore body of “Peremoha” area are presented. Originality.The study has revealed that phosphorus-containing substance in the phosphorite samples is the mass that cements barren minerals (mainly quartz, glauconite, calcite and plagioclase). Practical implications. According to the phosphate content level, the phosphorites from Malokamyshevatske, Iziumske and Sinichino-Yaremovske deposits can be treated as minerals for ferrophosphorus smelting. Keywords: ferrophosphorus, ore substance, phosphorite, mineral varieties, petrography, apatite

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Osli, Liyana Nadiah, Mohamed Ragab Shalaby et Md Aminul Islam. « Source rock characteristics and hydrocarbon generation potential in Brunei-Muara district, Brunei Darussalam : a comparative case study from selected Miocene-Quaternary formations ». Journal of Petroleum Exploration and Production Technology 11, n^o 4 (20 mars 2021) : 1679–703. http://dx.doi.org/10.1007/s13202-021-01142-0.

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AbstractA comparative analysis on source rock properties has been carried out on the Miocene-Pliocene formations as well as the Quaternary terrace deposits using Rock–Eval pyrolysis results and organic petrography as well as some biomarkers results. Samples were obtained from outcrops of the Quaternary terrace deposits, Pliocene-aged Liang Formation together with the Miocene Miri and Setap Shale formations in Brunei-Muara district, with sample lithologies ranging from coal, coaly shale, shale and lignitic sand. High total organic carbon (TOC) and S2 values ranging from 41.8 to 62.4% and 7.40 mg HC/g rock to 122 mg HC/g rock, respectively, are identified in coals of the terrace deposit, Liang and Miri formations, making these as the best potential source rock due to the “good to excellent” generating potential. Meanwhile, a “fair to poor” potential is exhibited for the coaly shale, shale and lignitic sand samples as a result of their low TOC, HI and S2 values. The organic matter is composed of kerogen type III (gas prone) and type II-III (mixed oil and gas prone). Organic matter in all studied formations originate from a terrestrial-source, as proven by the abundance of huminite. Organic petrographical and biomarkers studies suggest that the coals and lignitic sand samples were deposited in a mangrove-type mire in a lower delta setting, under oxic and limnic to limnotelmatic conditions, except sample DD2-1, which is deposited in a less water-saturated environment. The samples display the presence of bi-modal and normal distribution of n-alkanes. For all of the samples, the dominating plant types in the palaeomire are of soft, herbaceous plants and this is supported by the low vegetation index and moderate Paq values. All the studied samples are thermally immature to early mature, as exhibited by the Tmax values that range from 300 to 437 °C and vitrinite reflectance readings of 0.22% to 0.46%.

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Pointon, Michael A., Helen Smyth, Jenny E. Omma, Andrew C. Morton, Simon Schneider, Peter Hülse, Stephen J. Rippington et al. « A Multi-proxy Provenance Study of Late Carboniferous to Middle Jurassic Sandstones in the Eastern Sverdrup Basin and Its Bearing on Arctic Palaeogeographic Reconstructions ». Geosciences 13, n^o 1 (28 décembre 2022) : 10. http://dx.doi.org/10.3390/geosciences13010010.

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A multi-proxy provenance study of Late Carboniferous to Middle Jurassic sandstones from the eastern Sverdrup Basin was undertaken employing optical petrography and heavy mineral analysis, chemical analysis of apatite, garnet and rutile grains, as well as detrital zircon U–Pb geochronology and Hf isotope analysis. Late Carboniferous to Middle Jurassic strata on the southern basin margin are inferred as being predominantly reworked from Silurian to Devonian strata within the adjacent Franklinian Basin succession. Higher-grade metamorphic detritus appeared during Middle to Late Triassic times and indicates exhumation and erosion of lower (Neoproterozoic to Cambrian) levels within the Franklinian Basin succession and/or a direct detrital input from the Canadian-Greenland Shield. The provenance of northern-derived sediments is more enigmatic owing to the subsequent opening of the Arctic Ocean. Northern-derived Middle Permian to Early Triassic sediments were likely derived from proximal areas of the Chukotkan part of the Arctic Alaska-Chukotka microplate. Late Triassic northern-derived sediments have different detrital zircon U–Pb age spectra from Middle Permian to Early Triassic ones and were likely derived from the Uralian orogenic belt and/or the Arctic Uralides. The loss of this sand input during latest Triassic times is interpreted to reflect drainage reorganisation farther upstream on the Barents Shelf. Middle Jurassic sands in the northern and axial parts of the basin were largely reworked from local northern-derived Late Triassic strata. This may have been facilitated by rift flank uplift of the northern basin margin in response to rifting in the adjacent proto-Amerasia Basin.

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Musu, Junita Trivianty, Hadi Prasetyo et Bambang Widarsono. « Integrating Petrography With Core-Log-Well Test Data For Low Permeability Sandstone Reservoir Characterization : Preliminary Recommendation For Production Optimization ». Scientific Contributions Oil and Gas 33, n^o 3 (22 février 2022) : 198–203. http://dx.doi.org/10.29017/scog.33.3.823.

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Integrating petrographic core information into combined core petrophysics, log, and well test data for understanding facies and environmental deposition in rock characterization has proved itself useful to improving quality and reliability of the required conclusions. This integrated approach has specifically shown its use in the cases of complex reservoirs such ones characterized as low-permeability sandstone reservoirs. It is in this spirit that this paper demonstrates how this virtually cost efficient analysis provides preliminary recommendations for the exploitation of such reservoirs. As case study, two types of producing reservoirs (Bekasap, Bangko, Pematang, and Tanjung Formations) have been taken in 2009. The first type is strongly controlled by depositional environment. It is found in the upper part of Bekasap and Bangko formations (1900 - 2300 ft-ss), deposited in estuarine system, and made of very fine to fine grained sand with low to moderate bioturbation. This mostly feldspathic and lithic greywackes have permeability of up to 200 mD. The second type is strongly dominated by diagenesis process and is mainly found in the Upper Pematang and Tanjung Formations (6200 - 7400 ft-ss). This reservoir type is characterized by its coarse-grained and conglomeratic sandstones resulted from fan- elta and braided channel depositional system. Diagenetic events such as compaction, recrystallization of matrix into microcrystalline clay minerals, precipitation of authigenic minerals in pore system are also well identified from the performed petrographic analysis. This is dominated by sublitharenite and litharenite sandstones exhibit horizontal permeability of up to several dozens mD. The two producing reservoir types have undergone carefully planned exploitation and stimulation operations, and the horizontal drilling and fracturing

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Santy, L. D., et A. J. Widiatama. « Pedaro formation, equivalent of Plover sandstone at Savu Island, Outer Banda Arc ». IOP Conference Series : Earth and Environmental Science 851, n^o 1 (1 octobre 2021) : 012052. http://dx.doi.org/10.1088/1755-1315/851/1/012052.

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Abstract Plover Sandstone have been widely known as a good quality of oil and gas reservoir in NW Australia. As the continuity of NW Australia margin, outer Banda Arc become the distribution area of the equivalent of Plover Sandstone units. Therefore, a clear distinction and characterization of equivalent of Plover Sandstones distributed in this area is needed. Thick unit of quartz rich sandstone is scrap out in south Savu Island. Refers to the location where the lithology is found widely distributed, the unit is suggested to be called as Pedaro Formation. The characteristic of the lithology is determined through detailed measured section from two trajectories and laboratory analysis, including fourteen samples of petrography analysis, eight samples of Scanning Electron Microscope (SEM) analysis, and three samples of X-Ray Difraction (XRD) analysis. The lower part of the unit is initiated by braided fluvial conglomerates which gradually become tidal sand flat association of shale layers, coal seams and sandstone insertion. While the upper part of the unit is consisting of thick bedded quartz sandstone with thin siltstone insertion, deposited in the shoreface environment. Those facies association developed at transgressive conditions in the estuarine environment. The characteristic of the sandstone unit of Pedaro Formation is thickly bedded quartz wacke to quartz arenite, white to light grey in color, moderately to very well sorted, mostly mature sand. Pedaro Formation is identified to be deposited at Early Jurassic in interior craton tectonic setting. The characterization of sandstone unit of Pedaro Formation is showing that the unit can be correlate to the equivalent of Plover Sandstone found in Timor. Sandstone unit of Pedaro Formation can play a role as reservoir candidate in petroleum system of Savu and surrounding area.

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Cao, Binfeng, Xiaorong Luo, Likuan Zhang, Fenggui Sui, Huixi Lin et Yuhong Lei. « Diagenetic Heterogeneity of Deep Sandstones and Its Relationship to Oil Emplacement : A Case Study from the Middle Jurassic Toutunhe Formation in the Fukang Sag, Central Junggar Basin (NW China) ». Geofluids 2017 (2017) : 1–23. http://dx.doi.org/10.1155/2017/4292079.

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The Middle Jurassic Toutunhe Formation at depths of approximately 4000–6000 m has increasingly come into focus as a current deep reservoir target in the central Junggar Basin (NW China). Based on petrography, SEM, stable isotopes, and fluid inclusion analyses, the goals of this study were to investigate the effect of depositional lithofacies on sandstone diagenetic heterogeneity and to examine the relationship between diagenetic evolution and oil charge within a heterogeneous reservoir. Grain size controls the overall abundance of cement and porosity and reservoir properties through its effect on ductile lithic sand grains and hence on mechanical compaction. Early diagenetic calcite cement is an exception to this trend. Ductile lithic-rich, very fine-grained sandstones featured compaction of easily deformed, clay-rich grains, resulting in a very rapid loss of porosity during burial. In contrast, dissolution and cementation occurred as well as ductile compaction in the fine-grained sandstones. Two episodes of oil charge occurred in the relatively coarser-grained sandstone lithofacies. Diagenesis progressed alternately with oil emplacement, and some diagenetic alterations and oil charge occurred simultaneously. Ductile lithic-rich, highly compacted sandstones and tightly calcite-cemented sandstones can create permeability barriers embedded in permeable reservoir sandstones, probably resulting in heterogeneous flow.

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Al-Wosabi, Mohammed A., et Sa’ad Z. Al-Mashaikie. « Investigation of Facies Types and Associations of Kuhlan Red Bed Formation in NW Yemen : A New Hypothesis for Origin and Depositional Environment ». Sultan Qaboos University Journal for Science [SQUJS] 11 (1 juin 2006) : 11. http://dx.doi.org/10.24200/squjs.vol11iss0pp11-38.

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Varieties of thirteen facies types were recognized in the Kuhlan Formation represented by red bed siliciclastic sequences of argillaceous sediments. Examination of the Kuhlan stratigraphic column included sequence relationships, lithology, sedimentary characters, structures and petrography of the dominant rock types. These facies types are grouped in three distinct associations of facies. The lower unit A comprises association of facies (Distal turbidites) represented by alternates of turbidity sequences including sandstone, siltstone and thick shale beds. These facies types confirm a regressive depositional environment in deep marine shelf conditions. There are three facies types which are identified as massive sandstone, cross-bedded sandstone and pebbly sandstone facies. The middle unit B association of facies (Proximal turbedites) represents glaciomarine sequences displaying high lateral and vertical facies changes of glacioturbidite sediment alternates with diamictites and tillite beds. The sequences are affected by eustatic and eustatism of the glacial advance and retreat. This unit B includes eight types of facies. These are identified as; tillite, massive diamictites, stratified diamictites, laminated siltstone/shale, deformed siltstone/mudstone, graded rhythmic siltstone, massive conglomerate and cross-stratified sandy conglomerate facies. The upper unit C association of facies is represented by shallow marine shelf sequences displaying very thick massive and locally cross-bedded sand bar sandstone overlying the laminated siltstone/shale interbeds. The upward gradual changes in mineralogical composition and color confirms the start of marine transgression and later deposited platform Amran Group. Mineralogical composition of Kuhlan sandstone displays impure dirty rocks consisting of more than 30% of argillaceous matrix, 50% of cristobalite and quartz grains, more than 10% of ferruginous cement and 10% of detrital iron oxide grains, potash feldspar, igneous rock fragments and carbonate cement. It is classified as quartz greywacke type in the lower and middle parts and as quartz arenite with subarkoses in the upper part.

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Andrews-Speed, C. P. « The role of silica and iron oxide mobility in the formation of gold-bearing fluvial sediments in the Proterozoic Mporokoso Basin, northern Zambia ». Geological Magazine 123, n^o 2 (mars 1986) : 143–52. http://dx.doi.org/10.1017/s0016756800029794.

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AbstractGold-bearing sandstone and conglomerate near the base of the Proterozoic Mporokoso Group were deposited in a braided river system. The detrital sand grade material is mainly of quartz, sericite and haematite, and the pebbles are of vein-quartz, chert, silicic volcanics, quartzose metasediment and jaspilite. The basement rocks presently exposed in the basement are silicic igneous rocks and quartzose metasediments.The petrography of the fluvial sediments suggests that silica and, to a lesser extent, iron oxide were mobile both in the source-area and in the braided river system. Evidence for silica-mobility includes jaspilite pebbles with spherulites and glaebules of chalcedony, abundant vein-quartz pebbles, intra-basinal sandstone pebbles, and the silicification of volcanic pebbles. The detrital haematite in the fluvial sandstone forms pseudomorphs after magmatic magnetite. Authigenic iron oxide occurs in several forms which suggest that iron oxide was mobile in the source-area and in the fluvial sediments. Uranium is locally abundant in basement and sedimentary rocks, cassiterite is a common heavy mineral in the fluvial sediments, and fluorite has been found in the basement.These features may be explained by intense weathering which mobilized both silica and iron. The silica was concentrated near the surface to form silcretes in the basement and later in the overlying fluvial sediments. Hydrothermal convection cells driven by the granites may have carried silica, iron, tin, fluorine and uranium towards the surface before and during the erosion of the igneous basement.

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Dill, Harald G., Andrei Buzatu, Christopher Kleyer, Sorin-Ionut Balaban, Herbert Pöllmann et Martin Füssl. « A Natural GMS Laboratory (Granulometry-Morphometry-Situmetry) : Geomorphological-Sedimentological-Mineralogical Terrain Analysis Linked to Coarse-Grained Siliciclastic Sediments at the Basement-Foreland Boundary (SE Germany) ». Minerals 12, n^o 9 (1 septembre 2022) : 1118. http://dx.doi.org/10.3390/min12091118.

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The “natural GMS laboratory” (granulometry-morphometry-situmetry) is located within the Variscan Basement in SE Germany (Fichtelgebirge Mts.), which is uplifted relative to its Permo-Mesozoic foreland along a deep-seated lineamentary fault zone. This transitional study area is crossed by straight to low drainage systems in the basement, turning meandering channel systems into high sinuosity when entering the foreland. Due to its good geological coverage, the entire region is subjected to an advanced-level terrain analysis and completed with a sedimentological study focusing on the GMS tool. Unlike many applications in the past, the three components of the GMS tool that are of almost equal value ought to be used in combination and not as stand-alone procedures so as to be integrated into other near-surface geoscientific methods, e.g., sediment petrography. The strong points of granulometry of coarse-grained/gravel-sized sediments are its extension into the smaller sand and clay grain size intervals using the sorting, mean and/or median values for an environmental analysis. Morphometry can be linked to the compositional geosciences, e.g., mineralogy and geochemistry. The grain shape is intimately connected with the lithology, providing options from triaxial measuring of the lithoclast to the digital image analysis. It is a favorable tool to supplement the provenance of lithoclasts. Situmetry is the key element of hydrodynamic research and directly builds upon its sister methods. Its applications and numerical approaches are useful for the identification and quantification of physical land-forming processes. It is the fan sharpness and the orientation of lithoclasts relative to the direction of the talweg and in relation cross-sectional valley features that integrate the GMS tool into geological and geomorphological mapping, both of which result in a digital terrain model. Horizontal rose diagrams are useful for the upper reaches of drainage systems, be they of alluvial or non-alluvial types, and vertical ones for alluvial channels in the distal and proximal foreland where stacked patterns of depositional terraces are of widespread occurrence. In general, the GMS tool can be applied to sedimentological, geomorphological, petrographic and tectonic objects in basements and foreland basins; in applied geosciences, it is suitable for the identification of mineral resources and of areas vulnerable to geohazards, and in genetic geosciences for the discrimination of supergene chemical and physical depositional and land-forming processes.

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Aminu, Mu’awiya B., Simon D. Christopher, Changde A. Nanfa, Ahmad T. Dahiru, Andarawus Yohanna, Nengak Musa et Simon Tobias. « Petrography and Heavy Mineral Studies of Lokoja Formation along Mount Patti North Central Nigeria : Implication for provenance Studies ». European Journal of Environment and Earth Sciences 3, n^o 2 (31 mars 2022) : 36–51. http://dx.doi.org/10.24018/ejgeo.2022.3.2.243.

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The Southern Bida basin consists of the Lokoja, Patti, and Agbaja formations. This study focuses on the Lokoja formation and samples gotten were used for petrography and heavy mineral analysis. Results of all analytical techniques employed in the study are presented here. A critical assessment of each set of results and their integration aided the proper interpretation and useful discussion. This study focuses on the Southern Bida Basin, specifically the Lokoja Formation because the exposures of Patti are poorly exposed. Outcrop samples were obtained from the exposed sections of the study area in Kabawa and Robinson street respectively. Different features were observed, such as the thickness of the exposure, the nature of the lithology, color, and sedimentary structures. The dominant lithologies in the area include sandstone and ironstone. The sandy facies are generally arkosic characterized by poorly sorted very fine to conglomeratic sandstone sequence. Laboratory investigations of samples included petrography and heavy mineral analysis. Sandstone samples were collected from the study area. Each sample was divided into two parts: the first part for petrographic studies and the second part for heavy mineral analysis.

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Strohmenger, Christian J., Abdulla Al-Mansoori, Omar Al-Jeelani, Ali Al-Shamry, Ismail Al-Hosani, Khalil Al-Mehsin et Hesham Shebl. « The sabkha sequence at Mussafah Channel (Abu Dhabi, United Arab Emirates) : Facies stacking patterns, microbial-mediated dolomite and evaporite overprint ». GeoArabia 15, n^o 1 (1 janvier 2010) : 49–90. http://dx.doi.org/10.2113/geoarabia150149.

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ABSTRACT The Mussafah Channel is a man-made canal cut perpendicular to the coastline, located to the southwest of the city of Abu Dhabi, United Arab Emirates, and is ideal for studying coastal depositional processes in an arid environment. The channel walls reveal a few meters of Pleistocene reworked dune deposits, unconformably overlain by Holocene carbonates and sabkha evaporites. The Holocene succession consists of intertidal to shallow subtidal sediments that vary significantly along depositional strike direction. Bladed gypsum crystals, gypsum rosettes, and nodular to highly contorted, discontinuous bands of classic sabkha anhydrite are present along the channel walls. Sedimentology, petrography, SEM, X-ray diffraction, and radiocarbon age-dating analyses of the sabkha sequence show the following profile from base to top: (1) non-bedded carbonate-rich sand: reworked aeolianite with an approximate (ca.) radiocarbon age in years (yrs) before present (BP) ca. 26,800 14C yrs BP; (2) cross-bedded to non-bedded carbonate-rich sand: aeolianite/reworked aeolianite (ca. 24,000–23,500 14C yrs BP); (3) crinkly-laminated stromatolitic bindstone: intertidal, low-energy microbial mat (ca. 6,600–6,200 14C yrs BP); (4) lower, discontinuous and in places reworked hardground: cemented channel-lag deposits (ca. 6,400 14C yrs BP); (5) peloid-skeletal packstone with rootlets or microbial-laminated peloid-skeletal packstone, laterally grading into fine- to coarse-grained, cross-bedded, cerithid-rich, bioclastic packstone, grainstone, and rudstone: lowermost intertidal to shallow subtidal, low-energy, mud-rich rooted and microbial-laminated lagoonal deposits and moderate- to high-energy, intertidal to shallow subtidal tidal-channel, tidal-delta, and tidal-bar deposits (ca. 6,200–5,200 14C yrs BP); (6) upper discontinuous and shingled hardground: cemented beach rock (ca. 5,700 14C yrs BP); (7) cross-bedded, bioclastic rudstone/grainstone, grading laterally into intervals displaying bladed gypsum crystals and nodular to enterolithic anhydrite: intertidal to shallow subtidal, high-energy longshore beach bar and beach spit deposits; overprinted by sabkha gypsum and anhydrite (ca. 5,000 14C yrs BP). Significant amounts of dolomite were found within the rooted and microbial-laminated mud-rich lagoonal carbonates, some of the tidal-channel/lagoonal deposits, the buried crinkly-laminated microbial mats, and within some of the Pleistocene carbonate-rich sands. The dolomite is very fine-crystalline and displays spherical morphologies as well as subhedral to euhedral dolomite rhombohedra. The formation of dolomite is interpreted to be related to dolomite-mediating microbial organisms which form the widespread microbial mat along the Abu Dhabi coastline. Microbial organisms are also present within the rooted and microbial-laminated lagoonal carbonates and, most probably, within all the other studied carbonates and the Pleistocene carbonate-rich sands. Biopolymers of microbial origin, referred to as Extracellular Polymeric Substances (EPS), are interpreted to play a key role in primary dolomite formation. The sabkha sequence at Mussafah Channel formed during the post-glacial Flandrian transgression, resulting in the reworking of the Pleistocene aeolian dunes and the deposition of intertidal to shallow subtidal carbonates. Recent find of whale bones within tidal-channel deposits overlying the microbial mat further document the initial Holocene transgression. During a subsequent slight sea-level fall (regression), these carbonates were overprinted by gypsum and anhydrite. The observed lateral and vertical facies variations reflect primary reservoir quality variations, an important aspect to be considered for geological facies and reservoir quality modeling.

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Yatsyshyn, Andriy, Maciej Bąbe, Danuta Olszewska-Nejber, Andriy Bogucki et Stephania Vas’kiv. « Lithological and sedimentological characteristics of the alluvium of the sixth terrace of the Dniester river (Loyeva level) in the Torhanovychi 2 section ». Visnyk of the Lviv University. Series Geography, n^o 41 (17 septembre 2013) : 382–95. http://dx.doi.org/10.30970/vgg.2013.41.2011.

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The main lithological characteristics of the alluvium of the sandy-gravelly bed of the sixth terrace of the Dniester river (Loyeva level) at environs of Sambir was analysed, in particular textural elements, granulometric and petrographic composition of the gravelly material (enclosing coarse sands, granules, pebbles, cobbles and boulders), its roundness, and the orientation of grains. The conditions of sedimentation of the studied alluvial sandy-gravelly bed of the sixth terrace of the Dniester river (Loyeva level) were reconstructed. Key words: granulometric composition, petrographic composition, roundness, sorting, imbrication, braided channel, depositional conditions.

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Garzanti, Eduardo. « Petrographic classification of sand and sandstone ». Earth-Science Reviews 192 (mai 2019) : 545–63. http://dx.doi.org/10.1016/j.earscirev.2018.12.014.

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Rossato, Sandro, Anna Carraro, Giovanni Monegato, Paolo Mozzi et Fabio Tateo. « Glacial dynamics in pre-Alpine narrow valleys during the Last Glacial Maximum inferred by lowland fluvial records (northeast Italy) ». Earth Surface Dynamics 6, n^o 3 (26 septembre 2018) : 809–28. http://dx.doi.org/10.5194/esurf-6-809-2018.

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Abstract. During the Last Glacial Maximum (LGM), most of the major glaciated basins of the European Southern Alps had piedmont lobes with large outwash plains; only a few glaciers remained within the valley. Piedmont glaciers have left well-preserved terminal moraines, which allow for investigations to be carried out and inferences to be made regarding their evolution and chronology. Valley glaciers' remnants, on the contrary, are often scantly preserved, and changes can only be detected through correlations with glaciofluvial deposits in downstream alluvial basins. The Brenta glacial system's dynamics in the glacier's terminal tract have been inferred through a wide range of sediment analysis techniques on an alluvial stratigraphic record of the Brenta megafan (northeast Italy), and via the mapping of in-valley glacial/glaciofluvial remnants. Glaciers flowing across narrow gorges could possibly be slowed/blocked by such morphology, and glacial/sediment fluxes may then be diverted to lateral valleys. Moreover, narrow valleys may induce glaciers to bulge and form icefalls at their front, preventing the formation of terminal moraines. The Brenta Glacier was probably slowed/blocked by the narrow Valsugana Gorge downstream of Primolano and was effectively diverted eastwards across a wind gap (Canal La Menor Valley), joining the Cismon/Piave glaciers near Rocca and ending ∼2 km downstream. The Cismon and Piave catchments started to contribute to the Brenta system just after 27 ka cal BP until at least ∼19.5 ka cal BP. After the glaciers collapsed, the Piave River once again flowed into its main valley, whilst the Cismon continued to merge with the Brenta. This investigation shows that glacial catchments may vary significantly over time during a single glaciation in rugged Alpine terrains. Sand petrography and the chemical/mineralogical composition of sediments are powerful proxies for tracing such variations, as they propagate through the glacial and glaciofluvial systems and can be recognized in the alluvial stratigraphic record far downstream from the glacier front.

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Medina, Daniel Alonso, et David Budd. « Critical Diagenetic Features Controlling Intergranular Flow Paths and Matrix Permeability in the Codell Sandstone, Northeastern Colorado ». Mountain Geologist 57, n^o 2 (1 avril 2020) : 95–120. http://dx.doi.org/10.31582/rmag.mg.57.2.95.

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The Codell Sandstone is a hydrocarbon-bearing, tight sand (permeability <0.1 mD) that is an active target for unconventional hydrocarbon production in the Denver-Julesburg Basin. In northeastern Colorado, the intergranular microporous drainage network within this clay-rich sandstone is poorly understood, with a strong diagenetic control suggested by the lack of correlation between permeability and depositional facies. Core samples from the Wattenberg Field and Redtail areas in Weld County were used to identify which diagenetic processes were most important in developing a connected pore network. Thirteen diagenetic features were defined using thin-section petrography and electron microprobe mineralogical phase mapping, and skeletonized flow paths were delineated by epifluorescence imaging. Quartz overgrowths, mechanical compaction, and clay cements (illite, chlorite, and kaolinite) are better developed in the laminated facies than the burrowed facies. Authigenic calcite and pyrite, and dissolution of framework grains are equally developed in both types of facies. Cumulative 2D flow-path lengths positively co-vary with permeability, indicating that the skeletonized paths capture the features that control permeability. The longest flow paths in high permeability (≥0.09 mD) samples follow micropores created along the periphery of framework grains where the discontinuous quartz overgrowths abut clays. Micropores within intergranular clay masses (detrital, pore-filling cements, and authigenic replacements) associate with shorter flow paths that dominate in low permeability (≤ 0.01 mD) samples and feed the longer paths in high permeability samples. While compaction and all types of cements had a negative impact on the original pore network, the development of long contacts between quartz overgrowths and mechanically juxtaposed grains eventually became beneficial to the drainage system. The increased surface area along those contacts increased the continuity of the flow paths developed along grain surfaces. All observations indicate that the minute quartz overgrowths, and the high authigenic rugosity they created along grain boundaries, were a key diagenetic event in creating the most efficient drainage networks that now facilitate the movement of hydrocarbons at the core-plug scale.

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Remírez, Mariano N., Luis A. Spalletti, Manuel F. Isla et Ernesto Schwarz. « Fine-grained distal deposits of a mixed siliciclastic–carbonate marine system : Origin of mud and implications on mixing processes ». Journal of Sedimentary Research 92, n^o 3 (15 mars 2022) : 210–31. http://dx.doi.org/10.2110/jsr.2021.080.

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ABSTRACT Mixed siliciclastic–carbonate sediments in the distal settings of marine systems (i.e., offshore and basin areas) are the result of the complex interaction between production of benthic and pelagic biogenic carbonates and the exportation of terrigenous, and/or carbonate mud from shallow-marine settings. Thus, the origin of mud (particles < 63 mm) of different compositions and the processes responsible for mixing them play a key role in the final distal deposits of mixed systems. Although the understanding of these topics in shallow settings has made significant progress, one of the critical issues is to recognize them in the offshore and basinal settings for understanding the link between shallow-marine and deep-marine areas. In this study, a thick Lower Cretaceous succession (330–650 m) of the Neuquén Basin, composed mostly of mixed (siliciclastic–carbonate) fine-grained marine deposits, was studied through a high-resolution analysis of petrography, SEM analysis, and mineralogy, to define and characterize the origin of carbonate and terrigenous mud as well as to characterize the processes involved in the mixing of terrigenous and carbonate mud on a storm-dominated ramp. Contrary to previous suggestions, most of the carbonate recognized in the basinal setting is composed of silt- to sand-size skeletal remains and micrite (micarbs) and is likely derived from a pelagic biogenic factory combined with carbonate derived from the maceration of benthic organism. Furthermore, micarbs are possibly diagenetic in origin but with a distally produced carbonate precursor. In contrast, the siliciclastic fraction is entirely detrital, being silt-size quartz particles and clay minerals (mainly illite) the most important constituents. Most of the terrigenous mud delivered from shallow areas acts to dilute the distally produced carbonate mud. However, a bloom of carbonate production able to dilute terrigenous supply is recorded, and its origin is likely triggered by the input of waters charged with nutrients from the paleo–Pacific Ocean in addition to nutrients derived from proto-Andes volcanic activity. This demonstrates that the relation between the terrestrially derived siliciclastic components and the biogenically produced carbonates in mixed systems is not linear, but a complex interaction of climate, sea-level, origin of the components, and hydrography of the basin, among others.

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Velazco, M. A., A. Bruce, M. Ferris, J. Reed et R. Kandasamy. « The role of ferrous clays in the interpretation of wettability – a case study ». E3S Web of Conferences 89 (2019) : 03002. http://dx.doi.org/10.1051/e3sconf/20198903002.

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Clean sandstone, with minimal clay content, is expected to be strongly water wet once the rock has been through an effective cleaning process. Even samples containing significant clay minerals are usually expected to be water wet after appropriate cleaning. However, tests carried out on core samples from Fields in three different global locations show mixed indices, even for clean state samples where no aging with crude oil has taken place. A few hypotheses for this behaviour considered herein are: whether the cleaning method was adequate, whether wettability was altered by an external factor, or if wettability was due to mineral composition. This paper presents the results obtained from wettability studies on fresh, clean and restored state core plug samples from three different Fields. Wettability indices were obtained by using the combined Amott-USBM method. Petrography was performed on sample end-trims to investigate the possible presence of halite or barite in the clean state samples, thought to be from drilling fluid infiltration, which should have been removed by the methanol cleaning cycle. This showed no organic material or salt (halite), negating wetting change from inefficient cleaning. From a reactive clays [1] model perspective, these rock samples are considered clean-sand (i.e. illite/ smectites- as total clay content), determined by XRD analysis, are lower than 10%. SEM and XRD results showed the presence of grain-coating chlorite in one sample set and glauconite grains in the others. Only once the unusual wettability indices were obtained was the grain-coating chlorite identified as chamosite by SEM/EDX, which is an iron-rich form of chlorite. The presence of chamosite or glauconite appears to influence the wetting tendency. In summary, USBM vs Amott wettability indices of the analysed samples are consistent between both methods, showing a mixed to oil-wet tendency for all samples where chamosite was identified, regardless of the initial test condition. Samples with glauconite appeared to be more mixed wet after wettability restoration. The results suggest that iron rich clay/mineral content is the main contributor to the oil wet tendency of the evaluated rocks.

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Kumar, Roselyn, Patrick D. Nunn et Elia Nakoro. « Identifying 3000-Year Old Human Interaction Spheres in Central Fiji through Lapita Ceramic Sand-Temper Analyses ». Geosciences 11, n^o 6 (31 mai 2021) : 238. http://dx.doi.org/10.3390/geosciences11060238.

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Petrographic analyses of sand tempers in Pacific Island potsherds reveal information about ancient human interactions within archipelagic contexts. By comparison with bedrock mineralogy, analyses of 45 sherds from the Lapita settlement at Naitabale on Moturiki Island (central Fiji) show that most sherds were manufactured locally but that a minority is exotic. Using ternary plots of LF-QF-FM (LF—lithic fragments; QF—quartz + feldspar; FM—ferromagnesian), it is shown that exotic material (either pots or temper sands) most likely came from elsewhere in Fiji, probably southeast Viti Levu Island, central Lau, Lomaiviti and Kadavu. Geoscientific analyses of archaeological samples therefore gives us insights into how people likely interacted within the Fiji Archipelago three millennia ago.

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Ismiyati. « STUDI PETROGRAFI BATUPASIR FORMASI WALAT DAERAH CIBADAK, SUKABUMI : IMPLIKASINYA TERHADAP TIPE PROVENAN ». INTAN Jurnal Penelitian Tambang 4, n^o 1 (1 avril 2022) : 54–58. http://dx.doi.org/10.56139/intan.v4i1.82.

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The Walat Formation is an Paleogen siliciclastic sedimentary rock formed in the Bogor Basin. Outcrops of this formation are widespread in the Cibadak area such as in Gunung Walat, the Sand Bongkok Complex, Aseupan Sand, and the Cicareuh River. Several studies have been done before on this formation. However, studies on provenance with petrographic methods are still rarely conducted, especially in the research area. This is the basis of this study. The data used in this study consisted of field data and previous research literature. The location of field data collection is located in the south of Gunung Walat, precisely in the Holcim Educational Forest (HEF) using the measured stratigraphic method. A total of 18 sandstone samples were using the petrographic. From one existing track, three facies were identified, namely Sp (planar-cross-bedded sand), Gh (clast supported, horizontally stratified gravel), and Fl (laminated sand, silt, and mud). This facies distribution is based on lithology, grain size, and sedimentary structure. Petrographic data indicate that the sandstones of the Walat Formation are mostly lithic arenite, sublithic arenite, and lithic-graywacke. Comparison of QFL composition shows that all sandstones come from orogenic deposits with Q compositions (78.51% - 97.74%), F (0 - 1%), and L (2.26% - 21.13%) meanwhile, QmFLt comparisons show originating from quartz recycled (three samples), transitional recycled (11 samples), and lithic recycled (four samples).

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Antolik, Aneta, Daria Jóźwiak-Niedźwiedzka, Kinga Dziedzic, Karolina Bogusz et Michał A. Glinicki. « Microscopic analysis of the alkali-silica reactivity of various origin fine aggregate ». MATEC Web of Conferences 322 (2020) : 01025. http://dx.doi.org/10.1051/matecconf/202032201025.

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Alkali silica reaction (ASR) is a harmful phenomenon occurring as a result of chemical interactions between sodium and potassium hydroxides in the pore solution and reactive minerals contained in the aggregate. Reactive minerals like microcrystalline, cryptocrystalline or strained quartz dissolve in the alkaline solution and form an expansive gel product. Proper selection of concrete constituents is necessary to ensure the durability of concrete structures. The proper recognition of the aggregate mineralogical composition is a very important element in the process of selection of concrete components due to the risk of ASR occurrence. This paper presents the results of detailed microscopic analysis of alkali-silica reactivity of domestic fine aggregates of various origins. Six siliceous sands from different locations in Poland and one limestone sand were tested. Detailed petrographic analysis was performed on thin sections. In all siliceous sands micro- and cryptocrystalline quartz was recognized as a reactive mineral. Digital image analysis was performed for quantitative assessment of the potential of reactivity of sands. It revealed, that siliceous river sands were the most susceptible to an alkali-silica reaction, which was confirmed by mortar bar expansion test performed according to the standard test method.

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Umar, Hamid, Dadang A. Suriamihardja, Lawalenna Samang et Ulva Ria Irfan. « Impact of compaction test on mineral texture breakage in Tanjung Bunga Beach, Makassar ». MATEC Web of Conferences 181 (2018) : 11002. http://dx.doi.org/10.1051/matecconf/201818111002.

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Rate of mineral deterioration in Tanjung Bunga Beach, Makassar city sediment, as a coastal city area that temporarily evolved with infrastructure development, through a Compaction test has found damage mineral from cracks, split and shatter. The aim of this research is to classify the compaction test from mineral as result texture breakage from compression test. Tanjung Bunga beach sediments based on grain size was classified from fine sand, medium sand and coarse sand. Petrographic analysis of 15 samples of in three drilling sites with 5 meters depth, found quartz mineral composition from 20 – 25%, hornblende bertween 5 – 20%, pyroxene 5 – 15%, pagioclast 5 – 15%, orthoclast 5 – 15%, biotite 10 – 20%, and opaque minerals 10 – 25%. Value of Compaction Test laboratory Fine Sand has 4 - 14.4 Div, Medium Sand has 6.7 - 20 Div, and Coarse Sand has 3.2 - 24 Div. Petrographic analysis after Mineral Compaction Test on fine sand was cracked up to 2 – 20%, split 2 – 12%, and shattered 2 – 10%, medium sand was cracked mineral up to 2 – 15%, split up to 1 – 13%, and shattered up to 1 – 5%, and coarse sand up to 1 – 10% cracked minerals, split up to 2 – 15%, and shattered up to 2 – 7%. High percentage of crack minerals were found in fine sand with low Compaction Test values and coarse sand with low crack mineral and high Compression Strength values. More cracked mineral was found in Quartz and no opaque minerals were shatter. Mineral pyroxene is founded as most shatter shape and orthoclase mineral with the most split shape.

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Malhame, Pierre, et Reinhard Hesse. « Quartz arenites of the Cambro–Ordovician Kamouraska Formation, Quebec Appalachians, Canada : II. Eolian sands in deep-sea sedimentary gravity-flow deposits ». Canadian Journal of Earth Sciences 52, n^o 4 (avril 2015) : 261–77. http://dx.doi.org/10.1139/cjes-2014-0030.

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The Kamouraska Formation is a quartz-arenitic unit of latest Cambrian – earliest Ordovician age in the Quebec Appalachians that was deposited by hyperconcentrated to concentrated density flows in a meandering submarine canyon on the continental slope bordering the Iapetus Ocean, as outlined in a companion paper. Detailed petrographic study of the quartz arenites of the Kamouraska Formation combined with scanning electron microscopy of grain surface textures suggests that the quartz sands are of eolian origin having been derived from an inland desert or, less likely, a barrier beach dune system. Transport of the mature quartz-arenitic sand onto the shelf and deposition into the deep sea was not accompanied by substantial mixing with material from other sources thus preserving the inherited eolian characteristics. A modern analogue for the eolian interpretation of the deep-sea quartz-arenite beds is as follows: thick, Late Pleistocene eolian sand beds on a modern abyssal plain in the East Atlantic referred to as eolian-sand turbidites that were deposited in the deep sea during glacial sea level lowstands when eolian sand transport to canyon heads was enabled by an exposed and shortened shelf. Similarly, an established sea level lowstand at the Cambro–Ordovician boundary would have facilitated the introduction of eolian sand of the Kamouraska Foundation into canyon heads on the upper slope from where turbidity currents and related density flows were triggered. Correlation of the Kamouraska Formation with the quartz arenites of the Cairnside Formation of Quebec (Keeseville Formation in northern New York State, Nepean Formation in southern Ontario) links the deep-sea deposits with remnants of an inland dune system.

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Mpalatsas, I., I. Rigopoulos, B. Tsikouras et K. Hatzipanagiotou. « Evaluation of cretaceous limestones from the Aitoloakarnania province (Western Greece) for their use as road aggregates in terms of their content in swelling clay minerals ». Bulletin of the Geological Society of Greece 47, n^o 4 (5 septembre 2013) : 1990. http://dx.doi.org/10.12681/bgsg.11023.

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The aim of this paper is to assess the suitability of a significant number of carbonate rocks from the Aitoloakarnania province (Western Greece) for their use as road construction aggregates, in terms of their content in swelling clay minerals. The study focuses on Cretaceous limestones from the Olonos-Pindos zone. Detailed petrographic analysis and the sand equivalent and methylene blue tests are carried out, in order to estimate the quantity of swelling clay minerals in aggregate particles. Special emphasis is given on correlating the results of the sand equivalent and methylene blue tests, as well as on the relationships between these engineering parameters and the petrographic data. The results are evaluated in accordance with the Greek and International suitability Standards for road construction aggregates. Although the results of the sand equivalent test indicate the suitability of the studied samples, the results of the methylene blue test imply that they are not suitable for use in all applications of road construction. Hence, it is proved that the methylene blue test is of fundamental importance for the determination of the lithotypes which are suitable for use as road aggregates in various applications.

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