scholarly journals A petrographic study of bauxite of Kenco area, Landak District, West Kalimantan Province

2021 ◽  
Vol 921 (1) ◽  
pp. 012048
Author(s):  
S R Nurhawaisyah ◽  
N Jafar ◽  
S Bakri ◽  
A Artiningsih ◽  
S Widodo
Keyword(s):  
Source Rock ◽  
Mineral Content ◽  
Quartz Diorite ◽  
Petrographic Analysis ◽  
Thin Sections ◽  
West Kalimantan ◽  
Cretaceous Volcanism ◽  
Granodiorite Porphyry ◽  
Petrographic Study

Abstract Lateritic bauxite are the products of intense weathering of rocks. It is largely controlled by bedrock type, time, climate (rainfall), and geomorphology. It is located in Kenco area, Landak district, West Kalimantan Province which the rest of the development of Cretaceous volcanism consisting of the island of Borneo Volcanic Formations Mensibau with unit members Granodiorite, quartz diorite and diorite, and the Formation of the Kingdom Volcanic Andesite-trachite units and Formations of alluvium and swamp sediment quarter. Bauxite deposits of Kenco area in Landak are investigated to determine the characteristics of rocks using petrographic analysis. Petrographic analysis aims to determine mineral content and type of source rock based on Travis classification (1955). The results of 15 thin sections showed that aluminum-bearing minerals consisted of orthoclase, plagioclase, and biotite which are the type of source rock are granodiorite, granodiorite porphyry, gabbro porphyry, and basalt porphyry based on Travis classification (1955).

scholarly journals Mineralogical and Microstructure Analysis for Characterization and Provenance of Ceramic Artifacts from Late Helladic Kastrouli Settlement, Delphi (Central Greece)

Geosciences ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 36
Author(s):  
Vayia Xanthopoulou ◽  
Ioannis Iliopoulos ◽  
Ioannis Liritzis
Keyword(s):  
Raw Materials ◽  
Analytical Techniques ◽  
Sem Analysis ◽  
Petrographic Analysis ◽  
Ceramic Assemblage ◽  
Thin Sections ◽  
Central Greece ◽  
High Calcium ◽  
Local Geology

The present study deals with the characterization of a ceramic assemblage from the Late Mycenaean (Late Helladic III) settlement of Kastrouli, at Desfina near Delphi, Central Greece using various analytical techniques. Kastrouli is located in a strategic position supervising the Mesokampos plateau and the entire peninsula and is related to other nearby coeval settlements. In total 40 ceramic sherds and 8 clay raw materials were analyzed through mineralogical, petrographic and microstructural techniques. Experimental briquettes (DS) made from clayey raw materials collected in the vicinity of Kastrouli, were fired under temperatures (900 and 1050 °C) in oxidizing conditions for comparison with the ancient ceramics. The petrographic analysis performed on thin sections prepared from the sherds has permitted the identification of six main fabric groups and a couple of loners. The aplastic inclusions recognized in all fabric groups but one confirmed the local provenance since they are related to the local geology. Fresh fractures of representative sherds were further examined under a scanning electron microscope (SEM/EDS) helping us to classify them into calcareous (CaO > 6%) and non-calcareous (CaO < 6%) samples (low and high calcium was noted in earlier pXRF data). Here, the ceramic sherds with broad calcium separation are explored on a one-to-one comparison on the basis of detailed mineralogical microstructure. Moreover, their microstructure was studied, aiming to estimate their vitrification stage. The mineralogy of all studied samples was determined by means of X-ray powder diffraction (XRPD), permitting us to test the validity of the firing temperatures revealed by the SEM analysis. The results obtained through the various analytical techniques employed are jointly assessed in order to reveal potters’ technological choices.

scholarly journals Lithostratigraphy and microfacies analysis of Avanah Formation (Middle Eocene) in Gomaspan section northeast Erbil City, Kurdistan region, Iraq

2021 ◽  
Author(s):  
Irfan Sh. Asaad ◽  
Keyword(s):  
Middle Eocene ◽  
Planktonic Foraminifera ◽  
Middle Part ◽  
Petrographic Analysis ◽  
Microfacies Analysis ◽  
Dolomitic Limestone ◽  
Kurdistan Region ◽  
Thin Sections ◽  
Lithostratigraphic Units ◽  
Lagoon Environment

Lithostratigraphy and microfacies analysis of the Avanah Formation (Middle Eocene) were studied in the Gomaspan section in the Bina Bawi anticline, northeast of Erbil city, Kurdistan Region, Iraq. The field observations refer that the formation attains 56 m of medium to thick bedded yellow limestone, grey dolomitic limestone and blue marly dolomitic limestone interbedded with thin beds of blue marl and dark grey shale with an interval of sandy limestone in the middle part and thin to medium bedded limestone interbedded with red mudstone. The petrographic study of 29 thin sections of Avanah carbonates revealed that the majority of the matrix is carbonate mud (micrite) with few microspar. The skeletal grains include benthic foraminifera, dasycladacean green algae, ostracods, calcispheres, pelecypods, rare planktonic foraminifera and bryozoa in addition to bioclasts. Non-skeletal grains encompass peloids, oncoids, intraclasts and extraclasts with common monocrystalline quartz. Based on the field observation and petrographic analysis, three different lithostratigraphic units were identified. They are in ascending order: A-Thick bedded dolomitic marly limestone interbedded with shale. B- Bedded dolomitic limestone interbedded with shale and marl. C- Thin to medium bedded limestone interbedded with red mudstone. Depending on detailed microfacies analysis of carbonate rocks, three main microfacies and 12 submicrofacies are recognized. From the sum of all petrographic, facies, textural analyses, it is concluded that Avanah Formation in Gomaspan section, was deposited in shallow marine environment, semi restricted lagoon, in lower and upper parts and open lagoon environment in the middle part interval.

scholarly journals Petrographic Study of Sedimentary Iron Ore in Shendi -Atbara Basin, River Nile State, Sudan.

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Abubaker A. M. A. Abasher ◽  
Sadam H.M.A. Eltayib ◽  
El Sheikh M. Abdelrahman ◽  
Mohammed M.A. Amlas
Keyword(s):  
Chemical Weathering ◽  
Iron Ore ◽  
Field Work ◽  
Chemical Precipitation ◽  
Office Work ◽  
River Nile ◽  
Stratigraphic Sequence ◽  
Thin Sections ◽  
Geological Conditions ◽  
Petrographic Study

This paper presents the results of petrographic study of sedimentary iron ore from surface strata of the Shendi -Atbara Basin, River Nile State, Sudan. The aims of this study are to investigate the geological behavior and geological conditions affecting precipitation of sedimentary iron ore. The methodologies have been used to realize the objectives of this study included; field work, office work and labrotary work include thin sections and polished sections analysis. According to field observation sedimentary iron ore can broadly be considered as occurring in three major classes: Ferribands iron, ferricrete iron and oolitic iron ores. The modes of occurrence of iron ore was described at the outcrops and vertical sedimentary profiles revealed that the iron occurred in study area at different types in stratigraphic sequence such as cap, beded and interbeded conformable with Shendi Formation. Petrographic study of iron ore in collected samples using polarized microscope and ore microscope includes study of the textures and structures of ores to obtain ore history. The main types of textures and structures in studied samples are oolitic, granular, lamellar and bands. According to these results the origin of iron ore is formed by chemical precipitation during chemical weathering of surrounding areas in continental lacustrine environment. The iron ore in study area is potential for future mining works and steals industry.

scholarly journals Petrographic study of oil migration on the example of Imilorskoye field (Kogalymsky petroleum region, Western Siberia)

LITOSFERA ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 592-600
Author(s):  
G. H. Shaikhutdinova
Keyword(s):  
Western Siberia ◽  
Hydraulic Fractures ◽  
Petrographic Analysis ◽  
Reservoir Properties ◽  
Oil Migration ◽  
Bazhenov Formation ◽  
Three Stages ◽  
Lower Berriasian ◽  
Petrographic Study ◽  
Fluid Fracturing

Subject. This paper presents the results of studies of the mechanism of primary oil migration in the boundary sediments of the late Jurassic (Bazhenov formation)–early Cretaceous (Achimov pack) on the example of the well 431Р of the Imilor field. Materias and methods. Based on the working hypothesis of fluid fracturing as the main mechanism of primary oil migration, using optical-petrographic analysis, supplemented by geochemical research methods, systems of interconnected microcracks in the Tithonian-lower Berriasian and early Valanginian deposits were studied. Results. It is established that the investigated cracks occurred in three stages: 1) formation of primary sedimentary-lithogenetic fissures as a result of dehydration of clays in the stage of diagenesis and hydraulic fractures in the implementation of the Achimov of terrigenous rocks; 2) partial healing of cracks with secondary minerals in the catagenesis; 3) restoration of patency of the cracks in the generation of large amounts of free hydrocarbons of protopetroleum. It is shown that the migration of hydrocarbons generated by the formation occurred both within the Bazhenov formation itself and through a system of interconnected cracks in the contact zone of the Bazhenov formation with the Achimov formation. Conclusion. A detailed study of the mechanism of oil migration allows us to expand our understanding of the reservoir properties of the oil column, which in the future will allow us to forecast the reservoir properties of the Bazhenov formation including in the zones of anomalous sections (for example, in the Kogalym region).

Borehole image electrofacies with a comparative carbonate petrography analysis: An outcrop well study associated with reservoir application in the Ordovician Tarim Basin

2018 ◽  
Vol 6 (3) ◽  
pp. T723-T737
Author(s):  
Tao Nian ◽  
Zaixing Jiang ◽  
Hongyu Song
Keyword(s):  
Diagnostic Criteria ◽  
Carbonate Platform ◽  
Image Interpretation ◽  
Image Data ◽  
Depth Interval ◽  
Petrographic Analysis ◽  
Thin Sections ◽  
Direct Interpretation ◽  
Borehole Image ◽  
Subsurface Reservoir

Electrical borehole image logs have the potential for direct interpretation of lithofacies characteristics. The challenge is to establish a set of reliable diagnostic criteria with which electrical images can be correlated to lithofacies features such as lithology, sedimentary structures, and bedding sequences. We used the “behind-outcrop” logging procedure that can link borehole images to actual rocks and also reduce errors that are associated with core-shift process. To better reveal the correlation between borehole images and carbonate lithofacies for subsurface reservoir applications, and also make a comparative petrographic analysis with the aim of establishing diagnostic criteria for borehole images, a 200 m well was drilled in the Tarim Ordovician outcrop. A full set of borehole image data and cores with approximately 100% coring recovery rate was acquired at the same depth interval, and more than 100 stained thin sections were prepared. Electrical borehole images in wells adjacent to the outcrop were further interpreted to validate the proposed criteria. Borehole image electrofacies were established according to the image elements, such as stacked mode, bed thickness, conglomerate diameter, rim characteristics, and internal structure of bed/conglomerate, to interpret depositional/diagenetic textures and platform-slope associations. Nine image electrofacies types, corresponding to mud/wacke/pack/grain/bindstone texture, were identified and interpreted in detail. Our method reveals a set of diagnostic criteria for borehole image interpretation in carbonate platform slope, and it finally provides a powerful tool for direct interpretation of electrical images in similar reservoir environment.

An Archaeometric Characterization of Ancient Pottery from Huagangshan Site, Eastern Taiwan

2020 ◽  
Author(s):  
Ying San Liou
Keyword(s):  
Amorphous Carbon ◽  
Firing Temperature ◽  
Raw Materials ◽  
River Sediments ◽  
Archaeological Site ◽  
Point Of View ◽  
Petrographic Analysis ◽  
Main Stream ◽  
Thin Sections ◽  
Metal Age

&lt;p&gt;Micro-Raman spectroscopy and petrographic analysis was carried out on ancient potsherds and sediments excavated from the Huagangshan site and river sediments collected from the northern part of eastern Taiwan. The ceramic fragments analyzed, dating back to 1600-2100 B.P., are recognized to be Early Metal Age of Taiwan. The aims of this study are mainly to identify the mineralogical compositions of ceramics, to explore technical processes such as firing temperature and redox state, and to decipher the nature of clays and its raw materials source.&lt;/p&gt;&lt;p&gt;The results of micro-Raman analysis for ancient potsherds show the presence of 12 minerals. Quartz, anatase, amorphous carbon, hematite, and pyroxenes are the main components of tempers. In addition, amorphous carbon and hematite are the main constitutes for black- and red- hues pottery, respectively. From the point of view of manufacturing techniques, a large amount of amorphous amorphous carbon indicates that the gray-black pottery is fired under a reducing condition. On the contrary, hematite reveals an oxidizing atmosphere for red-hues pottery. The presence of quartz and anatase implies that the firing temperature is estimated to be 750-950&amp;#176;C. A total of 66 samples, containing 23 ceramic fragments (local and imported products) and 6 sediment from cultural strata of archaeological site and 33 river sediments around the site, is implemented by petrographic analysis of thin sections. Petrographic analytic results of 23 potshards show that the proportion of clay is consistent (60.5~69.1%). The inclusions principally include quartz (polycrystalline and monocrystalline quartz), feldspar, muscovite, and volcanic, sedimentary and metamorphic lithic fragments, and quartz is the main component. In addition, the triangle map with ingredients (volcanic lithics+quartz&amp;#65293;sedimentary lithics&amp;#65293;metamorphic lithics) shows that the raw materials source of local and main stream pottery recognized by archaeologist is not local, but comes from a distance area (the Coastal Range). On the other hand, imported pottery indicates the raw materials source is indeed from the central and southern Central Range (some distance south of the site). The result further illustrates the vigorous exchange and/or trade activities between the populations of eastern Taiwan during the Early Metal Age (1600-2100 B.P.).&lt;/p&gt;

Fractures in continental shale reservoirs: a case study of the Upper Triassic strata in the SE Ordos Basin, Central China

2015 ◽  
Vol 153 (4) ◽  
pp. 663-680 ◽  
Author(s):  
WENLONG DING ◽  
PENG DAI ◽  
DINGWEI ZHU ◽  
YEQIAN ZHANG ◽  
JIANHUA HE ◽  
...  
Keyword(s):  
Organic Matter ◽  
Shale Gas ◽  
Mineral Content ◽  
Ordos Basin ◽  
Total Content ◽  
Upper Triassic ◽  
Thin Sections ◽  
Yanchang Formation ◽  
Fracture Development ◽  
Shale Reservoirs

AbstractFractures are important for shale-gas reservoirs with low matrix porosity because they increase the effective reservoir space and migration pathways for shale gas, thus favouring an increased volume of free gas and the adsorption of gases in shale reservoirs, and they increase the specific surface area of gas-bearing shales which improves the adsorption capacity. We discuss the characteristics and dominant factors of fracture development in a continental organic matter-rich shale reservoir bed in the Yanchang Formation based on observations and descriptions of fracture systems in outcrops, drilling cores, cast-thin sections and polished sections of black shale from the Upper Triassic Yanchang Formation in the SE Ordos Basin; detailed characteristics and parameters of fractures; analyses and tests of corresponding fracture segment samples; and the identification of fracture segments with normal logging. The results indicate that the mineral composition of the continental organic-matter-rich shale in the Yanchang Formation is clearly characterized by a low brittle mineral content and high clay mineral content relative to marine shale in the United States and China and Mesozoic continental shale in other basins. The total content of brittle minerals, such as quartz and feldspar, is c. 41%, with quartz and feldspar accounting for 22% and 19% respectively, and mainly occurring as plagioclase with small amounts of carbonate rocks. The total content of clay minerals is high at up to 52%, and mainly occurs as a mixed layer of illite-smectite (I/S) which accounts for more than 58% of the total clay mineral content. The Upper Triassic Yanchang Formation developed two groups of fracture (joint) systems: a NW–SE-trending system and near-E–W-trending system. Multiple types of fractures are observed, and they are mainly horizontal bedding seams and low-dip-angle structural fractures. Micro-fractures are primarily observed in or along organic matter bands. Shale fractures were mainly formed during Late Jurassic – late Early Cretaceous time under superimposed stress caused by regional WNW–ESE-trending horizontal compressive stress and deep burial effects. The extent of fracture development was mainly influenced by multiple factors (tectonic factors and non-tectonic factors) such as the lithology, rock mechanical properties, organic matter abundance and brittle mineral composition and content. Specifically, higher sand content has been observed to correspond to more rapid lithological changes and more extensive fracture development. In addition, higher organic matter content has been observed to correspond to greater fracture development, and higher quartz, feldspar and mixed-layer I/S contents have been observed to correspond to more extensive micro-fracture development. These results are consistent with the measured mechanical properties of the shale and silty shale, the observations of fractures in cores and thin-sections from more than 20 shale-gas drilling wells, and the registered anomalies from gas logging.

scholarly journals Analysis of Ultramafic Rocks Weathering Level in Konawe Regency, Southeast Sulawesi, Indonesia Using the Magnetic Susceptibility Parameter

2020 ◽  
Vol 5 (2) ◽  
pp. 73-81
Author(s):  
Jahidin ◽  
LO. Ngkoimani ◽  
LM. Iradat Salihin ◽  
Hasria ◽  
Erzam S. Hasan ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Source Rock ◽  
Ultramafic Rock ◽  
Nickel Content ◽  
Ultramafic Rocks ◽  
Petrographic Analysis ◽  
Magnetic Minerals ◽  
Rock Samples ◽  
Weathering Process

The Konawe region is part of the Sulawesi Southeast Arm ophiolite belt where ultramafic rocks are exposed in the form of dunite and peridotite. The formation of nickel deposits is closely related to the weathering process of ultramafic rocks as a source rock. Ultramafic rocks exposed to the surface will experience weathering which is influenced by many factors, including in the form of climate change, topography, and existing geological structures. The weathering process in the source rock can influence variations in chemical elements and magnetic properties in laterite soil profiles. For example, the chemical weathering might affect magnetic mineralogy and the physical weathering could affect granulometry as well as the quantity of magnetic minerals in the soil. Condition of weathering of ultramafic rocks (initial, moderate and advanced) can affect nickel content in laterite sediments. The weathering profile study of serpentine mineral is an indication of the lateralization process that occurs in ultramafic rocks and is carried out through petrographic analysis of thin cuts and polish cuts. Determination of weathering level like this is based on the level of weathering of the mineral serpentine. In this study, the determination of the weathering level of ultramafic rocks (initial, moderate, and continued) uses magnetic susceptibility parameter. A total of 232 ultramafic rock core samples obtained from 34 hand samples were taken from different places and weathered levels were analyzed. The results of the research have shown that the magnetic susceptibility of ultramafic rocks in the study area varies, from 580 x 10-6 SI to 4.724 x 10-6 SI. Based on the value of magnetic susceptibility, magnetic minerals contained in ultramafic rock samples are hematite and geotite minerals. This means that the weathering level of ultramafic rock samples is the continued weathering level. The level of continued weathering that occurs in ultramafic rocks in the study area produces nickel laterite deposits with a nickel content of 1.65 - 2.40% in the saprolite zone, 0.42% in the saprock zone, and 0.20 - 0.51% in the basic rock zone (bedrock).

scholarly journals The Lithofacies of Pandua Formation Shale in the Andowia Area, North Konawe, Southeast Sulawesi and Its potential as Petroleum source rock

2021 ◽  
Vol 325 ◽  
pp. 08013
Author(s):  
Mawar Towan Lestari Ramli ◽  
Hendra Amijaya ◽  
Akmaluddin
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Source Rock ◽  
Depositional Environment ◽  
Petrographic Analysis ◽  
Hydrocarbon Accumulation ◽  
High Concentration ◽  
Area North ◽  
Excellent Source ◽  
Petroleum Source Rock

Research on the Late Miocene of Pandua Formation shale in Andowia area, Southeast Sulawesi is fundamental because it is considered to have the potential as a source rock in Manui Basin. This study aimed to determine the lithofacies and its potential as petroleum source rock using megascopic, petrographic, and total organic carbon analyses in Pandua Formation shale. Based on the megascopic and petrographic analysis of outcrops, the shale can be subdivided into 11 lithofacies consists of clayey shale, massive claystone, clastic detritus-rich claystone, massive mudstone, mica-rich mudstone, iron oxide-rich mudstone, low-angle laminated mudstone, massive siltstone, carbon-rich massive siltstone, laminated siltstone, and carbon-rich laminated siltstone. The results of the analysis of 19 samples of shale showed that the total organic carbon (TOC) content was classified as poor to excellent (<0.5%- >4%). The lithofacies with a high concentration of TOC are carbon-rich massive siltstone and carbon-rich laminated siltstone. Both lithofacies were categorized as potentially excellent source rock which the TOC value content is 5.78% and 5.74%.The result implies the better understanding of the depositional environment and hydrocarbon accumulation potential of the Manui basin for future exploration.

Sign in / Sign up

Export Citation Format

Share Document