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Surjono, Sugeng Sapto, and Mustafid Gunawan. "ONSHORE-OFFSHORE FACIES CHANGE OF NGRAYONG SANDSTONE IN MADURA AREAINDONESIA." ASEAN Engineering Journal 8, no. 2 (December 1, 2018): 1–15. http://dx.doi.org/10.11113/aej.v8.15499.
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Ngrayong sandstone composes a siliciclastic reservoir that produces oil for more than a century in North East Java Basin of Indonesia. Clean sand facies makes the best reservoir in western part of the basin, onshore East Java Island. Meanwhile, sand quality decreases eastward to Madura Island. In Madura, rock gradually changes to be more calcareous and shaly, due to the change of depositional environment. In offshore of Madura, the depositional environment is still questionable. This study is aimed to reveal differences between onshore and offshore facies of Ngrayong sandstone in Madura as their distribution is not well known and oil potential of Madura Strait is not well identified. Study methods consisted of geological field work, well correlation, and petrophysical analysis from several well data. The results show that Ngrayong sandstone was deposited during Middle Miocene, composed by interbedding of thickly bedded sandstone and alternating thinly bedded sandstoneshale. The succession is commonly intercalated by mudstone and thinly bedded limestone. At Madura Island, Ngrayong sandstone overlies the Early-Middle Miocene Tawun Formation, which both represent the Megasequence (MS) 3 interval. Due to regional subsidence and transgression during Late Miocene, Ngrayong sandstone and other equivalent rocks were overlain by monotonous mudstone and calcareous sandstone of Wonocolo Formation. The Ngrayong sandstone is evenly distributed in whole surface area of Madura Island and it spreads further 25-50 Km to the south and 100-125 Km to eastern part of offshore Madura Strait. Sandstone distribution is roughly depleted from the gross thickness hundreds of meters in northern part to only few centimeters in southeast part of study area. The facies changes to be more calcareous to the east, while the southward facies is shaly due to a deeper depositional environment. Despite of facies changing into shales or carbonate facies, Ngrayong sandstone potential in offshore Madura Strait needs to be considered as upside potential due to its distribution is wider than initial estimation, and its petrology and petrophysic data support it as a clastic reservoir.
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Liu, Zhi Rong, Jin Gyi Huang, Li Na Lu, Zhi Dan Chen, and Xiu Liang Li. "Research on Sedimentary Palaeoenvironments of the Sanmianjing Formation in Zhengxiangbaiqi, Mongolia." Applied Mechanics and Materials 316-317 (April 2013): 286–90. http://dx.doi.org/10.4028/www.scientific.net/amm.316-317.286.
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In Zhengxiangbaiqi, the Sanmianjing Formation of Middle Permian exposes most completely. The Lithology is mainly clastic rocks, in the lower part of the section, there are 60m gray middle-thick-bedded limestone. Based on detailed measurement of the Elitu Pasture Ⅱ, indoor research, identifications with microscope, paleontology and sequence stratigraphy studies, explored sedimtentary facies and sedimentary paleoenvironment of the Sanmianjing formation. The lower part and the upper part of Sanmianjing formation might be deposited in a shore setting with a high energy, and the middle part might be formed in an epicontinental sea with a relative low-energy. Fossils and sedimentary facies further enrich the biological face of the section, and prove new informations for contrasting between different stratigraphic and plaeoenvironment. This study proved principal geological data for further research on palaeogeography, oil and gas exploration.
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McKie, Thomas. "A model for marine shelf storm deposition in the Lower Cambrian Fucoid Beds of northwest Scotland." Geological Magazine 127, no. 1 (January 1990): 45–53. http://dx.doi.org/10.1017/s0016756800014151.
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AbstractThe Lower Cambrian Fucoid Beds of northwest Scotland are a 20 m thick mixed clastic-carbonate sequence of thinly bedded storm beds deposited on the western margin of the Iapetus Ocean. Proximal facies display plane beds, current ripple laminations and wave ripple laminations and were deposited under the influence of combined steady andoscillatory currents. The steady component of flow appears to have expanded in an offshore direction and weakened during the final stages of storm deposition with respect to the oscillatory component, producing less asymmetrical ripples with less evidence of a preferred migration direction. Distal facies are represented by thin ‘graded rhythmites’. The palaeocurrent data suggest a wide spread of sediment transport directions, but with a north to northeasterly mode which may reflect a geostrophic component of flow. Following storms these beds were burrowed and echinoderms colonized the sea floor, although the limited extent of these processes and the presence of abundant collophane suggests that the fairweather Fucoid Beds shelf was generally quiescent and possibly dysaerobic.
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Cipriani, Mara, Rocco Dominici, Alessandra Costanzo, Massimo D'Antonio, and Adriano Guido. "A Messinian Gypsum Deposit in the Ionian Forearc Basin (Benestare, Calabria, Southern Italy): Origin and Paleoenvironmental Indications." Minerals 11, no. 12 (November 24, 2021): 1305. http://dx.doi.org/10.3390/min11121305.
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This study reports the first accurate record of the Messinian Resedimented Gypsum in the forearc and back-arc basins connected to the Calabrian-Peloritan orogen. A multidisciplinary approach has been used to investigate a gypsum deposit located in the Benestare’s area (Calabria, Southern Italy). Such deposit is made of bedded gypsrudites displaying clastic selenite with chaotical textures. On the top, the gypsrudites are interspersed with gypsum lenses belonging to the branching-like facies. Despite these two facies seem different macroscopically, they show petrographic features, fluid inclusions, organic matter and Strontium isotopic values very similar to each other. On the other hand, both facies show fractured and folded crystals. Crystals are only locally corroded and preserve primary structure relict as well as allochthonous (organic debris) and autochthonous putative microbial remains. All crystals are rich in fluid inclusions but these are visibly affected by stretching and leaking (re-equilibration processes) suggesting a moderate plastic deformation during re-sedimentation and subsequent burial. Minimal transport of the deposit is testified by subangular shapes of the gypsum crystals. The gypsrudite and branching-like facies reveal an 87Sr/86Sr average value of 0.709045 and 0.709082, respectively. These values suggest a strong connection with the global Ocean and reduced freshwater input. The Benestare’s deposit originated from the partial to complete dismantling of selenite crystals related to the first stage (5.97–5.60 Ma) of the Messinian Salinity Crisis through gravitational collapse due to local controlling factors.
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Barbosa, Roberto Cesar de Mendonça, Afonso César Rodrigues Nogueira, and Fábio Henrique Garcia Domingos. "Famennian glaciation in the eastern side of Parnaíba Basin, Brazil: evidence of advance and retreat of glacier in Cabeças Formation." Brazilian Journal of Geology 45, suppl 1 (August 2015): 13–27. http://dx.doi.org/10.1590/2317-4889201530147.
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ABSTRACTGlaciotectonic features studied in the siliciclastic deposits of Cabeças Formation, Upper Devonian, represent the first evidence of Famennian glaciation in Southeastern Parnaíba Basin, Brazil. Outcrop-based stratigraphic and facies analyses combined with geometric-structural studies of these deposits allowed defining three facies association (FA). They represent the advance-retreat cycle of a glacier. There are: delta front facies association (FA1) composed of massive mudstone, sigmoidal, medium-grained sandstone with cross-bedding and massive conglomerate organized in coarsening- and thickening-upward cycles; subglacial facies association (FA2) with massive, pebbly diamictite (sandstone, mudstone and volcanic pebbles) and deformational features, such as intraformational breccia, clastic dikes and sills of diamictite, folds, thrust and normal faults, sandstone pods and detachment surface; and melt-out delta front facies associations (FA3), which include massive or bedded (sigmoidal cross-bedding or parallel bedding) sandstones. Three depositional phases can be indicated to Cabeças Formation: installation of a delta system (FA1) supplied by uplifted areas in the Southeastern border of the basin; coastal glacier advance causing tangential substrate shearing and erosion (FA1) in the subglacial zone (FA2), thus developing detachment surface, disruption and rotation of sand beds or pods immersed in a diamicton; and retreat of glaciers accompanied by relative sea level-rise, installation of a high-energy melt-out delta (FA3) and unloading due to ice retreat that generates normal faults, mass landslide, folding and injection dykes and sills. The continuous sea-level rise led to the deposition of fine-grained strata of Longá Formation in the offshore/shoreface transition in the Early Carboniferous.
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Abdulsamad, Esam O., Saleh A. Emhanna, Ramzi S. Fergani, Hamad N. Hamad, Moataz A. Makhlouf, Hamad A. Asbeekhah, Ali K. Khalifa, and Mohammed H. Al Riaydh. "Miocene Rocks Around the Marádah Oasis, Central Sirt Basin, Libya: Facies Development and Implication on Stratigraphy." Earth Science Research 10, no. 1 (January 13, 2021): 8. http://dx.doi.org/10.5539/esr.v10n1p8.
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The Miocene rocks of the Marádah Formation have been stratigraphically investigated from four stratigraphical sections around the Marádah Oasis in the Central Sirt Basin of Libya. The field investigations led to the identification of two members, the lower Qarat Jahannam Member and the upper Ar Ráhlah Member. Fourteen sedimentary facies at the outcrop-scale representing a gradual development of sedimentation from a continental clastic witness in the southwestern outcrops to transitional estuarine, lagoonal, and beaches to the proximal offshore in the northern outcrops, were recognized. The results indicates that the accumulation of the Marádah Formation is transgressive in nature and corresponding to two phases of deposition which have been mentioned in the earlier studies.
The first phase is continental-dominated facies in which cross-bedded sandstones and calcareous sands comprise most of the depositional sequence of the lower Qarat Jahannam Member at the southwestern outcrops. This phase, however, is characterized by extremely bioturbated laminated-shale conquered by Skolithos ichnofacies in the lower part of the upper Ar Ráhlah Member at the northern outcrops. This phase is providing further evidence that the contact between the two members is diachronous everywhere in the study area. The clastic-phase has thought to be deposited in the Lower Miocene (Aquitanian-Burdigalian) since the lower Qarat Jahannam Member rests on an erosional surface of submarine origin in the southwestern outcrops above a 0.5 m. thick of a nummulitic unit of the Oligocene Bu Hashish Formation.
The second phase is marine-dominated facies in which a bioclastic limestone unit rich in thick and disarticulated oysters, including Crassostrea gryphoides (Schlottheim), characterizes the sediments of the Ar Ráhlah Member at the southwestern outcrops. This phase also includes the upper part of the latter member at the northern outcrops in which a detrital limestone unit rich in turritelline gastropods is overlying by thick-bedded calcarenites rich in disarticulated oysters, gastropods, irregular echinoids (notably, Clypeaster and Echinolampas), bryozoans, and celestite corals. The upper part of the Ar Ráhlah Member at the northern outcrops, nevertheless, is terminated by a quite hard dolomitic limestone and by a pretty soft dolomitic marly limestone. Both lithologies, however, are combined with medium-sized oysters, including Ostrea digitalina Fuchs, and pectinid bivalves. The second phase, however, is interpreted to be deposited in the Middle Miocene (Langhian and Serravallian) based on the total-stratigraphic range of the larger benthic foraminifera Borelis melo melo (Fichtel & Moll), which recovered from the studied washed residues, and the associated microfacies.
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McPhie, Jocelyn, Karin Orth, Vadim Kamenetsky, Maya Kamenetsky, and Kathy Ehrig. "Characteristics, origin and significance of Mesoproterozoic bedded clastic facies at the Olympic Dam Cu–U–Au–Ag deposit, South Australia." Precambrian Research 276 (May 2016): 85–100. http://dx.doi.org/10.1016/j.precamres.2016.01.029.
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Szerbiak, R. B., G. A. McMechan, R. Corbeanu, C. Forster, and S. H. Snelgrove. "3‐D characterization of a clastic reservoir analog: From 3‐D GPR data to a 3‐D fluid permeability model." GEOPHYSICS 66, no. 4 (July 2001): 1026–37. http://dx.doi.org/10.1190/1.1487050.
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A three‐dimensional (3‐D) 100 MHz ground‐penetrating radar (GPR) data volume is the basis of in‐situ characterization of a fluvial reservoir analog in the Ferron Sandstone of east‐central Utah. We use the GPR reflection times to image the bounding surfaces via 3‐D velocity estimation and depth migration, and we use the 3‐D amplitude distribution to generate a geostatistical model of the dimensions, orientations, and geometries of the internal structures from the surface down to ∼12 m depth. Each sedimentological element is assigned a realistic fluid permeability distribution by kriging with the 3‐D correlation structures derived from the GPR data and which are constrained by the permeabilities measured in cores and in plugs extracted from the adjacent cliff face. The 3‐D GPR image shows that GPR facies changes can be interpreted to locate sedimentological bounding surfaces, even when the surfaces do not correspond to strong GPR reflections. The site contains two main sedimentary regimes. The upper ∼5 m contain trough cross‐bedded sandstone with average permeability of ∼40 md and maximum correlation lengths [Formula: see text]. The lower ∼7 m contain scour and fill fluvial deposits with average permeability varying from ∼30 md to ∼15 md as clay content increases, and maximum correlation lengths [Formula: see text]. These representations are suitable for input to fluid flow modeling.
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Gagnon, J. F., T. Barresi, John W. F. Waldron, J. L. Nelson, T. P. Poulton, and F. Cordey. "Stratigraphy of the upper Hazelton Group and the Jurassic evolution of the Stikine terrane, British Columbia1ESS Contribution 20120051." Canadian Journal of Earth Sciences 49, no. 9 (September 2012): 1027–52. http://dx.doi.org/10.1139/e2012-042.
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The Lower to Middle Jurassic Hazelton Group represents the final stage of magmatic arc activity in the intraoceanic Stikine terrane, which was followed by accretion within the Cordilleran terrane collage. The Hazelton Group is exposed in the following areas: (i) on the periphery of the Bowser Basin, where arc and back-arc strata are overlain by mainly sedimentary strata of the upper Hazelton Group and then by the clastic basin fill of the Bowser Lake Group; and (ii) within a 300 km long rift system, the Eskay rift, west of the Bowser basin, where a predominantly bimodal volcanic succession contains significant mineral deposits. Examination of representative stratigraphic sections throughout the regional extent of the upper Hazelton Group has suggested significant revisions and clarification of its stratigraphy and include the following: (i) informal division of the Hazelton Group into upper and lower parts and recognition of a diachronous unconformity or unconformities at the boundary between them; (ii) establishment of a type section for the sandstone-dominated Smithers Formation; (iii) establishment of separate Quock and revised Spatsizi formations in the north and extension of the Quock Formation to include all lithostratigraphically equivalent units of blocky, thinly bedded siliceous mudstone and tuff around the periphery of the Bowser basin; and (iv) introduction of the Iskut River Formation for rift-related and volcanic facies in the Eskay rift area. Two independent rifting events occurred during deposition of the Hazelton Group: a Late Sinemurian to Early Pliensbachian phase in the northwest-trending Hazelton trough and a more restricted Aalenian to Bajocian extensional event in the Eskay rift.
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David, Jean, and Jean Lajoie. "Sedimentology of an Archean submarine channel-fill deposit in the Abitibi greenstone belt of Canada." Canadian Journal of Earth Sciences 26, no. 7 (July 1, 1989): 1453–62. http://dx.doi.org/10.1139/e89-123.
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The Archean La Bruère Formation, which forms part of the Timiskaming Group of the Abitibi greenstone belt of Rouyn–Noranda, comprises a conglomerate–sandstone assemblage at least 360 m thick. The upward variations in grain size and con glomerate/sandstone ratio permit subdivision of the formation into three conglomeratic and two sandy members. Member 1 is composed essentially of conglomerate; members 2 and 4 consist of stacked composite beds of conglomerate and sandstone; member 3 is a sequence of cross-bedded sandstone. The formation is capped by a turbidite sequence (member 5).Three bed types (facies) were identified in the La Bruère Formation: two are restricted to the conglomerate; the third, to the upper member. Facies A, is characterized by matrix-supported, poorly sorted gravel beds, massive or reversely graded. In facies B, generally restricted to member 4, the conglomerate is commonly clast supported and transitional with the overlying sandstone bed, forming couplets that show primary structure sequences consisting, from base to top, of (i) normally graded gravel, (ii) plane-bedded sandstone, and (iii) cross-bedded sandstone. These sequences are similar to, although coarser and thicker than, some sequences found in turbidites. Facies C, observed only in member 5, is characterized by classic turbidites.In the conglomerate members of the formation, beds of facies A show no correlation between bed thickness and maximum grain size, whereas those of facies B show a fairly good correlation. The absence of correlation could result from accumulation in a channel rather than on an alluvial fan, but it may also be due to the nature of the flows responsible for the deposit and (or) the grain availability at the source.The characteristics of the three facies suggest that the La Bruère gravel accumulated from laminar and turbulent mass flows in a subaqueous channel, below storm wavebase and therefore in a relatively deep basin.
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Tanoli, Saifullah Khan, Riyasat Husain, and Abdul Aziz Sajer. "Facies in the Unayzah Formation and the Basal Khuff Clastics in subsurface, northern Kuwait." GeoArabia 13, no. 4 (October 1, 2008): 15–40. http://dx.doi.org/10.2113/geoarabia130415.
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ABSTRACT This is the first reporting of the Unayzah Formation from a northern Kuwait deep well where a 304 ft of core was cut in the upper part of the formation. The core consists of about 202 ft of the Unayzah Formation, 74 ft of the Basal Khuff Clastics and 28 ft of the Khuff Formation. Within the Unayzah Formation six major lithofacies were interpreted: (1) high-angle cross-bedded sandstone; (2) fine-grained sandstone; (3) normally graded coarse pebbly sandstone; (4) medium- to fine-grained sandstone and siltstone; (5) red mudstone and siltstone; and (6) black shale. In the Basal Khuff Clastics, four lithofacies were recognised: (1) fine- to medium-grained clean sandstone; (2) muddy bioturbated sandstone and siltstone; (3) dark grey to black carbonaceous shale with sand interbeds; and (4) interbedded sandstone, siltstone and dolomite. These lithofacies can be subdivided into four broad palaeoenvironments; ?eolian, braided fluvial, flood plain, and coastal plain. The possible eolian facies are represented by high-angle, cross-bedded sandstones of likely dune affinity. Braided fluvial facies consist of pebbly sandstones, which may grade normally to fine-grained sandstone and siltstone. Flood-plain environments are interpreted for the red mudstone, shale, and siltstone, which consist of prominent root casts and other subaerial exposure features. This facies is prominently repeated three times within the cored zone. Coastal plain environments are represented by tidal channels consisting of fine-grained and clean sandstone, crevasse splay and interfluve sediments consisting of bioturbated sandstone, siltstone and shale and by dark grey to black shale of coastal marsh in origin. The core did not cover the lower contact of the Unayzah Formation. The upper contact of the formation with the Basal Khuff Clastics is placed at the top of the last oxidised red zone. Due to the limited palynofloral information, the age of the cored interval is not definitive but most likely is of Kazanian to Tatarian (Wordian to mid-Wuchiapingian). The Basal Khuff Clastics and the overlying Khuff Formation is equivalent to the OSPZ6 biozone and the Unayzah Formation could be in part equivalent to the OSPZ5 biozone. The sediments belonging to the Basal Khuff Clastics mark the onset of a major transgression that developed into a platform where carbonates of the overlying Khuff Formation were deposited.
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Ineson, J. R., and J. S. Peel. "Cambrian platform - outer shelf relationships in the Nordenskiöld Fjord region, central North Greenland." Rapport Grønlands Geologiske Undersøgelse 133 (December 31, 1987): 13–26. http://dx.doi.org/10.34194/rapggu.v133.7972.
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Cambrian sequences around the head of Nordenskiöld Fjord, central North Greenland, preserve the transition from platform interior carbonates of the Ryder Gletscher Group (redefined) to outer shelf-slope and platform margin sequences assigned to the Brønlund Fjord and Tavsens Iskappe Groups. Study of this transition has allowed redefinition and integration of these two stratigraphic schemes. Shallow subtidal to intertidal, well-bedded carbonates of the platform interior grade north-eastwards into high-energy grainstones and algal boundstones of the platform margin complex. Platform foreslope facies show well-developed clinoform bedding and wedge out into dark carbonates and clastics of the outer shelf sequence.
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Strohmenger, Christian J., Abdulla Al-Mansoori, Omar Al-Jeelani, Ali Al-Shamry, Ismail Al-Hosani, Khalil Al-Mehsin, and Hesham Shebl. "The sabkha sequence at Mussafah Channel (Abu Dhabi, United Arab Emirates): Facies stacking patterns, microbial-mediated dolomite and evaporite overprint." GeoArabia 15, no. 1 (January 1, 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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Htwe, Paike, Sugeng Sapto Surjono, Donatus Hendra Amijaya, and Kyuro Sasaki. "DEPOSITIONAL MODEL OF NGRAYONG FORMATION IN MADURA AREA, NORTH EAST JAVA BASIN, INDONESIA." Journal of Applied Geology 7, no. 2 (July 26, 2015): 51. http://dx.doi.org/10.22146/jag.26947.
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The early Middle Miocene Ngrayong Formation, an important reservoir of North East Java Basin, is well exposed in the central anticlinal part of Madura Island. The purpose of current study is to classify the depositional environments of the study area based on the characteristics and geometry of sedimentary facies. In the Madura island, the thicker clastics and deeper carbonates of Ngimbang Formation and Kujung Formation of Late Oligocene-Early Miocene deposited in the northeast-southwest asymmetrical half grabens. After the deposition of Kujung Formation, the basin morphology developed nearly eastwest trending shelf edge and the deposition of Tuban Formation began. The fine grained complex of Tuban Formation was followed by the Ngrayong Sandstones deposition. The depositional model of Ngrayong Formation is being producing of wide variety of depositional environments. Large scale cross-bedded sandstones and bioturbated massive sandstones with thin to medium bedded argillaceous limestone that outcrop in the northern part of the study area are deposited in costal environment. The heterolithic sandstone with planar and trough cross-lamination, fine grained sandstone with interlaminated structure and bioclastic carbonate exposed in the central part of the study area are deposited in upper shallow marine area. Dark grey siltstones and mudstones deposited in lower shallow marine area are well exposed in southern part of the study area. In conclusion, Ngrayong Formation in Madura area is developed in three depositional units which are coastal, upper shallow marine and lower shallow marine.
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McMahon, William J., Alexander G. Liu, Benjamin H. Tindal, and Maarten G. Kleinhans. "Ediacaran life close to land: Coastal and shoreface habitats of the Ediacaran macrobiota, the Central Flinders Ranges, South Australia." Journal of Sedimentary Research 90, no. 11 (November 30, 2020): 1463–99. http://dx.doi.org/10.2110/jsr.2020.029.
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ABSTRACT The Rawnsley Quartzite of South Australia hosts some of the world's most diverse Ediacaran macrofossil assemblages, with many of the constituent taxa interpreted as early representatives of metazoan clades. Globally, a link has been recognized between the taxonomic composition of individual Ediacaran bedding-plane assemblages and specific sedimentary facies. Thorough characterization of fossil-bearing facies is thus of fundamental importance for reconstructing the precise environments and ecosystems in which early animals thrived and radiated, and distinguishing between environmental and evolutionary controls on taxon distribution. This study refines the paleoenvironmental interpretations of the Rawnsley Quartzite (Ediacara Member and upper Rawnsley Quartzite). Our analysis suggests that previously inferred water depths for fossil-bearing facies are overestimations. In the central regions of the outcrop belt, rather than shelf and submarine canyon environments below maximum (storm-weather) wave base, and offshore environments between effective (fair-weather) and maximum wave base, the succession is interpreted to reflect the vertical superposition and lateral juxtaposition of unfossiliferous non-marine environments with fossil-bearing coastal and shoreface settings. Facies comprise: 1, 2) amalgamated channelized and cross-bedded sandstone (major and minor tidally influenced river and estuarine channels, respectively), 3) ripple cross-laminated heterolithic sandstone (intertidal mixed-flat), 4) silty-sandstone (possible lagoon), 5) planar-stratified sandstone (lower shoreface), 6) oscillation-ripple facies (middle shoreface), 7) multi-directed trough- and planar-cross-stratified sandstone (upper shoreface), 8) ripple cross-laminated, planar-stratified rippled sandstone (foreshore), 9) adhered sandstone (backshore), and 10) planar-stratified and cross-stratified sandstone with ripple cross-lamination (distributary channels). Surface trace fossils in the foreshore facies represent the earliest known evidence of mobile organisms in intermittently emergent environments. All facies containing fossils of the Ediacaran macrobiota remain definitively marine. Our revised shoreface and coastal framework creates greater overlap between this classic “White Sea” biotic assemblage and those of younger, relatively depauperate “Nama”-type biotic assemblages located in Namibia. Such overlap lends support to the possibility that the apparent biotic turnover between these assemblages may reflect a genuine evolutionary signal, rather than the environmental exclusion of particular taxa.
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DIBENEDETTO, S., and J. GROTZINGER. "Geomorphic evolution of a storm-dominated carbonate ramp (c. 549 Ma), Nama Group, Namibia." Geological Magazine 142, no. 5 (September 2005): 583–604. http://dx.doi.org/10.1017/s0016756805000890.
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The well-exposed Hoogland Member (c. 549 Ma) of the northern Nama Group (Kuibis Subgroup), Namibia, represents a storm-dominated carbonate ramp developed in a foreland basin of terminal Proterozoic age. The ramp displays facies gradients involving updip grainstones which pass downdip into broad, spatially extensive tracts of microbial laminites and finely laminated mudstones deposited above and below storm wave base. Trough cross-bedded, coarse grainstones are shown to transit downdip into finer-grained calcarenites, irregular microbial laminites and mottled laminites. Siliciclastic siltstones and shales were deposited further downdip. Platform growth was terminated through smothering by orogen-derived siliciclastic deposits. Ramp morphology was controlled by several different processes which acted across many orders of magnitude (millimetres to kilometres), including in situ growth of mats and reefs, scouring by wave-produced currents, and transport and infilling of coarse-grained carbonates and fine-grained carbonates and clastics. At the smallest scale, ‘roughening’ of the sea-floor through heterogeneous trapping and binding by microbial mats was balanced by smoothing of the sea-floor through accumulation of loose sediment to fill the topographic lows within the upward-propagating mat. At the next scale up, parasequence development involved roughening of the sea-floor through shoal growth and grainstone progradation, balanced by sea-floor smoothing through shale infilling of resulting downdip accommodation, as well as the metre-scale topographic depressions within the mosaic of shoal-water facies. At even larger (sequence/platform) scales, roughening of the sea-floor occurred through aggradation and progradation of thick carbonates, balanced by infilling of the foreland basin with orogen-derived siliciclastic sediments. At all scales a net balance was achieved between sea-floor roughening and sea-floor smoothing to maintain a more or less constant ramp profile.
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Clarkson, Euan N. K., David A. T. Harper, and Cecilia M. Taylor. "Scottish Silurian shorelines." Earth and Environmental Science Transactions of the Royal Society of Edinburgh 91, no. 3-4 (2000): 479–87. http://dx.doi.org/10.1017/s0263593300008324.
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ABSTRACTThe Silurian inliers of the Midland Valley of Scotland all exhibit a regressive sequence, and despite evident facies differences between inliers, marine successions invariably pass upwards into redbeds of continental origin. Contrasting types of shoreline facies can be seen in different inliers; here the beds in the North Esk Inlier (NEI) are compared with those previously described from Knockgardner. At Knockgardner a high energy coastal environment prevailed, but in the NEI very different conditions can be identified in near-contemporaneous deposits. In the NEI thin sandstones and siltstones of the Reservoir and Deerhope formations are succeeded by the sandstones and conglomeratic beds of the Cock Rig Formation. These are overlain by the marine mudstones of the Wether Law Linn Formation and, at the top of the sequence, the continental redbeds of the Henshaw Formation.The Wether Law Linn Formation is interpreted, on various lines of evidence, as a lagoonal system. Conditions therein were initially fully marine, though within the photic zone, but subsequently the faunas were increasingly influenced by fluctuating salinity, prior to deposition of the redbeds. Such a lagoon would have required an offshore bar impounding it, which is represented by the Cock Rig Formation. These sedimentary rocks, previously interpreted as deposits of a laterally unconfined submarine channel, are now considered to be of shallow water origin. The succession closely conforms to classic models in which shoreface sands, consisting of small cross-bedded packets, are succeeded by tabular sandstone sheets representing foreshore beach deposits. Coarser and thicker beds, with herringbone cross-sets, linguoid ripples and trains of rounded pebbles, are interpreted as the deposits of tidal channels within the barrier complex. The barrier-lagoon system persisted throughout the whole of Cock Rig time and most or all of the time during which the Wether Law Linn Formation was deposited, and was either static or prograded seawards until the lagoon dried up during a final marine regression. The sedimentary and faunal evidence is consistent with this interpretation, and the contrast between the shoreline environments of the NEI and Knockgardner is striking. Brief reference is made to other inliers in the Midland Valley.
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Peters, Jeroen M., Jacek B. Filbrandt, John P. Grotzinger, Mark J. Newall, Mark W. Shuster, and Hisham A. Al-Siyabi. "Surface-piercing salt domes of interior North Oman, and their significance for the Ara carbonate ‘stringer’ hydrocarbon play." GeoArabia 8, no. 2 (April 1, 2003): 231–70. http://dx.doi.org/10.2113/geoarabia0802231.
Full textAbstract:
ABSTRACT The six surface-piercing salt domes of interior North Oman form prominent topographic and geological features in an otherwise flat, rocky desert environment. These domes in the central part of the Ghaba Salt Basin have been known since the 1950s but very little data has been published on them. Our geological survey in 2001 provided significant new lithological, stratigraphic, and sedimentological information on the rocks exposed in the domes. This paper provides a comprehensive overview of the morphology, geometry, structural geology and geological evolution of the salt domes. Furthermore, it incorporates relevant information from unpublished subsurface studies to place the new geological field data in the context of ongoing exploration for deep hydrocarbon plays in Oman. A wide variety of rocks is exposed in the salt domes: carbonates, clastics (conglomerates, sandstones, siltstones and clays), volcanics, evaporites and ‘caprocks’. Constituent rocks and structural style vary considerably from one dome to another, but at the surface the main lithological elements of the diapirs are carbonates and evaporites of the ‘Infracambrian’ (Late Precambrian to Early Cambrian) Ara Group, the uppermost unit of the Huqf Supergroup. Very large exotic blocks of bedded Ara carbonates––commonly hundreds of meters long––are well-exposed and form distinctive hills and ridges, thus allowing detailed field observations on intra-salt carbonate ‘stringers’ that have been carried up by rising diapiric salt. A close correlation exists between the facies of the carbonate exotics in the salt domes and Ara ‘stringer’ carbonates penetrated and extensively cored in recent deep exploration wells in the South Oman Salt Basin. This demonstrates the regional significance of the salt domes for the intra-salt ‘stringer’ hydrocarbon play in Oman. Our work has implications for the prospectivity of other ‘Infracambrian’ evaporite basins in Oman, and possibly also for time-equivalent (‘Hormuz’) salt basins elsewhere in the Middle East.
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Abu-Hashish, Mohamed F., and Hamdy M. Afify. "Effect of petrography and diagenesis on the sandstone reservoir quality: a case study of the Middle Miocene Kareem Formation in the North Geisum oil field, Gulf of Suez, Egypt." Arabian Journal of Geosciences 15, no. 6 (March 2022). http://dx.doi.org/10.1007/s12517-022-09686-z.
Full textAbstract:
Abstract Kareem Formation is one of the most important hydrocarbon reservoirs in the Gulf of Suez. It contributes significantly to the total Egyptian oil production; therefore, the current work is to emphasise the influence of siliclastic facies types and their diagenetic processes on the reservoir quality of the Kareem Formation. A comprehensive log and core analyses were used to determine both the petrophysical and petrographical characteristics. Three classic facies have been identified: two sandstone facies with reservoir potential and one shale facies. Facies I is coarse-grained sandstone with high-angle cross-bedding, distributary/braided channel deposits on the active part of a mid-submarine fan lobe and is represented by beds of (Shagar Member). Facies II is fine-grained sandy beds represented by low-angle crudely, cross-bedded sandstone encountered in the Rahmi Member. Facies III is mainly shale and recorded in the Rahmi clastic zone. Petrographically, the quartz arenite microfacies are dominant in the Shagar sand zone and show the highest potential zones in the Kareem Formation. On the other hand, quartz lithic arenite and calcareous lithic arenite constitute the major microfacies in the Rahmi clastic zone and show the lowest reservoir quality. The main diagenetic processes that enhance the sandstone reservoir intervals of the Kareem Formation are the microfracturing of mineral grains and the dissolution of both feldspar and carbonate cement. In contrast, the amount of cementing materials, particularly authigenic carbonate and clay cements, led to diminishing of the reservoir quality of the studied Kareem Formation.
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Martínez-Doñate, A., A. M.-L. J. Privat, D. M. Hodgson, C. A.-L. Jackson, I. A. Kane, Y. T. Spychala, R. A. Duller, et al. "Substrate Entrainment, Depositional Relief, and Sediment Capture: Impact of a Submarine Landslide on Flow Process and Sediment Supply." Frontiers in Earth Science 9 (November 16, 2021). http://dx.doi.org/10.3389/feart.2021.757617.
Full textAbstract:
Submarine landslides can generate complicated patterns of seafloor relief that influence subsequent flow behaviour and sediment dispersal patterns. In subsurface studies, the term mass transport deposits (MTDs) is commonly used and covers a range of processes and resultant deposits. While the large-scale morphology of submarine landslide deposits can be resolved in seismic reflection data, the nature of their upper surface and its impact on both facies distributions and stratal architecture of overlying deposits is rarely resolvable. However, field-based studies often allow a more detailed characterisation of the deposit. The early post-rift Middle Jurassic deep-water succession of the Los Molles Formation is exceptionally well-exposed along a dip-orientated WSW-ENE outcrop belt in the Chacay Melehue depocentre, Neuquén Basin, Argentina. We correlate 27 sedimentary logs constrained by marker beds to document the sedimentology and architecture of a >47 m thick and at least 9.6 km long debrite, which contains two different types of megaclasts. The debrite overlies ramps and steps, indicating erosion and substrate entrainment. Two distinct sandstone-dominated units overlie the debrite. The lower sandstone unit is characterised by: 1) abrupt thickness changes, wedging and progressive rotation of laminae in sandstone beds associated with growth strata; and 2) detached sandstone load balls within the underlying debrite. The combination of these features suggests syn-sedimentary foundering processes due to density instabilities at the top of the fluid-saturated mud-rich debrite. The debrite relief controlled the spatial distribution of foundered sandstones. The upper sandstone unit is characterised by thin-bedded deposits, locally overlain by medium-to thick-bedded lobe axis/off-axis deposits. The thin-beds show local thinning and onlapping onto the debrite, where it develops its highest relief. Facies distributions and stacking patterns record the progradation of submarine lobes and their complex interaction with long-lived debrite-related topography. The emplacement of a kilometre-scale debrite in an otherwise mud-rich basinal setting and accumulation of overlying sand-rich deposits suggests a genetic link between the mass-wasting event and transient coarse clastic sediment supply to an otherwise sand-starved part of the basin. Therefore, submarine landslides demonstrably impact the routing and behaviour of subsequent sediment gravity flows, which must be considered when predicting facies distributions and palaeoenvironments above MTDs in subsurface datasets.