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1
Melehan, Sean, Chrysanthos Botziolis, Angelos G. Maravelis, et al. "Sedimentology and Stratigraphy of an Upper Permian Sedimentary Succession: Northern Sydney Basin, Southeastern Australia." Geosciences 11, no. 7 (2021): 273. http://dx.doi.org/10.3390/geosciences11070273.
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This study integrates sedimentological and stratigraphic insights into the Upper Permian sedimentary rocks of the Wittingham, Tomago and Newcastle Coal Measures in the Northern Sydney Basin, Australia. Facies analysis documented fifteen facies that belong to seven facies associations. These facies associations correspond to different depositional environments and sub-environments including prodelta, delta-front, upper, lower delta-plain and fluvial. The stratigraphic development points to a shallowing upward trend and is reflected with fluvial deposits sitting on top of the deltaic deposits. The fluvio-deltaic contact is represented by an unconformity and displays an upward increase in sediment caliber. The delta front is mainly controlled by wave, storms- and/or river currents, even though the contribution of tides also occurs in the form of sedimentary structures that suggest tidal influence. In contrast, prodelta and delta-plain are significantly modulated by tidal currents. The impact of tides in the delta plain is fading away upward and therefore, the upper delta plain is much less impacted compared to the lower delta plain. The low abundance of wave ripples suggests that the wave action was not very important in the delta plain. Steep topographic gradients and increased sediment input are suggested, based on the limited or absent evidence of tides in the fluvial realm, related to the growing New England Orogen. In sequence stratigraphic terms, the deltaic system accumulated during highstand normal regression, while the deposition of the overlying fluvial system occurred during lowstand normal regression. The two systems are separated by a subaerial unconformity developed during an intervening forced regression. Short periods of transgression are inferred from the presence of higher frequency cycles in the delta-front.
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Breckenridge, Jake, Angelos G. Maravelis, Octavian Catuneanu, Kevin Ruming, Erin Holmes, and William J. Collins. "Outcrop analysis and facies model of an Upper Permian tidally influenced fluvio-deltaic system: Northern Sydney Basin, SE Australia." Geological Magazine 156, no. 10 (2019): 1715–41. http://dx.doi.org/10.1017/s0016756818000973.
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AbstractAn integrated study of sedimentological, sequence-stratigraphic and palaeodispersal analysis was applied to the Upper-Permian clastic sedimentary succession in the Northern Sydney Basin, Australia. The succession is subdivided into fifteen facies and three facies associations. The facies associations are further subdivided into eight sub-facies associations. The sedimentary evolution involves progradation from delta-front to delta-plain to fluvial depositional environments, with a significant increase in sediment grain size across the unconformable contact that separates the deltaic from the overlying fluvial system. In contrast to the delta front that is wave/storm- and/or river-influenced, the delta plain is significantly affected by tides, with the impact of tidal currents decreasing up-sequence in the delta plain. The general lack of wave-influenced sedimentary structures suggests low wave energy in the delta plain. The abrupt termination of the tidal impact in the fluvial realm relates to the steep topographic gradients and high sediment supply, which accompanied the uplift of the New England Orogen. The sequence-stratigraphic framework includes highstand (deltaic forest and topset) and lowstand (fluvial topset) systems tracts, separated by a subaerial unconformity. In contrast to most of the mud-rich modern counterparts, this is an example of a sand-rich tidally influenced deltaic system, developed adjacent to the source region. This investigation presents a depositional model for tidal successions in regions of tectonic uplift and confinement.
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Farooqui, Anjum, T. Karuna Karudu, D. Rajasekhara Reddy, and Ravi Mishra. "Organic matter depositional microenvironment in deltaic channel deposits of Mahanadi river, Andhra Pradesh." Journal of Applied and Natural Science 1, no. 2 (2009): 180–90. http://dx.doi.org/10.31018/jans.v1i2.58.
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Quantitative and qualitative variations in microscopic plant organic matter assemblages and its preservation state in deltaic channel deposits of Mahanadi River was correlated with the depositional environment in the ecosystem in order to prepare a modern analogue for use in palaeoenvironment studies. For this, palynological and palynofacies study was carried out in 57 surface sediment samples from Birupa river System, Kathjodi-Debi River system and Kuakhai River System constituting Upper, Middle and Lower Deltaic part of Mahanadi river. Theapex of the delta shows dominance of Spirogyra algae indicating high nutrient, low energy shallow ecosystem during most of the year and recharged only during monsoons. The depositional environment is anoxic to dysoxic in the central and south-eastern part of the Middle Deltaic Plain (MDP) and Lower Deltaic Plain (LDP) indicated by high percentage of nearby palynomorphs, Particulate Organic Matter (POM) and algal or fungal spores. The northern part of the delta show high POM preservation only in the estuarine area in LDP but high Amorphous Organic Matter (MOA) in MDP. The sediment here is deposited under dysoxic to oxic fluvial conditions. Thus, the monsoon intensity, direction of fluvial discharge, and the landward extent of sea water incursion through river mouths inducing bottom water salinity play an important role in defining the magnitude of POM and its preservation in the shallow Mahanadi deltaic ecosystem.
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Cook, A. C., Michelle Smyth, and R. G. Vos. "SOURCE POTENTIAL OF UPPER TRIASSIC FLUVIO-DELTAIC SYSTEMS OF THE EXMOUTH PLATEAU." APPEA Journal 25, no. 1 (1985): 204. http://dx.doi.org/10.1071/aj84018.
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The fluvio-deltaic rocks of the Upper Triassic Mungaroo Formation of the Exmouth Plateau contain abundant organic material in the form of both coal seams and dispersed fragments. Several thousand metres of these sediments lie within the oil generation window (0.5 to 1.3 per cent R̅O max vitrinite), but they have commonly not been considered as source rocks for oil because the organic matter is of terrestrial origin. Increasing acceptance of plant material as a source for oil warrants an assessment of the oil generating potential of the Mungaroo Formation.The maceral composition of organic matter is dependent on the depositional environment. The large-scale uniformity of environments (mostly lower delta plain) in the Mungaroo Formation leads to a similarity in the organic matter, with an approximate composition of 90 per cent vitrinite in the coals and 50 per cent vitrinite, 20 per cent exinite and 30 per cent inertinite for the dispersed organic matter (DOM). The exception to this is organic material from the alluvial plain environment, where the coal has a vitrinite content of 60 per cent and the dispersed organic matter has a composition of 20 per cent vitrinite, 20 per cent exinite and 60 per cent inertinite.A quantitative assessment of the oil-generating potential of the organic matter based on maceral composition, vitrinite reflectance and volume of coal and dispersed organic matter was made for a range of time-rock units. On this basis, the Carnian-Ladinian and Carnian sequences have the best source potentials.On the basis of vitrinite reflectance measurements, it appears that the Mungaroo Formation has been generating oil since late in the Triassic or early in the Jurassic, through to the Tertiary. Lack of suitable seals during the early generative phase may have permitted some oil to escape. However, significant oil generation has occurred subsequent to the deposition of the younger Mesozoic sequences, when trapping and sealing were more effective.
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Gnaedinger, Silvia C., and Ana María Zavattieri. "Coniferous woods from the Upper Triassic of southwestern Gondwana, Tronquimalal Group, Neuquén Basin, Mendoza Province, Argentina." Journal of Paleontology 94, no. 3 (2020): 387–416. http://dx.doi.org/10.1017/jpa.2020.1.
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AbstractLate Triassic coniferous species of silicified woods are described from the Tronquimalal Group, Llantenes Depocenter of the Neuquén Basin, southern Mendoza Province, Argentina. The new species Agathoxylon cozzoi and Agathoxylon lamaibandianus Crisafulli and Herbst, 2011 described in this study were found in proximal volcaniclastic facies deposited in alluvial fans and proximal braided river plains of the Chihuido Formation, which is the basal unit of the Group. The species A. lamaibandianus Crisafulli and Herbst, Protojuniperoxylon ischigualastense (Bonetti, 1966) Bodnar and Artabe, 2007, and the new species Cupressinoxylon llantenesense also described in this study were collected from the upper fluvio-deltaic plain and delta-plain deposits that prograded into a large, meromictic and wedge-shaped lake of the overlying Llantenes Formation. The Tronquimalal Group yields abundant and well-known Triassic plant remains of the Southern Gondwana “Dicroidium Flora,” although it also contains typical early Jurassic taxa displaying age affinities with other Argentinean “Florian Stage” communities of Late Triassic (Norian–?Rhaetian). The lignotaxa described from both units of the Tronquimalal Group may all together represent coniferous forests of the extratropical area of the Southwestern Province of Gondwana. Deciduous conifer forests associated with herbaceous and shrub communities dominated by ferns and smaller corystosperms, and other taxa including the Linguifolium leaves within the Llantenes Depocenter environments, were developed on the western margin of the continent under seasonal temperate-warm and humid to sub-humid climate with a marine influence from the west.
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BROWN, K. J., and G. B. PASTERNACK. "A palaeoenvironmental reconstruction to aid in the restoration of floodplain and wetland habitat on an upper deltaic plain, California, USA." Environmental Conservation 32, no. 2 (2005): 103–16. http://dx.doi.org/10.1017/s037689290500216x.
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While tens of millions of dollars have been spent on land acquisition and planning for current and future floodplain and wetland restoration in the Sacramento-San Joaquin Delta, knowledge of the historical processes and landscape heterogeneity that are helpful in guiding the environmental restoration are often scarce. This study used palaeoenvironmental reconstruction to increase the historical perspective, with the aim of improving environmental management. Twelve sediment cores collected from the McCormack-Williamson Tract (MWT) leveed farmland and the juxtaposed Delta Meadows (DM) tidal wetland were sampled for a suite of environmental proxies. MWT was a non-tidal flood plain during much of the late-Holocene, with a mosaic of other habitats including dry uplands, riparian forests, and freshwater wetlands persisting nearby. Comparison with the regional sea-level history suggests that the upper delta gradually came under tidal influence 3000–800 calendar years before present (cal BP). Despite this, floodplain landforms and habitats prevailed at DM from 3650–330 cal BP, after which wetlands expanded, suggesting that a flood-based disturbance regime typified the upper delta for most of the late-Holocene. Recently, the upper deltaic plain has been profoundly disturbed by agriculture and other activities, rendering significant loss of habitat. It is believed that a flood-based disturbance regime will recur at MWT if the levees surrounding the tract are intentionally breached as planned for restoration, culminating in a variety of habitats similar to pre-agricultural conditions. Concentrations of Hg, Pb, As, and P pollutants elevated several-fold in surficial sediments are of particular concern, potentially becoming problematic after restoration.
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Lin, Wen, Curtis Ferron, Sean Karner, and Janok P. Bhattacharya. "Classification of paralic channel sub-environments in an ancient system using outcrops: The Cretaceous Gallup system, New Mexico, U.S.A." Journal of Sedimentary Research 90, no. 9 (2020): 1094–113. http://dx.doi.org/10.2110/jsr.2019.191.
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ABSTRACT Distinguishing trunk channels and delta-plain distributary channels in ancient systems can be difficult due to poor or incomplete data (e.g., limited outcrop or sparse well data). Accurate channel classification is required to reconstruct the plan view of channel networks in a paralic fluvio-deltaic system and to quantify source-to-sink systems. Channel formative mechanisms, such as allogenic versus autogenic and avulsion versus bifurcation, also remain equivocal. In this paper we classify channel types and quantify their discharge and dimensions in an ancient paralic depositional system of the Late Cretaceous Gallup system, New Mexico, in a recently developed high-resolution sequence stratigraphic framework. Six key facies associations are identified and integrated into a detailed facies architectural analysis using bedding diagrams from two outcrop cliffs. Backwater lengths are calculated and used for interpretation of channel forming mechanisms and classification of channel types. Two types of channels are interpreted in the study area: meandering fluvial avulsive distributary channels formed in the upstream backwater region in an upper delta plain with a paleodischarge of 280–410 m3/s, and terminal distributary channels in a subaqueous lower delta plain with a paleodischarge of 80–190 m3/s. The results show that upper-delta-plain fluvial distributary channels are formed by erosive avulsion and resemble fluvial meandering rivers characterized by laterally accreting point bars and a wide range of paleocurrents, whereas terminal distributary channels are formed by both avulsion and bifurcation and show more aggradation with lateral confinement and relatively larger width-to-depth ratios of individual channel stories. The quantification of channels and their depositional system provides new data from a well-known ancient system for the global database and comparison with other modern and ancient systems.
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Olsen, Torben, and Gunver Krarup Pedersen. "The occurrence of marine fossils in the Upper Cretaceous deltaic sediments at Pautut, central West Greenland." Bulletin of the Geological Society of Denmark 39 (December 20, 1991): 111–22. http://dx.doi.org/10.37570/bgsd-1991-39-03.
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Finds of Upper Cretaceous marine macrofossils from Pautut have been reported since 1874. Subsequent investigations have led to contrasting views concerning the stratigraphic position of the fossils, the general depositional environment, and the amount of marine influence. During a brief visit to Pautut in the summer of 1989, a section of the exposed sediments was described. The sediments can be divided into 4 facies associations reflecting deposition on a prograding delta front, in distributary channels, on a subaerial to limnic delta plain and on an abandoned delta lobe during a marine transgression. The sedimentological model predicts that marine fossils, if present, should occur in the delta front association. The sediments were thoroughly searched for marine macrofossils, which were found in the lower part of the prominent coarsening-upward delta front sequences. The number of fossils is generally low. Bivalves and echinoids constitute the dominant groups of fossils and seem to have been well adapted to a life in muddy marine bays, subject to fluctuations in salinity and rate of deposition and with much suspended sediment. The fossils indicate that the beds at Pautut were deposited during latest Santonian to earliest Campanian times. Sediment accumulation rates were high. The stratigraphy within the Pautfit area is discussed and all the Cretaceous sediments are referred to the Atane Formation.
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Currie, Philip J., Gregory C. Nadon, and Martin G. Lockley. "Dinosaur footprints with skin impressions from the Cretaceous of Alberta and Colorado." Canadian Journal of Earth Sciences 28, no. 1 (1991): 102–15. http://dx.doi.org/10.1139/e91-009.
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Cretaceous dinosaur footprints discovered in the J Sandstone of the South Platte Formation (Dakota Group) in Colorado and the St. Mary River Formation of southwestern Alberta exhibit the first reported foot pad skin impressions of large ornithopods. The Canadian tracks occur as sandstone casts preserved in mudstones, whereas the Colorado tracks are natural impressions in a sandstone bed overlain by shale. The South Platte Formation tracks occur as impressions in a widespread "dinoturbated" sandstone bed representing low-gradient, delta plain – coastal plain facies assemblages associated with the upper member of the group, the J Sandstone. Only one of the many iguanodontid trackways exhibits good skin impressions.The St. Mary River Formation palaeoenvironment is interpreted as an anastomosed fluvial system that flowed northeast over a low-gradient floodplain from Montana. Footprints, often preserved in trackways, were left as dinosaurs walked across lake and marsh sediments that were relatively well drained or in various stages of dewatering. The quality of preservation is variable, depending on the properties of the substrate, and only one hadrosaur footprint includes clear casts of skin patches on the bottom of the footprint. Similar track-rich facies assemblages, representing lowland coastal plain and deltaic environments, are found in both the Lower (Gething Formation, British Columbia) and Upper Cretaceous (Mesa Verde, Colorado) successions of western North America. Few substrates of these depositional environments were suitable for the preservation of skeletal remains, so the information derived from tracks is palaeontologically significant.
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Syme, Caitlin E., and Steven W. Salisbury. "Taphonomy of Isisfordia duncani specimens from the Lower Cretaceous (upper Albian) portion of the Winton Formation, Isisford, central-west Queensland." Royal Society Open Science 5, no. 3 (2018): 171651. http://dx.doi.org/10.1098/rsos.171651.
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Taphonomic analysis of fossil material can benefit from including the results of actualistic decay experiments. This is crucial in determining the autochthony or allochthony of fossils of juvenile and adult Isisfordia duncani , a basal eusuchian from the Lower Cretaceous (upper Albian) distal-fluvial-deltaic lower Winton Formation near Isisford. The taphonomic characteristics of the I. duncani fossils were documented using a combination of traditional taphonomic analysis alongside already published actualistic decay data from juvenile Crocodylus porosus carcasses. We found that the I. duncani holotype, paratypes and referred specimens show little signs of weathering and no signs of abrasion. Disarticulated skeletal elements are often found in close proximity to the rest of the otherwise articulated skeleton. The isolated and disarticulated skeletal elements identified, commonly cranial, maxillary and mandibular elements, are typical of lag deposits. The holotype QM F36211 and paratype QM F34642 were classified as autochthonous, and the remaining I. duncani paratypes and referred specimens are parautochthonous. We propose that I. duncani inhabited upper and lower delta plains near the Eromanga Sea in life. Their carcasses were buried in sediment-laden floodwaters in delta plain overbank and distributary channel deposits. Future studies should refer to I. duncani as a brackish water tolerant species.
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Shettima, Bukar, Mohammed Bukar, and Fatimoh Dupe Adams. "FLUVIO-DELTAIC DEPOSITIONAL COMPLEX OF THE CAMPANO-MAASTRICHTIAN GOMBE FORMATION OF THE GONGOLA SUB-BASIN, NORTHERN BENUE TROUGH, N.E. NIGERIA." International Journal of Research -GRANTHAALAYAH 8, no. 9 (2020): 96–106. http://dx.doi.org/10.29121/granthaalayah.v8.i9.2020.1320.
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Evaluation of the stratigraphic architecture of the Gombe Formation of the Gongola Sub-basin in the Northern Benue Trough indicated a build-up from six facies assemblage that consist of trough crossbedded sandstone, planar crossbedded sandstone, massive bedded sandstone, ripple laminated sandstone, parallel laminated sandstone and mudstones. These units were packaged into three facies association that constitutes of bedded sandstone facies association (FAgI), interbedded sandstone and mudstone facies association (FAgII) and amalgamated trough crossbedded sandstone facies association (FAgIII). These reflects mouth-bars, pro-delta and delta slope deposits and upper delta plain respectively. This deltaic prism is characterized by unidirectional current system devoid of signatures of tide and waves hydrodynamics in the subaqueous delta regions, thus indicating that the delta system of the Gombe Formation is a fluvial dominated delta.
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Haggart, James W., J. Brian Mahoney, Michelle Forgette, et al. "Paleoenvironmental and chronological constraints on the Mount Tatlow succession, British Columbia: first recognition of radiolarian and foraminiferal faunas in the Intermontane Cretaceous back-arc basins of western Canada1This article is one of a series of papers published in this Special Issue on the theme of New insights in Cordilleran Intermontane geoscience: reducing exploration risk in the mountain pine beetle-affected area, British Columbia.2Geological Survey of Canada Contribution 20100279." Canadian Journal of Earth Sciences 48, no. 6 (2011): 952–72. http://dx.doi.org/10.1139/e11-019.
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The Cretaceous succession at Mount Tatlow, British Columbia, is a cornerstone of Cordilleran stratigraphy, preserving a mostly continuous record of upper Lower Cretaceous to lower Upper Cretaceous sedimentary strata. The succession is capped by volcanic strata of the Powell Creek formation. Lithofacies assemblages within the Mount Tatlow succession reflect sedimentation in a deep-water submarine fan system at the base of the section, to overlying submarine-fan and to pro-deltaic deposition, and, finally, to delta-plain sedimentation at the top of the succession. Radiolarian and foraminifer fossils from the lower part of the Mount Tatlow section are the first recovered from the Intermontane basins of British Columbia and indicate a middle Albian to Cenomanian age, most likely Cenomanian. The presence of these fossils indicates that open-marine conditions existed locally in the basin at this time, but the strongly altered and pyritized nature of the fauna suggests that a reducing environment fostered early diagenetic pyritization processes in the subsurface sediments. Detrital zircon populations collected from the succession are in agreement with the paleontological ages.
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Izart, Alain, Christian Palain, Fabrice Malartre, Stéphanie Fleck, and Raymond Michels. "Paleoenvironments, paleoclimates and sequences of Westphalian deposits of Lorraine coal basin (Upper Carboniferous, NE France)." Bulletin de la Société Géologique de France 176, no. 3 (2005): 301–15. http://dx.doi.org/10.2113/176.3.301.
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Abstract Facies and sequences of the Westphalian C are identified in cores and well logs of three boreholes and three seismic lines supplied by Conoco-Phillips from the Lorraine coal Basin. The lithofacies associations suggest various paleoenvironments and sequences during the Westphalian C. Decameter-thick sedimentary bodies display alluvial fan deposits in the northwestern border of the basin (Chaumont borehole). Decametric sedimentary bodies constituted either of conglomeratic and sandy facies with cylindrical shape in well logs represent braided river deposits, or alternations of fining and coarsening upward sequences with sandy, silty and clayey facies with bell and funnel shapes in well log correspond to meander river and lacustrine deltaic deposits in the Saulcy and Lorettes boreholes. Three fining upward third order sequences in the center of the basin in the Lorettes and Saulcy boreholes represent a period 1 with braided river deposits, a period 2 with flood plain, lake and meandering river deposits and a period 3 with anastomosed or meandering river deposits. Period 1 is correlated with a subsidence period in the basin and uplift of the borders, period 2 with the maximum fresh water flooding period with flood plain or lake deposits and period 3 with the filling period. The seismic profiles of Conoco-Phillips confirm the tectonic structures described by previous authors in Lorraine Basin. We agree that this basin was a strike-slip basin as demonstrated by previous authors with depocenters near the South Hunsrück and Metz faults from the Westphalian to the Permian. Biomarkers show that paleoclimate changes (wet/dry) of weak amplitude in the equatorial climate could also modify the sedimentation of this basin and act on sequences of second order.
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Kennedy, Kirsten, and Martin R. Gibling. "The Campbellton Formation, New Brunswick, Canada: paleoenvironments in an important Early Devonian terrestrial locality." Canadian Journal of Earth Sciences 48, no. 12 (2011): 1561–80. http://dx.doi.org/10.1139/e11-055.
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Strata of the Campbellton Formation, nearly 1 km-thick and known for its diverse fossil assemblage of early plants, arthropods, and fish, can be divided into six facies associations: (1) restricted lacustrine, (2) marginal lacustrine, (3) near-shore lacustrine, (4) coastal-deltaic, (5) sandy to gravelly alluvial plain, and (6) gravelly proximal alluvial environments. Lacustrine deposits with restricted circulation, due to depth or stagnation, are fine-grained with preserved organic material. The marginal lacustrine association consists of massive siltstone and very fine sandstone, interbedded with conglomerate. The latter are interpreted to have shed from older volcanic units forming the basin walls. The near-shore lacustrine association is characterized by rippled sandstone with microbialites. Alluvial strata include interbedded imbricate to nonimbricate conglomerate, trough cross-stratified sandstone, and barren to plant-bearing siltstone. Rare exposures of thickly bedded imbricate to weakly imbricated cobble–boulder conglomerate with sandy plant-bearing lenses are interpreted as products of hyperconcentrated debris flows. In the western belt, a braided-fluvial system had paleocurrents flowing WNW. Coastal-deltaic deposits west of the fluvial outcrops, containing aquatic vertebrates and invertebrates, had paleocurrents flowing ESE, suggesting a confined body of fresh or brackish water. In lower parts of the eastern belt, lacustrine facies are prevalent, representing a large open lake. Alluvial facies dominate upper parts of the formation, representing an eastward-flowing axial braided river system, with proximal alluvium shed transversely from the basin margins. Although most strata have a volcanic provenance, only one outcrop in the lacustrine beds shows evidence of active volcanism during deposition of the Campbellton Formation.
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Yan, Bai Quan, Xiao Lei Tian, Hong Qing Kang, and Long Wang. "Spatial Distribution of Thin Interbeds in Point Bars of Meadering Channels: Case Study of Block X in Daqing Oilfield." Advanced Materials Research 524-527 (May 2012): 199–204. http://dx.doi.org/10.4028/www.scientific.net/amr.524-527.199.
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Reservoirs in point bars of meandering channels account for a high proportion in oil and gas reservoirs, with much impact of complicated architecture on remaining oil accumulation and distribution. Thus study on inner architecture of point bars and its impact on remaining oil distribution are important. This paper selects Unit III in Block A in Daqing Oilfield with data in filled well patterns and cores to study inner architecture of subsurface single sand bodies, and analyzes 3D structural features of meandering point bars in Xingbei deltaic plain in Daqing Placanticline. Architecture parameters of lateral accretion shale interbeds are: eastward dip averagely 7°, the upper, middle and lower dip in same accretion face are respectively 10°, 7° and 3°, the width is 15-42m. They are vertically imbricated series and areally corner points of abandoned channels on both sides of meandering rings as track collection intersections, and progressive and curvature reducing arc sets with abandoned channels of meandering rings as outer boundary. This pattern provides geologic basis for successive study on remaining oil.
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Eberth, David A., and Sandra L. Kamo. "High-precision U–Pb CA–ID–TIMS dating and chronostratigraphy of the dinosaur-rich Horseshoe Canyon Formation (Upper Cretaceous, Campanian–Maastrichtian), Red Deer River valley, Alberta, Canada." Canadian Journal of Earth Sciences 57, no. 10 (2020): 1220–37. http://dx.doi.org/10.1139/cjes-2019-0019.
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The non-marine Horseshoe Canyon Formation (HCFm, southern Alberta) yields taxonomically diverse, late Campanian to middle Maastrichtian dinosaur assemblages that play a central role in documenting dinosaur evolution, paleoecology, and paleobiogeography leading up to the end-Cretaceous extinction. Here, we present high-precision U–Pb CA–ID–TIMS ages and the first calibrated chronostratigraphy for the HCFm using zircon grains from (1) four HCFm bentonites distributed through 129 m of section, (2) one bentonite from the underlying Bearpaw Formation, and (3) a bentonite from the overlying Battle Formation that we dated previously. In its type area, the HCFm ranges in age from 73.1–68.0 Ma. Significant paleoenvironmental and climatic changes are recorded in the formation, including (1) a transition from a warm-and-wet deltaic setting to a cooler, seasonally wet-dry coastal plain at 71.5 Ma, (2) maximum transgression of the Drumheller Marine Tongue at 70.896 ± 0.048 Ma, and (3) transition to a warm-wet alluvial plain at 69.6 Ma. The HCFm’s three mega-herbivore dinosaur assemblage zones track these changes and are calibrated as follows: Edmontosaurus regalis – Pachyrhinosaurus canadensis zone, 73.1–71.5 Ma; Hypacrosaurus altispinus – Saurolophus osborni zone, 71.5–69.6 Ma; and Eotriceratops xerinsularis zone, 69.6–68.2 Ma. The Albertosaurus Bonebed — a monodominant assemblage of tyrannosaurids in the Tolman Member — is assessed an age of 70.1 Ma. The unusual triceratopsin, Eotriceratops xerinsularis, from the Carbon Member, is assessed an age of 68.8 Ma. This chronostratigraphy is useful for refining correlations with dinosaur-bearing upper Campanian–middle Maastrichtian units in Alberta and elsewhere in North America.
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ΚΑΡΥΜΠΑΛΗΣ, Ε., Μ. ΤΕΓΟΥ, and Ο. ΤΣΑΛΚΙΤΖΗ. "Study of delta formation factors at Central Greece." Bulletin of the Geological Society of Greece 34, no. 1 (2001): 381. http://dx.doi.org/10.12681/bgsg.17040.
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The aim of this study is to determine the correlation between morphological features of the drainage basins of seven Greek rivers (Pinios, Sperchios, Evinos, Acheloos, Arachthos, Louros and Kalamas) and features of their deltas. The Greek mainland is an area with suitable conditions for delta development (high relief, high precipitation, high sediment load, shallow, tectonically inactive, gulfs). Large Greek deltas include wetlands of great environmental importance as well as important areas of great socioeconomic significance. The above rivers have been considered in the present investigation because they all have formed extensive deltas. Furthermore their catchment areas are located entirely within Greece so it was easy to collect elements of great importance about the morphology, the geology and the climate conditions of the studied areas. The morphometric parameters of the drainage basins (drainage basin area, perimeter, total channel length within the basin, contour length within the basin)) were measured using topographic maps at a scale of 1:200.000. The morphological features of the deltaic formations (area of the delta, length of the channel within the deltaic plain) were measured from topographic maps at a scale of 1:50.000. Furthermore morphometric parameters such as drainage density, drainage frequency, slope of the valley and circularity were estimated. In order to determine the influence of the basin lithology upon the evolution of the deltas, the rocks were grouped in five types according to their hydrogeological behavior. A positive correlation between morphometric features of the drainage basins such as the basin area and the length of the main channel of the river and the area of the delta was confirmed while deviation such as the case of Pinios and Louros were determined. The same positive correlation was observed for the slope of the valley and the area of the delta. Elongated basins with rough relief tend to form extensive deltaic formations. Thus is confirmed the importance of the fluvial sediment supply for the evolution and progradation of the Greek deltas. Human activities are another important factor for the future of the deltas. The construction of dams in the upper reaches of the basins caused dramatic reduction in the sediment flux. Human interference includes also the draining of marshy areas, cultivation, fisheries, the artificial diversion and confinement of the main river channel. Another long term natural hazard that will affect the deltaic environment is the projected 34cm sea level rise by the year 2100. It is estimated that the total area of the studied delta that will be inundated by the sea until that year is about 112,7km2.
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Eberth, David A., David C. Evans, Donald B. Brinkman, François Therrien, Darren H. Tanke, and Loris S. Russell. "Dinosaur biostratigraphy of the Edmonton Group (Upper Cretaceous), Alberta, Canada: evidence for climate influence." Canadian Journal of Earth Sciences 50, no. 7 (2013): 701–26. http://dx.doi.org/10.1139/cjes-2012-0185.
Full textAbstract:
A high-resolution biostratigraphic analysis of 287 dinosaurian macrofossils and 138 bonebeds in the Edmonton Group (Upper Cretaceous) of southern Alberta provides evidence for at least three dinosaurian assemblage zones in the Horseshoe Canyon Formation (HCFm). From bottom to top the zones comprise unique assemblages of ornithischians and are named as follows: (1) Edmontosaurus regalis – Pachyrhinosaurus canadensis (lower zone); (2) Hypacrosaurus altispinus – Saurolophus osborni (middle zone); and (3) Eotriceratops xerinsularis (upper zone). Whereas the lower and middle zones are well defined and based on abundant specimens, the validity of the uppermost zone (E. xerinsularis) is tentative because it is based on a single specimen and the absence of dinosaur taxa from lower in section. The transition from the lower to the middle zone coincides with the replacement of a warm-and-wet saturated deltaic setting by a cooler, coastal-plain landscape, characterized by seasonal rainfall and better-drained substrates. Whereas changes in rainfall and substrate drainage appear to have influenced the faunal change, changes in mean annual temperature and proximity to shoreline appear to have had little influence on faunal change. We speculate that the faunal change between the middle and upper zones also resulted from a change in climate, with ornithischian dinosaurs responding to the re-establishment of wetter-and-warmer climates and poorly-drained substrates. Compared with the shorter-duration and climatically-consistent dinosaurian assemblage zones in the older Dinosaur Park Formation of southern Alberta, HCFm assemblage zones record long-term morphological stasis in dinosaurs. Furthermore, the coincidence of faunal and paleoenvironmental changes in the HCFm suggest climate-change-driven dinosaur migrations into and out of the region.
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Karymbalis, E., K. Gaki-Papanastassiou, and H. Maroukian. "Recent geomorphic evolution of the fan delta of the Mornos river, Greece: natural processes and human impacts." Bulletin of the Geological Society of Greece 40, no. 4 (2007): 1538. http://dx.doi.org/10.12681/bgsg.17057.
Full textAbstract:
The Mornos river fan delta is located on the northern side of the western Gulf of Corinth is a Gilbert-type fan delta with an arcuate form characterised by the abundance of coarse sediments. In order to determine the processes which contributed in the configuration of the fan delta during the last two centuries a detailed geomorphic map was prepared depicting both the deltaic plain and the coastal zone features. Comparative examination of 1945, 1986 and 1998 aerial photographs and reliable maps of the last two centuries along with field observations detected recent changes of the fan delta. The construction of a dam in the upper reaches of the basin in 1980 has significantly decreased the sediment supply downstream and has slackened the growth of the fan delta. After 1980 the eastern distributary has been abandoned causing a 120 m retreat at the river mouth. Although a progradation rate of 4 m/year has been observed for the western active distributary in the period between 1945 and 1986, no remarkable changes have occurred since that period. Additionally, an assessment of the impact of the potential global future sea-level rise to the fan delta is attempted.
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Cicimurri, David J., James L. Knight, Jean M. Self-Trail, and Sandy M. Ebersole. "Late Paleocene glyptosaur (Reptilia: Anguidae) osteoderms from South Carolina, USA." Journal of Paleontology 90, no. 1 (2016): 147–53. http://dx.doi.org/10.1017/jpa.2016.16.
Full textAbstract:
AbstractHeavily tuberculated glyptosaur osteoderms were collected in an active limestone quarry in northern Berkeley County, South Carolina. The osteoderms are part of a highly diverse late Paleocene vertebrate assemblage that consists of marine, terrestrial, fluvial, and/or brackish water taxa, including chondrichthyan and osteichthyan fish, turtles (chelonioid, trionychid, pelomedusid, emydid), crocodilians, palaeopheid snakes, and a mammal. Calcareous nannofossils indicate that the fossiliferous deposit accumulated within subzone NP9a of the Thanetian Stage (late Paleocene, upper part of Clarkforkian North American Land Mammal Age [NALMA]) and is therefore temporally equivalent to the Chicora Member of the Williamsburg Formation. The composition of the paleofauna indicates that the fossiliferous deposit accumulated in a marginal marine setting that was influenced by fluvial processes (estuarine or deltaic).The discovery of South Carolina osteoderms is significant because they expand the late Paleocene geographic range of glyptosaurines eastward from the US midcontinent to the Atlantic Coastal Plain and provide one of the few North American records of these lizards inhabiting coastal habitats. This discovery also brings to light a possibility that post-Paleocene expansion of this group into Europe occurred via northeastward migration along the Atlantic coast of North America.
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Innes, James B., and Yongqiang Zong. "History of Mid- and Late Holocene Palaeofloods in the Yangtze Coastal Lowlands, East China: Evaluation of Non-Pollen Palynomorph Evidence, Review and Synthesis." Quaternary 4, no. 3 (2021): 21. http://dx.doi.org/10.3390/quat4030021.
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The surface of the lowland deltaic plain around Taihu (Lake Tai), south of the Yangtze river mouth in eastern China, lies near sea level and until recent drainage and development by human societies was mostly covered by wetlands of various types. It was created by regular overbank flooding, mainly from the Yangtze, and the deposition of mostly mineral sediments over the several millennia since sea level regained its current altitude in the early mid-Holocene and progradation of the Yangtze delta began. Fluvial activity has therefore been the dominant influence on sedimentation in the Taihu lowlands, and in the lower Yangtze valley generally, and has determined the character of the mainly inorganic sediment sequences that have accumulated there, with autochthonous deposition of organic sediments within the local wetland plant communities playing a minor role. The presence of both clastic flood horizons and peat layers within the deposits of the Taihu plain attests to great variability in the magnitude of fluvial input from the Yangtze, with repeated extreme floods occurring at some periods, but with periods when the growth of peat layers shows low water tables, little exogenic sediment input and so little fluvial influence. We have examined the published evidence for these different depositional environments in the lower Yangtze and the Taihu plain during the Holocene, comparing the flood history with the middle and upper reaches of the Yangtze catchment. Discrete phases of high or low flooding influence are recognised, and these correspond with large-scale Holocene climate history. Intensified human land use in recent millennia has complicated this relationship, amplifying the flooding signal. Our palynological research shows that algal microfossil type and abundance is a useful proxy for changing water depth and quality in the aquatic environments of the Holocene Taihu wetlands, and can recognise flooding events that are not registered in the floodplain lithological sequences.
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Hickey, Leo, and Richard Yuretich. "The Paleocene Chance Member of the Fort Union Formation, northern Bighorn Basin, Montana and Wyoming: aperiodic cyclothems in a tectonically dominated lake basin." Mountain Geologist 53, no. 4 (2016): 259–81. http://dx.doi.org/10.31582/rmag.mg.53.4.259.
Full textAbstract:
A 400 m-thick sequence characterized by prominent tabular sandstone beds and a significant amount of marl and limestone occurs in Paleocene strata of the northern part of the Bighorn Basin (Clarks Fork Basin) of Wyoming and Montana. These strata, currently designated as the Belfry Member of the Fort Union Formation, actually consist of two separate but related lithogenetic units. The lower unit, which includes the Belfry Member stratotype, shows a gradual upward increase in tabular sandstone and marl or limestone and is inferred to have been deposited on a drowning flood plain under paralacustrine conditions. The upper unit, here proposed as the Chance Member, is characterized by the presence of six asymmetrical, basin-wide cyclothems. Each cycle begins abruptly with a transgressive surface overlain by laterally extensive tabular sandstone, followed by a micrite-dominated interval that together represent the lacustrine phase of the cycle. These are succeeded by lenticular interbeds of mudstone and sandstone inferred to have been deposited as a prograding fluvio-deltaic and flood plain sequence. The cyclothems are of variable thickness, ranging from ∼30m in the lowest cycle to ∼10 m in the uppermost cycles. Detailed stratigraphic mapping and correlation with the paleomagnetic and vertebrate biostratigraphic framework for the Bighorn Basin places the entire Chance Member within a portion of one vertebrate zone, Ti4, of the middle Tiffanian Provincial Age (59.2 to 58.5 Ma). The variable thickness of the cycles points toward deposition during unequal time intervals and suggests a tectonic origin most likely related to episodic movement of faults bounding the Bighorn Basin.
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Olivo, Mariana S., Ernesto Schwarz, and Gonzalo D. Veiga. "Depositional model and sequential evolution of the upper Quintuco Formation in its type area: implications for paleogeographic reconstructions for the southern Neuquén Basin during the Valanginian." Andean Geology 43, no. 2 (2016): 215. http://dx.doi.org/10.5027/andgeov43n2-a04.
Full textAbstract:
The Quintuco Formation (Berriasian-early Valanginian) in central Neuquén province comprise marine, transitional and continental deposits. These deposits were included in several regional stratigraphic studies since the 80’s but receiving little attention in terms of detailed facies analysis, palaeoenvironmental reconstructions and evolution. Understanding the evolutionary stage corresponding to cusp section of the Quintuco Formation and its relation with basal deposits of the Mulichinco Formation, is key to estimate the magnitude of associated change to the event of basin reconfiguration occurred in the early later Valanginian. In order to reconstruct the final stages of the evolution of the Quintuco Formation in its type locality (Sierra de la Vaca Muerta), a facial, architectural and sequence-stratigraphic analysis of the uppermost interval is presented. The study comprise the sedimentological description and interpretation of facies, combined with architectural analysis of key intervals. This allowed the identification of 7 facies associations, which represent the accumulation in prodelta (FA 1), delta front (FA 2 and FA 3), distal delta plain (FA 4 y FA 5) and proximal delta plain (FA 6 and FA 7). Subsequently, the spatial distribution of the different facies associations were analyzed and key surfaces related to significant changes in the depositional settings were identified across the investigated region. In this context, sequence-stratigraphic analysis of the studied interval was addressed and stacking patterns of the successions and vertical evolution of the interval are discussed. The upper interval of the Quintuco Formation represents the development of a deltaic system, where fluvial processes were dominant, but waves affected the off-axis parts of the system. The proximal areas were located towards the southwest with prodelta settings located toward the east. The delta system was built by successive shallowing-upward successions (15-40 m), bounded by regional transgressive surfaces, and with a long-term progradational staking. The reconstructed paleogeography for the last evolutionary stage of the Quintuco Formation suggest a well-established source area from the west-southwest, that would represent a new insight for paleogeographic settings for the southern Neuquén Basin during the Valanginian.
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Chaiwongsaen, Nikhom, Parisa Nimnate, and Montri Choowong. "Morphological Changes of the Lower Ping and Chao Phraya Rivers, North and Central Thailand: Flood and Coastal Equilibrium Analyses." Open Geosciences 11, no. 1 (2019): 152–71. http://dx.doi.org/10.1515/geo-2019-0013.
Full textAbstract:
Abstract The Chao Phraya River flows in the largest river basin of Thailand and represents one of the important agricultural and industrial areas in Southeast Asia. The Ping River is one major upstream branch flowing down slope southwardly, joining the Chao Phraya River in the low-lying central plain and ending its course at the Gulf of Thailand. Surprisingly, the overflow occurs frequently and rapidly at the Lower Ping River where channel slope is high, and in particular area, sand-choked is extensively observed, even in normal rainfall condition. In contrary, at the downstream part, the erosion of river bank and shoreline around the mouth of Chao Phraya River has been spatially increasing in place where there should be a massive sediment supply to form a delta. Here we use Landsat imageries taken in 1987, 1997, 2007 and 2017 to analyze geomorphological changes of rivers. Results show that both rivers have undergone the rapid decreasing of water storage capacity and increasing of sand bar areas in river embayment. The total emerged sand bar area in the Lower Ping River increases from 1987 to 2017 up to 28.8 km2. The excessive trapped bed sediments deposition along the upper reaches is responsible for the shallower of river embankment leading to rapid overflow during flooding. At the Chao Phraya River mouth, a total of 18.8 km2 of the coastal area has been eroded from 1987 to 2017.This is caused by the reducing of sediment supply leading to non-equilibrium in the deltaic zone of the upper Gulf of Thailand. There are several possibility implications from this study involving construction of weir, in-channel sand mining, reservoir sedimentation and coastal erosion management.
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Sebe, Krisztina, Marijan Kovačić, Imre Magyar, et al. "Correlation of upper Miocene–Pliocene Lake Pannon deposits across the Drava Basin, Croatia and Hungary." Geologia Croatica 73, no. 3 (2020): 177–95. http://dx.doi.org/10.4154/gc.2020.12.
Full textAbstract:
Upper Miocene to Pliocene (Pannonian) sediments of the Pannonian Basin System accumulated in the brackish Lake Pannon and the fluvial feeder systems, between 11.6-2.6 Ma. Their stratigraphic subdivision has been problematic for a long time due to the laterally prograding architecture of the basin fill and the historically independently evolving stratigraphic schemes of the neighbouring countries. We correlated the lithostratigraphic units of the Lake Pannon deposits between Hungary and Croatia in the Drava Basin, using lithological, sedimentological and palaeontological data from boreholes and outcrops, and seismic correlation. The Croatica and Medvedski breg formations in Croatia correspond to the Endrőd Fm. in Hungary, comprising shallow to deep water, open lacustrine, calcareous to argillaceous marls. The Andraševec fm. in Croatia corresponds to the Szolnok and Algyő Fms. in Hungary, consisting of sandstones and siltstones of turbidite systems and of clay marls deposited on the shelf-break slope. The Nova Gradiška fm. in Croatia is an equivalent of the Újfalu Fm. in Hungary, built up of a variety of lithologies, including sand, silt, clay and huminitic clay, deposited in deltaic environments. The Pluska fm. in Croatia corresponds to the Zagyva Fm. in Hungary, consisting of variegated clays, silts, sands and lignites, deposited in alluvial and fluvial environments. Coarse-grained (sand, gravel) basal layers are assigned to the Kálla and Békés Fms. and the Sveti Matej member of the Croatica fm. Coarse-grained intercalations within the deep-water marls belong to the Dorozsma Member of the Endrőd Fm. in Hungary, and to the Bačun member of the Medvedski breg fm. in Croatia. Sediment transport and lateral accretion of the shelf edge in the Drava Basin took place from the N, NW, and W, to the S, SE, and E, respectively. According to the biostratigraphic and chronostratigraphic analyses, the oldest shelf-break slopes in the Mura Basin are more than 8 Ma old, whereas the youngest ones in the southeasternmost part of the Drava Basin may be Pliocene in age (younger than 5.3 Ma). Thus, the 180 km long and at least 700 m deep Drava Basin was transformed into a fluvial plain during the last 3.5 million years of the Miocene.
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SELIM, S. S. "Sedimentological architecture, shelf-edge trajectories and evolution of an Oligocene reservoir, East Nile Delta." Geological Magazine 155, no. 3 (2016): 747–71. http://dx.doi.org/10.1017/s0016756816000522.
Full textAbstract:
Abstract3D seismic data and wireline logs from 17 wells in the onshore East Nile Delta were utilized to study the stratigraphic architecture and evolution of Oligocene deposits. The Oligocene is readily recognized on seismic cross-sections by a series of northward prograding clinoforms. The Oligocene sequences show lateral facies changes from fluvial to deepwater via a shelf-edge delta. Such deltaic features include distributary channels, interdistributary bay fill, and a delta plain and front, gradually changing downslope into prodelta and slope deposits. The slope deposits include three main depositional elements: a deeply incised channel, a complex of laterally switched leveed channels and lobes, and crevasses and frontal splays. These depositional elements are formed in the main western slope basin and local eastern intraslope ponded sub-basin. The reactivated E–W- and NW-trending faults as well as NE–SW inverted structures are the main controls on slope physiography that formed the main corridors for Oligocene sediment distribution. Two main globally correlated Oligocene sequences are encountered being separated by the major drop in global eustatic sea level at 28.1Ma. The lower Oligocene sequence has two main stages: (1) the formation and filling of a basal canyon; and (2) the formation and progradation of shelf deltas to form shelf-edge deltas, and then progradation with an ascending shelf-edge trajectory (clinoforms 1). The upper Oligocene sequence is characterized by accretionary shelf-edge deltas with descending and then flat trajectories (clinoforms 2–4). The frontal splay and lobe complex exhibits potentially favourable reservoir continuity and areal coverage followed by the slope channels.
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Kováč, Michal, Rastislav Synak, Klement Fordinál, et al. "Late Miocene and Pliocene history of the Danube Basin: inferred from development of depositional systems and timing of sedimentary facies changes." Geologica Carpathica 62, no. 6 (2011): 519–34. http://dx.doi.org/10.2478/v10096-011-0037-4.
Full textAbstract:
Late Miocene and Pliocene history of the Danube Basin: inferred from development of depositional systems and timing of sedimentary facies changesThe development of the northern Danube Basin (nDB) was closely related to the Late Miocene geodynamic evolution of the Pannonian Basin System. It started with a wide rifting which led to subsidence of several basin depocenters which were gradually filled during the Late Miocene and Early Pliocene. In the Late Pliocene the subsidence continued only in the basin's central part, while the northern marginal zone suffered inversion and the uplifted sedimentary fill began to be eroded. Individual stages of the basin development are well recorded in its sedimentary succession, where at least three great tectono-sedimentary cycles were documented. Firstly, a lacustrine cycle containing Lower, Middle and lowermost Upper Pannonian sediments (A-F Zones;sensuPapp 1951) deposited in the time span 11.6-8.9 Ma and is represented in the nDB in Slovakia by the Ivanka and Beladice Formations. In the Danube Basin of the southern part in Hungary, where the formations are defined by the appearance of sedimentary facies in time and space, the equivalents are: (1) the deep-water setting marls, clays and sandy turbidites of the Endrod and Szolnok Formations leading to the overlying strata deposits of the basin paleoslope or delta-slope represented by the Algyő Formation, and (2) the final shallow-water setting deposits of marshes, lagoons and a coastal and delta plain composed of clays, sands and coal seams, represented by the Újfalu Formation. The second tectono-sedimentary cycle was deposited in an alluvial environment and it comprises the Upper Pannonian (G and H Zones;sensuPapp 1951) and Lower Pliocene sediments dated 8.9-4.1? Ma. The cycle is represented in the nDB, by the Volkovce Formation and in the southern part by the Zagyva Formation in Hungary. The sedimentary environment is characterized by a wide range of facies from fluvial, deltaic and ephemeral lake to marshes. The third tectono-sedimentary cycle comprises the Upper Pliocene sediments. In Slovakia these are represented by the Kolárovo Formation dated 4.1-2.6 Ma. The formation contains material of weathering crust preserved in fissures of Mesozoic carbonates, diluvial deposits and sediments of the alluvial environment.
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Chisholm, J. I. "The Upper Band-Better Bed sequence (Lower Coal Measures, Westphalian A) in the central and south Pennine area of England." Geological Magazine 127, no. 1 (1990): 55–74. http://dx.doi.org/10.1017/s0016756800014163.
Full textAbstract:
AbstractAn analysis of outcrop and borehole information relating to the strata between the Upper Band and Better Bed coals of the central and south Pennines shows that two lithological facies can be recognized within a cyclic sequence of mudstones, siltstones and sandstones. In one facies, sandstones and siltstones contain abundant mica, and argillaceous beds are neutral grey in colour. Petrographically the sandstones are feldspathic but contain little lithic material other than multigrain quartz. In the other facies, mica is much less common, argillaceous beds are greenish grey, and sandstones and siltstones contain a notable proportion of chloritic lithoclasts. The sediments of both facies were deposited in lower delta plain/shallow-water delta environments, and palaeocurrent measurements show that the micaceous facies was supplied from the north or east while the green facies came in from the west.Three named divisions of the sequence are based on recognition of the two facies types. They correspond roughly with three upward-coarsening transgressive–regressive sedimentary cycles of presumed eustatic origin. In the lowest part of the succession (Shibden division) the main clastic input was of the micaceous type. Sandstones are found only in the north of the basin, where they form a series of superimposed delta-front bodies. Mudstones were deposited elsewhere, in a large body of open water which, although linked to the sea, was generally of lowered salinity. The restriction of the delta-front sandstones to the same geographical area over a long period of time is attributed to differential subsidence of the basin across deep-seated structures.The sediments of the overlying Brighouse division belong to the green facies, and the source of the elastics lay to the west. After an initial period of mudstone deposition in an extensive, apparently non-marine, body of open water, fluviodeltaic sand and silt spread across the entire area. There is no obvious control of sandstone distribution by basement structures.The succeeding Bradley Wood division includes sediments of both micaceous and green facies. A lobe of medium-grained micaceous sandstone around Sheffield (Thurlstone Channel) represents a fluvial incursion from the east and a linear body of fine-grained green-facies sandstone south of Chesterfield (Bole Hill Channel) represents a similar incursion from the west. Elsewhere, small units of finer-grained elastics are probably deltaic deposits linked to the same sources. The location of the channel sand-bodies suggests control by deep-seated fractures.
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Amer, Zainab. "Facies Analysis and Depositional Stages of The Albian-Aptian Succession in Balad Oil Field, Central Iraq." Iraqi Geological Journal 54, no. 1B (2021): 43–56. http://dx.doi.org/10.46717/igj.54.1b.4ms-2021-02-22.
Full textAbstract:
Carbonate-clastic succession which includes the Shu'aiba, Nahr Umr and Mauddud formations are representing a part of the Barremian-Aptian Sequence (Wasi'a Group). The present study includes three boreholes (Ba-1, 4 and 8) within the Balad Oil Field. The study area is located in central Iraq. This field represents a subsurface anticline with a northwest to southeast direction axis within the Mesopotamian Zone. Eight types of microfacies were recognized in the succession of the Mauddud and Shu’aiba formations. These microfacies represent shallow open marine, restricted and semi-restricted, reef - back reef, deep open marine and basinal depositional environments. While Nahr Umr Formation includes two successions, the first is the upper unit which is characterized by shale dominated rocks and the second is the lower unit which is characterized by sand-dominated rocks. Four major lithofacies were recognized in these two successions, they represent four depositional environments which are distributary channel, bay fill, delta plain and prodelta. The Albian-Aptian sequence was deposited during three cycles overlying the regional unconformity below the Shu’aiba Formation, the Zubair Formation, and ended with local unconformity with the Ahmadi Formation. The first stage is represented by deposition of Shu’aiba Formation during the sea-level rise after regression stage during the Zubair deposition which deposition in delta association facies. The second stage was showed a regressed of deposit the delta system above the shallow open marine of the Shu’aiba Formation, where the succession became characterized by mud-dominated rock with fissile and organic material. The third depositional stage is represented by the continuation of sea-level rise. This transgression leads to the building of carbonate ramp of the Mauddud Formation above the deltaic system of Nahr Umr Formation with a conformable surface. The Mauddud depositional stage was represented by two cycles of transgression succession, where appeared deepening upward in both cycles. The unconformity between these formations have been determined by observing the glauconite mineral and detected by log response in depth 2880m in well Ba-1.
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Kassi, A. M., J. A. Weir, J. McManus, and M. A. E. Browne. "Lithofacies and sedimentary cycles within the Late Dinantian (late Brigantian) of Fife and East Lothian: is a sequence stratigraphical approach valid?" Transactions of the Royal Society of Edinburgh: Earth Sciences 94, no. 2 (2003): 95–113. http://dx.doi.org/10.1017/s0263593300000547.
Full textAbstract:
ABSTRACTThe late Brigantian topmost parts of the Pathhead Formation (Aberlady Formation in East Lothian) and the succeeding Lower Limestone Formation crop out widely in Fife and East Lothian. The successions include nine deltaic, coastal floodplain and marine shelf cycles (cyclothems), of which the lowest examined terminates the Pathhead and Aberlady Formations and the remaining eight constitute the Lower Limestone Formation.The cyclothems conform broadly to the ‘Yoredale” transgressive/regressive pattern in which a transgressive marine shelf phase is succeeded by delta progradation and terminates with a fluvial delta plain phase. Cycles may combine to form compound cyclothems up to more than 50 m thick, in which a basal, typically complete initial cycle of Yoredale pattern is succeeded by up to five base-absent minor cycles. These are thinner, more variable and less laterally persistent units in which the marine phase is weakly represented or absent.Cyclothems reflect successive marine flooding events, possibly under eustatic control, succeeded by delta progradation and, ultimately, leading to extensive palaeosol formation, including coal seams. Sedimentation and palaeosol formation were partly controlled by fault-induced differential subsidence and are likely to have been related to autocyclic processes. Local uplift and subsidence associated with vulcanicity, as at Kinghorn and Elie, have led to thickening or thinning of sediments accumulated in a given time period.Initial cycles initiate longer-period allocycles, corresponding broadly to third-order Exxon Production & Research (EPR) Type 1 sequences having a periodicity of around 1 Ma, within the Milankovitch orbital band. Two parasequences constitute each initial cycle: a lower, initiated on a marine flooding surface, and an upper, bounded by the base of the lowest thick sandstone in the cycle; cyclothem bases and sequence bases thus alternate. Parasequences and sequences are less well defined in minor cycles due to the problem of tracing the combined disconformity and soil profile of the underclay beyond the edge of channel sandstones. Minor cycles were controlled primarily by short-period autocyclic sedimentary and, or, tectonic processes, including delta-lobe switching and differential subsidence.Although we have attempted to interpret the deposits of Fife and the Lothians in terms of sequence stratigraphy, we are not fully convinced that the patterns of associated changes widely recognised within the framework of sequence stratigraphy can be confidently applied in succesions in which autocyclic changes feature strongly in an area undergoing active basin subsidence associated with strike-slip faulting. There is no doubt that some of the cyclicity discerned in the late Brigantian successions of eastern Scotland was related to eustatic sea level changes, which gave rise to the widespread limestone platforms or marine bands. The formation of eight cyclothems within the 2·5–3·5 Ma of late Brigantian suggests a cyclicity of about 400 ka, which corresponds to the long period eccentricity cycles of Milankovitch rather than the 0·5–5·0 Ma of third-order EPR cycles.
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Thiry, Médard, Florence Quesnel, Johan Yans, et al. "Continental France and Belgium during the early Cretaceous: paleoweatherings and paleolandforms." Bulletin de la Société Géologique de France 177, no. 3 (2006): 155–75. http://dx.doi.org/10.2113/gssgfbull.177.3.155.
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Abstract During the early Cretaceous, successive tectonic phases and several sea level falls resulted in the emersion of the main part of western Europe and the development of thick “lateritic” weathering. This long period of continental evolution ended with the Upper Cretaceous transgressions. During this period, the exposed lands displayed a mosaic of diverse morphologies and weathered landscapes. Bauxites are the most spectacular paleoweathering features, known for long in southern France. Recently, new residual outcrops have been identified, trapped in the karstic depressions of the Grands Causses. Other bauxitic formations, containing gibbsite, have also been recognised, occurring with the Clay-with-Jurassic-cherts in the southeastern border of the Paris Basin. These bauxitic formations overlay Jurassic limestone and are buried beneath Upper Cretaceous marine deposits. The recognition of bauxites up north into the southern Paris Basin significantly widens the extension of the Lower Cretaceous bauxitic paleolandscapes. On the Hercynian basements thick kaolinitic weathering mantles occur. They have been classically ascribed to the Tertiary. The first datings of these in situ paleosoils, by means of paleomagnetism and/or radiogenic isotopes, record especially early Cretaceous ages. This is the case for the “Siderolithic” formations on the edges of the French Massif Central, but also for the kaolinitic profiles in the Belgian Ardennes. In the Flanders, the Brabant basement is deeply kaolinised beneath the Upper Cretaceous cover. These paleosoils show polygenetic evolutions. The relief of these basement paleolandscapes may have been significant. There where probably high scarps (often of tectonic origin) reaching 200 m in elevation or beyond, as well as wide surfaces with inselbergs, as in the present day landscapes of tropical Africa and South America. On the Jurassic limestone platforms occur diverse kaolinitic and ferruginous weathering products. Around the Paris Basin they show various facies, ranging from kaolinitic saprolites to ferricretes. Due to the lack of sedimentary cover, the age of these ferruginous and kaolinitic weathering products has been debated for long, most often allocated to the Siderolithic sensu lato (Eocene-Oligocene). Recent datings by paleomagnetism have enabled to date them (Borne de Fer in eastern Paris Basin) back also to the early Cretaceous (130 ± 10 Ma). These wide limestone plateaus show karstified paleolandforms, such as vast closed and flat depressions broken by conical buttes, but also deep sinkholes in the higher areas of the plateaus and piedmonts. The depth of the karst hollows may be indicative of the range of relative paleoelevations. Dissolution holes display seldom contemporaneous karst fillings, thus implying that the karstland had not a thick weathering cover or that this cover had been stripped off before or by the late Cretaceous transgression. Nevertheless, some areas, especially above chert-bearing Jurassic limestone or marl, show weathering products trapped in the karst features or as a thick weathering mantle. In the Paris Basin, the Wealden gutter looked like a wide floodplain in which fluvio-deltaic sands and clays were deposited and on which paleosoils developed during times of non-deposition. The edges of the gutter were shaped as piedmonts linked up with the upstream basement areas. The rivers flowing down to the plain deposited lobes of coarse fluvial sands and conglomerates. The intensity of the weathering, the thickness of the profiles and their maturation are directly dependent on the duration of the emersion and the topographic location relative to the gutter. Near the axis of the gutter, where emersion was of limited duration, the paleoweathering features are restricted to rubefaction and argillization of the Lower Cretaceous marine formations. On the other hand, on the borders of the basin and on the Hercynian basement, where emersion was of longer duration, the weathering profiles are thicker and more intensively developed. The inventory of the Lower Cretaceous paleoweathering features shows the complexity of the continental history of this period. Moreover, the preserved weathering products are only a part of this long lasting period, all the aspects relative to erosion phases are still more difficult to prove and to quantify. In this domain, apatite fission tracks thermochronology (AFTT) can be helpful to estimate the order of magnitude of denudation. Residual testimonies and subsequent transgressions may enable to estimate relative elevations, but in return, we presently have no reliable tool to estimate absolute paleoelevations. In the work presented here, the inventory enabled to draw a continental paleogeographic map showing the nature of the weathering mantles and the paleolandscape features, just as paleoenvironments and paleobathymetry presently appear on marine paleogeographic maps. For the future, the challenge is to make progress in dating the paleoweathering profiles and especially in the resolution of these datings, in order to correlate precisely the continental records with the different events which trigger them (eustatism, climate, regional and global geodynamics). The final goal will be to build up a stratigraphic scale of the “continental geodynamic and climatic events” in parallel with “sequential stratigraphy” in the marine realm.
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van Kessel, Onno. "Champion East: Low-Cost Redevelopment of Shallow, Stacked, and Faulted Heavy-Oil Reservoirs." SPE Reservoir Evaluation & Engineering 5, no. 04 (2002): 295–301. http://dx.doi.org/10.2118/78674-pa.
Full textAbstract:
Summary The Champion East area offshore Brunei Darussalam consists of approximately 50 stacked, shallow, and intensely faulted heavy oil reservoirs. These reservoirs have been under development since 1975 and have to date produced just 9% of the oil initially in place. Over the period 1998-2003, Brunei Shell Petroleum (BSP) is embarking on a major redevelopment with the aim of converting a further 30 million m3 of oil-in-place volume into commercial reserves. An overview will be given of how new technology is adding value to the total redevelopment, supported by actual application results and learning points. The primary development of Champion East is now nearing completion. The use of existing facilities and ultra shallow, long reach horizontal wells - with innovative sand exclusion and downhole intelligence - has achieved a 60% unit cost reduction over previous drilling campaigns in the area. The only way to unlock another 5 to 15% of the oil-in-place volume is to start secondary recovery through water injection, in combination with the use of electric submersible pumps (ESPs). Introduction The Champion Asset comprises the Champion Field offshore Brunei Darussalam (Fig. 1) and all associated facilities and infrastructure, which also serve as an export hub for BSP's entire Offshore East production division. Oil production from the Champion Field averages approximately one-third of total BSP production. A large scope for recovery, mostly technology-driven, remains, even at low oil prices. Subsurface, the area comprises a hydrostatic, heterolithic sequence of interbedded thin sandstones and mudstones (with reservoir flow units no more than 15 m thick and permeabilities ranging from 0.01 to 0.2 µm2 in lower shoreface sands to 0.5 to 5 µm2 in tidal channels) deposited in environments spanning a systems tract that extends from the outer shelf into the lower coastal plain. Other key features are significant lateral thickness variations, compartmentalization caused by syndepositional tectonics, and the presence of multiple growth faults. The Champion field can be divided into two distinct parts (Fig. 2): Champion East, spanning a depth of approximately 200 to 1200 m, with hydrocarbons in some places seeping through the seabed and feeding a coral reef; and Champion Main, which encompasses a depth of approximately 1000 to 2000 m. Champion Main contains the mature core of the Champion field, where both primary and secondary (water-injection) recovery processes are well advanced and 28% of the oil initially in place has been produced. The main focus in Champion Main is on water-injection maintenance, production-system optimization, and scope for recompleting or sidetracking existing wells-all aimed at slowing the decline in oil production. Most efforts in the area are, however, focused on the growth potential offered by shallow reservoirs. The Champion East area is much less mature than Champion Main, with a cumulative oil production to date of just 9% of the oil initially in place. Historically, Champion East is underdeveloped because of its subsurface complexity and heterogeneity (leading to erratic well performance), less favorable reservoir and oil properties [density of 930 g/cm3 (20° API) and viscosity between 5 and 15 mPa's], and a perceived lack of spare conductor slots, which would necessitate large investments in new infrastructure. In 1995, it was estimated that an upfront investment in excess of U.S. $400 million would be required to advance the development of Champion East by accessing another 30 million m3 of undeveloped reserves. Out of this total, 40% would be required for new facilities, and the remaining 60% would be for drilling new wells. This hurdle essentially halted further developments (between 1992 and 1997, just one well was drilled in the area), and it was obvious that major changes were required to all the fundamentals (average reserves and rates per well, well costs, and facilities costs) to break this deadlock. The case for change, together with plans for possible solutions, is further described in Ref. 1. Reservoir Modeling Technology Traditionally, Champion East had been modeled with 2D methods of mapping gross interval properties for groups of reservoirs ranging in thickness from 20 to 40 m, using the previous 3D seismic survey shot in 1983 (relatively poor resolution) and well correlation methods based on lithostratigraphy. However, these methods often can prove unreliable in deltaic reservoirs that have undergone synsedimentary tectonics. The previous major Champion East infill drilling campaign (1990-92) was relatively unsuccessful because approximately 35% of all target reservoirs were found to be either nonexistent, water-bearing, or depleted. It then became clear that it was necessary to understand the structure, sequence stratigraphy, and fluid distribution of these reservoirs in greater detail. Two key data acquisition activities occurred in 1994: a high-resolution 3D seismic survey and the retrieval of some 350 m of continuous cores to review the sedimentology and high-resolution sequence stratigraphy, as described in Ref. 2. After screening studies to establish the correct priority and level of detail required, Shell's proprietary reservoir modeling software (GEOCAP-MoReS) was used to provide detailed 3D reservoir models for reservoir simulation. A total of 16 models were built and history matched (with approximately 50,000 grid cells each) between 1996 and 1999; together, they covered the entire area, with boundaries positioned (generally at sealing faults) to minimize crossflow effects. This allowed fast optimization of reservoir development plans by identifying connected oil in place and transmissibility for individual reservoir flow units, such as an upper shoreface sandbody or a tidal channel, which have remained undrained from previous development.
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Kurnio, Hananto, and Yudi Darlan. "LINGKUNGAN PENGENDAPAN SEDIMEN PERANGKAP GAS BIOGENIK DI DELTA SUNGAI KAPUAS KALIMANTAN BARAT." JURNAL GEOLOGI KELAUTAN 7, no. 2 (2016). http://dx.doi.org/10.32693/jgk.7.2.2009.173.
Full textAbstract:
Lingkungan pengendapan delta Sungai Kapuas di Kalimantan Barat terdiri dari dataran delta atas, dataran delta bawah dan lingkungan marin. Pada wilayah pesisir, dataran delta bawah terdiri dari kanal cabang (distributary channels), rawa (swamp) pada pulau-pulau delta dan pantai.
 Lingkungan pengendapan marin terdiri muka delta (delta front) dan prodelta; dengan lingkungan muka delta sedimen bersifat pasiran karena mengendapkan muatan sedimen (bed load) dari sungai, sedangkan pada lingkungan prodelta, sedimen yang diendapkan bersifat suspensi pada paparan dengan pengaruh proses marin lemah.
 Reservoar pasir pada kanal cabang dan pantai purba delta Sungai Kapuas merupakan tempat akumulasi gas biogenik. 
 
 Kata kunci: lingkungan pengendapan delta, gas biogenik, Sungai Kapuas 
 
 
 Deltaic deposition environment of Kapuas River in Western Kalimantan is consisted of upper delta plain, lower delta plain and marine environment. Within coastal zone, lower delta plain can be classified into distributary channels, swamp, deltaic islands and coasts.
 Marine environment is composed of delta front and prodelta; with delta front environment characterized by sandy sediments derived from river bed load. While prodelta sediments are suspension materials deposited in shelf of weak marine influences.
 Sand reservoirs at paleo distributary channels and paleo coasts of Kapuas River delta is the media for biogenic gas accumulations.
 
 Key words: deltaic deposition environments, biogenic gas, Kapuas River
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Sakai, Tetsuya, Ananta Prasad Gajurel, Hideo Tabata, and Bishal Nath Upreti. "Small-amplitude lake-level fluctuations recorded in aggrading deltaic deposits of the Upper Pleistocene Thimi and Gokarna formations, Kathmandu Valley, Nepal." Journal of Nepal Geological Society 25 (December 1, 2001). http://dx.doi.org/10.3126/jngs.v25i0.32049.
Full textAbstract:
Small-amplitude lake-level fluctuations have been recognized from the aggrading delta-plain deposits in the lower parts of the Thimi and Gokarna formations, Kathmandu Valley, Nepal. The delta-plain deposits consist or gravelly sand beds of fluvial channel origin (coarse-sediment interval) and alternation of' fine to very line sand and sandy silt beds (line-sediment interval). Wave generated structures occur in the sand beds or the fine sediment intervals.
 The vertical and lateral facies changes suggest that the deposition or a set of coarse- and fine-sediment intervals associated with prograding delta front deposits was controlled by a lake-level rise and fall sequence superimposed on a long-term lake level rise trend. The aggradation of fluvial sediments occurred during a lake-level rise period with sufficient sediment supply to fill a newly created accommodation space on the delta plain. The observation or wave-generated structures in an overlying fine-sediment interval suggests that the delta plain was subsequently inundated due to further lake-level rise, exceeding the sedimentation rate. Subsequent delta progradation occurred during a lake-level stabilized phase after a lake level fall. The small-amplitude lake-level changes are thought to be attribute able to seasonal wet and dry cycles, as inferred based on the presence of peculiar aggrading delta successions, implying that lake-level fluctuations may have occurred over short time scales, and on the results of a previous palaeopalynological study in which a moist palacoclimate was inferred in the lower part of the Gokarna Formation in particular.
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Luca Minarelli, Sara Amoroso, Gabriele Tarabusi, Marco Stefani, and Gabriele Pulelli. "Down-hole geophysical characterization of middle-upper Quaternary sequences in the Apennine Foredeep, Mirabello, Italy." Annals of Geophysics 59, no. 5 (2016). http://dx.doi.org/10.4401/ag-7114.
Full textAbstract:
The 2012 earthquakes sequence stroke a wide area of the alluvial plain in the Emilia-Romagna Region and triggered a new research interest on the role of the subsurface stratigraphic architecture and petrophysical property distribution in the modulation of the local seismic effects. Few direct shear wave velocity V_S data were however available below the depth of 50m. The only available V_S measurements were obtained from an anticline area, characterized by a reduced stratigraphic thickness and peculiar sedimentary facies, hardly representative of the majority of the alluvial plain subsurface. The study provides the first V_S profile available from middle-upper Quaternary successions deposited into a fast subsiding syncline area of the Apennine Foredeep Basin. The P-wave velocity V_P and the S-wave velocity V_S logs fill in the previous data gap on the geophysical parameters needed for the estimation of the local seismic response. Both V_P and V_S logs were continuously acquired to the depth of 265 m. The log records a velocity increase with depth, punctuated by sharp increases at some stratigraphic discordance surfaces. The value of 800 m/s that characterizes the “seismic bedrock”, as defined by the Italian building code [NTC 2008] was never reached at any depth. The investigated succession records a depositional evolution from deltaic-marine to alluvial plain conditions, punctuated by six glacio-eustatic depositional cycles, developed in Middle-Upper Quaternary times. The stratigraphic units described in the syncline log were correlated at a regional scale, with the thinner anticline succession of Mirandola. Correlatable units deposited into syncline and anticline areas reveal similar shear wave velocity values, supporting the regional extrapolation of the measured values.<br /><br /><br /><em></em>
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Colombo, Ferran, Jordi Serra, Patricia Cabello, José Bedmar, and Federico I. Isla. "Chronology of recent sedimentary infill of the Inner Río de la Plata Estuary, Argentina." Journal of Iberian Geology, August 24, 2021. http://dx.doi.org/10.1007/s41513-021-00176-x.
Full textAbstract:
AbstractThe Inner Río de la Plata Estuary is a sedimentary depositional system that resulted from fluvial-deltaic activity. Gentle Pliocene–Pleistocene slopes make-up the northern side of the estuary whereas small cliffs of the same age constitute the southern side. A long coastal estuarine barrier developed at about 6000 years BP when the maximum flooding surface occurred. Attached to this barrier, and at a lower elevation, is a large strandplain (covering an area of about 2400 km2) which displays more than 220 beach ridges. In different areas, the dating indicates a periodicity of 13.4–13.7 years for the development of each beach ridge. These data are like the periodicity of the ENSO effects, which could be associated with the variability of Sunspots. These ridges were formed shortly after the maximum flooding surface, which was followed by a gradual fall in sea-level that contributed significantly to the Inner Río de la Plata Estuary sedimentary infill. In addition, ENSO activities were probably instrumental in the distribution of the main geoforms in the Inner Rio de la Plata Estuary. Small deltas, which were generated by other rivers and creeks such as the Nogoyá Arroyo and the Gualeguay River, developed coevally with the coastal estuarine barrier. The Ibicuy Delta grew in the middle of the inner Río de la Plata Estuary when the former Paraná River flowed northwards during the sea-level fall. The upper part of the delta front was reworked, giving rise to a large dunefield. Thereafter, a chenier plain developed along with tidal flats. The current Paraná Delta continues to prograde at a rate of about 56–64 m/year (m year−1). The sedimentary infill of the Inner Río de la Plata Estuary occurred along the Holocene.