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1
Wang, H., and X. Jia. "Selective deposition response to aeolian-fluvial sediment supply in the desert braided channel of the Upper Yellow River, China." Natural Hazards and Earth System Sciences Discussions 3, no. 2 (February 10, 2015): 1269–90. http://dx.doi.org/10.5194/nhessd-3-1269-2015.
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Abstract. Rivers flow across aeolian dunes and develop braided stream channels. Both aeolian and fluvial sediment supplies regulate sediment transport and deposition in such a cross-dune braided river. Here we show a significant selective deposition in response to both aeolian and fluvial sediment supplies in the Ulan Buh desert braided channel. This selective deposition developed by the interaction between the flows and the Aeolian-fluvial sediment supplies, making the coarser sediments (> 0.08 mm) from aeolian sand supply and bank erosion to accumulate in the channel center and the finer fluvial sediments (< 0.08 mm) to be deposited on the bar and floodplain surfaces and forming a coarser-grained thalweg bed bounded by finer-grained floodplain surfaces. This lateral selective deposition reduces the downstream sediment transport and is a primary reason for the formation of "above-ground river" in the braided reach of the Upper Yellow River in response to aeolian and fluvial sediment supplies.
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Wang, H., X. Jia, Y. Li, and W. Peng. "Selective deposition response to aeolian–fluvial sediment supply in the desert braided channel of the upper Yellow River, China." Natural Hazards and Earth System Sciences 15, no. 9 (September 2, 2015): 1955–62. http://dx.doi.org/10.5194/nhess-15-1955-2015.
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Abstract. Rivers flow across aeolian dunes and develop braided stream channels. Both aeolian and fluvial sediment supplies regulate sediment transport and deposition in such cross-dune braided rivers. Here we show a significant selective deposition in response to both aeolian and fluvial sediment supplies in the Ulan Buh desert braided channel. The Ulan Buh desert is the main coarse sediment source for this desert braided channel, and the mean percentage of the coarser (> 0.08 mm) grains on the aeolian dunes surface is 95.34 %. The lateral selective deposition process is developed by the interaction between the flows and the aeolian–fluvial sediment supplies, causing the coarser sediments (> 0.08 mm) from aeolian sand supply and bank erosion to accumulate in the channel centre and the finer fluvial sediments (< 0.08 mm) to be deposited on the bar and floodplain surfaces, forming a coarser-grained thalweg bed bounded by finer-grained floodplain surfaces. This lateral selective deposition reduces the downstream sediment transport and is a primary reason for the formation of an "above-ground" river in the braided reach of the upper Yellow River in response to aeolian and fluvial sediment supplies.
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Sigdel, Ashok, and Tetsuya Sakai. "Sedimentary facies analysis of the fluvial systems in the Siwalik Group, Karnali River section, Nepal Himalaya, and their significance for understanding the paleoclimate and Himalayan tectonics." Journal of Nepal Geological Society 51 (December 31, 2016): 11–26. http://dx.doi.org/10.3126/jngs.v51i0.24084.
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Fluvial sediments of the Siwalik successions in the Himalayan Foreland Basin are one of the most important continental archives for the history of Himalayan tectonics and climate change during the Miocene Period. This study reanalyzes the fluvial facies of the Siwalik Group along the Karnali River, where the large paleo-Karnali River system is presumed to have flowed. The reinterpreted fluvial system comprises fine-grained meandering river (FA1), flood-flow dominated meandering river with intermittent appearance of braided rivers (FA2), deep and shallow sandy braided rivers (FA3, FA4) to gravelly braided river (FA5) and finally debris-flow dominated braided river (FA6) facies associations, in ascending order. Previous work identified sandy flood-flow dominated meandering and anastomosed systems, but this study reinterprets these systems as a flood-flow dominated meandering river system with intermittent appearance of braided rivers, and a shallow sandy braided system, respectively. The order of the appearance of fluvial depositional systems in the Karnali River section is similar to those of other Siwalik sections, but the timing of the fluvial facies changes differs. The earlier appearance (3-4 Ma) of the flood-flow dominated meandering river system in the Karnali River section at about 13.5 Ma may have been due to early uplift of the larger catchment size of the paleo-Karnali River which may have changed the precipitation pattern i.e. intensification of the Indian Summer Monsoon. The change from a meandering river system to a braided river system is also recorded 1 to 3 Ma earlier than in other Siwalik sections in Nepal. Differential and diachronous activities of the thrust systems could be linked to change in catchment area as well as diachronous uplift and climate, the combination of which are major probable causes of this diachronity.
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Miall, Andrew D., and Mohamud Arush. "Cryptic sequence boundaries in braided fluvial successions." Sedimentology 48, no. 5 (October 21, 2001): 971–85. http://dx.doi.org/10.1046/j.1365-3091.2001.00404.x.
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Sun, Yu, Xiu Li Zhang, Jin Yan Zhang, and Chen Chen. "Analysis on Grain-Size Characteristics and Sedimentary Environment of Conglomerate Reservoirs in Ying-4 Section of Xingcheng Gas Field of Songliao Basin." Advanced Materials Research 734-737 (August 2013): 286–89. http://dx.doi.org/10.4028/www.scientific.net/amr.734-737.286.
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Aimed at difficulty of conglomerate in Ying-4 Section of Xingcheng Gas Field, Songliao Basin, which it is impossible to be carried out, using routine granularity analysis methods, and the iconic grain-size analysis is carried out. According to iconic two-dimension grain-size analysis, and contacting to fundamental sedimentary characteristics of conglomerate, sedimentary environment analysis is carried out. It is thought that this area is Shallow gravel-bed braided fluvial fan deltas, to braided fluvial delta transition, which supported an important geological foundation for the next disposition of exploration in Xingcheng Gas Field.
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Liu, Yuming, Luxing Dou, Xiaoxu Ren, and Jiagen Hou. "Sedimentary characteristics of muddy deposits in sandy braided fluvial system: A case study from outcrops of the Jurassic Yungang Formation in the Datong Basin, Central China." Interpretation 8, no. 3 (July 1, 2020): SM139—SM149. http://dx.doi.org/10.1190/int-2019-0174.1.
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The sandbodies within braided fluvial deposits are important reservoirs for the oil fields in China, and they usually have complex sedimentary architecture. A lot of research has been concentrated on characterizing the architecture of the sandbodies. Based on the observation that muddy deposits are commonly well preserved in fluvial deposits, we find that understanding the contact relationship between the muddy deposits and surrounding sand bodies can help characterize the depositional process of sandy braided fluvial systems. We have determined the effectiveness of this idea by characterizing a well-exposed outcrop of sandy braided fluvial system in the Datong Basin, Shanxi Province of China. We first define six muddy lithofacies by integrating the thickness of the muddy deposits, the morphology of the muddy deposit, and the lithofacies of surrounding sand deposits. The six muddy lithofacies include floodplain muddy deposits between intermittent channel complex, lateral covering muddy deposits and fall-silt seam muddy deposits between migrated bar complex, muddy gravel deposits in erosional bar complex, and channel-fill muddy deposits and gully-fill muddy deposits in abandoned bar complex. We then analyze the depositional environments according to the defined muddy lithofacies. We finally build the architecture of the outcrops by integrating the lithofacies of sand deposits and evolution of the depositional environments deduced from the muddy lithofacies.
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Ulak, Prakash Das. "Evolution of fluvial system and reconstruction of paleohydrology of late Cenozoic Siwalik Group, related to tectonic uplift of Himalaya and climatic change, Kankai River section, east Nepal Himalaya." Journal of Nepal Geological Society 51 (December 31, 2016): 59–72. http://dx.doi.org/10.3126/jngs.v51i0.24093.
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This paper focuses on evolution of the fluvial system in the late Cenozoic Siwalik Group along the Kankai River section of East Nepal. The Siwalik Group lies on the southern flank of the Himalaya and composed of molasse sediments, which were derived from upheaval of the Himalaya. On the basis of lithology, assemblage of sedimentary structures and sediment body architectures, seven facies associations (FA1 to FA7) are recognized in the Kankai River section, East Nepal Himalaya. These recognized facies associations are closely related to each lithostratigraphic units of the area (Ulak 2009). The lower and upper members of the Lower Siwaliks are the products of the fine-grained meandering and flood flow-dominated meandering systems, respectively. The lower, middle and upper members of the Middle Siwaliks are interpreted as the deposits of the sandy meandering, deep sandy braided and shallow braided systems, respectively whereas the lower and upper members of the Upper Siwaliks are the products of the gravelly braided and debris flow-dominated braided systems, respectively. Paleohydrological characteristics and its evolutional changes of the group have been estimated by using grain diameter and thickness of fining upward fluvial successions. The paleohydrology suggests an increase in of flow velocity, channel slope gradient, and discharge of the fluvial system. Paleovelocity varies from 0.19 m/s to 5.31 m/s paleochannel gradient and paleodischarge changes from 6.67x10-5 to 2.97x10-4 m/m and 101 to 104 m3/s, respectively in stratigraphic upward. The progressively changes in the paleohydrology reflect the southward propagation of thrust activities, caused upheaval of the Himalaya.
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Payenberg, T. H. D., and S. C. Lang. "RESERVOIR GEOMETRY OF FLUVIAL DISTRIBUTARY CHANNELS—IMPLICATIONS FOR NORTHWEST SHELF, AUSTRALIA, DELTAIC SUCCESSIONS." APPEA Journal 43, no. 1 (2003): 325. http://dx.doi.org/10.1071/aj02017.
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The exploration and development of stratigraphically trapped hydrocarbons requires detailed knowledge of the morphologies and reservoir characteristics of the stratigraphic body. Fluvial distributary channels are important exploration targets because they are typically isolated reservoirs, laterally and vertically sealed by delta plain and abandoned channel mudstone, and thus form excellent stratigraphic traps. The morphology and reservoir characteristics of fluvial distributary channels have been confused with fluvial channels in the past. Knowing the characteristics of fluvial distributary channels and their difference from fluvial channels is the key to the successful exploration and development of distributary channel reservoirs.Fluvial distributary channels, formed by mixed-load systems, are commonly rectilinear channel segments found only on the delta plain between the head of passes and the depositional mouthbars. While fluvial channel reservoirs are mainly sandstone deposits of meander pointbars or braided sheets, fluvial distributary channel reservoirs are typically elongated sandy channel sidebars attached to morphologically rectilinear channel walls. The sidebars form by both lateral and downstream accretion resulting from flow in a confined, but lowsinuosity thalweg, which may be filled with organic mud following channel abandonment. On 3D seismic data the morphology of a fluvial distributary channel is often slightly sinuous and can easily be mistaken for part of a meander channel belt.Fluvial distributary channels are usually thinner and shallower compared to their updip fluvial channel belts. Width-thickness ratios for fluvial distributary channel reservoirs are on average 50:1 (range 15:1 to 100:1), while meandering fluvial channel reservoirs have widththickness ratios typically >100:1, and braided river reservoirs show ratios of 500:1 or higher. Examples from the Mahakam Delta are used to illustrate these issues. Implications for exploration and development of deltaic deposits on the North West Shelf of Australia are discussed.
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Fan, Er Ping, Yue Hong Cheng, Yuan Zhi Zhang, and Zhen Hua Bai. "Sedimentology and Reservoir Characteristics of He8 Member, in a Gas Field of Ordos Basin, Northern China." Advanced Materials Research 734-737 (August 2013): 161–65. http://dx.doi.org/10.4028/www.scientific.net/amr.734-737.161.
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The rapid lateral variation of fluvial sand-bodies seriously affect the development of oil and gas field. One long-term base-level cycle (LSC), four middle-term base-level cycles (MSC) and nine short-term base level cycles (SSC) are recognized by researching the stacking patterns and volumetric partitioning according to the core, well log and seismic data in He8 member of A gas field, Ordos basin. The base level cycles which are mainly base level rise half cycles are mainly composed of braided and meandering river deposits. The evolution of depositional system has experienced three stages: braided river deposition in the earlier stage, braided and meandering river transition coexistence in the middle stage and only meandering river deposition in later period. The braided channel sand, mid-channel bar and point bar are mainly reservoirs which show belt and ribbon along the SEE trending. These sand-bodies are vertically and laterally stacked with good continuity in the early MSC1, MSC2 and MSC3, while isolated and with poor continutiy in the early MSC4. The sedimentary microfacies and diagenesis affect the fluvial reservoir quality including lateral continuity, porosity and permeability and the buried depth of the good reservoirs with development of secondary solution pores is less than 3500m in this area.
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Luo, Shun She, Fei Shang, Qi Qi Lv, Zhong Bao Liu, and Ying Meng. "Influence of Hydrodynamics on Formation of Braided Fluvial Delta." Applied Mechanics and Materials 318 (May 2013): 453–59. http://dx.doi.org/10.4028/www.scientific.net/amm.318.453.
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The changes of hydrodynamics will influence the formation of braided river delta. Based on many previous studies, this article does some quantitative analysis of migration rate of channel, sedimentation position for sandbody and the shape of bar under the conditions of flood, common water and low water on the basis of sedimentary simulation techniques, and transportation model of sandbody is set up under the experimental condition. The results of flume experiment show that the difference exists in the position of the thickest sandbody under diffident hydrodynamic conditions. Migration rate of channel is the highest in common water period, followed by flood period and low water period. The ratio of sandbody width/height increases and the ratio of length/width decrease gradually from flood period to common water period to low water period.
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Andrews-Speed, C. P. "The role of silica and iron oxide mobility in the formation of gold-bearing fluvial sediments in the Proterozoic Mporokoso Basin, northern Zambia." Geological Magazine 123, no. 2 (March 1986): 143–52. http://dx.doi.org/10.1017/s0016756800029794.
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AbstractGold-bearing sandstone and conglomerate near the base of the Proterozoic Mporokoso Group were deposited in a braided river system. The detrital sand grade material is mainly of quartz, sericite and haematite, and the pebbles are of vein-quartz, chert, silicic volcanics, quartzose metasediment and jaspilite. The basement rocks presently exposed in the basement are silicic igneous rocks and quartzose metasediments.The petrography of the fluvial sediments suggests that silica and, to a lesser extent, iron oxide were mobile both in the source-area and in the braided river system. Evidence for silica-mobility includes jaspilite pebbles with spherulites and glaebules of chalcedony, abundant vein-quartz pebbles, intra-basinal sandstone pebbles, and the silicification of volcanic pebbles. The detrital haematite in the fluvial sandstone forms pseudomorphs after magmatic magnetite. Authigenic iron oxide occurs in several forms which suggest that iron oxide was mobile in the source-area and in the fluvial sediments. Uranium is locally abundant in basement and sedimentary rocks, cassiterite is a common heavy mineral in the fluvial sediments, and fluorite has been found in the basement.These features may be explained by intense weathering which mobilized both silica and iron. The silica was concentrated near the surface to form silcretes in the basement and later in the overlying fluvial sediments. Hydrothermal convection cells driven by the granites may have carried silica, iron, tin, fluorine and uranium towards the surface before and during the erosion of the igneous basement.
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Fambrini, Gelson Luís, Diego da Cunha Silvestre, José Acioli Bezerra de Menezes-Filho, Ian Cavalcanti da Costa, and Virgínio Henrique de Miranda Lopes Neumann. "Architectural and facies characterization of the Aptian fluvial Barbalha Formation, Araripe Basin, NE Brazil." Geological Society, London, Special Publications 488, no. 1 (2019): 119–50. http://dx.doi.org/10.1144/sp488-2017-275.
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AbstractThe Aptian Barbalha Formation records the beginning of the post-rift stage of the Araripe Basin. It consists predominantly of sandstones and mudstones interbedded with thin layers of bituminous black shales and conglomerates. The depositional and architectural features of the alluvial succession of the Barbalha Formation were characterized by detailed study and descriptions of the selected outcrops and analysis of well core data. In this study, two main depositional sequences were identified. The lower depositional sequence is more than 100 m thick and comprises a vertical facies succession composed of amalgamated, multistorey, braided fluvial channel sandstone bodies overlain by a widespread lacustrine black shale up to 10 m thick. The lacustrine black shales–carbonate mixed interval is known as the Batateira Beds and constitutes a regionally important stratigraphic correlation marker in the basin. This interval records the establishment of a large lake that experienced severe water-level fluctuations and anoxic events. The upper depositional sequence is 60–95 m thick, and mainly consists of thin, yellowish, medium- to fine-grained sandstones and variegated shales. The upper sequence rests unconformably on the lacustrine black shales of the Batateira Beds. Thin and discontinuous conglomerate beds at the base of the upper sequence laterally grade into coarse-grained sandstones. These coarse-grained sandstones are overlain by interbedded sandstones and mudstones organized in fluvial cycles. The upper and lower sequences of the Barbalha Formation are separated by an erosive unconformity, traceable throughout the study area, formed during a period of stratigraphic base-level lowering. This surface marks a change in the lower sequence from a dominantly fluvial depositional style, with amalgamated multistorey braided fluvial channel sand bodies, to a lacustrine system in the top to an eminently fluvial sedimentation, which in the basal section comprises amalgamated, multistorey, braided fluvial channel sand bodies, and in the superior section the amalgamated fluvial channels are overlain by floodplain and overbank sandstone bodies with fixed fluvial channel deposits, interpreted as a suspended-load-dominated fluvial system in the upper sequence. This change in the depositional style is accompanied by a reduction in grain size and a change in the fluvial regime, suggesting that the drainage system was restructured due to tectonic movements in the basin and climatic variations. In addition to the restructuring of the drainage basin, the characteristics of the discharge of the river system have changed, probably because of the more humid climatic conditions that dominated during the deposition of the upper sequence. The fluvial deposition in the lower sequence is associated with more ephemeral river systems, while the facies architecture of the upper sequence is associated with perennial systems and is suggestive of a suspended-load-dominated fluvial system. This fluvial system is capped by lacustrine deposits of the Crato Formation. The upper sequence grades upwards into the Crato Formation. The boundary between these two units is delineated by the presence of greenish calciferous shales that are covered by lacustrine laminated limestones and shales of Neoaptian age. Palaeocurrent readings from the fluvial deposits of both sequences display a consistent palaeoflow to the SE. Sedimentological and palaeontological evidence indicates a tectonic control on sedimentation and humid to subhumid climate conditions.
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García-Alix, Antonio, Raef Minwer-Barakat, Elvira Martín Suárez, and Matthijs Freudenthal. "Small mammals from the early Pleistocene of the Granada Basin, southern Spain." Quaternary Research 72, no. 2 (September 2009): 265–74. http://dx.doi.org/10.1016/j.yqres.2009.06.004.
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AbstractThe Pliocene and Pleistocene continental sedimentary records of the western sector of the Granada Basin, southern Spain, consist of alternating fluvial and lacustrine/palustrine sediments. Two Quaternary sections from this sector have been sampled: Huétor Tájar and Tojaire. They have yielded remains of rodents, insectivores and lagomorphs. The presence in the Huétor Tájar and Tojaire sections of Mimomys, Apodemus atavus, Castillomys rivas and two different species of Allophaiomys, indicates an Early Pleistocene age. These deposits, which are related to a fluvio-lacustrine system, can be differentiated from an older (Pliocene) braided fluvial system. Their dating has important repercussions on the paleogeographic reconstruction of the basin. The conditions inferred from the ecological preferences of the small mammal associations are wet and cold. These associations suggest a predominance of open herbaceous habitats, followed by forested habitats; semiaquatic habitats are the least represented.
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Li, Shunli, Xinghe Yu, Bintao Chen, and Shengli Li. "Quantitative Characterization of Architecture Elements and Their Response To Base-Level Change In A Sandy Braided Fluvial System At A Mountain Front." Journal of Sedimentary Research 85, no. 10 (October 1, 2015): 1258–74. http://dx.doi.org/10.2110/jsr.2015.82.
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Abstract: The Rockcave Member of the Yungang Formation (Middle Jurassic), in the Datong Basin, China, is a multistory sandstone that is interpreted as a sandy braided fluvial deposit based on grain size, lithofacies, and architectural elements. The depositional setting was the mountain front of the Datong Basin, which was tens of kilometers from the shoreline of a lacustrine basin during the Middle Jurassic. The concept of base level is used to analyze the architectural elements of the braided system obtained from photographic mosaics and high-resolution measurement of six outcrop sections from Yungang Rock Cave. Grain size, lithology, and bounding surfaces together with scale and dimension parameters of the sedimentary structures in various architectural elements were used to quantitatively characterize each group of architectural elements and stratigraphic units. Width/thickness values of trough crossbeds were found to be a fundamental component of the hydrodynamic regimes. During base-level rise the braided fluvial system developed large-scale channel units, bar units, and overbank fills. The relatively high proportion of bar units and overbank fills reflect processes operating during positive accommodation. However, during base-level fall there are a high proportion of small-scale channel units that reflect incision-dominated processes such as channels with low W/T values for trough crossbeds and less common overbank fines.
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Xu, Qinghai, Wanzhong Shi, Xiangyang Xie, Changmin Zhang, Walter L. Manger, Jian Wang, and Song Rao. "Multichannel systems in an ancient river-dominated delta: case study of the lower Yanchang Formation, southwest Ordos Basin, China." Canadian Journal of Earth Sciences 56, no. 10 (October 2019): 1027–40. http://dx.doi.org/10.1139/cjes-2018-0277.
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Distributary channels in large deltas can form a channel pattern similar to braided fluvial system or anastomosed fluvial system that have multichannel systems. Although both systems are of generally comparable platforms, their geometry, sedimentology, and facies associations may exhibit unique characteristics. Many ancient multichannel systems have been interpreted as braided patterns, but some are certainly anastomosed patterns. A reevaluation of ancient multichannel architectures and sedimentology patterns is needed to improve discrimination of braided and anastomosed patterns of multichannel systems. This study examines the characteristics of two modern anastomosed pattern channel systems. Those modern systems are compared to ancient examples in the lower Yanchang Formation, southwest Ordos Basin. This comparison indicates that the multichannel systems of the delta, southwest Ordos Basin, exhibit greater similarity to modern anastomosed channel systems of shallow-water deltas. Systems of low-sinuosity distributary channels and interdistributary bays or swamp islands are developed mainly between the channels, and there are no mouth bar deposits. Both modern and ancient multichannel systems suggest that low gradient slope is a significant controlling factor in the formation of anastomosed pattern channels in river-dominated deltas. The identification of anastomosed patterns plays a significant role in reservoir characterization and hydrocarbon exploration and production in delta systems.
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Malaza, Ntokozo, Kuiwu Liu, and Baojin Zhao. "Facies Analysis and Depositional Environments of the Late Palaeozoic Coal-Bearing Madzaringwe Formation in the Tshipise-Pafuri Basin, South Africa." ISRN Geology 2013 (December 11, 2013): 1–11. http://dx.doi.org/10.1155/2013/120380.
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The late Palaeozoic coal-bearing Madzaringwe Formation of the Karoo Supergroup in the Tshipise-Pafuri Basin in the Limpopo Province, South Africa, records part of the infill of a passive continental margin terrain. Lithofacies analysis was performed with a view to deduce the nature of depositional environments of the Formation. Sedimentological and sequence stratigraphic evidence indicates that this unit represents a complex siliciclastic facies that reflects a fluvial paleodepositional environment. Eleven facies, which were grouped into five facies associations, were recognised. The base of the Madzaringwe Formation (Lower Member) represents a sequence deposited by braided channels. The coal deposits represent flood plain and swamp deposits, which is characterised by shale, thick coal seams, siltstone, and sandstone. The Middle Member is characterised by both clast and matrix supported conglomerates, major tubular and lenticular sandstones, and finely calcareous, micaceous siltstone. The deposition represents a sequence being formed from fluvial and particularly braided channels. The crudely stratified, coarse to pebbly sandstone indicates channel lag deposits within a heavy loaded fluvial system. The fine-grained sandstone represents deposition by shift channel and side bar deposits during lower flow conditions. The Upper Member is characterised by facies associations similar to the Lower Member, representing a new depositional cyclothem.
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Preusser, Frank, Benjamin U. Müller, and Christian Schlüchter. "Luminescence Dating of Sediments from the Luthern Valley, Central Switzerland, and Implications for the Chronology of the Last Glacial Cycle." Quaternary Research 55, no. 2 (March 2001): 215–22. http://dx.doi.org/10.1006/qres.2000.2208.
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AbstractThe advancing glaciers of the last glacial maximum either eroded or deeply buried older sediments in the Swiss Alpine Foreland. However, part of the Swiss Plateau was not covered by ice and is therefore an excellent area for investigating climate and environmental change during the Upper Pleistocene. Repeated fluvial sequences can be studied in several pits along the Luthern Valley. The chronological framework is based on lithostratigraphy, pollen analysis, U/Th dating, and recently, heavy mineral analysis and luminescence dating. The oldest unit, the Untere Zeller Schotter braided river deposit, represents cold climate conditions and presumably a glaciation prior to the Eemian Interglaciation. The last interglacial period and the very beginning of the last glacial cycle is represented by the Mittlere Zeller Schotter, sediments of a meandering fluvial system. Younger braided river sediments, the Obere Zeller Schotter, seem to correlate with the cold climate of oxygen isotope stage (OIS) 4. Weathering of the top of the Obere Zeller Schotter is likely to represent the OIS 3. The advancing Reuss glacier caused erosion of the recent Luthern Valley, cutting into older sediments, with local loess accumulation during the last glacial maximum as indicated by cover sediments on top of the fluvial sequence.
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Kasse, C., R. T. Van Balen, S. J. P. Bohncke, J. Wallinga, and M. Vreugdenhil. "Climate and base-level controlled fluvial system change and incision during the last glacial–interglacial transition, Roer river, the Netherlands – western Germany." Netherlands Journal of Geosciences 96, no. 2 (December 19, 2016): 71–92. http://dx.doi.org/10.1017/njg.2016.50.
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AbstractThe fluvial development of the Roer river in the southeastern Netherlands and western Germany is presented for the Late Pleniglacial, Late-glacial and Early Holocene periods. Reconstruction of fluvial-style changes is based on geomorphological and sedimentological analysis. Time control comes from correlation to the pollen-based biochronostratigraphic framework of the Netherlands combined with independent optically stimulated luminescence (OSL) ages. At the Pleniglacial to Late-glacial transition a system and channel pattern change occurred from an aggrading braided to an incising meandering system. Rapid rates of meander migration, as established for the Late-glacial by optical dating, were likely related to the sandy nature of the substratum and the Late-glacial incision of the Meuse that resulted in a higher river gradient in the downstream part of the Roer. In the Roer valley the Younger Dryas cooling is not clearly reflected by a fluvial system response, but this may also be related to Holocene erosion of Younger Dryas fluvial forms. An important incision and terrace formation was established at the Younger Dryas to Early Holocene transition, probably related to forest recovery, reduced sediment supply and base-level lowering of the Meuse. The results of this study show a stepwise reduction in the number of channel courses from a multi-channel braided system in the Pleniglacial, to a double meander-belt system in the Late-glacial and a single-channel meandering system in the Early Holocene. The results show that the forcing factors of fluvial-system change in the Roer valley are climate change (precipitation, permafrost and vegetation) and downstream base-level control by the Meuse.
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Moscariello, A. "The Schooner Field, Blocks 44/26a, 43/30a, UK North Sea." Geological Society, London, Memoirs 20, no. 1 (2003): 811–24. http://dx.doi.org/10.1144/gsl.mem.2003.020.01.68.
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AbstractThe Schooner Field is Shell U.K.'s first Carboniferous gas development in the North Sea. The field was discovered in 1987 by well 44/26-2 and gas production began in October 1996 from four wells. In contrast to the majority of the fields in the Southern North Sea producing from the aeolian Leman Sandstones Formation (Rotliegend), Schooner targets the low net-to-gross, fluvial Upper Carboniferous Barren Red Measures and Coal Measures formations. The reservoir consists of discrete, low sinuosity fluvio-deltaic channels draining a swampy coastal floodplain evolving upwards into a highly aggrading, low gradient, distal fluvial fan, dominated by braided and anastomosing channels. In Schooner, like other Carboniferous fields, reservoir connectivity is one of the key subsurface uncertainties due both to channel lateral discontinuity and fault compartmentalization. Production data and reservoir properties distribution, together with a new stratigraphical subdivision driven mostly by chemostratigraphic techniques, have been used to reassess the volume of gas-in-place which currently is estimated at 29.98 Gm3 (1059 BCF)
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Ning, Zhao, Gao Xia, Chen Zhongmin, Huang Jiangqin, and Zhang Guangya. "High Resolution Sequence Stratigraphy Correlation and Sedimentary Model of Braided Rivers: A Case on Paleogene Palogue Oilfield, South Sudan." E3S Web of Conferences 53 (2018): 03024. http://dx.doi.org/10.1051/e3sconf/20185303024.
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Complicated fluvial sands correlation and braided river models are still challenges for heterogeneous anisotropic reservoir evaluation for petroleum development in oilfields. Based on high-resolution sequence stratigraphy and sedimentology, core observation, and the analysis of logging and seismic data, high-resolution sequence stratigraphy framework of Paleogene Yabus formation of Palogue Oilfield, South Sudan is established, and sedimentary characteristics of braided rivers are analyzed, (1) In braided river deposits, channel bars are usually pro-gradating seawards and going thicker upwards. And braided channels are retro-gradating landwards and going thinner upwards. Both of them can be subdivided into channel (bar) trunks and channels (bar) flanks, showing vertical stacking and lateral migration; (3) As the A/S (Accommodation space/sediments supply) increasing upwards, braided river sands are shifting frequently as a reciprocating migration in Yabus V/VI, and they are more stable as the A/S decreasing upwards as a vertical aggradation in Yabus VII/VIII; (4) With 77 wells sedimentary microfacies identification, sand thickness and sand/bed ratio distribution, sedimentary facies distribution of all members and zones are analyzed. According to the A/S change, three braided river models are concluded, including isolated channel type (high A/S period), crossed channels type (medium A/S period), and superposed channels type (low A/S period).
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Lin, Zhipeng, Le Chen, Jingfu Shan, Tan Zhang, Qianjun Sun, and Yiwu Wang. "A New Sequence Stratigraphic Framework of Terrestrial Fluvial." Studies in Engineering and Technology 4, no. 1 (July 30, 2017): 85. http://dx.doi.org/10.11114/set.v4i1.2521.
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Currently, the recognition and research on the classification of fluvial types mainly focus on the description and results of a series of indicators, such as the plane shape and sediment characteristics. However, there is limited literacy about how to demonstrate the fluvial types from the depositional process, especially less on sequence model of inland fluvial. Thus, this paper aims o propose a new kind of sequence stratigraphic framework, which is able to reflect the fluvial processes under the perspective of sequence stratigraphy. Accordingly, we use the principle of concrete analysis for concrete problems by comprehensively summing up the previous classification schemes of river types. With the research method of sedimentation process, new fluvial systems tracts for fluvial are presented here, including four parts: low fluvial system tract (LFST), advancing fluvial system tract (AFST), flooding fluvial system tract (FFST), receding fluvial system tract (RFST). Moreover, these could be applied to tackle the problem of the traditional division of fluvial. Various rivers have the different characteristics of systems tracts, then this may play a vital role in the discrimination of meandering river, braided river, anastomosing river and branched river. This study embodies the philosophical thought of Process Sedimentology and may contribute to revealing the deposition process of the fluvial system more profoundly from the aspect of genetic mechanism and evolution course. Most importantly, the fluvial classification system is definitely improved from the description stage to a complete rational stage.
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Weckwerth, Piotr. "Palaeoslopes of Weichselian sand-bed braided rivers in the Toruń Basin (Poland): results of a palaeohydraulic analysis." Geologos 17, no. 4 (December 1, 2011): 227–38. http://dx.doi.org/10.2478/v10118-011-0013-6.
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Palaeoslopes of Weichselian sand-bed braided rivers in the Toruń Basin (Poland): results of a palaeohydraulic analysis Palaeoslopes of Weichselian sand-bed braided rivers have been reconstructed for two stages of fluvial development in the Toruń Basin. (1) The palaeoslope of the ‘fossil’ fluvial succession (buried under Weichselian tills) was calculated on the basis of the median grain size and the Shields parameter. The hydraulic gradient thus found is comparable with the hydraulic gradient of the present-day river. (2) The second developmental stage of the Toruń Basin (as a apart of the Noteć-Warta ice-marginal valley) took place after deglaciation. The slopes of river terraces are a few times lower than those calculated on the basis of the Shields parameter. The palaeoslope of the then river was estimated on the basis of a constant interdependency between the braidplain width, the channel geometry and the grain size. The river gradient that was thus calculated is similar to the measured terrace slope. Palaeoslope estimates in valleys similar to those in the Toruń Basin should consider the width of the braidplain.
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Martin, John H. "A review of braided fluvial hydrocarbon reservoirs: the petroleum engineer’s perspective." Geological Society, London, Special Publications 75, no. 1 (1993): 333–67. http://dx.doi.org/10.1144/gsl.sp.1993.075.01.20.
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Zhang, Zili, Xiaomin Zhu, Qi Li, Ruifeng Zhang, Jing Zhang, and Yi Huang. "Depositional characteristics of fluvial facies in gentle slope zone of lacustrine rift basins: The third member of the Dongying Formation in the Wen’an Slope of Baxian Sag, Bohai Bay Basin, China." Interpretation 8, no. 2 (May 1, 2020): SF37—SF55. http://dx.doi.org/10.1190/int-2019-0125.1.
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We have integrated core, well logs, and seismic data to analyze fluvial types and reconstruct sediment dispersal patterns of the Dongying Formation in the Wen’an Slope, Bohai Bay Basin (China). We analyzed four meandering-braided fluvial successions from the Dongying Formation in the Wen’an Slope. The results indicate that the fluvial systems are dominantly northeast–southwest and consist of channel, channel bar, and flood plain subfacies, which can be further subdivided into six microfacies including braided channel, meandering channel, sandy channel bar, muddy channel bar, crevasse fan, and floodplain. With a paleoflow direction, [Formula: see text] ranges from 40° to 65°, the river belt width [Formula: see text] is estimated to be 1.47–2.64 km, whereas the main channel width varies from 0.02 to 0.29 km and its thickness/bankfull depth [Formula: see text] ranges from 1.2 to 6.4 m. The differential subsidence of rift basin during fault-depression transition period is the main control on fluvial evolution and sand body distribution. The climatic effect causes changes in river flow. During the flood season, river flow and flow rate are large, and early sediments and sand bodies are reconstructed. Lateral erosion and undercutting are very strong in this period. In the dry season, the river is dominated by weak lateral erosion. Our study also suggests that the development of thick mudstone in the upslope may limit hydrocarbon charging and migration and thick channel and channel bar deposits in the middle and downslope cross cut by faults, which are conduits for migration are likely to be the most potential reservoirs in the Bohai Bay Basin.
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Hickin, Edward J. "Fluvial facies models: a review of Canadian research." Progress in Physical Geography: Earth and Environment 17, no. 2 (June 1993): 205–22. http://dx.doi.org/10.1177/030913339301700207.
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Canadian river scientists made significant contributions to the early development (1960-80) of fluvial facies models, particularly to those for braided rivers. More recent Canadian studies (1980-92) have centred on understanding the facies sedimentology of anastomosed and wandering gravel-bed rivers. River planform facies models are distinctly limited as indicators of fluvial style because of: (1) spurious environmental correlations; (2) the difficulty of river planform definition; (3) differential preservation potential of facies; (4) inadequate and unsystematic field sampling; (5) flawed statistical testing; and (6) the inappropriate space scale adopted for analysis. The scale problems of facies analysis may be overcome by employing architectural element analysis in conjunction with modem geophysical methods such as shallow reflection seismology and ground-penetrating radar. Future research should focus on devising specific tests of element-scale sedimentological relationships based on the contemporary fluvial enrivonment.
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Slomka, J. M., and C. H. Eyles. "Characterizing heterogeneity in a glaciofluvial deposit using architectural elements, Limehouse, Ontario, Canada." Canadian Journal of Earth Sciences 50, no. 9 (September 2013): 911–29. http://dx.doi.org/10.1139/cjes-2013-0020.
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Major hydrocarbon and groundwater reservoirs are commonly hosted within coarse-grained alluvial deposits that contain a high degree of sedimentary heterogeneity. This paper presents a detailed characterization of the sedimentary heterogeneity of fluvial–deltaic deposits using architectural element analysis (AEA). Sedimentological data collected from outcrop faces exposing Late Quaternary glaciofluvial deposits in southern Ontario, Canada, is recorded in 31 sedimentary logs. These logs are used to identify nine different facies types, including gravel facies (Gm, Gp, Gt), sand facies (Sr, Sp, St, Ss), and fine-grained facies (Fl and Fd). Variations in facies associations and geometries are defined by five architectural elements (AEs): sand complex (SC), gravel sheet (GS), fine-grained sheet (FS), gravel foreset body (GFB), and concave fill (CF) elements. The spatial arrangement of bounding surfaces (first- to fifth-order) and AEs allows the classification of six EAs, which, in this study, are defined as the largest-scale architectural subunits that allow for architectural-based mapping over a large area. EAs delineated in this study are sandy braided-river (EA1), delta-front (EA2), gravelly braided-river to delta-top (EA3), delta-front to lacustrine (EA4), braided-river to deltaic (EA5), and sand-dominated fluvial (EA6). AEA is utilized here to capture three levels of heterogeneity, which allow detailed reservoir characterization based on geometric objects and can be readily used for computer-based modelling. Outcrop analogue studies such as this one provide insight to the geometries of more deeply buried coarse-grained deposits that form potential reservoirs and enhance paleoenvironmental reconstruction of subsurface alluvial deposits in Canada and elsewhere.
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Li, Jie, Junqiang Xia, Meirong Zhou, Shanshan Deng, and Zenghui Wang. "Channel geometry adjustments in response to hyperconcentrated floods in a braided reach of the Lower Yellow River." Progress in Physical Geography: Earth and Environment 42, no. 3 (June 2018): 352–68. http://dx.doi.org/10.1177/0309133318776492.
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Hyperconcentrated floods with more than 200–300 kg/m3 sediment concentrations often occur in the Lower Yellow River (LYR) during flood seasons, which leads to unique fluvial processes in the braided reach of the LYR. The investigation of channel geometry adjustments in response to hyperconcentrated floods can not only help to gain a better understanding of associated fluvial processes, but also is significant for making flood control strategies in the braided reach. In this study, pre- and post-flood bankfull channel dimensions in the braided reach were calculated based on the observed cross-sectional profiles in 15 years with the occurrence of hyperconcentrated flood events. Adjustments in channel geometry at section- and reach-scales were investigated, with several factors influencing adjustments in reach-scale channel geometry being analyzed. It indicates that the mean sediment transport rate was a key factor influencing the adjustment index, although pre-flood channel geometry and sediment deposition can also affect the index to some extent. An empirical relationship was developed between the characteristic parameter representing the pre- and post-flood channel geometries and mean sediment transport rate in hyperconcentrated floods. Eleven datasets were used to calibrate the parameters in the empirical relation, with the datasets in 1973, 1988, 1995, and 2002 verifying the relation. The calculated post-flood characteristic parameter of channel geometry using the empirical relation agreed well with observed data, and the proposed method can be used to predict the reach-scale adjustment of channel geometry during hyperconcentrated floods in alluvial rivers.
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Wang, Xixin, Fan Zhang, Shaohua Li, Luxing Dou, Yuming Liu, Xiaoxu Ren, Depo Chen, and Wen Zhao. "The Architectural Surfaces Characteristics of Sandy Braided River Reservoirs, Case Study in Gudong Oil Field, China." Geofluids 2021 (April 29, 2021): 1–12. http://dx.doi.org/10.1155/2021/8821711.
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The architecture analysis of the different orders sedimentary bodies is of great significance to the efficient development of oil and gas fields. In order to investigate the effects of the architectural interfaces on reservoir quality and heterogeneity, this study takes the Gudong oil field as a case to investigate the architectural characteristics of hierarchical bounding surfaces using detailed descriptions of core and wireline logs. Architectural models from the 7th-order to the 3rd-order are analyzed, and the developmental characteristics of the 5th-order braided river, 4th-order single sandstone, and 3rd-order accretion are summarized. The interlayer between two braided rivers is floodplain mud deposition, with poor physical properties, stable thickness, and strong blocking capacity. Two models of interlayers are found in the 4th-order deposition. The first interlayer is between the braided filling channel and midchannel bar, which is composed of generally fine-grained sediments with calcium cementation and poor physical properties. The second interlayer is a transformation belt between two midchannel bars and is generally composed of gravel-scoured deposition with penetration capability. The 3rd-order surfaces are defined as the surfaces of accretions within midchannel bars. Two models of interlayers are also found in the 3rd-order surfaces of accretions. The paleocurrent of the sandy braided river is reconstructed by synthesizing the core data, well logging data, and production performance data. A total of 1 fluvial system (7th-order), 2 compound braided rivers (6th-order), 11 braided rivers (5th-order), 41 midchannel bars (4th-order), and 96 accretions (3rd-order) are developed in the study area.
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Schwartz, Theresa M., Marieke Dechesne, and Kristine L. Zellman. "Evidence for variable precipitation and discharge from Upper Cretaceous–Paleogene fluvial deposits of the Raton Basin, Colorado–New Mexico, U.S.A." Journal of Sedimentary Research 91, no. 6 (June 10, 2021): 571–94. http://dx.doi.org/10.2110/jsr.2020.081.
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ABSTRACT The Raton Basin of Colorado–New Mexico, USA, is the southeasternmost basin of the Laramide intraforeland province of North America. It hosts a thick succession (4.5 km or 15,000 ft) of Upper Cretaceous to Paleogene marine and continental strata that were deposited in response to the final regression of the Western Interior Seaway and the onset of Laramide intraforeland deformation. The Upper Cretaceous–Paleogene Raton and Poison Canyon formations were previously described as meandering river and braided river deposits that represented distal and proximal members of rivers that drained the basin-bounding Sangre de Cristo–Culebra uplift. We present new observations of fluvial-channel architecture that show that both formations contain the deposits of sinuous fluvial channels. However, fluvial channels of the Raton Formation formed in ever-wet environments and were affected by steady discharge, whereas channels of the overlying Poison Canyon Formation formed in drier environments and were affected by variable discharge. The apparent transition in fluvial discharge characteristics was coeval with the progradation of fluvial fans across the Raton Basin during the Paleocene, emanating from the ancestral Sangre de Cristo–Culebra uplift. The construction of fluvial fans, coupled with the sedimentary features observed within, highlights the dual control of Laramide deformation and early Cenozoic climatic patterns on the sedimentary evolution of the Raton Basin.
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Waksmundzka, Maria I. "Braided-river and hyperconcentrated-flow deposits from the Carboniferous of the Lublin Basin (SE Poland) – a sedimentological study of core data." Geologos 18, no. 3 (November 1, 2012): 135–61. http://dx.doi.org/10.2478/v10118-012-0008-y.
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Abstract Fining-upwards cyclothems found in five boreholes in the Carboniferous (Lower Bashkirian) of the Lublin Basin were analysed sedimentologically. It was established that the cyclothems represent fluvial deposits, and the lithofacies were grouped into lithofacies associations. Most lithofacies associations represent three types of sand-bed braided rivers: (1) high-energy, (2) deep and (3) distal sheetflood-affected. Other associations represent hyperconcentrated flows. Both coarse-grained (type I) and fine-grained (types IIa and IIb) occur among the fining-upward cyclothems. The formation of most thick cyclothems was related mainly to allocyclic factors, i.e. a decrease in the river’s gradient. The thickest fining-upward cyclothems are characteristic of hyperconcentrated flows and braided-river channels. The aggradation ratios were commonly high. During the early Namurian C and early Westphalian A (Early Bashkirian), the eastern part of the Lublin Basin was located close to the source area. The sedimentary succession developed due to a transition from high-energy braidedrivers and hyperconcentrated flows to lower-energy braided rivers, controlled by a rise of the regional base level.
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Bukar, Shettima, Mohammed Bukar, Asabe Kuku, Bintu Shettima, and Ishaku H. Kamale. "Incised Valley Depositional System of the Cretaceous Yolde Formation of the Gongola Sub-basin Northern Benue Trough N.E. Nigeria." European Journal of Engineering Research and Science 5, no. 8 (August 19, 2020): 870–76. http://dx.doi.org/10.24018/ejers.2020.5.8.1999.
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This research was carried out in the Gongola Sub-basin of the Northern Benue Trough aimed at deciphering of the paleo-depositional environment of the Yolde Formation based on facies on facies analysis. Six lithofacies were identified to include trough crossbedded sandstone facies (St), massive bedded sandstone facies (Sm), planar crossbedded sandstone facies (Sp), ripple laminated sandstone facies (Sr), parallel sandstone facies (Sl) and mudstone facies (Fm). These build into two facies association of fluvial channel and tidally influenced fluvial channel facies associations. The fluvial successions typical characterizes the lower stratigraphic horizons and their contained dominances of trough crossbedded sandstone facies with high channel to overbank facies and contained mud-clast reflecting deep, high energy braided river system. The submergences of these channels by surging sea level rise generated the tidally influenced fluvial facies association and this package characteristically defines the upper interval stratigraphic architecture of this formation, displaying occasional bi-directional current system and abundant marine ichnogenera. This architectural symmetry is reflective of an incised valley fills, developing as a consequence of Cenomanian transgressive phase induced by the mid-Cretaceous global marine transgression.
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Weckwerth, Piotr, Krzysztof Przegiętka, Alicja Chruścińska, Barbara Woronko, and Hubert Oczkowski. "Age and sedimentological features of fluvial series in the Toruń Basin and the Drwęca Valley (Poland)." Geochronometria 38, no. 4 (December 1, 2011): 397–412. http://dx.doi.org/10.2478/s13386-011-0038-1.
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Abstract The deposits of the Toruń Basin are dominated by a few-metre thick sand series which fill up buried valley-like depressions. In many cases they underlie the Weichselian till which builds up the ice marginal streamway (pradolina) terraces or they are exposed at the basin slopes. As the results of the geological and sedimentological studies, as well as of the dating of the deposits at the sites in the Toruń Basin indicate, the deposits include two fluvial series accumulated before the advancement of the Leszno Phase ice sheet, i.e. in Middle Weichselian and at the beginning of Late Weichselian. The oldest fluvial series connected with the Saalian Glaciation was found at the mouth section of the Drwęca Valley. The fluvial system of the Toruń Basin during Middle Weichselian and at the beginning of Late Weichselian developed in two phases of the sand-bed braided river. During the first one the river channel were dominated by large mid-riverbed sandbars, while during the second phase the water flow was smaller and, as a result, low transverse sandbars and two-dimensional dunes developed. Other active river channel also showed low-energy flows, more intensive meandering than in the case of the braided rivers, as well as sandy side-bars. Analysis of the rounding and frosting of the quartz grains indicate that the studied series of the Weichselian sandy deposits represent alluvia of a river which were fed from two diverse sources. The first one might have represented the alluvia of a warm river which transformed its load, while the other one might have mainly carried the underlying Quaternary deposits.
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Catto, N. R. "Hydrodynamic distribution of palynomorphs in a fluvial succession, Yukon." Canadian Journal of Earth Sciences 22, no. 10 (October 1, 1985): 1552–56. http://dx.doi.org/10.1139/e85-163.
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Investigation of a sequence of alternating sand and silt deposits formed in an ephemeral braided stream channel adjacent to the modem Caribou River, Yukon, revealed differences in the palynological spectra of the sediment types. Picea, Betula, Alnus, and Gramineae are more concentrated in the silt units, whereas Cyperaceae, Chenopodium, Lycopodium, and Ericaceae are preferentially concentrated in the sand strata. These distribution patterns reflect the hydrodynamic properties of the grains, in addition to environmental differences. Grains of Picea, Betula, and Alnus settle through still water at the same rates as silt-sized quartz particles and are therefore concentrated in the portion of the deposit derived from the stream's suspended load. Thus, increases in percentages of these palynomorphs with decreasing grain size may not reflect vegetation changes or climatic alterations but may be consequences of the hydrodynamic situation.
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Muhlbauer, Jason G., and Christopher M. Fedo. "Architecture of a river-dominated, wave- and tide-influenced, pre-vegetation braid delta: Cambrian middle member of the Wood Canyon Formation, southern Marble Mountains, California, U.S.A." Journal of Sedimentary Research 90, no. 9 (September 1, 2020): 1011–36. http://dx.doi.org/10.2110/jsr.2020.023.
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ABSTRACT Across the Mojave Desert of southeastern California, outcrops of the Cambrian middle member of the Wood Canyon Formation preserve the deposits of pre-vegetation braided-fluvial and braid-delta environments. One 78-meter-thick section in the southern Marble Mountains, documented here through detailed stratigraphic logging, facies analysis, architectural panels based on “Structure-from-Motion” models, and a suite of paleocurrent and accretion-surface measurements, provides insight into the development of a river-dominated, wave- and tide-influenced braid delta at the distal end of a continent-scale braidplain. In contrast to other pre-Devonian braid-delta strata, in which mudrock is largely absent, the greater part of the middle member system contains over 5% mudstone. Four facies associations, FA4–7, constitute the middle member section and represent (in order of stratigraphic height) a braidplain-to-delta transition (FA4), proximal braid delta (FA5), distal braid delta (FA6), and upper braid-delta front (FA7). The 20 meters of braidplain-to-delta transition strata are largely similar to those of fluvial middle member sections, containing approximately 2% mudstone, unimodal north-northwest paleoflow, and vertical, downstream, and downstream-lateral accretion elements representing compound barforms and channel fills. Above, each braid-delta facies association (FA5–7) preserves high-sinuosity paleocurrent indicators, 6–12% mudstone, and symmetrical, wave-formed sand waves. Decimeter-thick fluid-mud deposits found chiefly in FA6 and less commonly in FA7 indicate the presence of a turbidity-maximum zone that records brackish-water conditions in the distal braid delta. Trace fossils concentrated in FA7 suggest that metazoans were confined to the upper braid-delta front and could not tolerate the variable salinity of the braid delta. Increased marine influence with stratigraphic height requires gradual transgression during deposition of the middle member of the Wood Canyon Formation, possibly as part of a lowstand systems tract.
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Francis, Robert A., Dov Corenblit, and Peter J. Edwards. "Perspectives on biogeomorphology, ecosystem engineering and self-organisation in island-braided fluvial ecosystems." Aquatic Sciences 71, no. 3 (June 2, 2009): 290–304. http://dx.doi.org/10.1007/s00027-009-9182-6.
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Noll, C. A., and M. Hall. "FLUVIAL ARCHITECTURE AND THE TECTONIC CONTROL ON DEPOSITION OF ONSHORE EUMERALLA FORMATION, OTWAY RANGES, VICTORIA: IMPLICATIONS FOR EXPLORATION IN THE EARLY CRETACEOUS OTWAY BASIN." APPEA Journal 43, no. 1 (2003): 99. http://dx.doi.org/10.1071/aj02005.
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Spectacular outcrops of the terrestrial Aptian-Albian Eumeralla Formation are exposed in the Skenes Creek– Wongarra region, located on the eastern margin of the Otway Ranges, Victoria. The succession comprises mudstone-dominated floodplain and lacustrine successions and fluvially-derived sandstones. Lithofacies observed in the study area comprise intraformational and exotically derived conglomerate, massive and planar laminated sandstone, trough and tabular cross-bedded sandstone, ripple laminated sandstone, interbedded sandstone and mudstone, massive to laminated mudstone and thin coal seams. Architectural analysis of the fluvial system reveals these lithofacies are arranged into architectural elements that include channel elements, sandy bedforms, downstream and lateral accretion elements, laminated sand sheets and overbank fines elements.The fluvial system is characterised by low-sinuousity, braided river channels with high width to depth ratios. Palaeocurrent data indicates that the generally westward palaeoflow is interpreted to have been diverted into local axial-through drainage patterns by active northeast trending normal faults. One of these, the Skenes Creek Fault, is also likely to have structurally isolated floodplain and lacustrine successions from the main channel belt, leading to the deposition of an anomalously thick coal measure sequence in the hanging wall of the fault. The local study therefore provides insight into regional lithofacies and potential source rock distributions, and the associated tectonostratigraphic evolution of the Eumeralla Formation in the eastern Otway Basin. While the nature of the Eumeralla Formation sandstone does not lend itself to good reservoir properties, the geometry and internal structure of the sands provide an excellent model for other fluvial sandstone reservoir reconstructions.
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Zang, Dongsheng, Zhidong Bao, Mingyi Li, Ping Fu, Min Li, Bo Niu, Zhuolun Li, et al. "Sandbody architecture analysis of braided river reservoirs and their significance for remaining oil distribution: A case study based on a new outcrop in the Songliao Basin, Northeast China." Energy Exploration & Exploitation 38, no. 6 (August 27, 2020): 2231–51. http://dx.doi.org/10.1177/0144598720951280.
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The reservoir architecture analysis of braided rivers, especially falling-silt seam forms, has played a key role in predicting remaining oil distributions. However, no studies have used architecture analyses that document braided river outcrops and researched the tapping of the few remaining oil distributions based on outcrops in the Songliao basin, northeast China. In this paper, the architecture characteristics and remaining oil distribution of braided river reservoirs are studied using a combination of an outcrop, modern deposition and subsurface well data. The new 8–13 m thick Lower Cretaceous Quantou Formation outcrop of the Songliao basin is a braided fluvial succession arranged in one large fining-upward cycle. Eight facies (Gt, St, Sm, Sh, Sp, Sw, Fl and Fm), four architecture elements (CH, DA, LV, and FF), and three orders of bounding surfaces (third-, fourth-, and fifth-order) are recognized. A new distribution pattern of falling-silt seams and a braided river architecture model are presented according to the analysis of the outcrop. In the mid-channel bar, the falling-silt seams thin from the mid-bar to the bar tail following the flow direction. Each falling-silt seam is oriented tangentially to the basal surface of the mid-channel bar, and the upper falling-silt seam extends farther than the lower one. In a Daqing Oilfield exploitation block in the Songliao basin, while channels and bars are the main reservoir units, they have different remaining oil distribution patterns. For bars, water injection wells located at the mid-bar, zonal injection technology, the drilling of horizontal wells, and proper well patterns are proposed. Fourth-order bounding surfaces, single braided channels, stacking patterns, and the lateral blocking of levees and floodplains are the key factors affecting the remaining oil distribution in channels.
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Vandenberghe, Jef, and Ming-ko Woo. "Modern and ancient periglacial river types." Progress in Physical Geography: Earth and Environment 26, no. 4 (December 2002): 479–506. http://dx.doi.org/10.1191/0309133302pp349ra.
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Climate has been proposed conventionally as the primary factor that determines periglacial river activity (aggradation) and pattern (braided). This concept does not explain the rich diversity in river patterns and morphological processes in both the present and past periglacial environments: besides braided rivers and sandur, meandering, anabranching, transitional and deltaic rivers also occur. A first attempt is made to combine past and present periglacial river types with regard to their morphology, processes and environments. The processes that control river energy and morphology are discussed especially for periglacial conditions. This approach permits an assessment of the responses of periglacial rivers to climatic conditions and the modulation of the responses due to changes in the basin properties. Examples drawn from palaeo- and present-day periglacial rivers and environments demonstrate that there is no unique type of periglacial river but rather an azonal fluvial system with a number of periglacial variants.
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Marren, Philip M. "Sedimentology of proglacial rivers in eastern Scotland during the Late Devensian." Transactions of the Royal Society of Edinburgh: Earth Sciences 92, no. 2 (June 2001): 149–71. http://dx.doi.org/10.1017/s0263593300000110.
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ABSTRACTThis paper reconstructs the characteristics of rivers which deposited proglacial fluvial sediments in east-central Scotland during the Late Devensian. Sediment depositional architecture and geometry, together with the relationship between high-stage and falling and low-stage depositional elements, were used to relate the proglacial sediments to the glacial meltwater discharge regime. The proglacial river systems studied were dominated by ‘normal’ ablation controlled discharge, rather than by high magnitude flood events. Consequently there is a great deal of spatial and vertical variability. Deposition occurred during short intervals of rapid aggradation, so that relatively fine-grained falling-stage sediments, as well as coarser, bar-core sediments are well preserved. Models relating the characteristics of the final deposit to the nature of the river are presented. These emphasise the role of stage changes and aggradation rates in controlling sediment architecture in braided fluvial deposits.
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Ryder, June M., and Michael Church. "The Lillooet terraces of Fraser River: a palaeoenvironmental enquiry." Canadian Journal of Earth Sciences 23, no. 6 (June 1, 1986): 869–84. http://dx.doi.org/10.1139/e86-089.
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The history of Holocene fluvial terraces was investigated by stratigraphic, morphological, and palaeohydrologic methods. The terraces were formed in glaciofluvial and glaciolacustrine sediments by the Fraser River: degradation alternated with episodes of stability and aggradation. The uppermost terraces, four nonpaired surfaces, were occupied by a braided river. Vertical stability was controlled either by the water and sediment discharge of the river or by backwater effects from downstream landslides. The lower terraces, two paired surfaces, and associated fluvial sediments provide evidence for at least two cycles of aggradation and downcutting. These can be attributed to the effects of landslides that occurred a short distance downstream. Climatic variations may also have influenced terrace formation, but direct evidence is lacking. Palaeohydraulic investigations based on gravel texture, terrace gradients, and geometry of palaeochannels provide results that although approximate, conform with conclusions based upon terrace morphology and stratigraphy.
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Autin, W. J. "Stratigraphic analysis and paleoenvironmental implications of the Wijchen Member in the lower Rhine-Meuse Valley of the Netherlands." Netherlands Journal of Geosciences - Geologie en Mijnbouw 87, no. 4 (December 2008): 291–307. http://dx.doi.org/10.1017/s0016774600023362.
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AbstractThe Late Pleistocene Wijchen Member (WM) and its informal stratigraphic precursors have been recognized for decades in the Rhine-Meuse Valley of the Netherlands. Although the WM marks the top of the Kreftenheye Formation (KF) at the boundary between Pleistocene and Holocene lithofacies and provides a confining bed for the regional alluvial aquifer, significant issues remain regarding WM depositional environment and processes of sedimentation. Regional WM chronology suggests a time-transgressive, millennium scale response of the Rhine River to Lateglacial climate oscillations. This paper compares interpretations of sedimentation process, stratigraphic pattern, and paleoenvironmental significance to prevailing viewpoints on the WM mode of origin.A flood basin in the Over Betuwe between the channel belts of the Neder Rijn and River Waal is investigated to characterize WM stratigraphy. The KF braided stream deposits (Kb) form a regionally extensive sandy to gravelly lithofacies. As Kb aggradation ceased, fluvial channels incised into local braid plain swales. The WM was deposited during episodes of fluvial activity as a suspended load mud drape across segments of the abandoned braid plain. The WM is a gray silty lithofacies that also contains local admixtures of sand. Explanations for the origin of the sand admixed into the mud include variability in hydrodynamic load across the flood plain, eolian mixing, and/or biogenic mixing. In the study area, eolian deposition of sand onto a wet flood plain surface is the most probable cause for the admixed sand fraction. Pedogenesis of the WM in the study area is limited to gleying under reduced wetland conditions and the development of organic rich vegetation horizons that formed on top of relatively unaltered fluvial strata. Similar reduced soil properties and limited pedogenic development occur downdip to the present coast, but updip of the study area, the WM is the parent material for poorly drained to well drained and oxidized profiles that range from Entisols to weakly expressed Alfisols.The presence of pumice granules in Kb deposits of the study area indicate that channel belt deposition continued after the Laacher See volcanic eruption in Germany at ~12,900 cal yr. Deposition of the WM occurred episodically throughout the Lateglacial and terminated by the early Holocene. The time interval between the end of WM deposition and subsequent burial by flood basin peat reflects a duration of exposure of at least 3500 yrs. Since regional water table rise affected the area ~5000 cal yrs ago, the early Holocene water table must have been maintained by spring fed ground water sources from nearby ice pushed ridges.Deposition of the WM is associated with transitional braided to meandering fluvial channels during times when the Rhine-Meuse Valley experienced a sensitive response to rapid climate change. The WM is regionally time transgressive and probably formed during flood plain transitions between permafrost and base-flow driven hydrologic regimes. Regional landscape dynamics suggest that WM deposition and subsequent preservation was driven by fluctuations of the southern limit of permafrost during Northern Hemisphere deglaciation.
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Spalletti, Luis, and Ferrán Colombo. "Architecture of intereruptive and syneruptive facies in an Andean Quaternary palaeovalley: the Huarenchenque Formation, western Argentina." Andean Geology 46, no. 3 (September 30, 2019): 471. http://dx.doi.org/10.5027/andgeov46n3-3170.
Full textAbstract:
The Huarenchenque Formation is a volcano sedimentary unit deposited to the east of the Plio-Quaternary Andean Magmatic Arc. In order to define depositional settings, two lithofacies associations (fluvial and pyroclastic) were defined. The fluvial facies association is composed of polymictic conglomerates with the predominance of basalt- dominated clasts, coarse- medium-grained conglomeratic sandstones and medium- to coarse-grained sandstones. These deposits occur as stacked or single bodies, display both sheet and channelized geometries, and contain a range of internal sedimentary structures, such as planar, low angle stratification and cross-bedding. This facies association is interpreted as the deposit of a multichannel fluvial system characterized by high bed load, steep gradient and non-cohesive bank materials. Facies and architecture of the fluvial deposits are the result of high bank full discharge related to rapid deglaciation of the Andean Last Glacial Maximum. The pyroclastic facies association is characterized by lapilli and ash tuffs deposited from air fall, pyroclastic density current, and density stratified surge mechanisms. In the Huarenchenque Formation the fluvial and the pyroclastic facies associations show a clear physical separation, suggesting that sedimentation occurred in two distinct (intereruptive and syneruptive) phases. During the long-lived intereruptive phases the sedimentary record corresponds mainly to the deposits of the gravelly braided fluvial system, whereas during syneruptive phases the fluvial valley was almost entirely occupied by primary pyroclastic deposits related to high-explosive episodes of the neighbor Andean strato-volcanoes.
Although most of the cross-bedded sandstones and conglomerate sandstones are rich in basaltic fragments, some strata are composed almost entirely of pumiceous fragments, while in others there is a marked alternation between “basalt” and “pumiceous” foresets. These attributes reflect the preservation of intrabasinal pyroclastic fragments and allow suggest that: i. explosive volcanic events could be more frequent than reflected by the pyroclastic deposits themselves; ii. syneruptive pyroclastic materials could be eroded (even eliminated) by the fluvial system; iii. contributions of primary pyroclastic material persisted during intereruptive (fluvial-dominated) phases.
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Kalicki, Tomasz, Aleksander F. Sanko, and Yury Yu Trifonov. "Types of underfit stream valleys on the territory of Belarus." Journal of the Belarusian State University. Geography and Geology, no. 2 (November 29, 2019): 108–20. http://dx.doi.org/10.33581/2521-6740-2019-2-108-120.
Full textAbstract:
According to the materials of geological and geomorphological mapping and the results of the analysis of remote sen sing data (ERS), the authors identify several types of valleys of underfit rivers in Belarus. They differ from each other according to their relief, features of sediment accumulation and stages of postglacial evolution of river valleys. Their sections are located in the section of the meltwater valleys and within outwash plains. Authors distinguish: Dnieperian type (one active and one dead channel of the valley), Drutian type (narrow fluvial and wide non-fluvial zones within one valley, the valley bends may resemble the channel bends of the palaeo-river that formed the valley), West Berezinian type with erosion and non-erosion variant (all stages of river development are presented – from braided channels through large mean ders to small meanders), the Palaeo-Islochian type (dead river channels, including meandering on the outwash plains).
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Yu, Sheng Yun, Qing Yun Meng, and Hai Ying Xu. "Study of the Fluvial Facies Reservoir Sedimentary Characteristics of an Oil Field in China." Advanced Materials Research 753-755 (August 2013): 66–69. http://dx.doi.org/10.4028/www.scientific.net/amr.753-755.66.
Full textAbstract:
In this paper, 6 kinds of reservoir sedimentary microfacies distribution model-conceptual model have been established by the use of reservoir sedimentology theory and methods, namely, large sandy braided river sand body sedimentary model, large meandering river sand body sedimentary model, low bending-straight distributary channel sedimentary model, crevasse splay (crevasse river) sedimentary model, heart beach sedimentary model, flood plain and distributary plain sheet sand body sedimentary model. On this basis, the sedimentary facies figures of four sedimentary units have been painted, putting forward the evolution law of sedimentary environment in the research zone, thus providing basic data for the facies control modeling.
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Pedersen, G. K., and M. W. Jeppesen. "Examples of bar accretion in fluvial sand, the Atane Formation, eastern Disko, West Greenland." Rapport Grønlands Geologiske Undersøgelse 140 (December 31, 1988): 38–43. http://dx.doi.org/10.34194/rapggu.v140.8030.
Full textAbstract:
The aim of the present paper is to supply additional sedimentological observations and to add new details to the existing interpretation of the Atane Formation on eastern Disko. Examples of epsilon cross-bedding reflect formation of point bars and indicate intermittent development of sinuous channels in the coarse-grained braided river. Large tabularsets of planar cross-bedding are interpreted as transverse bars and the coalescerice of two such bars are discussed in detail. The field work was carried out during five days in July 1987 as part of a sedimentological research project supported by GGU and financed by SNF.
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IELPI, ALESSANDRO. "Lateral accretion of modern unvegetated rivers: remotely sensed fluvial–aeolian morphodynamics and perspectives on the Precambrian rock record." Geological Magazine 154, no. 3 (May 12, 2016): 609–24. http://dx.doi.org/10.1017/s001675681600025x.
Full textAbstract:
AbstractModern unvegetated rivers flowing through aeolian-dune fields demonstrate potential as analogues for pre-vegetation fluvial landscapes. A prominent example is contained in the Lençóis Maranhenses of Brazil, a coastal aeolian system hosting the semi-perennial Rio Negro. Remotely sensed images covering c. 45 years display the rhythmic expansion and wind-driven shift of single-threaded and sinuous fluvial trunks alternating with wider braided plains. Sinuous tracts feature mid-channel and bank-attached bars, including expansional point bars with subdued relief. The morphology, accretion and sediment transport of unvegetated point bars in the Rio Negro are compared to the morphodynamics of vegetated meandering rivers. Unvegetated point bars are composed of large coalescent unit bars, lack apparent scroll topography and are preferentially attached to channel banks located on the windward side of the river course. Unvegetated meanders have expansional behaviour related to downwind channel trailing. Point bars maintain an expansional planform despite spatial confinement induced by aeolian dunes. Channel-flow impingement onto cohesion-less banks favours scouring of deep pools along the bar tails, which host bank-collapse deposits subsequently reworked into new bars. Analogies to Precambrian rivers suggest that ancient unvegetated fluvial landscapes were not unequivocally featured by low sinuosity, especially if characterized by a low gradient and stable discharge. This inference is supported by ongoing studies on Proterozoic fluvial–aeolian systems in the Canadian Shield. Lack of scroll topography introduces overlap with low-sinuosity fluvial facies models, underscoring the value of observing ancient fluvial deposits in planform, or along 3D sections where the palaeodrainage of channel bodies and attached bars can be compared.
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Rust, B. R., M. R. Gibling, M. A. Best, S. J. Dilles, and A. G. Masson. "A sedimentological overview of the coal-bearing Morien Group (Pennsylvanian), Sydney Basin, Nova Scotia, Canada." Canadian Journal of Earth Sciences 24, no. 9 (September 1, 1987): 1869–85. http://dx.doi.org/10.1139/e87-177.
Full textAbstract:
The onshore part of the Sydney Basin, Nova Scotia, contains a 2 km fining-upward coal-bearing succession, the Pennsylvanian Morien Group. Facies analysis indicates an upward change in depositional environment from mid- through distal braid-plain to meandering fluvial plain. This change occurred earliest in the southeast part of the basin, where the meandering channels were incised through penecontemporaneous duricrusts. Northeastward drainage was maintained throughout, and the basin fill records gradually decreasing slopes as source relief was worn down and rate of subsidence declined during a period of increasing tectonic quiescence. The uneconomic coals of the lower Morien Group (South Bar and Waddens Cove formations) are thin and inextensive and formed in well-drained swamps of anabranches from the active braided system or between incised meandering channels. The economic coals of the upper Morien (Sydney Mines Formation) are more extensive and formed in broad, humid swamps of large flood basins between the unconfined channels of large meandering rivers.
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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 (December 2011): 1561–80. http://dx.doi.org/10.1139/e11-055.
Full textAbstract:
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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MCLOUGHLIN, STEPHEN, and ANDREW N. DRINNAN. "Fluvial sedimentology and revised stratigraphy of the Triassic Flagstone Bench Formation, northern Prince Charles Mountains, East Antarctica." Geological Magazine 134, no. 6 (November 1997): 781–806. http://dx.doi.org/10.1017/s0016756897007528.
Full textAbstract:
The Flagstone Bench Formation ranges in age from earliest Triassic to Norian (Late Triassic) and is exposed in the Beaver Lake area of the northern Prince Charles Mountains. This sandstone-dominated formation rests conformably on the Bainmedart Coal Measures and represents the upper part of the Permian–Triassic Amery Group. It is divisible into three members: the Ritchie, Jetty and McKelvey members (in ascending order). Nine sedimentary facies assignable to three facies associations (major channel, crevasse/fan and flood-basin deposits) are recognized within the formation. Ritchie Member sedimentation took place during a transition from consistently hygric to seasonally dry conditions and the unit comprises sandstone-dominated, sheet-like channel deposits interspersed with few, thin, mottled, haematite-rich flood-basin siltstones. Deposition took place under fluctuating discharge conditions chiefly within the channel tracts of axially (northwesterly/northeasterly) flowing, low-sinuosity braided rivers. The Jetty Member shows a gross upward-fining profile dominated in the lower part by poorly sorted pebbly sandstones and in the upper part by ferruginous mudcracked siltstones, mottled palaeosols, calcrete and thin massive sandstone sheets. This unit reflects deposition of easterly directed alluvial fans and extensive flood-basin silt under a semi-arid climatic regime. The Upper Triassic sandstone-dominated McKelvey Member shows a return to axial drainage along the Lambert Graben with sedimentation occurring primarily within low-sinuosity braided channel tracts under wetter climatic conditions.
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Zieliński, Paweł, Robert J. Sokołowski, Stanisław Fedorowicz, Barbara Woronko, Beata Hołub, Michał Jankowski, Michał Kuc, and Michał Tracz. "Depositional conditions on an alluvial fan at the turn of the Weichselian to the Holocene – a case study in the Żmigród Basin, southwest Poland." Geologos 22, no. 2 (June 1, 2016): 105–20. http://dx.doi.org/10.1515/logos-2016-0012.
Full textAbstract:
Abstract Presented are the results of research into the fluvio-aeolian sedimentary succession at the site of Postolin in the Żmigród Basin, southwest Poland. Based on lithofacies analysis, textural analysis, Thermoluminescence and Infrared-Optical Stimulated Luminescence dating and GIS analysis, three lithofacies units were recognised and their stratigraphic succession identified: 1) the lower unit was deposited during the Pleni-Weichselian within a sand-bed braided river functioning under permafrost conditions within the central part of the alluvial fan; 2) the middle unit is the result of aeolian deposition and fluvial redeposition on the surface of the fan during long-term permafrost and progressive decrease of humidity of the climate at the turn of the Pleni- to the Late Weichselian; 3) the upper unit accumulated following the development of longitudinal dunes at the turn of the Late Weichselian to the Holocene; the development of dunes was interrupted twice by the form being stabilised by vegetation and soil development.