Estrutura dos depósitos sedimentares quaternários da bacia hidrográfica do rio Santana, Miguel Pereira, Estado do Rio de Janeiro

1999 ◽  
Vol 22 ◽  
pp. 8-22 ◽  
Author(s):  
Claudio Valdetaro Madeira ◽  
Leonardo Borghi
Keyword(s):  
Alluvial Fans ◽  
Fluvial System ◽  
Soil Horizons ◽  
Hydrographic Basin ◽  
Sedimentary Deposits ◽  
River Bed ◽  
Anthropogenic Action ◽  
High Terrace ◽  
Crevasse Splay ◽  
Geomorphological Features

The present work deals with stratigraphy, sedimentology and geomorphology of Quaternary sedimentary deposits of Santana river hydrographic basin. through facies and arquitectural elements descriptions. Based on five arquitectural elements characterized by ten lithofacies the following structural and depositional evolutions were scheduled: 1) formation of thick soil horizons over the basement; 2) deposition of several alluvial fans on the soils (lithofacies Gm and Fm, element E); 3) above an unconformity we can recognize a fluvial system, characterized by a non well drainage floodplain. This floodplain is overlaid by high-sinuosity channels (lithofacies Sp and St, element C) genetically related to other floodplain (lithofacies Fl and Fsc, element A) where the interfigering with crevasse splay deposits (lithofacies Sh, Sl, and Sp, element B) is ususal; 4) an erosional phase suceed by a new depositional phase characterized by low-sinuosity channels (lithofacies Gp, Gt, Sp, St, and Sh, element D). Nowadays anthropogenic action produces a new erosional phase. The geomorphological features recognized were scheduled: 1) the present floodplain 1.5m above the river bed; 2) the low terrace ( named T2) 5m above the river bed and its deposits is related to element D; 3) the high terrace ( named T1) 11m above the river bed and its deposits is related to elements A, B, C and E.

scholarly journals Aqra Anticline: A Growing Structure in the Iraqi Kurdistan Region

2019 ◽  
Vol 7 (2) ◽  
pp. 27-33
Author(s):  
Ala A. Ghafur ◽  
Varoujan K. Sissakian ◽  
Hawkar A. Abdulhaq ◽  
Hassan O. Omar
Keyword(s):  
Satellite Images ◽  
Structural Features ◽  
Alluvial Fans ◽  
Lateral Growth ◽  
Kurdistan Region ◽  
Iraqi Kurdistan ◽  
Geomorphological Features

Aqra Anticline is a double plunging anticline, oriented NW–SE with a steep southwestern limb and even overturned. Geomorphological features are interpreted using satellite images, as a result, it was found that the anticline shows clear geomorphological and structural features which indicate the lateral growth of the anticline. Among those features are water gaps, wind gaps, forked-shaped valleys, curved valleys, inclined valleys and dislocated and abandoned alluvial fans. Some of the vague interpreted features were checked and confirmed in the field.

scholarly journals Interactions between channels and tributary alluvial fans: channel adjustments and sediment-signal propagation

2019 ◽  
Author(s):  
Sara Savi ◽  
Stefanie Tofelde ◽  
Andrew D. Wickert ◽  
Aaron Bufe ◽  
Taylor F. Schildgen ◽  
...  
Keyword(s):  
Boundary Conditions ◽  
Signal Propagation ◽  
Main Channel ◽  
Alluvial Fan ◽  
Sediment Supply ◽  
Alluvial Fans ◽  
Fluvial System ◽  
Channel Network ◽  
Fluvial Deposits ◽  
The Impact

Abstract. Climate and tectonics impact water and sediment fluxes to fluvial systems. These boundary conditions set river form and can be recorded by fluvial deposits. Reconstructions of boundary conditions from these deposits, however, is complicated by complex channel-network interactions and associated sediment storage and release through the fluvial system. To address this challenge, we used a physical experiment to study the interplay between a main channel and a tributary under different forcing conditions. In particular, we investigated the impact of a single tributary junction, where sediment supply from the tributary can produce an alluvial fan, on channel geometries and associated sediment-transfer dynamics. We found that the presence of an alluvial fan may promote or prevent sediment to be moved within the fluvial system, creating different coupling conditions. A prograding alluvial fan, for example, has the potential to disrupt the sedimentary signal propagating downstream through the confluence zone. By analyzing different environmental scenarios, our results indicate the contribution of the two sub-systems to fluvial deposits, both upstream and downstream of the tributary junction, which may be diagnostic of a perturbation affecting the tributary or the main channel only. We summarize all findings in a new conceptual framework that illustrates the possible interactions between tributary alluvial fans and a main channel under different environmental conditions. This framework provides a better understanding of the composition and architecture of fluvial sedimentary deposits found at confluence zones, which is essential for a correct reconstruction of the climatic or tectonic history of a basin.

scholarly journals Revised modelling of the post-AD 79 volcanic deposits of Somma-Vesuvius to reconstruct the pre-AD 79 topography of the Sarno River plain (Italy)

2011 ◽  
Vol 62 (1) ◽  
pp. 5-16 ◽  
Author(s):  
Sebastian Vogel ◽  
Michael Märker ◽  
Florian Seiler
Keyword(s):  
Model Performance ◽  
Regression Tree ◽  
Classification And Regression Tree ◽  
Alluvial Fans ◽  
Digital Elevation ◽  
Volcanic Deposits ◽  
Elevation Model ◽  
River Plain ◽  
Geomorphological Features ◽  
Sarno River

Revised modelling of the post-AD 79 volcanic deposits of Somma-Vesuvius to reconstruct the pre-AD 79 topography of the Sarno River plain (Italy) In this study the methodology proposed by Vogel & Märker (2010) to reconstruct the pre-AD 79 topography and paleo-environmental features of the Sarno River plain (Italy) was considerably revised and improved. The methodology is based on an extensive dataset of stratigraphical information from the entire Sarno River plain, a high-resolution present-day digital elevation model (DEM) and a classification and regression tree approach. The dataset was re-evaluated and 32 additional stratigraphical drillings were collected in areas that were not or insufficiently covered by previous stratigraphic data. Altogether, an assemblage of 1,840 drillings, containing information about the depth from the present-day surface to the pre-AD 79 paleo-surface (thickness of post-AD 79 deposits) and the character of the pre-AD 79 paleo-layer of the Sarno River plain was utilized. Moreover, an improved preprocessing of the input parameters attained a distinct progress in model performance in comparison to the previous model of Vogel & Märker (2010). Subsequently, a spatial model of the post-AD 79 deposits was generated. The modelled deposits were then used to reconstruct the pre-AD 79 topography of the Sarno River plain. Moreover, paleo-environmental and paleo-geomorphological features such as the paleo-coastline, the paleo-Sarno River and its floodplain, alluvial fans near the Tyrrhenian coast as well as abrasion terraces of historical and protohistorical coastlines were identified. This reconstruction represents a qualitative improvement of the previous work by Vogel & Märker (2010).

scholarly journals The Spatial Distribution of Bed Sediment on Fluvial System: A Mini Review of the Aceh Meandering River

2016 ◽  
Vol 5 (2) ◽  
Author(s):  
Muhammad Irham
Keyword(s):  
Spatial Distribution ◽  
Bed Load ◽  
Sieve Analysis ◽  
Left Bank ◽  
Fluvial System ◽  
Dynamic Interactions ◽  
Meandering River ◽  
River Bed ◽  
Meander Bends ◽  
Mechanical Weathering

Dynamic interactions of hydrological and geomorphological processes in the fluvial system result in accumulated deposit on the bed because the capacity to carry sediment has been exceeded. The bed load of the Aceh fluvial system is primarily generated by mechanical weathering resulting in boulders, pebbles, and sand, which roll or bounce along the river bed forming temporary deposits as bars on the insides of meander bends, as a result of a loss of transport energy in the system. This dynamic controls the style and range of deposits in the Aceh River. This study focuses on the spatial distribution of bed-load transport of the Aceh River. Understanding the spatial distribution of deposits facilitates the reconstruction of the changes in controlling factors during accumulation of deposits. One of the methods can be done by sieve analysis of sediment, where the method illuminates the distribution of sediment changes associated with channel morphology under different flow regimes. Hence, the purpose of this mini review is to investigate how the sediment along the river meander spatially dispersed. The results demonstrate that channel deposits in the Aceh River are formed from four different type of materials: pebble deposited along upstream left bank; sand located on the upstream, downstream, and along meander belts; and silt and clay located along the cut bank of meander bends. Because of different depositional pattern, the distribution of the sediment along the river can be used as a surrogate to identify bank stability, as well as to predict critical geometry for meander bend initiation

scholarly journals Sediment burial dating using terrestrial cosmogenic nuclides

2008 ◽  
Vol 57 (1/2) ◽  
pp. 210-225 ◽  
Author(s):  
Andreas Dehnert ◽  
Christian Schlüchter
Keyword(s):  
Cosmogenic Nuclides ◽  
Quaternary Geology ◽  
Alluvial Fans ◽  
Bearing Material ◽  
Sedimentary Deposits ◽  
River Terraces ◽  
River Incision ◽  
Scientific Disciplines ◽  
Numerical Dating

Abstract. Burial dating using in situ produced terrestrial cosmogenic nuclides is a relatively new method to date sediments and quantify geomorphological processes such as erosion, accumulation and river incision. Burial dating utilises the decay of previously in situ produced cosmogenic nuclides and can be applied to sedimentary deposits such as cave fillings, alluvial fans, river terraces, delta deposits, and dunes. Using the established 10Be/26Al nuclide pair allows numerical dating of quartz bearing material from ~100 ka to 5 Ma, where other dateable material is often unavailable. To date, a number of studies have demonstrated the successful application of in situ produced cosmogenic nuclides in various scientific disciplines, such as Quaternary geology, geomorphology and palaeoanthropology. However, insufficiently defined physical properties such as nuclide half lives and complex depth dependent nuclide production rates result in relatively large uncertainties. Nevertheless, burial dating represents a promising method for determining numerical ages.

scholarly journals Etude de l'impact des barrages sur la réduction des transports sédimentaires jusqu'à la mer par approche paléohydrologique dans la basse vallée de la Medjerda

2018 ◽  
Vol 377 ◽  
pp. 67-76 ◽  
Author(s):  
Fatma Kotti ◽  
Laurent Dezileau ◽  
Gil Mahé ◽  
Hamadi Habaieb ◽  
Malik Bentkaya ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Global Climate ◽  
Sediment Cores ◽  
Sediment Supply ◽  
Water Storage Capacity ◽  
Sedimentary Deposits ◽  
The Core ◽  
River Bed ◽  
History Of ◽  
Marine Influence

Abstract. The sedimentary contributions of the Medjerda to the coastal zone are poorly measured, and there is no chronicle of observations. In this context, the sediment monitoring appears indispensable for the quantification of sediment transport at the outlet. This study focuses on the largest watershed in Tunisia, the Wadi Medjerda (23 600 km2). The main objective of this work is to assess the reduction of sediment transport following anthropogenic intensification on the basin, especially since the construction of many large dams. In order to collect information on actual deposits over several years, the paleo-hydrological approach was applied through the study of sediment cores sampled in the low valley meanders on alluvial terraces, after the last dam (Sidi Salem, the largest water storage capacity over the basin), but before the estuary to avoid marine influence and near a hydrological station (Jdaida). The sedimentary deposits of the river provide key information on the past sedimentary inputs. A visible succession of sedimentary layers corresponding to the deposits of successive floods on the study site has been determined and the history of the sedimentary contributions of the Medjerda is reconstructed by this approach. The thickest layers of sedimentary deposits are related to exceptional events. They are mainly concentrated on the lower part of the core and are mainly composed of sands. The first 1.2 m of the core from the bottom upward relates to 10 years of river discharges, as can be determined from the 137Cs datation. The next upward 1.05 m of core relates to the following 20 years of discharges, up to 1981, date of the construction of the Sidi Salem dam, and is composed of a mix of sand, silts and clays. The last 75 cm of core near the surface is only composed of clays with thin silt bands, and relates to a period of 32 years. We thus observe that there is no more sand deposits in the river bed since the construction of the Sidi Salem dam. The deficit of sediment supply to the sea is viewed as a major factor to be taken into account for better understanding of the dynamics of coastal areas in the context of global climate change.

scholarly journals Irrigation canals in Melo creek basin (Rio Espera and Capela Nova municipalities, Minas Gerais, Brazil): habitats to Biomphalaria (Gastropoda: Planorbidae) and potential spread of schistosomiasis

2016 ◽  
Vol 76 (3) ◽  
pp. 638-644 ◽  
Author(s):  
M. G. P. Leite ◽  
E. C. Pimenta ◽  
M. A. G. Fujaco ◽  
E. M. Eskinazi-Sant'Anna
Keyword(s):  
Flow Rate ◽  
Seasonal Cycle ◽  
Specific Growth ◽  
Minas Gerais ◽  
Low Flow ◽  
Hydraulic Characteristics ◽  
Irrigation Canals ◽  
Hydrographic Basin ◽  
Minas Gerais State ◽  
Anthropogenic Action

Abstract This study analyzed the presence of Biomphalaria in Melo creek basin, Minas Gerais state, and its relationship to irrigation canals. Seventeen of these canals were used to determine a limnological, morphological and hydrological characterization during an annual seasonal cycle. Biomphalaria samples were sent to René Rachou Research Center/FIOCRUZ for identification and parasitological examination. Six canals were identified as breeding areas for mollusks and in one of them it was registered the coexistence of B. tenagophila (first report to this basin) and B. glabrata species. Results indicated that the low flow rate and speed of water flow were the main characteristics that contributed to this specific growth of the mollusks in the area. These hydraulic characteristics were created due to anthropogenic action through the canalization of lotic areas in Melo creek, which allowed ideal ecological conditions to Biomphalaria outbreak. The results emphasize the need of adequate handling and constant monitoring of the hydrographic basin, subject to inadequate phytosanitary conditions, aiming to prevent the occurrence and propagation of schistosomiasis.

scholarly journals Interactions between main channels and tributary alluvial fans: channel adjustments and sediment-signal propagation

2020 ◽  
Vol 8 (2) ◽  
pp. 303-322
Author(s):  
Sara Savi ◽  
Stefanie Tofelde ◽  
Andrew D. Wickert ◽  
Aaron Bufe ◽  
Taylor F. Schildgen ◽  
...  
Keyword(s):  
Boundary Conditions ◽  
Signal Propagation ◽  
Main Channel ◽  
Alluvial Fan ◽  
Sediment Supply ◽  
Alluvial Fans ◽  
Fluvial System ◽  
Channel Network ◽  
Fluvial Deposits ◽  
The Impact

Abstract. Climate and tectonics impact water and sediment fluxes to fluvial systems. These boundary conditions set river form and can be recorded by fluvial deposits. Reconstructions of boundary conditions from these deposits, however, is complicated by complex channel–network interactions and associated sediment storage and release through the fluvial system. To address this challenge, we used a physical experiment to study the interplay between a main channel and a tributary under different forcing conditions. In particular, we investigated the impact of a single tributary junction, where sediment supply from the tributary can produce an alluvial fan, on channel geometries and associated sediment-transfer dynamics. We found that the presence of an alluvial fan may either promote or prevent the movement of sediment within the fluvial system, creating different coupling conditions. By analyzing different environmental scenarios, our results reveal the contribution of both the main channel and the tributary to fluvial deposits upstream and downstream from the tributary junction. We summarize all findings in a new conceptual framework that illustrates the possible interactions between tributary alluvial fans and a main channel under different environmental conditions. This framework provides a better understanding of the composition and architecture of fluvial sedimentary deposits found at confluence zones, which can facilitate the reconstruction of the climatic or tectonic history of a basin.

Permian inheritance : post-orogenic extension and metamorphic core complex formation (Western Pyrenees)

2020 ◽  
Author(s):  
Nicolas Saspiturry ◽  
Bryan Cochelin ◽  
Philippe Razin ◽  
Sophie Leleu ◽  
Benoit Issautier ◽  
...  
Keyword(s):  
Hanging Wall ◽  
Structural Response ◽  
Metamorphic Core Complex ◽  
Rift System ◽  
Alluvial Fans ◽  
Fluvial System ◽  
Core Complex ◽  
Domal Structure ◽  
Metamorphic Core ◽  
Western Pyrenees

<p>This study documents the sedimentary and structural response of continental crust in relatively hot lithosphere that is subjected to extension. We focus on the Permian rift system in the Western Pyrenees, where the narrow, post-orogenic intracontinental extensional Bidarray Basin is in contact with late Variscan granulites of the Ursuya massif. The western margin of the N-S trending Bidarray Basin preserves alluvial fans dominated by hyperconcentrated flows and interdigitating eastward into a N-S trending fluvial system. Structural analysis of the Ursuya granulites shows that they underwent orogen-parallel mid-crustal flow and were exhumed owing to strain localization during retrogressive metamorphism within an extensional shear zone flanking an E-W elongated domal structure. We show that the Bidarray Basin formed during Permian time on the hanging wall of a south-vergent detachment system that developed in response to the formation of an immature “a-type” metamorphic core complex (the Ursuya massif) under regional E-W extension, resulting in homogeneous thinning of the hot crust. This core complex was later exposed by denudation during Cenomanian time. The preservation of the Permian and Triassic paleogeography and structure indicates that there has been no lateral motion between Iberia and Europe in the study area. The Cretaceous Pamplona transfer zone, responsible for the shift of the Mesozoic rift axis, reactivated a N-S trending Permian crustal heterogeneity.</p>

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