Fluvial Components Research Articles

Diagenesis, facies and palaeocurrent analysis of Upper Rewa Sandstone around Sagar, Central India

The stratigraphic surface represented by a major contact between the Archean Bundelkhand Granite and the extensive Proterozoic Vindhyan sediments is a regional basement cover unconformity. This crystalline–sedimentary interface reflects an intense weathering of continental crust during marine transgression. Three time-transgressive sand deposition events viz. Kaimur, Rewa and Bhander are mainly witnessed during the entire Vindhyan sedimentation. Stratigraphically, the Upper Rewa Sandstone comprises one of these events in the Vindhyan Basin. Considerable progress has been made in interpreting these sandstones as a function of entirely marine process to a combination of tidal–fluvio–eolian activities. All the results have so far been attained on the basis of sedimentary facies, provenance, palaeocurrent analysis, and some of petrography. A distinct differentiation between marine and fluvial components of the Upper Rewa Sandstone still remains uncertain. Here, we use diagenesis as a parameter for the first time along with facies and palaeocurrent analysis to acquire a clear comprehension of marine- and fluvial-dominated processes. The present study spans 27 square kilometer area covering 15 stratigraphic sections with a collection of 571 directional data from the facies specific sedimentary structures, and 28 samples obtained for the thin section analysis.The lower unit of the Upper Rewa Sandstone shows facies association typical of tidal environment, along with polymodal palaeocurrent. These rocks are well sorted and dominantly lithified by authigenic cement. Profuse development of a complex of syntaxial, passive pore fills, and grain replacive cements reflect normally pressured nature of the lower unit sandstones. The upper unit of the Upper Rewa Sandstone however, reveals a facies pattern resembling fluvial processes and unimodal palaeocurrent plot. They exhibit poor sorting, siliceous, and ferruginous matrix, and development of intense stylolites. Since, pressure solution is a dominant mode of lithification; the upper unit rocks therefore, are overpressured. Sand deposition event pertaining to the Upper Rewa Sandstone is found to comprise both marine and fluvial processes. Such a diagenesis based approach can be applied for marking a possible facies based unconformity between genetically different depositional units.

Assessment of Spatial – Temporal Variations in Freshwater Pollution by Means of Water Quality Index: A Case Study of Hasanağa Stream Basin (Edirne, Turkey)

In this research, spatial – temporal variations of water quality in the fluvial components of the Hasanaga Stream Basin were evaluated by using the Water Quality Index. Surface water samples were taken from seven stations selected on the basin in the winter seasons of 2019 and 2020. Eleven variables including dissolved oxygen, oxygen saturation, pH, electrical conductivity, total dissolved solids, salinity, turbidity, nitrate, nitrite, phosphate and sulphate were measured in freshwater samples. The Water Quality Index (WQI) and Cluster Analysis (CA) were applied to the detected data in order to determine the differences among the spatial – temporal contamination levels and classify the investigated locations according to their similar water quality characteristics. According to the detected data, the water of the Hasanaga Stream Basin has 1. – 2. Class quality in 2019 and 2. – 3. in 2020, in general. According to the results of WQI, although it was determined that the water quality decreased significantly in 2020, the basin was found to be of A Grade – Excellent water quality (

ASSESSMENT OF WATER CONTAMINATION IN FLUVIAL ECOSYSTEMS OF THE THRACE REGION (TURKEY) BY MEANS OF WATER QUALITY INDEX AND GEOGRAPHIC INFORMATION SYSTEM TECHNOLOGY

Aim of the study: Thrace Region is the most important geographical regions of Turkey in terms of agricultural and industrial production. Meriç – Ergene River Basin is the main watershed of this significant region and there are many streams feeding the basin. In the current research, water qualities of fluvial ecosystems of Thrace Region were evaluated by using some ecological and statistical indicators. Material and methods: For each water sample, 27 physical and chemical limnological parameters (EC, TDS, turbidity, NO3, NO2, SO4, F, COD, BOD5, As, Se, Cu, Zn, Cd, Sb, Ba, Pb, B, Na, Mg, Cr, Mn, Al, K, Ca, Fe, Ni) were analysed and all the investigated parameter values were used to develop the Water Quality Index (WQI). Furthermore, Cluster Analysis (CA) were applied to detected data in order to classify the investigated locations and also Geographic Information System (GIS) was used to provide a visual summary of contamination levels in the basin components. Results and conclusions: The results show quite high WQI coefficients of COD (20.773), Se (9.667) and BOD5 (9.216) parameters in fluvial components of Thrace Region. The WQI values of the fluvial habitats of Thrace Region ranged from 33.91 – 329.84 and Çorlu Stream and Ergene River were determined as the most contaminated fluvial ecosystems. According to the results of applied CA, 2 statistically significant clusters were formed, which were named as “High Contaminated Zones” and “Low Contaminated Zones”.

Early Sevier orogenic deformation exerted principal control on changes in depositional environment recorded by the Cretaceous Newark Canyon Formation

ABSTRACT Terrestrial sedimentary archives record critical information about environment and climate of the past, as well as provide insights into the style, timing, and magnitude of structural deformation in a region. The Cretaceous Newark Canyon Formation, located in central Nevada, USA, was deposited in the hinterland of the Sevier fold–thrust belt during the North American Cordilleran orogeny. While previous research has focused on the coarser-grained, fluvial components of the Newark Canyon Formation, the carbonate and finer-grained facies of this formation remain comparatively understudied. A more complete understanding of the Newark Canyon Formation provides insights into Cretaceous syndeformational deposition in the Central Nevada thrust belt, serves as a useful case study for deconvolving the influence of tectonic and climatic forces on sedimentation in both the North American Cordillera and other contractional orogens, and will provide a critical foundation upon which to build future paleoclimate and paleoaltimetry studies. We combine facies descriptions, stratigraphic measurements, and optical and cathodoluminescence petrography to develop a comprehensive depositional model for the Newark Canyon Formation. We identify six distinct facies that show that the Newark Canyon Formation evolved through four stages of deposition: 1) an anastomosing river system with palustrine interchannel areas, 2) a braided river system, 3) a balance-filled, carbonate-bearing lacustrine system, and 4) a second braided river system. Although climate undoubtedly played a role, we suggest that the deposition and coeval deformation of the synorogenic Newark Canyon Formation was in direct response to the construction of east-vergent contractional structures proximal to the type section. Comparison to other contemporary terrestrial sedimentary basins deposited in a variety of tectonic settings provides helpful insights into the influences of regional tectonics, regional and global climate, catchment characteristics, underlying lithologies, and subcrop geology in the preserved sedimentary record.

Facies characteristics and terrigenous sedimentation features of the lower Riphean Mukun Group (Anabar Uplift, Siberia)

The Mukun Group represents a thick (>750 m) complex of terrigenous features sediments in the lower part of the Riphean sedimentary cover of the Anabar region was formed on the spacious cratonic block. The complex is remarkable for its pure quartzarenitic composition. The facies analysis with emphasis on the genetic interpretation of various sedimentary structures revealed three facies associations in its sedimentary succession: alluvial, eolian-fluvial, and fluvial-sabkha. It is shown that sedimentary material was transported into the terminal basin by a braided system of permanent rivers. Relationships between the eolian and fluvial components in the single sedimentation system of the Mukun paleobasin is considered in line with the proposed model, according to which alternation of long periods with the eolian and fluvial sedimentation was controlled by tectonics.

Differentiating fluvial components of upper Canada Basin waters on the basis of measurements of dissolved barium combined with other physical and chemical tracers

The utility of dissolved barium (Ba) as a quasi‐conservative tracer of Arctic water masses has been demonstrated previously. Here we report distributions of salinity, temperature, and Ba in the upper 200 m of the Canada Basin and adjacent areas observed during cruises conducted in 2003–2004 as part of the Joint Western Arctic Climate Study and Beaufort Gyre Exploration Project. A salinity–oxygen isotope mass balance is used to calculate the relative contributions from sea ice melt, meteoric, and saline end‐members, and Ba measurements are incorporated to resolve the meteoric fraction into separate contributions from North American and Eurasian sources of runoff. Large fractions of Eurasian runoff (as high as 15.5%) were observed in the surface layer throughout the Canada Basin, but significant amounts of North American runoff in the surface layer were only observed at the southernmost station occupied in the Canada Basin in 2004, nearest to the mouth of the Mackenzie River. Smaller contributions from both Eurasian and North American runoff were evident in the summer and winter Pacific‐derived water masses that comprise the underlying upper halocline layer in the Canada Basin. Significant amounts of Eurasian and North American runoff were observed throughout the water column at a station occupied in Amundsen Gulf in 2004. This suggests the export of runoff from both sources through the passages of the Canadian Arctic Archipelago.

Parent material influence on soil distribution and genesis in a Paleudult and Kandiudult complex, southeastern USA

Parent materials greatly influence soil development and the distribution of soils on the southeastern US Coastal Plain. We examined the physical, chemical, and mineralogical properties of 11 pedons in a 1-ha plot on the Upper Coastal Plain of Georgia, USA. Uniformity of parent materials was assessed by sand grain size characteristics. The soils have sandy epipedons of variable thickness and argillic horizons of variable texture. Six of the pedons also have kandic horizons. They are classified (US Soil Taxonomy) in Psammentic, Grossarenic, Arenic, and Typic subgroups of Paleudults and Kandiudults. Loamy pedons possess argillic horizons with two distinct increases in clay and greater differences between eluvial and illuvial horizons than sandy pedons. The upper boundary of the argillic horizon is approximately parallel to the present geomorphic surface, suggesting that it is associated with the contemporary surface. Discontinuities, identified by changes in sand grain size ratios and plots of the third (skewness) and fourth (kurtosis) moments of sand grain distribution, roughly correspond to the bottom of the solum. Our data suggest that there are both eolian and fluvial components in the solum, whereas subjacent horizons are completely derived from fluvial deposits. Sandier pedons have greater gibbsite/kaolinite ratios, possibly because greater permeability has enhanced leaching and Si loss. Our data suggest parent materials largely control soil distribution over this plot.

Topographic outcomes predicted by stream erosion models: Sensitivity analysis and intermodel comparison

Mechanistic theories of fluvial erosion are essential for quantifying large‐scale orogenic denudation. We examine the topographic implications of two leading classes of river erosion model, detachment‐limited and transport‐limited, in order to identify diagnostic and testable differences between them. Several formulations predict distinctly different longitudinal profile shapes, which are shown to be closely linked to terrain morphology. Of these, some can be rejected on the basis of unrealistic morphology and slope‐area scaling. An expression is derived for total drainage basin relief and its apportionment between hillslope and fluvial components. Relief and valley density are found to vary with tectonic forcing in a manner that reflects erosion physics; these properties therefore constitute an additional set of testable predictions. Finally, transient responses to tectonic perturbations are shown to depend strongly on the degree of nonlinearity in the incision process. These findings indicate that given proper constraints, fluvial erosion theories can be tested on the basis of observed topography.

The Effects of Wind Transport on the Shapes of Quartz Silt Grains

ABSTRACT Wind-blown terrigenous silt is a common component in marine sediment, but it is often difficult to distinguish from fluvial silt. A field experiment was conducted in the Loess Plateau of China to determine the effect of eolian transport on the shapes of detrital quartz silt grains and to define grain-shape criteria for the recognition of eolian silt. The results show that eolian transport results in a rapid downwind increase in the roundness of quartz silt grains, and that this increase in roundness is apparently due to preferential transport, or shape-sorting, of more rounded grains. This capacity for shape-sorting distinguishes eolian from fluvial transport, which has no great effect upon the shapes of quartz silt grains, and provides a petrographic criteria for the distinction of t e eolian and fluvial silt components in marine sediments.

Urban geo-archaeology in medieval alzira (Prov. Valencia, Spain)

Abstract Alzira is situated in a cut-off meander loop of the Rio Jucar. Geo-archaeological study shows that the Islamic city wall was built during the second quarter of the 11th century AD, at a time when the river had a low-amplitude and low-energy flood regime. After mid-century, overbank silts began to invade the city as peak flood discharge increased, with a spate of destructive floods reflected by high-energy deposits during the late 11th century. Urban expansion within the city wall is dated to the later 11th or early 12th century, interrupted by local abandonment and moderate-energy flood silts. Major construction during the mid-12th century was followed by protracted abandonment (after a siege in AD 1171?) and further, moderate-energy flood silts that redistributed occupation and collapse debris. Reoccupation, during the late 14th century, was terminated by catastrophic floods in 1517 and 1571, after which much of the western end of Alzira was not rebuilt. Following further flood catastrophes during the 17th century, parts of the central walled city remained abandoned until the 19th century. with new occupation atop flood sands of yet another disaster in 1864. The change in flood regime after 1150 was a result of deforestation of the watershed, but progradation of a downstream tributary fan after 1517 created an unstable, aggrading floodplain increasingly prone to severe flooding. Climatic anomalies were responsible for periods of recurrent severe floods, archaeologically verified during the 11th and 12th centuries, and historically documented, beginning in 1318. The geo-archaeological methodology illuminates the constructional and settlement history of Alzira, allows distinction of fluvial and cultural components, and provides the necessary microstratigraphic detail and dating control to document the true complexity of alluvial processes during the last 1000 years.