GSA Bulletin ; 95 12 : — Analysis of fault and fluvial terrace scarps in the West Yellowstone Basin south of Hebgen Lake, Montana, indicates that, during degradation, the gradient of the scarp face and the curvatures of the basal concavity and crestal convexity of the scarp face decrease become more rounded with time. The pattern of degradation is identical with that predicted by a simple analytical model for degradation by creep, in which the change in elevation at a point on a hillslope is proportional to the curvature of the profile at that point. The model therefore provides the basis for morphologic dating, a technique for determining the age of a scarp by the extent to which its initial morphology has been degraded. In order to date a scarp, the coefficient of proportionality, c , must be known. The technique is probably not suitable for use on hillslopes degraded by processes other than creep. Both the potential and the limitations of morphologic dating are demonstrated via measurements of a sequence of terrace scarps along the Madison River. The calculated relative ages are in agreement with the known relative ages, despite the fact that the gradient of the youngest scarp is significantly less than that of the older scarps.
Dating fluvial terraces with and profiles: application to the Wind River, Wyoming
Climate and tectonics effect the fluvial evolution of the Mediterranean Mut basin. These river terraces records tectonic uplift in the Mut basin. Optically stimulated luminescence OSL dating of the fluvial sediments of the youngest terrace T16 provides a chronology for the assessment of the important impacts of climatic changes.
Extended-range luminescence dating of fluvial terraces (Duero basin) associated with La Maya I, II and Burganes Lower Palaeolithic (Acheulean) sites.
Cohen, Kirstie Fryirs. Fluvial terraces in the upper Hunter catchment, southeastern Australia provide a long-term record of river activity in response to climate change in the late Quaternary. Single-grain optically stimulated luminescence OSL dating of quartz was applied in this study to investigate the timing of the formation of three fluvial terraces in the upper Hunter catchment. A detailed examination of luminescence properties of individual quartz grains revealed some correlation between their OSL decay rates, intrinsic brightness and dose saturation characteristics.
Some quartz grains containing a higher proportion of non-fast components exhibit low brightness in OSL signals and high dose saturation levels. Some grains with slow OSL decays pass the standard rejection criteria, but are likely to yield underestimated equivalent doses D e s because of a higher contribution of non-fast components, which are shown to have low thermal stability. Different rejection criteria, including the fast ratio, the dose saturation level and the OSL sensitivity criteria, were tested on the single-grain D e results.
Application of a fast ratio rejection criterion is able to successfully identify thermally unstable grains. A new rejection criterion based on dose saturation property was also applied to improve the age of one sample with a large D e. The aggradational episodes of the terraces in the upper Hunter catchment are correlated with glacial or stadial periods since MIS 6.
These phases of valley-floor aggradation are inferred to be a function of increased sediment supply during the cold periods resulting from strong periglacial activities in the adjacent Australian highlands.
Luminescence Chronology of Terrace Development in the Upper Paraná River, Southeast Brazil
Jonathan L. Garber , College of William and Mary. I determined ages and on fluvial terraces of the South Fork of the Shenandoah River, Virginia, obtained from depth profiles of in situ 10Be. These dates represent the first numerically constrained ages on fluvial terraces in the Shenandoah system, and allow us to assess the timing of perturbations to the river system and to estimate longterm river incision rates.
Optically stimulated luminescence (OSL) dating shows that fine-grained and homogeneous sediment in the studied fluvial terrace was deposited at ± ka.
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated. A chronological framework for these terraces is established here by integrating geomorphological, stratigraphical and archaeological information with ages from luminescence dating. These values indicate that the duration and rate of both aggradation and river downcutting episodes were variable.
There is widespread evidence for neotectonic activity in this intraplate region. Neither eustatic nor climatic changes during the Quaternary provide clear trends that might explain the observed pattern of valley incision, thus we conclude that this tectonic activity is the most likely driving mechanism. This long-term incision was probably determined by an increase in the relative uplift rate, resulting from the intensification of intraplate compressive stress. Terrace formation was also promoted by soft bedrock Tertiary arkoses and by impoundment of alluvium behind resistant barriers crossed by the river.
Geomorphological evidence for terrace tectonic offset was also supported by luminescence dating. Page view s Download s 20 1,
However, the geological history of its fluvial plain is poorly understood due the lack of geochronological data. Most of the studies are focused in the low and middle reaches, whereas the region upstream of the Porto Primavera dam is an almost unknown area in terms of geomorphic evolution. In order to achieve this goal, we used an integrated approach including remote sensing data, geomorphology, sedimentology, geochronology and bathymetric profiles.
The geomorphological units were correlated with previous studies downstream of the studied area and their sedimentary characteristics and depositional ages suggest that their genesis is linked to changes in climatic and hydrological conditions during the Late Quaternary.
The Causes of Fluvial Terraces Inland and Its Implication. Abstract: Date of Conference: 31 July-4 Aug. Date Added to IEEE Xplore: 18 June
Skip to search form Skip to main content You are currently offline. Some features of the site may not work correctly. DOI: Repka and R. Anderson and R. Repka , R. Anderson , R. Finkel Published Geology. Absolute dating of river terraces can yield long-term incision rates, clarify the role of climate in setting times of aggradation and incision, and establish the rates of pedogenic processes. While surface exposure dating using cosmogenic 10Be and 26Al would seem to be an ideal dating method, the surfaces are composed of individual clasts, each with its own complex history of exposure and burial.
Landscape dynamics revealed by luminescence signals of feldspars from fluvial terraces
In the mountains of central Taiwan, however, the formation time of sediments in the Puli Basin is still unclear. In this study, we investigate the fluvial sediments of a fluvial terrace in the Taomi River catchment in the Puli Basin in terms of sedimentology and geochronology and consider their implications for geomorphic evolution in the Puli Basin. Optically stimulated luminescence OSL dating shows that fine-grained and homogeneous sediment in the studied fluvial terrace was deposited at These dating results are consistent with the age of A third OSL age of 8.
Dating fluvial terraces by Th/U on pedogenic carbonate, Wind River Basin, Wyoming – Volume 59 Issue 2 – Warren D. Sharp, Kenneth R. Ludwig, Oliver A.
Skip to search form Skip to main content You are currently offline. Some features of the site may not work correctly. DOI: Hancock and R. Anderson and O. Chadwick and R. Hancock , R. Finkel Published Geology. Abstract Fluvial strath terraces provide a record of river incision and the timing of climatic perturbations to the fluvial system. Dating depositional surfaces like terraces that are older than the range of 14 C , however, is difficult.
We employ a cosmogenic radionuclide CRN profile technique that addresses a major problem of CRN dating on such surfaces: nuclide inheritance. View via Publisher.
The Yellow River, well-known for its tremendous sediment load, originates from the northeast of the Tibetan Plateau, and flows eastwards to the Bohai Sea. As one of the longest rivers in the world, the evolution of the Yellow River is a very interesting topic for Chinese geomorphologists. River terraces provide compelling evidence to understand the evolution history of rivers Bridgland and Westaway, ; Vandenberghe,
I determined ages and on fluvial terraces of the South Fork of the Shenandoah River, Virginia, obtained from depth profiles of in situ 10Be. These dates.
The Osip-cheon River flows along a linear valley that runs approximately parallel to the Osip-cheon Fault. The present study was undertaken to elucidate the tectono-geomorphic evolution of the Osip-cheon Basin during the late Quaternary by employing cosmogenic 10 Be surface exposure dating and optically stimulated luminescence OSL dating on a flight of fluvial strath terraces. Several morphometric indices e. Thus, it is suggested that the Osipcheon River is a kind of subsequent stream that follows the weakened fault-line in the center of the basin.
To determine the fluvial incision rate as an equivalent to the rate of local tectonic uplift, samples for cosmogenic 10Be dating and OSL dating were collected from the surfaces of strath terraces at two different areas along the Osip-cheon River. The terraces can be divided into three groups T1: oldest to T3: youngest depending on the height above the present river level. According to our data, the strath terraces formed at ca. The fluvial incision rate was determined by dividing the height of the terraces above the river by their respective ages.
The fluvial incision rate has decreased over the last ka, with a maximum rate of 0. Tong-ri Canyon is deeply incised up to the major knickpoint of the Mi-in Falls. Here, the rock-cut strath terraces can be divided into two groups: the farther upstream part of the Tong-ri area Site-1 was dated to 5. Given the active upstream migration of the knickpoint Mi-in Falls found in the upper reach of the river, the incision rate provided by the ages of the strath terraces in the Tong-ri Canyon should be higher than that for any other reach of the river.
However, the incision rate of the reach below the mouth of Tong-ri Canyon is similar to the value of the reach above the major knickpoint, suggesting that knickpoint migration in the Tong-ri area was not active during the last Rather, it seems to have advanced to a certain level of incision in the past.
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sediments on seven terraces of Huang He (the Yellow River) and Daxia He in the Linxia. Basin at the northeastern margin of the Tibetan.
Skip to Main Content. Skip to Search Box. Skip to Top Navigation Bar. Skip to Left Navigation Bar. Skip to Organizational Offices. Skip to Bottom Navigation. This study differs from previous work in the southeastern Atlantic Coastal Plain in that numerical age estimates are provided for all terraces in the valley of mappable extent by direct dating of fluvial sediments. The Little River valley contains a floodplain and five fluvial terraces with average heights above modern river bed level that range from 3.
Dating indicates the floodplain has a late Holocene 1. Age separation of the six fluvial surfaces is corroborated by distinct differences in soil morphology and chemistry.
Cosmogenic dating of fluvial terraces, Fremont River, Utah
Fluvial sequences, particularly terrace staircases, represent archives of Quaternary palaeoclimatic fluctuation and can serve as stratigraphical frameworks for geochronology and for correlation with other depositional environments, in particular, the global marine oxygen isotope record. Fluvial lithostratigraphical frameworks also provide contexts for records, from fossils and artefacts, of faunal evolution and human occupation; conversely, both records can be means of relative dating of riverine sequences.
Three fluvial sequences are examined as case studies. First is the Severn-Avon system in the English Midlands, which has biostratgraphical evidence and an amino acid geochronology, together with marker inputs from three different glaciations. The fluvial terraces of the River Arun, the final case study, lack dating evidence but are interspersed within the Sussex raised beach staircase.
OSL dating of the T4a channel deposit provides maximum ages of 28, 20 and 18 kyr. However Keywords: Fluvial terraces; Sea-level changes; Pollen analysis;.
All publications more feeds DOI: BibTeX file. Fluvial terraces are widespread geomorphic features, which formed dominantly during the Quaternary. Besides tectonics, the formation of Quaternary fluvial terraces is related to paleoclimatic changes and corresponding changes in fluvial discharge and sediment load. However, within the Pleistocene, the exact timing and the paleoenvironmental conditions for terrace formation are still under debate and traditional concepts are questioned.
To shed light on the Pleistocene environmental conditions for terrace formation, we investigate their timing by establishing a local terrace chronostratigraphy based on numerical dating. The study is located in a small valley in northern Bavaria, Germany. Here, within a former interconnection between two headwater streams of the Main River, five Pleistocene terraces are distinguished. The terraces are interpreted as the result of a complex landscape evolution, which is characterized by an at least twofold river deflection.
COSMOGENIC DATING OF FLUVIAL TERRACES, FREMONT RIVER, UTAH
Dating fluvial terraces has long been a challenge for geologists and geomorphologists, because terrace straths and treads are not usually directly dated. In this study, the formation ages of the Yellow River terraces in the Baode area in China were determined by dating fluvial deposits overlying bedrock straths using optically stimulated luminescence OSL dating techniques.
Seven terraces from the lowest terrace T1 to the highest terrace T7 in the study area were recognized, and they are characterized by thick fluvial terrace deposits overlaid by loess sediments.
Abstract Fluvial strath terraces provide a record of river incision and the timing of climatic perturbations to the fluvial system. Dating depositional surfaces like.
Long term fluvial incision spanning the Late Cenozoic is recorded in many fluvial systems around the world by terrace landform sequences. The incision manifests itself as inset sequences of river terraces which form terrace staircases. The timing of the onset of incision and the rate incision then proceeds at is poorly constrained due to the difficulties in dating river terraces. This study applies the technique of cosmogenic exposure dating to a fluvial staircase, for the first time, in the Sorbas Basin, SE Spain.
Cosmogenic exposure dating allows the timing of abandonment of the fluvial terraces to be calculated therefore recording periods of incision. Cosmogenic exposure dating and the profile method offer a viable way to date Early and Middle Pleistocene terrace deposits. The fluvial deposits in the Sorbas Basin record 1.