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 Inferring the timing of abandonment of aggraded alluvial surfaces dated with cosmogenic nuclides

2019 ◽  
Author(s):  
Mitch K. D'Arcy ◽  
Taylor F. Schildgen ◽  
Jens M. Turowski ◽  
Pedro DiNezio
Keyword(s):  
Cosmogenic Nuclides ◽  
Glacial Till ◽  
Tectonic Deformation ◽  
Alluvial Fans ◽  
Artificial Data ◽  
New Approach ◽  
Past Climate ◽  
Geomorphic Surfaces ◽  
Exposure Ages

Abstract. Information about past climate, tectonics, and landscape evolution is often obtained by dating geomorphic surfaces comprising deposited or aggraded material, e.g., fluvial fill terraces, alluvial fans, volcanic flows, or glacial till. Although surface ages can provide valuable information about these landforms, they can only constrain the period of active deposition of surface material, which may span a significant period of time in the case of alluvial landforms. In contrast, surface abandonment often occurs abruptly and coincides with important events like drainage reorganisation, climate change, or landscape uplift. However, abandonment cannot be directly dated because it represents a cessation in the deposition of dateable material. In this study, we present a new approach to inferring when a surface was likely abandoned using exposure ages derived from in situ-produced cosmogenic nuclides. We use artificial data to measure the discrepancy between the youngest age randomly sampled from a surface and the true timing of surface abandonment. Our analyses simulate surface dating scenarios with variable durations of surface formation and variable numbers of sample exposure ages. From our artificial data, we derive a set of probabilistic equations and a Matlab tool that can be applied to a set of real sampled surface ages to estimate the probable period of time within which abandonment is likely to have occurred. Our new approach to constraining surface abandonment has applications for geomorphological studies that relate surface ages to tectonic deformation, past climate, or the rates of surface processes.

scholarly journals Late Pliocene-Pleistocene incision in the Ebro Basin (North Spain)

2021 ◽  
Vol 192 ◽  
pp. 30
Author(s):  
Vincent Regard ◽  
Arnaud Vacherat ◽  
Stéphane Bonnet ◽  
Frédéric Mouthereau ◽  
Jesper Nørgaard ◽  
...  
Keyword(s):  
Cosmogenic Nuclides ◽  
Middle Pleistocene ◽  
Ebro Basin ◽  
Fluvial Terrace ◽  
Climate Fluctuations ◽  
River Terraces ◽  
River Incision ◽  
Middle Pleistocene Transition ◽  
Age Constraints ◽  
Fluvial Network

The Ebro Basin constitutes the central part of the southern foreland of the Pyrenees. It was endorheic during the Cenozoic and accumulated sediments. By the end of the Miocene, erosion and river incision reconnected the basin to the Mediterranean Sea, establishing a post-opening drainage network. Those rivers left terraces that we study in this work. We first synthesize previous works on river terraces that are widely dispersed in the basin. We provide new age constraints, up to 3 Ma, obtained thanks to cosmogenic nuclides using both profile and burial methods. We derive a unified fluvial terrace chronology and a homogenized map of the highest terraces over the entire Ebro Basin. The dated terraces labeled A, B, C, D, and E are dated to 2.8 ± 0.7 Ma, 1.15 ± 0.15 Ma, 850 ± 70 ka, 650 ± 130 ka, and 400 ± 120 ka, respectively. The chronology proposed here is similar to other sequences of river terraces dated in the Iberian Peninsula, around the Pyrenees, and elsewhere in Europe. The oldest terraces (A, B, C) are extensive, indicating they form a mobile fluvial network while from D to present, the network was stable and entrenched in 100 to 200 m-deep valleys. The transition from mobile to fixed fluvial network is likely to have occurred during the Middle Pleistocene Transition (MPT, between 0.7 and 1.3 Ma), when long-period/high-intensity climate fluctuations were established in Europe. We estimate that between 2.8–1.15 Ma and present, the incision rates have tripled.

scholarly journals Inferring the timing of abandonment of aggraded alluvial surfaces dated with cosmogenic nuclides

2019 ◽  
Vol 7 (3) ◽  
pp. 755-771 ◽  
Author(s):  
Mitch K. D'Arcy ◽  
Taylor F. Schildgen ◽  
Jens M. Turowski ◽  
Pedro DiNezio
Keyword(s):  
Cosmogenic Nuclides ◽  
Glacial Till ◽  
Tectonic Deformation ◽  
Alluvial Fans ◽  
Artificial Data ◽  
New Approach ◽  
Past Climate ◽  
Geomorphic Surfaces ◽  
Exposure Ages

Abstract. Information about past climate, tectonics, and landscape evolution is often obtained by dating geomorphic surfaces comprising deposited or aggraded material, e.g. fluvial fill terraces, alluvial fans, volcanic flows, or glacial till. Although surface ages can provide valuable information about these landforms, they can only constrain the period of active deposition of surface material, which may span a significant period of time in the case of alluvial landforms. In contrast, surface abandonment often occurs abruptly and coincides with important events like drainage reorganization, climate change, or landscape uplift. However, abandonment cannot be directly dated because it represents a cessation in the deposition of dateable material. In this study, we present a new approach to inferring when a surface was likely abandoned using exposure ages derived from in situ-produced cosmogenic nuclides. We use artificial data to measure the discrepancy between the youngest age randomly obtained from a surface and the true timing of surface abandonment. Our analyses simulate surface dating scenarios with variable durations of surface formation and variable numbers of exposure ages from sampled boulders. From our artificial data, we derive a set of probabilistic equations and a MATLAB tool that can be applied to a set of real sampled surface ages to estimate the probable period of time within which abandonment is likely to have occurred. Our new approach to constraining surface abandonment has applications for geomorphological studies that relate surface ages to tectonic deformation, past climate, or the rates of surface processes.

Neolithic Pits, a Bronze Age Cremation and an Early Iron Age Ring-Ditch at Newton Farm, Cambuslang, Lanarkshire

2009 ◽  
Vol 31 (1-2) ◽  
pp. 1-31
Author(s):  
Leonora O'Brien ◽  
Victoria Clements ◽  
Mike Roy ◽  
Neil Macnab
Keyword(s):  
Bronze Age ◽  
Iron Age ◽  
Housing Development ◽  
Early Iron Age ◽  
Small Ring ◽  
Late Bronze Age ◽  
River Terraces

Fieldwork at Newton Farm, Cambuslang (NGR NS 672 610) was undertaken in advance of housing development in 2005–6. A cluster of six shallow Neolithic pits were excavated, and a collection of 157 round-based, carinated bowl sherds and a quern fragment were recovered from them. The pits produced a date range of 3700 to 3360 cal BC. Most of the pits yielded burnt material, and one of the pits showed evidence of in situ burning. The pottery may form ‘structured deposits’. A Bronze Age adult cremation placed in a Food Vessel dated to 3610±30 BP (2040–1880 cal BC) was set in a wider landscape of single and multiple cremations and inhumations on the river terraces overlooking the Clyde. A possible unurned cremation was also identified. This was cut by the course of a small ring-ditch dated to the very late Bronze Age or early Iron Age 2520±30 BP (800–530cal BC).

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 Caracterização de parâmetros hidráulicos em depósitos fluviais paleogênicos na Bacia de Volta Redonda, RJ

2007 ◽  
Vol 30 (2) ◽  
pp. 118-132
Author(s):  
Ana Carolina Lisbôa Barboza ◽  
Gerson Cardoso da Silva Jr ◽  
Claudio Limeira Mello
Keyword(s):  
Hydraulic Conductivity ◽  
Sedimentary Facies ◽  
Fine Sand ◽  
Sedimentary Deposits ◽  
Hydrogeological Parameters ◽  
Variable Head ◽  
Medium Reservoir ◽  
Maximum Permeability

The present study aims for the characterization of the hydrogeological parameters of the Paleogenic fluvial deposits of Volta Redonda Geological Basin, through hydraulic conductivity determinations and grain sized analyses. The overall goal was to produce a hydrogeological data base applicable to the characterization of hydrofacies (interconnected sedimentary bodies with distinct hydraulic properties) and the modeling groundwater flow. The used methods used consisted of in situ permeability determinations (Guelph permeameters) and laboratory tests (variable head permeameter), besides grain size analyses carried out in each sedimentary facies in the study area. These sedimentary facies were characterized by Marques (2006) and belong to the Resende and Pinheiral formations. The permeameter results were coherent to the sedimentological characteristics. The Resende Formation sedimentary deposits are constituted by medium to fine sand with presence of argillaceous matrix and present moderate to very low hydraulic conductivity, varying between 10-4 to 10-8 cm/s, which indicates a poor reservoir. The Pinheiral Formation presents sandy layers with conglomeratic lenses, limited by small thickness pelitic intervals, with a very low permeability, with a hydraulic conductivity varying between 10-5 to 10-7 cm/s. The upper layer has the maximum permeability, around 10-3 cm/s. This formation presents a medium reservoir characteristics and it must be taken into consideration that the upper layer has as role in recharge to the aquifer. From the results of hydraulic conductivity, that varies from 10-8 to 10-3 cm/s for the Resende and Pinheiral formations, it is concluded that these deposits a low to medium hydraulic conductivity, explaining the low productivity of the water-bearing multilayered aquifer of Volta Redonda Basin.

Plant Taphonomy and Paleoecology of Late Pennsylvanian Intramontane Wetlands in the Graissessac-Lodève Basin (Languedoc, France)

Palaios ◽  
2005 ◽  
Vol 20 (3) ◽  
pp. 249-265 ◽  
Author(s):  
CARLES MARTÍN-CLOSAS ◽  
JEAN GALTIER
Keyword(s):  
Detailed Comparison ◽  
Alluvial Fans ◽  
Fluvial Sediments ◽  
Tree Fern ◽  
Massif Central ◽  
Fine Grained ◽  
Tree Ferns ◽  
First Time ◽  
Diverse Plant

Abstract The Late Pennsylvanian Graissessac-Lodève basin is a small, fluvio-palustrine depocenter located in the southern part of the Massif Central (France). A taphonomic and sedimentologic study carried out in this area allows a reconstruction of Late Carboniferous vegetation in an intramontane context. The paleoecology of such limnic settings is poorly known, and this study permits detailed comparison with paralic basins for the first time. The Graissessac peat mires developed in abandoned fluvial channels, in floodplains, and above distal alluvial fans. The vegetation was dominated by monospecific stands of the arborescent lycopsid Sigillaria brardii, whereas the tree fern Psaronius occurred during the later stages of mire accretion. This is in contrast to coeval North American peat mires, which generally were dominated by tree ferns and pteridosperms throughout the mire profile. Stephanian floodplains and distal alluvial fans of the Graissessac-Lodève Basin were devoid of vegetation, with the exception of isolated thickets of sphenopsids that were composed of Calamites and Sphenophyllum. These plants were found growing in situ in the floodplain mudstones as well as in fine-grained sands of secondary channels. Parautochthonous foliage assemblages of ferns and pteridosperms found in floodplain mudstones represent the most diverse plant community. The plants supplying these remains were growing in exposed areas close to floodplains. Large logs attributed to cordaitaleans and monotypic assemblages of large Cordaites leaves were found in fluvial sediments, and suggest that the plants were riparian elements in the basin.

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