Predicting reach-specific properties of fluvial terraces to guide future fieldwork. A case study for the Late Quaternary River Allier (France) with the FLUVER2 model
Veldkamp, Tom ; Schoorl, Jeroen M. ; Viveen, Willem - \ 2016
Earth Surface Processes and Landforms 41 (2016)15. - ISSN 0197-9337 - p. 2256 - 2268.
erosion rate - field work - numerical model - Quaternary - terrace
Numerical models have not yet systematically been used to predict properties of fluvial terrace records in order to guide fieldwork and sampling. This paper explores the potential of the longitudinal profile model FLUVER2 to predict testable field properties of the relatively well-studied, Late Quaternary Allier system in France. For the Allier terraces an overlapping 14C and U-series chronology as well as a record of 10Be erosion rates exist. The FLUVER2 modelling exercise is focused on the last 50 ka of the upper Allier reach because for this location and period the constraints of the available dating techniques are tightest. A systematic calibration based on terrace occurrence and thicknesses was done using three internal parameters related to (1) the sediment erodibility; (2) the sediment transport distance; and (3) the sediment supply derived from the surrounding landscape. As external model inputs, the best available, reconstructed, tectonic, climatic and base-level data were used. Calibrated model outputs demonstrate a plausible match with the existing fluvial record. Validation of model output was done by comparing the modelled and measured timing of aggradation and incision phases for the three locations. The modelled range of landscape erosion rates showed a reasonably good match with existing erosion rate estimates derived from 10Be measurements of fluvial sands. The quasi-validated model simulation was subsequently used to make new testable predictions about the timing and location of aggradation and erosion phases for three locations along the Allier river. The validated simulations predict that along the Allier, reach-specific dynamics of incision and aggradation, related to the variations in sediment supply by major tributaries, cause relevant differences in the local fluvial terrace stratigraphy.
Violet stimulated luminescence dating of quartz from Luochuan (Chinese loess plateau) : Agreement with independent chronology up to ∼600 ka
Ankjærgaard, C. ; Guralnik, B. ; Buylaert, J.P. ; Reimann, T. ; Yi, S.W. ; Wallinga, J. - \ 2016
Quaternary Geochronology 34 (2016). - ISSN 1871-1014 - p. 33 - 46.
Chinese loess plateau - Luminescence dating - Luochuan - Natural dose response curve - Quaternary - Violet stimulated luminescence (VSL)
Luminescence dating at the Luochuan loess type (China) section is at present limited to ∼0.1 Ma using quartz blue light stimulated luminescence (BLSL), but can be extended back in time to ∼0.5 Ma by resorting to the more developmental post-infrared infrared stimulated luminescence (post-IR IRSL) and thermally transferred OSL (TT-OSL) signals. Since both the latter are associated with systematic uncertainties due to the potential (a)-thermal instability of these signals, a search continues for alternative, and demonstrably stable luminescence signals that can cover the entire Quaternary timescale. Here we explore the violet stimulated luminescence (VSL) signal at the Luochuan section, which provides a continuous archive of homogenous sediment with favourable luminescence characteristics and a solid independent age framework. By testing several VSL protocols and their associated performance, we demonstrate that the Multi-Aliquot Additive-Dose (MAAD) protocol produces a VSL chronology at Luochuan which is in agreement with independent ages up to ∼0.6 Ma. For a more representative environmental dose rate of ∼2 Gy/ka (∼35% lower than at Luochuan), the documented range of MAAD-VSL sensitivity (200-1800 Gy) would correspond to the ability to date sediment up to ∼1 Ma back in time, offering a remarkable advance over existing methods.
Validating post IR-IRSL dating on K-feldspars through comparison with quartz OSL ages
Kars, R.H. ; Busschers, F.S. ; Wallinga, J. - \ 2012
Quaternary Geochronology 12 (2012). - ISSN 1871-1014 - p. 74 - 86.
Feldspar - Luminescence dating - OSL - Post IR-IRSL - Quaternary - Sediments
Recent developments have opened up the possibilities of using potassium feldspar for dating Pleistocene sediments; a stable (less-fading) part of the infrared stimulated luminescence (IRSL) signal can be selected by largely depleting the unstable part of the IR signal, using a combination of thermal and IR stimulation: post IR-IRSL dating (pIR-IRSL).This study aims to test the validity of pIR-IRSL dating on feldspars. We obtained pIR-IRSL ages on a large suite of samples from several locations in the Netherlands area, covering a wide range of depositional environments and ages. Age control was provided by quartz optically stimulated luminescence (OSL) ages on the same samples; these ages were shown to accord with geological age constraints. Comparison with IRSL ages enabled us to evaluate the improvement that pIR-IRSL dating provides over conventional IRSL methods.The majority of feldspar ages obtained with pIR-IRSL showed good agreement with both the quartz OSL ages and the geological age constraints. Our study demonstrates that pIR-IRSL dating is more robust than conventional IRSL and should be the method of choice in feldspar luminescence dating of Pleistocene sediments.
Luminescence dating of Netherland's sediments
Wallinga, J. ; Davids, F. ; Dijkmans, J.W.A. - \ 2007
Netherlands journal of geosciences 86 (2007)3. - ISSN 0016-7746 - p. 179 - 196.
Feldspar - Luminescence dating - OSL - Quartz - Quaternary
Over the last decades luminescence dating techniques have been developed that allow earth scientists to determine the time of deposition of sediments. In this contribution we revity: 1) the development of the methodology, 2) tests of the reliability of luminescence dating on Netherlands' sediments; and 3) geological applications of the method in the Netherlands. Our review shows that optically stimulated luminescence dating of quartz grains using the single aliquot regenerative dose method yields results in agreement with independent age control for deposits ranging in age from a few years up to 125 ka. Optical dating of quartz has successfully been applied to sediments from a wide range of depositional environments such as coastal dunes, cover sands, fluvial channel deposits, colluvial deposits and fimic soils. These results demonstrate that optical dating is a powerful tool to explore the natural archive of the Netherlands' subsurface.
Timing of the last sequence boundary in a fluvial setting near the highstand shoreline - Insights from optical dating
Tornqvist, Torbjorn E. ; Wallinga, Jakob ; Busschers, Freek S. - \ 2003
Marine Geology 31 (2003)3. - ISSN 0091-7613 - p. 279 - 282.
Optical dating - Quaternary - Rhine-Meuse system - Sequence stratigraphy
We investigated, by means of optical dating, the chronostratigraphic nature of the sequence boundary associated with the last glacial in a sandy to gravelly compound paleovalley fill, just landward of the highstand shoreline in the Rhine-Meuse Delta (Netherlands). Laterally extensive fluvial strata deposited during oxygen isotope stage 4, coeval with a major sea-level fall, unconformably overlie estuarine deposits from stage 5 or fluvial deposits from the penultimate glacial (stage 6). These chronostratigraphic relationships differ substantially from widely used models and indicate (1) that sequence-boundary formation in this setting was associated with the onset of pronounced sea-level fall, shortly after 80 ka; (2) that the time gap represented by the sequence boundary may be extremely small (<10 k.y.); (3) that the age of the sequence boundary may decrease both updip and downdip of the highstand shoreline; and (4) that our study does not provide viable diagnostic criteria for a sea-level-controlled sequence boundary above the falling-stage systems tract. Despite the high-frequency, high-amplitude glacio-eustatic regime that might be considered ideal for the formation of an unambigous unconformity, the last sequence boundary in this setting is commonly cryptic.
Response of the Rhine-Meuse system (west-central Netherlands) to the last Quaternary glacio-eustatic cycles : A first assessment
Törnqvist, Torbjörn E. ; Wallinga, Jakob ; Murray, Andrew S. ; Wolf, Hein De; Cleveringa, Piet ; Gans, Wim De - \ 2000
Global and Planetary Change 27 (2000)1-4. - ISSN 0921-8181 - p. 89 - 111.
OSL dating - Palaeoecology - Quaternary - Rhine-Meuse system - Sedimentology - Sequence stratigraphy
An almost 50-m-deep core from the Weichselian Rhine-Meuse palaeovalley, near the present Dutch coast, reveals new insights into how this continental-scale fluvial system responded to relative sea-level fluctuations associated with the last Quaternary glaciations. A multidisciplinary study of this core included sedimentological and stratigraphic analysis augmented with data on shell, diatom and pollen content to infer depositional environments. Optically stimulated luminescence dating provides a first numerical chronostratigraphy for these strata. Net fluvial incision due to relative sea-level fall associated with the Weichselian glaciation (notably oxygen-isotope stage 4) is estimated at > 10 m, and we argue that this amount of incision decreases both updip and downdip, because our study area is located near the thickest part of the Eemian/Early Weichselian (oxygen-isotope stage 5) highstand coastal prisms that were particularly sensitive to erosion during ensuing relative sea-level falls. Coastal prism geometry, with a relatively steep upper shoreface, is extremely important in promoting erosion, as demonstrated by the Rhine-Meuse system that borders an exceptionally wide, low-gradient continental shelf. Our results show that fluvial deposits associated with relative sea-level fall (80-40 ka) can constitute a considerable part of preserved strata ('falling-stage systems tract'). Interglacial transgressive and highstand systems tracts tend to have a relatively low preservation potential; in our core these are represented by estuarine deposits scoured into underlying fluvial strata. Furthermore, we note that sequence boundaries in such settings may be relatively undistinct, whereas tidal ravinement surfaces can be more conspicuous and may represent considerably longer time gaps.