Long-term denudation rates of actively uplifting hillcrests in the Boso Peninsula, Japan, estimated from depth profiling of in situ-produced cosmogenic 10Be and 26Al

Geomorphology ◽  
2006 ◽  
Vol 82 (3-4) ◽  
pp. 283-294 ◽  
Author(s):  
Yuki Matsushi ◽  
Sachi Wakasa ◽  
Hiroyuki Matsuzaki ◽  
Yukinori Matsukura
Keyword(s):  
Depth Profiling ◽  
Boso Peninsula ◽  
Denudation Rates ◽  
Cosmogenic 10Be

scholarly journals Denudation systematics inferred from in situ cosmogenic <sup>10</sup>Be concentrations in fine (50–100 µm) and medium (100–250 µm) sediments of the Var River basin, southern French Alps

2019 ◽  
Vol 7 (4) ◽  
pp. 1059-1074 ◽  
Author(s):  
Apolline Mariotti ◽  
Pierre-Henri Blard ◽  
Julien Charreau ◽  
Carole Petit ◽  
Stéphane Molliex ◽  
...  
Keyword(s):  
Glacial Cycles ◽  
Size Fractions ◽  
French Alps ◽  
Fine Grained ◽  
Denudation Rates ◽  
Variable Morphology ◽  
Cosmogenic 10Be ◽  
The Impact ◽  
Quartz Grains

Abstract. Marine sedimentary archives are well dated and often span several glacial cycles; cosmogenic 10Be concentrations in their detrital quartz grains could thus offer the opportunity to reconstruct a wealth of past denudation rates. However, these archives often comprise sediments much finer (<250 µm) than typically analyzed in 10Be studies, and few studies have measured 10Be concentrations in quartz grains smaller than 100 µm or assessed the impacts of mixing, grain size, and interannual variability on the 10Be concentrations of such fine-grained sediments. Here, we analyzed the in situ cosmogenic 10Be concentrations of quartz grains in the 50–100 and 100–250 µm size fractions of sediments from the Var basin (southern French Alps) to test the reliability of denudation rates derived from 10Be analyses of fine sands. The Var basin has a short transfer zone and highly variable morphology, climate, and geology, and we test the impact of these parameters on the observed 10Be concentrations. Both analyzed size fractions returned similar 10Be concentrations in downstream locations, notably at the Var's outlet, where concentrations ranged from (4.02±0.78)×104 to (4.40±0.64)×104 atoms g−1 of quartz. By comparing expected and observed 10Be concentrations at three major river junctions, we interpret that sediment mixing is efficient throughout the Var basin. We resampled four key locations 1 year later, and despite variable climatic parameters during that period, interannual 10Be concentrations were in agreement within uncertainties, except for one upper subbasin. The 10Be-derived denudation rates of Var subbasins range from 0.10±0.01 to 0.57±0.09 mm yr−1, and spatial variations are primarily controlled by the average subbasin slope. The integrated denudation rate of the entire Var basin is 0.24±0.04 mm yr−1, in agreement with other methods. Our results demonstrate that fine-grained sediments (50–250 µm) may return accurate denudation rates and are thus potentially suitable targets for future 10Be applications, such as studies of paleo-denudation rates using offshore sediments.

scholarly journals <sup>10</sup>Be depth profiles in glacial sediments on the Swiss Plateau: deposition age, denudation and (pseudo-) inheritance

2017 ◽  
Vol 66 (2) ◽  
pp. 57-68 ◽  
Author(s):  
Lorenz Wüthrich ◽  
Claudio Brändli ◽  
Régis Braucher ◽  
Heinz Veit ◽  
Negar Haghipour ◽  
...  
Keyword(s):  
Radioactive Decay ◽  
Glacial Sediments ◽  
Depth Profiles ◽  
Denudation Rates ◽  
Last Glaciation ◽  
The Alps ◽  
Swiss Plateau ◽  
High Concentrations ◽  
Cosmogenic 10Be

Abstract. During the Pleistocene, glaciers advanced repeatedly from the Alps onto the Swiss Plateau. Numeric age control for the last glaciation is good and thus the area is well suited to test a method which has so far not been applied to till in Switzerland. In this study, we apply in situ produced cosmogenic 10Be depth profile dating to several till deposits. Three sites lie inside the assumed Last Glacial Maximum (LGM) extent of the Rhône and Aare glaciers (Bern, Deisswil, Steinhof) and two lie outside (Niederbuchsiten, St. Urban). All sites are strongly affected by denudation, and all sites have reached steady state, i.e., the 10Be production is in equilibrium with radioactive decay and denudational losses. Deposition ages can therefore not be well constrained. Assuming constant denudation rates of 5 cm kyr−1, total denudation on the order of 100 cm for sites within the extent of the LGM and up to tens of meters for older moraines are calculated. Denudation events, for example related to periglacial conditions during the LGM, mitigate the need to invoke such massive denudation and could help to explain high 10Be concentrations at great depths, which we here dub pseudo-inheritance. This term should be used to distinguish conceptionally from true inheritance, i.e., high concentrations derived from the catchment.

scholarly journals Long-term background denudation rates of southern and southeastern Brazilian watersheds estimated with cosmogenic 10Be

Geomorphology ◽  
2016 ◽  
Vol 268 ◽  
pp. 54-63 ◽  
Author(s):  
Veronica Sosa Gonzalez ◽  
Paul R. Bierman ◽  
Nelson F. Fernandes ◽  
Dylan H. Rood
Keyword(s):  
Denudation Rates ◽  
Cosmogenic 10Be

scholarly journals Denudation rates derived from spatially-averaged cosmogenic nuclide analysis in Nelson/Tasman catchments, South Island, New Zealand

2021 ◽  
Author(s):  
◽  
Abby Jade Burdis
Keyword(s):  
New Zealand ◽  
Dynamic Environment ◽  
Low Frequency ◽  
Short Term ◽  
Erosion Rates ◽  
Cosmogenic Nuclide ◽  
Denudation Rates ◽  
Conventional Methods

<p>New Zealand’s tectonically and climatically dynamic environment generates erosion rates that outstrip global averages by up to ten times in some locations. In order to assess recent changes in erosion rate, and also to predict future erosion dynamics, it is important to quantify long-term, background erosion. Current research on erosion in New Zealand predominantly covers short-term (100 yrs) erosion dynamics and Myr dynamics from thermochronological proxy data. Without competent medium-term denudation data for New Zealand, it is uncertain which variables (climate, anthropogenic disturbance of the landscape, tectonic uplift, lithological, or geomorphic characteristics) exert the dominant control on denudation in New Zealand. Spatially-averaged cosmogenic nuclide analysis can effectively offer this information by providing averaged rates of denudation on millennial timescales without the biases and limitations of short-term erosion methods.  Basin-averaged denudation rates were obtained in the Nelson/Tasman region, New Zealand, from analysis of concentrations of meteoric ¹⁰Be in silt and in-situ produced ¹⁰Be in quartz. The measured denudation rates integrate over ~2750 yrs (in-situ) and ~1200 yrs (meteoric). Not only do the ¹⁰Be records produce erosion rates that are remarkably consistent with each other, but they are also independent of topographic metrics. Denudation rates range from ~112 – 298 t km⁻² yr⁻¹, with the exception of one basin which is eroding at 600 - 800 t km⁻² yr⁻¹. The homogeneity of rates and absence of a significant correlation with geomorphic or lithological characteristics could indicate that the Nelson/Tasman landscape is in (or approaching) a topographic steady state.  Millennial term (¹⁰Be-derived) denudation rates are more rapid than those inferred from other conventional methods in the same region (~50 – 200 t km⁻² yr⁻¹). This is likely the result of the significant contribution of low frequency, high magnitude erosive events to overall erosion of the region. Both in-situ and meteoric ¹⁰Be analyses have the potential to provide competent millennial term estimates of natural background rates of erosion. This will allow for the assessment of geomorphic-scale impacts such as topography, tectonics, climate, and lithology on rates of denudation for the country where many conventional methods do not. Cosmogenic nuclides offer the ability to understand the response of the landscape to these factors in order to make confident erosion predictions for the future.</p>

scholarly journals Denudation systematics inferred from in situ cosmogenic <sup>10</sup>Be concentrations in fine (50–100 μm) and medium (100–250 μm) sediments of the Var River basin, southern French Alps

2019 ◽  
Author(s):  
Apolline Mariotti ◽  
Pierre-Henri Blard ◽  
Julien Charreau ◽  
Carole Petit ◽  
Stéphane Molliex ◽  
...  
Keyword(s):  
River Basin ◽  
Glacial Cycles ◽  
French Alps ◽  
Denudation Rates ◽  
Cosmogenic 10Be ◽  
Quartz Grains

Abstract. Marine sedimentary archives are well dated and often span several glacial cycles; cosmogenic 10Be concentrations in their detrital quartz grains could thus offer the opportunity to reconstruct a wealth of past denudation rates. However, these archives often comprise sediments much finer (

Massif-wide denudation of the Vosges Mountains (NE France) inferred from in situ 10Be concentrations in stream sediments

2021 ◽  
Author(s):  
Timothée Jautzy ◽  
Gilles Rixhon ◽  
Régis Braucher ◽  
Laurent Schmitt ◽  
Aster Team*
Keyword(s):  
Stream Sediments ◽  
Tectonic Activity ◽  
Mountain Range ◽  
Vosges Mountains ◽  
Eastern Side ◽  
Denudation Rates ◽  
The Alps ◽  
Western Side

&lt;p&gt;&lt;span&gt;The Vosges Mountains in NE France belong to the belt of Variscan massifs located in the foreland of the Alps. Despite its rather limited extension barely reaching 6000 km&amp;#178;, this range of low mountains peaking at ~1425 m presents three contrasting primary characteristics. Firstly, a bipartite N-S subdivision can be achieved based on the geological basement: whereas the southern part, traditionally referred to as the crystalline Vosges, is composed of a mosaic of Palaeozoic rocks, including igneous (mostly intrusive and secondarily extrusive), metamorphic, and sedimentary rocks, the northern part is much more homogeneous given its Triassic sandstone cover (&amp;#8220;sandstone Vosges&amp;#8221;). Secondly, a clear E-W topographic gradient characterises the mountain range. By contrast to the steep hillslopes and elevation drops regularly exceeding 600 m (sometimes reaching 900-1000 m) between the summits and the valley floors on the eastern side (Alsace; south-western border of the Upper Rhine Graben, URG), the western side exhibits more gently-sloping hillslopes along with a longer extension (Lorraine; eastern border of the Parisian Basin). This results from the sharp E-W contrast in Late Cenozoic tectonic activity between sustained subsidence in the URG to the east and weak rock uplift characterising the Parisian Basin to the west. Finally, the imprint left by Quaternary climatic fluctuations yielded a N-S gradient: whereas the southern part (roughly covering 80-90% of the crystalline Vosges) hosted abundant valley glaciers and still bears traces of significant glacial erosion (cirques and U-shaped valleys), the northern part (mostly the sandstone Vosges) was void of ice cover.&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;In spite of these advantageous characteristics, very little is known about the Quaternary evolution of the massif, in particular regarding the long-term interactions between denudation&lt;/span&gt;&lt;span&gt;, lithological control, climatic forcing and tectonic activity. &lt;/span&gt;&lt;span&gt;Against this background, this contribution aims to present the first data of long-term, massif-wide denudation. Modern stream sediments from 21 river catchments of different size draining the whole massif were thus sampled for &lt;/span&gt;&lt;span&gt;&lt;em&gt;in situ&lt;/em&gt;&lt;/span&gt; &lt;sup&gt;&lt;span&gt;10&lt;/span&gt;&lt;/sup&gt;&lt;span&gt;Be concentration measurements at the outlet of their mountainous reach. Catchment-wide denudation rates inferred from cosmogenic &lt;/span&gt;&lt;sup&gt;&lt;span&gt;10&lt;/span&gt;&lt;/sup&gt;&lt;span&gt;Be will be combined with the analysis of morphometric parameters and structural connectivity resulting from the processing of a high-resolution DEM (5 m). Catchment selection was operated according to the threefold subdivision above: i.e. heterogeneous vs homogenous petrography, tectonically-active eastern side vs &amp;#8220;quiescent&amp;#8221; western side and glaciated vs unglaciated catchments. We thus test the main hypothesis that the four NE, NW, SE, SW quarters of the Vosges massif shall be characterised by contrasting denudation rates, reflecting the respective role played by the controlling factors on long-term denudation. To our knowledge, this contribution is the first attempt to quantify denudation at the massif scale of a European low mountain range. This is especially relevant as long-term landscape evolution in the Variscan belt, by contrast to the numerous works focusing on denudation in high-mountains ranges (e.g. the Alps), has been regularly disregarded in recent geomorphological studies.&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;*Georges Auma&amp;#238;tre, Didier L. Bourl&amp;#232;s and Karim Keddadouche&lt;/span&gt;&lt;/p&gt;

Denudation rates in the Pancas Bornhardt Province (SE Brazil), inferred from in situ produced cosmogenic 10Be

2018 ◽  
Vol 62 (1) ◽  
pp. 13-22
Author(s):  
Cesar Augusto Chicarino Varajão ◽  
Fernando Flecha de Alkmim ◽  
Régis Braucher ◽  
Issamu Endo ◽  
Luis Felipe Soares Cherem ◽  
...  
Keyword(s):  
Denudation Rates ◽  
Se Brazil ◽  
Cosmogenic 10Be

Quantifying denudation rates and sediment storage on the eastern Altiplano, Bolivia, using cosmogenic 10Be, 26Al, and in situ 14C

Geomorphology ◽  
2012 ◽  
Vol 179 ◽  
pp. 58-70 ◽  
Author(s):  
Kristina Hippe ◽  
Florian Kober ◽  
Gerold Zeilinger ◽  
Susan Ivy-Ochs ◽  
Colin Maden ◽  
...  
Keyword(s):  
Sediment Storage ◽  
Denudation Rates ◽  
Cosmogenic 10Be

Quantifying denudation rates on inselbergs in the central Namib Desert using in situ–produced cosmogenic 10Be and 26Al

Geology ◽  
1999 ◽  
Vol 27 (5) ◽  
pp. 399 ◽  
Author(s):  
Hermione A. P. Cockburn ◽  
Michele A. Seidl ◽  
Michael A. Summerfield
Keyword(s):  
Namib Desert ◽  
Denudation Rates ◽  
Cosmogenic 10Be

scholarly journals Calibrating a long-term meteoric <sup>10</sup>Be delivery rate into eroding western US glacial deposits by comparing meteoric and in situ produced <sup>10</sup>Be depth profiles

Geochronology ◽  
2020 ◽  
Vol 2 (2) ◽  
pp. 411-423
Author(s):  
Travis Clow ◽  
Jane K. Willenbring ◽  
Mirjam Schaller ◽  
Joel D. Blum ◽  
Marcus Christl ◽  
...  
Keyword(s):  
Delivery Rate ◽  
Estimation Methods ◽  
Solar Modulation ◽  
Depth Profiles ◽  
Fine Grained ◽  
Denudation Rates ◽  
Solar Intensity ◽  
A Site

Abstract. Meteoric 10Be (10Bemet) concentrations in soil profiles have great potential as a geochronometer and a tracer of Earth surface processes, particularly in fine-grained soils lacking quartz that would preclude the use of in situ produced 10Be (10Bein situ). One prerequisite for using this technique for accurately calculating rates and dates is constraining the delivery, or flux, of 10Bemet to a site. However, few studies to date have quantified long-term (i.e., millennial) delivery rates, and none have determined a delivery rate for an eroding soil. In this study, we compared existing concentrations of 10Bein situ with new measurements of 10Bemet in eroding soils sampled from the same depth profiles to calibrate a long-term 10Bemet delivery rate. We did so on the Pinedale (∼ 21–25 kyr) and Bull Lake (∼ 140 kyr) glacial moraines at Fremont Lake, Wyoming (USA), where age, grain sizes, weathering indices, and soil properties are known, as are erosion and denudation rates calculated from 10Bein situ. After ensuring sufficient beryllium retention in each profile, solving for the delivery rate of 10Bemet, and normalizing for paleomagnetic and solar intensity variations over the Holocene, we calculate 10Bemet fluxes of 1.46 (±0.20) × 106 atoms cm−2 yr−1 and 1.30 (±0.48) × 106 atoms cm−2 yr−1 to the Pinedale and Bull Lake moraines, respectively, and compare these values to two widely used 10Bemet delivery rate estimation methods that substantially differ for this site. Accurately estimating the 10Bemet flux using these methods requires a consideration of spatial scale and temporally varying parameters (i.e., paleomagnetic field intensity, solar modulation) to ensure the most realistic estimates of 10Bemet-derived erosion rates in future studies.

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