Les nucleides cosmogeniques produits in-situ; de nouveaux outils en geomorphologie quantitative

2000 ◽  
Vol 171 (4) ◽  
pp. 383-396 ◽  
Author(s):  
Lionel L. Siame ◽  
Regis Braucher ◽  
Didier L. Bourles
Keyword(s):  
Cosmic Ray ◽  
Spatial Variations ◽  
Surface Exposure Dating ◽  
Exposure Dating ◽  
Mineral Fraction ◽  
Surficial Deposits ◽  
Geomorphic Processes ◽  
Quantitative Tool ◽  
In Situ Production

Abstract Measurement of 10 Be and 26 Al concentrations produced by cosmic ray bombardment within the quartz mineral fraction of surficial deposits and exposed bedrocks (in situ-production) is rapidly becoming an important quantitative tool in geomorphology. Whereas conventional methods provide age control on stratigraphic profiles, surface exposure dating using in situ-produced 10 Be and 26 Al is particularly well-suited not only for continuous dating but also for quantifying spatial variations and rates of geomorphic processes.

Quantifying post-glacial erosion at the Gorner glacier, Switzerland, using OSL and 10Be surface exposure dating.

2020 ◽  
Author(s):  
Joanne Elkadi ◽  
Benjamin Lehmann ◽  
Georgina King ◽  
Olivia Steinemann ◽  
Susan Ivy-Ochs ◽  
...  
Keyword(s):  
Spatial Scales ◽  
Cosmic Ray ◽  
Western Alps ◽  
Optically Stimulated Luminescence ◽  
Surface Erosion ◽  
Glacial Erosion ◽  
Surface Exposure Dating ◽  
Erosion Rates ◽  
Exposure Dating

<p>Quaternary erosion through glacial and post-glacial processes has left an imprint on Alpine topography. There are few methods capable of resolving these processes on Late glacial to Holocene timescales. The aim of this study is to contribute towards a more detailed understanding of post-glacial erosion across the Central and Western Alps by better constraining the post-glacial erosion history of the Gorner glacier in Zermatt, Switzerland. This is done using a new approach that combines Optically Stimulated Luminescence (OSL) and <sup>10</sup>Be cosmogenic nuclide surface exposure dating to invert for post-glacial erosion rates (Lehmann et al., 2019). Both dating methods are influenced by surface erosion but operate on different spatial scales- OSL signals form within the first 1-5 mm of a rock surface (Sohbati et al., 2011) whereas the <sup>10</sup>Be signal accumulates within approximately the first 3 m (Lal, 1991). Six bedrock samples, exposed progressively since the Last Glacial Maximum, were collected along a vertical transect spanning an elevation of 641 m. Preliminary results show inheritance in the bottom three samples suggesting multiple advances and retreat. Further results for the post-glacial erosion rates down the transect, and comparison to other glaciers in the Western Alps, will be presented.</p><p>References:</p><p>Lal, D., 1991. Cosmic ray labelling of erosion surfaces: in situ nuclide production rates and erosion models. Earth and Planetary Science Letters, 104, 424-439.</p><p>Lehmann, B et al., 2019. Evaluating post-glacial bedrock erosion and surface exposure duration by coupling in situ optically stimulated luminescence and <sup>10</sup>Be dating. Earth Surface Dynamics, 7.</p><p>Sohbati, R. et al., 2011. Investigating the resetting of OSL signals in rock surfaces. Geochronometria, 38(3), 249-258.</p>

Surface exposure dating by in-situ produced cosmogenic nuclides: chemical mineral separation of purified quartz

2001 ◽  
Vol 89 (11-12) ◽  
Author(s):  
M. Altmaier ◽  
W. Klas ◽  
U. Herpers
Keyword(s):  
Cosmic Radiation ◽  
Cosmogenic Nuclides ◽  
Surface Exposure Dating ◽  
Exposure Dating ◽  
Mineral Separation

The interaction of cosmic radiation with terrestrial matter leads to the

Cosmogenic Be-10 surface exposure data from the Sub-Antarctic Kerguelen Archipelago

2020 ◽  
Author(s):  
Henriette Linge ◽  
Jostein Bakke ◽  
Talin Tuestad ◽  
Philip Deline ◽  
Ludovic Ravanel ◽  
...  
Keyword(s):  
Hydrothermal Fluids ◽  
Large Igneous Province ◽  
Geochemical Composition ◽  
Surface Exposure Dating ◽  
Exposure Dating ◽  
Ice Cap ◽  
Wide Range ◽  
Exposure Ages ◽  
Kerguelen Archipelago

<p>The Kerguelen archipelago (around 49°S 69°E) is the emerged part of the Kerguelen Plateau, a large igneous province in the southwestern Indian Ocean. Information on past climatic and environmental conditions in the region is vital for understanding the past behaviour of the southern westerly winds. The cross-disciplinary project SOUTHSPERE seeks to investigate past variations in this weather system through reconstruction of temporal and spatial glacier variability from lake records and glacial landforms N and NE of the Cook Ice Cap. Reliable and accurate chronological control is crucial in this context.</p><p>Surface exposure dating of glacial geomorphological features S and SE of the Cook Ice Cap has previously been done using in situcosmogenic Cl-36 [1, 2]. Solifluction and gelifraction processes appear very active in our field area, as do aeolian erosion. Also, highly variable geochemical composition of the basalts and associated intrusions, as well as the degree and type of metamorphosis, lead to strong lithology-dependant weathering and erosion rates, as evident from differential weathering reliefs on cm and m scales. The very active surface environment constitutes a challenge for obtaining accurate surface exposure ages.</p><p>In the NW part of the archipelago, basaltic lava units altered by meteoric-hydrothermal fluids contain a wide variety of secondary silicate and carbonate minerals [3]. In settings where quartz-filled geodes and fractures in the basalt are located in favourable positions on bedrock and boulder surfaces, analysis of Be-10 in euhedral and microcrystalline quartz offers a means of validating in situ Cl-36 surface exposure ages. Moreover, multi-nuclide analysis would open up for a wide range of process and landscape development studies on this young archipelago. Percolation of hydrothermal fluids in fractures and geodes is probably related to the intrusion of younger (15-5 Ma) subvolcanic rocks [see 3 and references therein]. A meteoric source of the fluids would imply that the secondary silicates contain meteoric Be-10. As meteoric production is greater than in situ production, this may represent a problem for utilising in situ Be-10 for surface exposure dating. If secondary silicate formation occurred early, rather than late in the intrusive phase, complete radioactive decay of the meteoric Be-10 component is expected prior to surface exposure.</p><p>110 rock samples were collected for surface exposure dating with in situ cosmogenic nuclides during a field campaign in November and December 2019. Here we present the first Be-10 data from rock surfaces of glacially transported boulders and exposed bedrock.</p><p>[1] Jomelli et al. 2017. Quaternary Science Reviews 162, 128-144.</p><p>[2] Jomelli et al. 2018. Quaternary Science Reviews 183, 110-123.</p><p>[3] Renac et al. 2010. European Journal of Mineralogy 22, 215-234.</p>

scholarly journals Surface exposure dating using in situ cosmogenic 10Be

2004 ◽  
Vol 53 (1) ◽  
pp. 3
Author(s):  
U Abramowski ◽  
B Glaser ◽  
P W Kubik ◽  
R Zech ◽  
W Zech
Keyword(s):  
Surface Exposure Dating ◽  
Exposure Dating ◽  
Cosmogenic 10Be

First cosmic ray exposure dating (in situ produced10Be) of the late pleistocene and holocene glaciation in the Nanhutashan Mountains (Taiwan)

Terra Nova ◽  
2007 ◽  
Vol 19 (5) ◽  
pp. 331-336 ◽  
Author(s):  
J. Carcaillet ◽  
L. L. Siame ◽  
H.-T. Chu ◽  
D. L. Bourlès ◽  
W.-C. Lu ◽  
...  
Keyword(s):  
Late Pleistocene ◽  
Cosmic Ray ◽  
Exposure Dating

scholarly journals Application of in-situ produced terrestrial cosmogenic nuclides to archaeology: A schematic review

2008 ◽  
Vol 57 (1/2) ◽  
pp. 226-238
Author(s):  
Naki Akcar ◽  
Susan Ivy-Ochs ◽  
Christian Schlüchter
Keyword(s):  
Cosmogenic Nuclides ◽  
Close Collaboration ◽  
Total Exposure ◽  
Surface Exposure Dating ◽  
Wide Applicability ◽  
Exposure Dating ◽  
The Past ◽  
Cosmogenic Nuclide ◽  
Time Period

Abstract. The wide applicability of in-situ produced Terrestrial Cosmogenic Nuclides (TCNs) to geological problems and experiences in development and testing gained over the past decade is encouraging for its application to archaeological questions, where there is a distinct need for an additional independent dating tool beyond the limits of radiocarbon (~ 40 ka). Just as TCNs are applicable to a broader time period with considerable precision in archaeology, so also are they applicable to all lithologies. Application of TCNs to archaeological problems is relatively simple: either surface exposure dating (using cosmogenic nuclide production) or burial dating (using decay of radioactive cosmogenic nuclides) can be applied. For a successful application, close collaboration between archaeologists and TCN experts is required. The total exposure from 100 a to 5 Ma of a given surface of archaeological origin can be determined by surface exposure dating. The range of burial dating is from ~0.1 to 5 Ma. TCNs have been successfully applied to many archaeological problems during the last decade and both surface exposure dating and burial dating show high potential in the solving of archaeological problems.

Cosmic ray exposure dating with in situ produced cosmogenic 3He: Results from young Hawaiian lava flows

1990 ◽  
Vol 97 (1-2) ◽  
pp. 177-189 ◽  
Author(s):  
Mark D. Kurz ◽  
Debra Colodner ◽  
Thomas W. Trull ◽  
Richard B. Moore ◽  
Keran O'Brien
Keyword(s):  
Cosmic Ray ◽  
Lava Flows ◽  
Exposure Dating ◽  
Hawaiian Lava

The CoNTESTA Project: Impacts of geomagnetic field changes on cosmogenic nuclide production-rate variability and implications for surface-exposure dating

2020 ◽  
Author(s):  
Margaret Jackson ◽  
Gordon Bromley ◽  
Pierre-Henri Blard ◽  
Sidney Hemming
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Production Rate ◽  
Magnetic Field Strength ◽  
Cosmic Ray ◽  
Glacial Deposits ◽  
Past Climate ◽  
Surface Exposure Dating ◽  
Exposure Dating ◽  
Cosmogenic Nuclide

<p>Determining the geographic footprint of past climate events is a fundamental step in identifying the mechanisms that drive and propagate these changes around the globe. Glacial deposits are a particularly robust source of such data; glaciers are sensitive indicators of climate that leave records of their past fluctuations on the landscape. Given precise chronologic control, glacial deposits can be used to reconstruct past climate variability. Recent advances in cosmogenic nuclide surface-exposure dating have established past glacial fluctuations as a key climate proxy. However, uncertainties in the application of cosmogenic nuclide production-rate-scaling frameworks hinder efforts to compare past glacial fluctuations with other records of past climate conditions. Production-rate scaling is particularly uncertain in the tropics, where the theorized impacts of changing magnetic field strength on the incoming cosmic ray flux are greatest. Here we present results in-progress from the CoNTESTA [Cosmogenic Nuclide Temporal and Elevation Scaling: Testing and Application] Project, which seeks to establish multiple nuclide production-rate calibration sites of varying age from the low latitudes in order to assess directly the impacts of changing magnetic field strength on nuclide production over time. We also report new data that address empirically the impacts of elevation on nuclide production. The results of this project will strengthen our understanding of cosmogenic nuclide production globally and will improve surface-exposure age calculations from all regions. This in turn will enable more robust assessment of the global phasing of glacial fluctuations and will forward our understanding of landscape dynamics and Earth surface history. </p>

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