Combining surface exposure dating and burial dating from paired cosmogenic depth profiles. Example of El Límite alluvial fan in Huércal-Overa basin (SE Iberia)

Abstract

Please cite this article as: Rod´es, A., Pall`as, R., Ortu˜no, M.´ı., Garc´ıa-Melendez, E., Masana, E.`a., Combining surface exposure dating and burial dating from paired cosmogenic depth profiles. Example of El Límite alluvial fan in Huércal-Overa basin (SE Iberia), Quaternary Geochronology (2013), doi: 10.1016/j.quageo.2013 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPTCombined surface exposure and burial dating provides robust minimum and maximum ages. It also provides constraints for the exhumation rate and sediment residence time. Results suggest that El Límite alluvial fat was deposited in the Late Pleistocene. El Límite sediments were reworked due to the activity of the South-AMF. M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPTCombining surface exposure dating and burial dating from paired cosmogenic depth profiles.Example of El Límite alluvial fan in Huércal-Overa basin (SE Iberia)Several authors * October 1, 2013Abstract Cosmogenic nuclide depth-profiles are used to calculate the age of landforms, the rates at which erosion has affected them since their formation and, in case of deposits, the paleo-erosion rate in the source area. However, two difficulties are typically encountered: 1) old deposits or strongly affected by cosmogenic nuclide inheritance often appear to be saturated, and 2) a full propagation of uncertainties often yields poorly constrained ages. Here we show how to combine surface-exposure-dating and burial-dating techniques in the same profile to get more accurate age results and to constrain the extent of pre-depositional burial periods. A 10 Be-26 Al depth-profile measured in an alluvial fan of SE Iberia is presented as a natural example.

Anatomy, Age and Origin of an Intramontane Top Basin Surface (Sorbas Basin, Betic Cordillera, SE Spain)

“…Dating of the top basin surface was undertaken using a 10 Be- 26 Al cosmonuclide depth-profile originally sampled and analysed by Ilott [38] as part of a broader chronological investigation of the timing of Quaternary fluvial landscape development within the Sorbas Basin. The paired isotope and depth-profile approach allowed for surface exposure and burial age quantification [50]. The surface exposure technique measures the concentration of cosmonuclides at the surface [51], with concentrations affected by the time of exposure to cosmic radiation, cosmonuclide loss due to erosion, sediment density variability (affects cosmic ray attenuation) and cosmonuclide production variations [15,52].…”

“…The concentration results revealed no hiatus within the profile so a simple exposure history was explored. This involved using a Chi square minimization method that was applied to the raw nuclide concentration data to allow fitting to the accumulation model equations of Lal [57] with variable inheritance, density and erosion data input values [15,50].…”

River terraces and alluvial fans: The case for an integrated Quaternary fluvial archive

“…However, evolving techniques in CRN burial dating of paired cosmogenic depth profiles ( 10 Be and 26 Al) are becoming increasingly more sophisticated and providing more robust results over longer timescales (e.g. Rodés et al, 2014). Similarly refinement of techniques in OSL alluvial fan studies means that smaller sand lenses in coarse grained deposits can now be used for OSL (e.g.…”

Datación de dos terrazas rocosas del valle del Río Lozoya (Comunidad De Madrid, España) mediante los isótopos cosmogénicos Be-10 y Al-26.

“…Para poder modelizar estos parámetros se ha usado una modelización inversa de chi-cuadrado para ajustar los valores medidos de ¹⁰Be y ²⁶Al en modelos de perfiles de profundidad (Siame et al, 2004;Braucher et al, 2009;Rodés et al, 2011;Balco et al, 2013;Rodés et al, 2013). Sin embargo, hay que indicar que cuando se estudian …”

“…Además, las edades calculadas mediante modelos de exposición a lo largo de perfiles de profundidad muestreados por debajo de la superficie actual pueden ser sensibles a los cambios de variación de densidad (Rodés et al, 2013) o por sus ratios de producción por resultado por espalación o muones .…”