Terrestrial cosmogenic nuclide dating Bootyteens

The results have important implications concerning our understanding of the temporal distribution of paraglacial rockslides and rock avalanches; they provide a better understanding of the volumes and failure mechanisms of recurrent failure events; and they represent the first absolute ages of a prehistoric high-magnitude event in the Canadian Rocky Mountains.

Funding for the research was provided by the Alberta Geological Survey.

Sie wird beispielsweise genutzt zur Altersbestimmung von Lavaströmen, Meteoriteneinschlägen, Rutschungen, Erosionsprozessen und Gletscherbewegungen.

Comparisons of Be TCN ages within sample sets on individual surfaces most closely approximate to the age of landforms that are younger than ~ 70 ka.

Alluvial fan surfaces older than ~ 70 ka have begun to undergo sufficient erosion such that the majority of Be TCN ages for beach bars near Beatty Junction and shorelines ~ 8 km south of Furnace Creek is large, ranging from ~ 119 ka to ~ 385 ka and ~ 109 ka to ~ 465 ka, respectively.

New and previously published luminescence ages and soil development suggest that these landforms may have formed during marine isotope stage (MIS) 2 (~ 22-18 ka), but these younger ages may reflect elluviation of material into the bar deposit long after deposition, and hence the younger ages do not record the true antiquity of the landforms.

This disparity between dates determined by different dating methods and the large spread of TCN ages suggests that the cobbles and boulders have considerable inherited Be concentrations, suggesting that the clasts have been derived from older shorelines or associated landforms.

AA(Department of Geology, University of Cincinnati, Cincinnati, Ohio, USA), AB(School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA), AC(Department of Geological Sciences, California State University, Fullerton, California, USA), AD(Department of Geology, University of Cincinnati, Cincinnati, Ohio, USA), AE(Department of Earth and Planetary Science Department, University of California, Berkeley, Berkeley, CA 94720-4767, USA), AF(Department of Earth Sciences, University of Southern California, Los Angeles, California, USA), AG(Department of Geological Sciences, Central Washington University, Ellensburg, Washington, USA)Be TCN inheritance within cobbles and boulders.

This suggests that the predominantly bedrock hillslopes erode very slowly and sediment is transferred very gradually in most regions within Death Valley.

These results highlight the problems associated with using surface cobbles and boulders to date Quaternary surfaces in Death Valley and emphasizes the need to combine multiple, different dating methods to accurately date landforms in similar dryland regions elsewhere in the world.

However, these results highlight the potential to use TCN methods, when used in combination with other dating techniques, to examine and quantify processes such as sediment transfer and denudation in drylands.

eine Gesteinsoberfläche an oder nahe der Erdoberfläche ausgesetzt war, unter bestimmten Annahmen berechnet.

Tags: , ,