干旱区生态环境知识资源中心(Arid): Paired-cosmogenic nuclide paleoaltimetry

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DOI	10.1016/j.epsl.2019.03.005
	Paired-cosmogenic nuclide paleoaltimetry
	Blard, Pierre-Henri 1,2; Lupker, Maarten 3; Rousseau, Moise 1,4
通讯作者	Blard, Pierre-Henri
来源期刊	EARTH AND PLANETARY SCIENCE LETTERS
ISSN	0012-821X
EISSN	1385-013X
出版年	2019
卷号	515 页码:271-282
英文摘要	Goal - The reconstruction of past topographies remains challenging and only a few methods allow accurate determination of past surface elevations. We propose here a new technique for deriving paleoelevations, in which multiple cosmogenic nuclides are measured in the same geological sample exposed at the Earth's surface. This method relies on the altitude dependence of the cosmogenic nuclides' production rates combined with the radioactive decays of nuclides with different half-lives. Theory - The position of the two cosmogenic nuclide exposure curves (Al-26/Be-10 vs Be-10 or Be-10/Ne-21 vs 10Be) depends on the altitude of exposure. If the studied surfaces have been exposed for sufficiently long durations (>500 ka), or have been affected by low erosion rates (<1 m Ma(-1)), measurement of two cosmogenic nuclides with different half-lives thus allow accurate elevations to be determined with a reasonable uncertainty (<1000 m at 1 sigma). For shorter exposure durations, the method is able to constrain minimum elevations. The main advantage of the method is that it is only slightly sensitive to erosion: even if the preservation state of the surface is unknown, the bias on the computed elevation remains lower than 1500 m in most cases. The approach can also be applied to previously exposed surfaces that have subsequently been buried, in order to reconstruct the paleo-elevation of a given surface over time ranges of similar to 0 to 8 Ma (using the Al-26-Be-10 pair) and similar to 0 to 12 Ma (using the Be-10-Ne-21 pair). Data comparison - We tested the method using the multiple cosmogenic nuclides dataset available for the western arid tropical Andes. The altitudes computed using the cosmogenic nuclide concentrations agree within uncertainties with the reported sampling altitudes over a range of 0 to more than 4000 m, illustrating the applicability of the method. Altitudes computed under the assumptions of continuous exposure or steady state erosion yields best fits that are statistically in agreement and close to the 1:1 line for both the Al-26-Be-10 and the Ne-21-Be-10 dataset. The Ne-21-Be-10 inventories in samples that have been exposed for more than 5 Ma yield elevations that are several hundreds of meters below their present-day elevations (similar to 1000 m). This may result from a post 10 Ma uplift of the West Andes, or from an unrecognized exposure underwater, or below a soil cover. Implications - This study may also have implications in other fields that rely on multiple cosmogenic nuclide measurements. The same approach might notably be used to compute the depth of exposure of samples located below the rock surface or underwater. This study may also help to improve the accuracy of the common burial dating method that uses multiple radioactive cosmogenic nuclides. For long pre-burial exposures (>500 ka), or low erosion rates (<1 m Ma(-1)), the values of the pre-burial nuclides ratios indeed depend strongly on the altitude of exposure. It may be important to consider the pre-burial altitude of exposure in order to calculate accurate burial ages. (C) 2019 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
英文关键词	paleoaltimetry in situ cosmogenic nuclides Be-10-Al-26-Ne-21 simple exposure curves Atacama desert Andes
类型	Article
语种	英语
国家	France ; Belgium ; Switzerland ; Canada
开放获取类型	Green Published, hybrid
收录类别	SCI-E
WOS记录号	WOS:000466251400025
WOS关键词	PRODUCTION-RATES ; LANDSCAPE EVOLUTION ; GEOMAGNETIC-FIELD ; CENOZOIC UPLIFT ; NORTHERN CHILE ; EROSION RATES ; HALF-LIFE ; BE-10 ; AL-26 ; PLATEAU
WOS类目	Geochemistry & Geophysics
WOS研究方向	Geochemistry & Geophysics
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/215073
作者单位	1.Univ Lorraine, CRPG, CNRS, UMR 7358, 15 Rue Notre Dame Pauvres, F-54500 Vandoeuvre Les Nancy, France; 2.Univ Libre Bruxelles, Lab Glaciol, DGES IGEOS, B-1050 Brussels, Belgium; 3.Swiss Fed Inst Technol, Geol Inst, Sonnegstr 5, CH-8092 Zurich, Switzerland; 4.UQAT Polytech, RIME, Montreal, PQ, Canada
推荐引用方式 GB/T 7714	Blard, Pierre-Henri,Lupker, Maarten,Rousseau, Moise. Paired-cosmogenic nuclide paleoaltimetry[J],2019,515:271-282.
APA	Blard, Pierre-Henri,Lupker, Maarten,&Rousseau, Moise.(2019).Paired-cosmogenic nuclide paleoaltimetry.EARTH AND PLANETARY SCIENCE LETTERS,515,271-282.
MLA	Blard, Pierre-Henri,et al."Paired-cosmogenic nuclide paleoaltimetry".EARTH AND PLANETARY SCIENCE LETTERS 515(2019):271-282.