Global S&T Development Trend Analysis Platform of Resources and Environment
DOI | 10.1130/B31644.1 |
Addressing time-scale-dependent erosion rates from measurement methods with censorship | |
McElroy, Brandon1; Willenbring, Jane2; Mohrig, David3 | |
2018-03-01 | |
发表期刊 | GEOLOGICAL SOCIETY OF AMERICA BULLETIN
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ISSN | 0016-7606 |
EISSN | 1943-2674 |
出版年 | 2018 |
卷号 | 130页码:381-395 |
文章类型 | Article |
语种 | 英语 |
国家 | USA |
英文摘要 | In a degrading landscape, does the episodic nature of erosion affect observed erosion rates in a systematic way, and can one account for the effects? We present a null hypothesis for surface change rate variations based on minimal assumptions about the processes of topographic evolution. Variance in erosion along with censorship of topographic change distributions combine to act as a first-order control on time-scale dependence of erosion rates. In general, censorship is ubiquitous, and as a result, time-scale dependence of rates is likely to apply to almost every system. In detail, this occurs because at short time scales, surface changes can be censored from field measurements that become inherently incorporated by natural surface evolution at longer time scales. Additionally, the granularity of systems implies minimum time scales below which specific rate measurements have no physical interpretation. Finally, we show the existence of a crossover time scale at which the short-term rate dependence of a process gives way to the long-term rate that is no longer subject to censoring. We demonstrate these points by applying the proposed framework to a growing seepage channel network in Florida, United States. Using a dendrogeomorphic approach in concert with cosmogenic radionuclide methods, we estimate denudation rates averaged over annual to multimillennial time scales. Exposure of hundreds of tree roots combined with tree ages supplies surface change rates along approximately one third of the valley bottom within the studied area. Erosion rates are distributed approximately between 1 mm/yr and 10 mm/yr. This erosion exhibits variance that depends linearly on time scale and is interpreted to represent a process well modeled as normal diffusion. As a result, the erosion rates show an inverse-square dependence on time scale. We used the Be-10 contents from nine quartz sand samples to estimate long-term erosion rates and then coupled them with existing estimates of long-term erosion. These estimates of erosion are of the order of 0.01 mm/yr to 0.1 mm/yr and correspond to time scales of roughly 10(5) yr. Based on theory derived from censored measurements of rate distributions, the short-term rates can be used to infer expected long-term rates. In this case, distributions of measured and expected long-term rates do not overlap, and an explicit test of a null hypothesis is not necessary. We interpret the large-magnitude, short-time-scale rates as a product of recent influences on the ravines, and we discuss how this framework could be applied in other settings. |
领域 | 地球科学 |
收录类别 | SCI-E |
WOS记录号 | WOS:000427362500002 |
WOS关键词 | LAST GLACIAL MAXIMUM ; COSMOGENIC NUCLIDES ; CLIMATE-CHANGE ; DENUDATION RATES ; RIVER SEDIMENT ; ANOMALOUS DIFFUSION ; LATE QUATERNARY ; INCISION RATES ; HUMAN IMPACTS ; IN-SITU |
WOS类目 | Geosciences, Multidisciplinary |
WOS研究方向 | Geology |
引用统计 | |
文献类型 | 期刊论文 |
条目标识符 | http://119.78.100.173/C666/handle/2XK7JSWQ/24707 |
专题 | 地球科学 |
作者单位 | 1.Univ Wyoming, Dept Geol & Geophys, 1000 E Univ Ave, Laramie, WY 82071 USA; 2.Univ Calif San Diego, Earth Div, Scripps Inst Oceanog, 9500 Gilman Dr, La Jolla, CA 92093 USA; 3.Univ Texas Austin, Dept Geol Sci, 1 Univ Stn C9000, Austin, TX 78712 USA |
推荐引用方式 GB/T 7714 | McElroy, Brandon,Willenbring, Jane,Mohrig, David. Addressing time-scale-dependent erosion rates from measurement methods with censorship[J]. GEOLOGICAL SOCIETY OF AMERICA BULLETIN,2018,130:381-395. |
APA | McElroy, Brandon,Willenbring, Jane,&Mohrig, David.(2018).Addressing time-scale-dependent erosion rates from measurement methods with censorship.GEOLOGICAL SOCIETY OF AMERICA BULLETIN,130,381-395. |
MLA | McElroy, Brandon,et al."Addressing time-scale-dependent erosion rates from measurement methods with censorship".GEOLOGICAL SOCIETY OF AMERICA BULLETIN 130(2018):381-395. |
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