Erosion of an Ancient Mountain Range, The Great Smoky Mountains, North Carolina and Tennessee

Clicks: 1
ID: 293405
2003
Free PDF
Article Quality & Performance Metrics
Overall Quality
Not rated
Combines reader engagement with the AI quality analysis. This article has not been analysed, so there is no overall score — reader engagement is measured and shown alongside.
AI Quality Assessment
Not analyzed
Readership in this journal

Ranked #3,787 of 8,486 articles by views in american journal of science

Most read Least read

Bar heights use a square-root scale. Only the 120 most-read articles are drawn; the journal has 8,486 in total.

Mint this article as an NFT
Not yet minted

Create a permanent, verifiable on-chain record of this article on the Scimatic Network. The NFT is held in your Journament account, and you can withdraw it to your own wallet at any time.

5 SUSD one-off · no wallet required
Sign in to mint
Abstract
Analysis of ^10^Be and ^26^Al in bedrock (n=10), colluvium (n=5 including grain size splits), and alluvial sediments (n=59 including grain size splits), coupled with field observations and GIS analysis, suggest that erosion rates in the Great Smoky Mountains are controlled by subsurface bedrock erosion and diffusive slope processes. The results indicate rapid alluvial transport, minimal alluvial storage, and suggest that most of the cosmogenic nuclide inventory in sediments is accumulated while they are eroding from bedrock and traveling down hill slopes. Spatially homogeneous erosion rates of 25 - 30 mm Ky^−1^ are calculated throughout the Great Smoky Mountains using measured concentrations of cosmogenic ^10^Be and ^26^Al in quartz separated from alluvial sediment. ^10^Be and ^26^Al concentrations in sediments collected from headwater tributaries that have no upstream samples (n=18) are consistent with an average erosion rate of 28 ± 8 mm Ky^−1^, similar to that of the outlet rivers (n=16, 24 ± 6 mm Ky^−1^), which carry most of the sediment out of the mountain range. Grain-size-specific analysis of 6 alluvial sediment samples shows higher nuclide concentrations in smaller grain sizes than in larger ones. The difference in concentrations arises from the large elevation distribution of the source of the smaller grains compared with the narrow and relatively low source elevation of the large grains. Large sandstone clasts disaggregate into sand-size grains rapidly during weathering and downslope transport; thus, only clasts from the lower parts of slopes reach the streams. ^26^Al/^10^Be ratios do not suggest significant burial periods for our samples. However, alluvial samples have lower ^26^Al/^10^Be ratios than bedrock and colluvial samples, a trend consistent with a longer integrated cosmic ray exposure history that includes periods of burial during down-slope transport. The results confirm some of the basic ideas embedded in Davis' *geographic cycle* model, such as the reduction of relief through slope processes, and of Hack's *dynamic equilibrium* model such as the similarity of erosion rates across different lithologies. Comparing cosmogenic nuclide data with other measured and calculated erosion rates for the Appalachians, we conclude that rates of erosion, integrated over varying time periods from decades to a hundred million years are similar, the result of equilibrium between erosion and isostatic uplift in the southern Appalachian Mountains.
Reference Key
openalex_W2007711793 Use this key to autocite in the manuscript while using SciMatic Manuscript Manager or Thesis Manager
Authors Ari Matmon
Journal american journal of science
Year 2003
DOI
10.2475/ajs.303.9.817
URL
https://ajs.scholasticahq.com/article/61707.pdf
Keywords Keywords not found

Citations

No citations found. To add a citation, contact the admin at info@scimatic.org

Comments

No comments yet. Be the first to comment on this article.