Impact of the North American monsoon on isotope paleoaltimeters: Implications for the paleoaltimetry of the American southwest

Clicks: 4
ID: 301155
2017
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
Emerging

Ranked #219 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
Paleoaltimetric studies have characterized in detail the relationship between carbonate oxygen isotope ratios (δ^18^O~c~) and elevation in orogens with simple, single-moisture-source hydrological systems, and applied this relationship to ancient continental carbonates to provide constraints on their past elevation. However, mixing of different atmospheric moisture sources in low-elevation orogens should affect δ^18^O~c~ values, but this effect has not yet been confirmed unequivocally. In the American Southwest, summer monsoonal moisture, sourced in the Equatorial Pacific and the Gulf of Mexico, and winter moisture, sourced in the East Pacific, both contribute to annual rainfall. We present stable isotope results from Quaternary carbonates within the American Southwest to characterize the regional δ^18^O~c~-elevation relationship. We then provide stable isotope results from local Eocene carbonates to reconstruct late Laramide paleoelevations. The Quaternary δ^18^O~c~-elevation relationship in the American Southwest is not as straightforward as in more simple hydrological systems. δ^18^O~c~ changes with altitude are non-linear, scattered, and display an apparent isotopic lapse rate inversion above 1200 m of elevation. We speculate that decreasing surface temperatures at high altitudes limit the duration of carbonate growth to the summer months, biasing δ^18^O~c~ values toward higher values typical of the summer monsoon and leading to lapse rate inversion. δ^18^O~c~-elevation relationships based on modern water isotope data or distillation models predict paleoelevations that range up to as much as 2 km higher than the modern elevations of 2000 to 2400 m for our late Eocene sites located at the southern edge of the Colorado Plateau. By contrast, our δ^18^O~c~-elevation relationship for the American Southwest yields lower paleoelevation estimates. These alternate estimates nonetheless suggest that significant elevation (at least ∼1 km) had already been attained by the Eocene, but are also compatible with \< 1 km of uplift by post-Laramide mechanisms. Our results show the limitations of standard δ^18^O~c~-elevation models in complex hydrological systems and suggest that similar mechanisms may have led to summer-biased paleoaltimetry estimates for the initial stages of other orogenies ---in the American Southwest and elsewhere.
Reference Key
openalex_W2588508611 Use this key to autocite in the manuscript while using SciMatic Manuscript Manager or Thesis Manager
Authors Alexis Licht, Jay Quade, Andrew Kowler, Marie de los Santos, Adam M. Hudson, Andrew J. Schauer, Katharine W. Huntington, Peter Copeland, Timothy F. Lawton
Journal american journal of science
Year 2017
DOI
10.2475/01.2017.01
URL
https://doi.org/10.2475/01.2017.01
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.