Controls on the Termination of Cretaceous Oceanic Anoxic Event 2 in the Tarfaya Basin, Morocco

Clicks: 1
ID: 294669
2024
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 #2,829 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
Oceanic Anoxic Event 2 (OAE2) has been the focus of considerable research, but biogeochemical dynamics during the recovery from the carbon cycle disturbance largely remain unknown. Here, we present a high-resolution reconstruction of water column redox and nutrient cycling across the final stages of OAE2, in order to assess controls on the termination of widespread ocean anoxia. We focus on calcareous black shales deposited on a subtropical shelf at Tarfaya, Morocco, representing a location prone to water column anoxia beyond the temporal extent of the OAE itself. Our multi-proxy approach combining iron-sulfur systematics with redox-sensitive trace metal (U and Mo) concentrations documents persistent anoxia, with cyclic fluctuations between weakly euxinic (or possibly ferruginous) conditions and more intense euxinia. During the end of the carbon isotope plateau phase, elemental weathering ratios indicate muted variability in chemical weathering intensity, although fluctuating redox conditions may have been driven by changes in continental weathering inputs of sulfate and reactive iron. By contrast, during the recovery phase, changes in chemical weathering intensity appear to have exerted a strong control on redox fluctuations. Overall, the recovery phase documents progressively less reducing conditions and less intense chemical weathering, which resulted in decreased P recycling and intervals of P drawdown, as indicated by P phase partitioning results. These trends were interrupted by the Holywell Event, during which more intense euxinia and enhanced P recycling transiently returned during an interval of particularly low chemical weathering. Nevertheless, the general trend towards lower P bioavailability in the water column, due to both sequestration of P in the sediments and a likely progressive decrease in P supply via continental weathering, appears to have exerted a major control on the recovery from oceanic anoxia in this shelf setting, and potentially on a global scale.
Reference Key
openalex_W4399872128 Use this key to autocite in the manuscript while using SciMatic Manuscript Manager or Thesis Manager
Authors Chiara Krewer, Simon W. Poulton, Robert J. Newton, Christian März, Benjamin Mills, Thomas Wagner
Journal american journal of science
Year 2024
DOI
10.2475/001c.118797
URL
https://ajsonline.org/article/118797.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.