Title: The Toarcian oceanic anoxic event in the Western Saharan Atlas, Algeria (North African paleomargin): Role of anoxia and productivity
Abstract: Research Article| September 01, 2012 The Toarcian oceanic anoxic event in the Western Saharan Atlas, Algeria (North African paleomargin): Role of anoxia and productivity Matías Reolid; Matías Reolid † 1Departamento Geología, Universidad Jaén, 23071 Jaén, Spain †E-mails: [email protected]; [email protected] Search for other works by this author on: GSW Google Scholar Francisco J. Rodríguez-Tovar; Francisco J. Rodríguez-Tovar † 2Departamento Estratigrafía y Paleontología, Universidad Granada, 18071 Granada, Spain †E-mails: [email protected]; [email protected] Search for other works by this author on: GSW Google Scholar Abbas Marok; Abbas Marok 3Département Sciences Terre, Université Abou-Bekr Belkaid, 13000 Tlemcen, Algeria Search for other works by this author on: GSW Google Scholar Abbes Sebane Abbes Sebane 4Département Sciences Terre, Université d'Es-Sénia, 31000 Oran, Algeria Search for other works by this author on: GSW Google Scholar GSA Bulletin (2012) 124 (9-10): 1646–1664. https://doi.org/10.1130/B30585.1 Article history received: 04 Aug 2011 rev-recd: 24 Apr 2012 accepted: 03 May 2012 first online: 08 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Matías Reolid, Francisco J. Rodríguez-Tovar, Abbas Marok, Abbes Sebane; The Toarcian oceanic anoxic event in the Western Saharan Atlas, Algeria (North African paleomargin): Role of anoxia and productivity. GSA Bulletin 2012;; 124 (9-10): 1646–1664. doi: https://doi.org/10.1130/B30585.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract We used an integrated analysis of benthic foraminiferal assemblages, geochemical proxies (paleoproductivity, redox, and detrital proxies), and C and O stable isotopes to characterize the Toarcian oceanic anoxic event along the North African paleomargin, more precisely in the Saharan Atlas (Algeria). Special emphasis was placed on time intervals previous to the anoxic event and the recovery of normal conditions after this event. The Fisher's alpha diversity of the foraminiferal assemblages decreased with respect to the end of the Pliensbachian in the polymorphum Zone, with lower values of shallow infaunal forms and an increase in opportunists (Reinholdella, Lenticulina, and Eoguttulina). This indicates fluctuations in the oxygenation degree of the infaunal microhabitat in the polymorphum Zone despite the fact that redox proxies do not show any fluctuations, indicating that dysoxic conditions were not reached. The lower part of the levisoni Zone reflects an abrupt paleoenvironmental change, evidenced by the extinction of foraminifera, enrichment in redox-sensitive elements, increase in detrital and paleoproductivity proxies, and fluctuations of δ13C and δ18O. An anoxic or strongly dysoxic event happened by the polymorphum-levisoni zone boundary in the Western Saharan Atlas, coincident with increasing eolian detrital input and paleoproductivity. The upper part of the levisoni Zone represents a return to normal oxic conditions, and the slow recovery of benthic foraminiferal assemblages dominated by opportunistic forms (Lenticulina, Eoguttulina, and Reinholdella) of low diversity. The Toarcian oceanic anoxic event occurred in a generalized transgression that may have favored water stratification and confinement of bottom waters in the subbasins developed in the Atlasic domain. This research demonstrates the potential of the integration of data from foraminiferal assemblages and a wide range of geochemical proxies for understanding anoxic events during the Mesozoic. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.
Publication Year: 2012
Publication Date: 2012-08-10
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 84
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