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The Paleocene-Eocene Thermal Maximum; new data on microfossil turnover at the Zumaia section, Spain

Laia Alegret, Silvia Ortiz, Xabier Orue-Etxebarria, Gilen Bernaola, Juan I. Baceta, Simonetta Monechi, Estibaliz Apellaniz and Victoriano Pujalte
The Paleocene-Eocene Thermal Maximum; new data on microfossil turnover at the Zumaia section, Spain
Palaios (May 2009) 24 (5): 318-328


The benthic foraminiferal turnover and extinction event (BEE) associated with the negative carbon isotope excursion (CIE) across the Paleocene-Eocene Thermal Maximum (PETM) is analyzed in the Zumaia section (Spain), one of the most complete and expanded deep-water sequences known worldwide. New biostratigraphic, paleoecologic, and paleoenvironmental data on benthic foraminifera are correlated to information on planktic foraminiferal and calcareous nannofossil turnover in order to evaluate possible causes and consequences of the PETM. Gradual but rapid extinction of 18% of the benthic foraminiferal species starts at the onset of the CIE, after the initial ocean warming (as inferred from calcareous nannofossils) recorded in the last 46 kyr of the Paleocene. This gradual extinction event culminated approximately 10.5 kyr after the onset of the CIE and led to the main BEE, affecting 37% of the species. Therefore, extinctions across the PETM affected a total of 55% of the benthic foraminiferal species at Zumaia. The gradual extinction occurred under inferred oxic conditions without evidence for carbonate dissolution, indicating that carbonate corrosivity and oxygenation of the ocean bottom waters were not the main cause of the event. An interval characterized by dissolution occurs above the main BEE, suggesting that bottom waters became corrosive after the main extinction. Carbonate is progressively better preserved through the overlying deposits, and carbon isotope values gradually return to background levels. These data are consistent with a slow deepening of the carbonate compensation depth after its initial rise owing to abrupt acidification of the oceans. Microfossil data support a rapid onset of the PETM, followed by long-term effects on calcareous plankton and benthic foraminifera.

ISSN: 0883-1351
Serial Title: Palaios
Serial Volume: 24
Serial Issue: 5
Title: The Paleocene-Eocene Thermal Maximum; new data on microfossil turnover at the Zumaia section, Spain
Affiliation: Universidad de Zaragoza, Departamento de Ciencias de la Tierra, Saragossa, Spain
Pages: 318-328
Published: 200905
Text Language: English
Publisher: Society for Sedimentary Geology, Tulsa, OK, United States
References: 100
Accession Number: 2009-048591
Categories: Stratigraphy
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sect., strat. col., geol. sketch map
N43°17'60" - N43°17'60", W02°15'00" - W02°15'00"
Secondary Affiliation: Universidad del Pais Vasco, ESP, SpainUniversita degli Studi di Firenze, ITA, Italy
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by SEPM (Society for Sedimentary Geology), Tulsa, OK, United States
Update Code: 200926
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