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Please use this identifier to cite or link to this item: http://hdl.handle.net/2122/5051

Authors: Agnini, C.*
Macrì, P.*
Backman, J.*
Brinkhuis, H.*
Fornaciari, E.*
Giusberti, L.*
Luciani, V.*
Rio, D.*
Sluijs, A.*
Speranza, F.*
Title: An early Eocene carbon cycle perturbation at ~52.5 Ma in the Southern Alps: Chronology and biotic response
Title of journal: Paleoceanography
Series/Report no.: / 24 (2009)
Publisher: AGU
Issue Date: 14-May-2009
DOI: 10.1029/2008PA001649
Keywords: Paleoclimate
Hyperthermal events
Early Eocene
Bio-magnetostratigraphy
Geochemistry
Abstract: At least two transient events of extreme global warming occurred superimposed on the long-term latest Paleocene and early Eocene warming trend in the Paleocene-Eocene thermal maximum (PETM) (or ETM1 ~55.5 Ma) and the Elmo (or ETM2 ~53.6 Ma). Other than warmth, the best known PETM is characterized by (1) significant injection of 13C-depleted carbon into the ocean-atmosphere system, (2) deep-sea carbonate dissolution, (3) strong biotic responses, and (4) perturbations of the hydrological cycle. Documentation of the other documented and suspected "hyperthermals" is, as yet, insufficient to assess whether they are similar in nature to the PETM. Here we present and discuss biomagnetostratigraphic data and geochemical records across two lower Eocene successions deposited on a continental margin of the western Tethys: the Farra and Possagno sections in the Venetian pre-Alps. We recognize four negative carbon isotope excursions within chron C24. Three of these shifts correlate to known or suspected hyperthermals: the PETM, the Eocene thermal maximum 2 (~53.6 Ma), and the informally named "X event" (~52.5 Ma). The fourth excursion lies within a reverse subchron and occurred between the latter two. In the Farra section, the X event is marked by a ~0.6% negative carbon isotope excursion and carbonate dissolution. Furthermore, the event exhibits responses among calcareous nannofossils, planktic foraminifera, and dinoflagellates that are similar to, though less intense than, those observed across the PETM. Sedimentological and quantitative micropaleontological data from the Farra section also suggest increased weathering and runoff as well as sea surface eutrophication during this event.
Appears in Collections:04.05.09. Environmental magnetism
04.05.06. Paleomagnetism
04.04.10. Stratigraphy
Papers Published / Papers in press

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