Dinocyst and acritarch biostratigraphy of the Late Pliocene to Early Pleistocene at Integrated Ocean Drilling Program Site U1307 in the Labrador Sea

Aubry, Aurélie; De Schepper, Stijn et de Vernal, Anne (2020). « Dinocyst and acritarch biostratigraphy of the Late Pliocene to Early Pleistocene at Integrated Ocean Drilling Program Site U1307 in the Labrador Sea ». Journal of Micropalaeontology, 39, pp. 41-60.

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Résumé

We have analyzed marine palynomorphs (mainly dinocysts and acritarchs) from the Integrated Ocean Drilling Program Site U1307 in the Labrador Sea in order to establish a detailed biostratigraphy for the Late Pliocene to Early Pleistocene. We have defined three magnetostratigraphically calibrated dinocyst and acritarch biozones in the Late Pliocene to Early Pleistocene. Zone LS1 is defined based on the highest occurrence of Barssidinium graminosum and covers the later Pliocene from 3.21 to 2.75 Ma. Zone LS2 is marked by the acme of Pyxidinopsis braboi which occurs between 2.75 and 2.57 Ma, thus encompassing the Plio–Pleistocene transition. Finally, zone LS3 extends from 2.57 to 2.23 Ma in the Early Pleistocene. The palynostratigraphic record of IODP Site U1307 is difficult to correlate to other North Atlantic and Nordic Seas sites mainly because of a different temporal resolution and a lack of well-defined biostratigraphic marker species at the basin scale. The low abundance, discontinuous occurrence and asynchronous events of warm-water Pliocene taxa such as Invertocysta lacrymosa, Impagidinium solidum, Ataxiodinium confusum, Melitasphaeridium choanophorum and Operculodinium? eirikianum suggest cooler conditions in the Labrador Sea than elsewherein the North Atlantic, reflecting a strong regionalism. Nevertheless, as recorded at other locations in the North Atlantic, the disappearance of many dinocyst and acritarch taxa around 2.75 Ma at Site U1307 reflects a strong ecological response accompanying the intensification of the Northern Hemisphere glaciation.

Type: Article de revue scientifique
Informations complémentaires: Il s'agit du Chapitre I de la thèse de doctorat en sciences de la Terre de l'UQAM d'Aurélie Aubry. L'article est publié en "Open access"
Mots-clés ou Sujets: Pliocène, glaciations, Groenland, dinokystes, biostratigraphie
Unité d'appartenance: Centres institutionnels > Centre de recherche en géochimie et géodynamique (GEOTOP)
Déposé par: Anne de Vernal
Date de dépôt: 23 mars 2020 09:43
Dernière modification: 23 mars 2020 09:43
Adresse URL : http://archipel.uqam.ca/id/eprint/13316

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