Orbital parameters controlling the western Iberian vegetation and climate during the Middle Pleistocene Transition; evidence from the extreme interglacial MIS 31

Online Access: Get full text
http://meetingorganizer.copernicus.org/EGU2018/EGU2018-19826.pdf
Author(s): Oliveira, Dulce; Desprat, Stéphanie; Naughton, Filipa; Polanco-Martínez, Josué M.; Jimenez-Espejo, Francisco J.; Grimalt, Joan O.; Martrat, Belen; Voelker, Antje H. L.; Trigo, Ricardo; Hodell, David; Abrantes, Fatima; Goñi, Maria Fernanda Sánchez
Author Affiliation(s): Primary:
Université Bordeaux, EPOC, UMR 5805, PESSAC, France
Other:
Instituto Portugues do Mar e da Atmosfera (IPMA), Divisao de Geologia e Georecursos Marinhos, Portugal
Japan Agency for Marine-Earth Science and Technology, Japan
CSIC, Department of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA), Spain
Universidade de Lisboa, Instituto Dom Luiz, Portugal
University of Cambridge, Godwin Laboratory for Palaeoclimate Research, United Kingdom
Volume Title: European Geosciences Union general assembly 2018
Source: Geophysical Research Abstracts, Vol.20; European Geosciences Union general assembly 2018, Vienna, Austria, April 8-13, 2018. Publisher: Copernicus GmbH on behalf of the European Geosciences Union (EGU), Katlenburg-Lindau, Germany. ISSN: 1029-7006
Note: In English
Summary: The study of past interglacials, periods of reduced ice volume like our present interglacial, the Holocene, is crucial for understanding the future climate. The so-called "super interglacial" MIS 31 (1.082-1.062 ka) is a period of primary interest in this regard as it is considered among the best analogues for the current and projected global warming. However, key questions remain about the regional signature of its extreme orbital forcing and intra-interglacial variability. Based on a new direct land-sea comparison in SW Iberian margin IODP Site U1385 we examine the climatic variability between 1100 and 1050 ka including the "super interglacial" MIS 31, a period dominated by the 41-ky obliquity periodicity. Pollen and biomarker analyses at centennial-scale-resolution provide new insights into the regional vegetation, precipitation regime and atmospheric and oceanic temperature variability on orbital and suborbital timescales. The MIS 31 extreme insolation (precession) forcing was favorable for an anomalously warm interglacial characterized by enhanced seasonality in the SW Iberia region. However, our study shows that, unlike other locations at higher latitudes, atmospheric and sea-surface temperatures were not exceptionally high in the context of other middle- to late Pleistocene interglacials. Moreover, the Site U1385 pollen-based vegetation record reveals for the first time an unexpected temperate and humid climate regime marked by low abundance of Mediterranean sclerophylls and the development of diverse summer drought-intolerant trees. This muted seasonality during MIS 31 is consistent with analysis of vegetation dynamics and cross-correlation coefficients showing a dominant influence of obliquity on the forest development rather than precession. Prevailing obliquity-driven vegetation and climatic changes, in agreement with modeling experiments, are likely associated to a decrease in the seasonal distribution of rainfall in SW Iberia resulting from higher summer precipitation associated to obliquity maxima rather than to precession minima. [Copyright Author(s) 2018. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]
Year of Publication: 2018
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Atlantic Ocean; Cenozoic; Expedition 339; IODP Site U1385; Integrated Ocean Drilling Program; Interglacial environment; Middle Pleistocene; North Atlantic; Paleoclimatology; Paleoecology; Paleoenvironment; Pleistocene; Quaternary
Coordinates: N373417 N373417 W0100719 W0100720
Record ID: 2019022954
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from European Geosciences Union, Munich, Germany