Fluvio-deltaic record of increased sediment transport during the Middle Eocene Climatic Optimum (MECO), Southern Pyrenees, Spain
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License: CC BY 4.0
UNIL restricted access
State: Public
Version: author
License: CC BY 4.0
Serval ID
serval:BIB_1623EA1734BE
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Fluvio-deltaic record of increased sediment transport during the Middle Eocene Climatic Optimum (MECO), Southern Pyrenees, Spain
Journal
Climate of the Past
ISSN
1814-9332
Publication state
Published
Issued date
08/03/2023
Peer-reviewed
Oui
Volume
19
Number
3
Pages
533-554
Language
english
Abstract
The early Cenozoic marine sedimentary record is punctuated by several brief episodes (<200 kyr) of abrupt global warming, called hyperthermals, that have disturbed ocean life and water physicochemistry. Moreover, recent studies of fluvial–deltaic systems, for instance at the Palaeocene–Eocene Thermal Maximum, revealed that these hyperthermals also impacted the hydrologic cycle, triggering an increase in erosion and sediment transport at the Earth's surface. Contrary to the early Cenozoic hyperthermals, the Middle Eocene Climatic Optimum (MECO), lasting from 40.5 to 40.0 Ma, constitutes an event of gradual warming that left a highly variable carbon isotope signature and for which little data exist about its impact on Earth surface systems. In the South Pyrenean foreland basin (SPFB), an episode of prominent deltaic progradation (Belsué–Atarés and Escanilla formations) in the middle Bartonian has been usually associated with increased Pyrenean tectonic activity, but recent magnetostratigraphic data suggest a possible coincidence between the progradation and the MECO warming period. To test this hypothesis, we measured the stable-isotope composition of carbonates (δ13Ccarb and δ18Ocarb) and organic matter (δ13Corg) of 257 samples in two sections of SPFB fluvial–deltaic successions covering the different phases of the MECO and already dated with magnetostratigraphy. We find a negative shift in δ18Ocarb and an unclear signal in δ13Ccarb around the transition from magnetic chron C18r to chron C17r (middle Bartonian). These results allow, by correlation with reference sections in the Atlantic and Tethys, the MECO to be identified and its coincident relationship with the Belsué–Atarès fluvial–deltaic progradation to be documented. Despite its long duration and a more gradual temperature rise, the MECO in the South Pyrenean foreland basin may have led, like lower Cenozoic hyperthermals, to an increase in erosion and sediment transport that is manifested in the sedimentary record. The new data support the hypothesis of a more important hydrological response to the MECO than previously thought in mid-latitude environments, including those around the Tethys.
Keywords
Paleontology, Stratigraphy, Global and Planetary Change
Open Access
Yes
Funding(s)
Swiss National Science Foundation / 200020_182017
Create date
12/03/2023 19:21
Last modification date
06/05/2023 6:49