Latest Cretaceous climatic and environmental change in the South Atlantic region

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Author(s): Woelders, Lineke; Vellekoop, Johan; Smit, Jan; Kroon, Dick; Casadío, Silvio; Prámparo, Mercedes; Dinarès-Turell, Jaume; Peterse, Francien; Sluijs, Appy; Speijer, Robert
Author Affiliation(s): Primary:
Katholieke Universiteit Leuven, Leuven, Belgium
Utrecht University, Netherlands
Vrije University Amsterdam, Netherlands
University of Edinburgh, United Kingdom
Universidad Nacional de Rio Negro, Argentina
IANIGLA, Argentina
Istituto Nazionale di Geofisica e Vulcanologia, Italy
Volume Title: AGU 2016 fall meeting
Source: American Geophysical Union Fall Meeting, Vol.2016; American Geophysical Union 2016 fall meeting, San Francisco, CA, Dec. 12-16, 2016. Publisher: American Geophysical Union, Washington, DC, United States
Note: In English
Summary: It is generally assumed that the Chicxulub impact resulted in the Cretaceous-Paleogene (K-Pg) boundary mass extinction (∼66 Ma). However, there is continuing debate about the contribution of latest Maastrichtian climate changes, possibly caused by Deccan volcanism, to this mass extinction event. This debate is complicated because of the lack of high quality latest Maastrichtian climatological and ecological reconstructions. Here we present an astronomically tuned late Maastrichtian - early Danian record of bulk carbonate δ18O, a proxy record of sea surface temperature (SST), from Southern Atlantic Ocean Drilling Program Site 1262 (Walvis Ridge) and a late Maastrichtian TEX86 sea surface temperature record from the Bajada del Jaguel site in the Neuquen Basin (Argentina). The combination of these inferred temperature records with foraminiferal and organic-walled dinoflagellate cyst (dinocyst) data from Bajada del Jaguel allows to reconstruct environmental changes across this time interval in a mid-latitude, Southern Atlantic setting. Our results show that latest Maastrichtian warming of ∼2.5-4°C started gradually around 66.7 Ma, culminating in the interval between 450 to 150 kyr before the K-Pg boundary. Highest temperatures occurred ∼200 kyr before the K-Pg boundary. During the last 150 kyr of the Maastrichtian, the temperature trend reversed again at both sites. Benthic foraminiferal and dinocyst assemblage changes indicate that late Maastrichtian warming resulted in more humid climate conditions in the Neuquen basin, causing enhanced runoff and stratification of the water column. Vice versa, the subsequent cooling induced again a drier climate in the basin, resulting in reduced salinity stratification and better ventilation of the basin. We conclude that late Maastrichtian climate and sea level change caused distinct environmental perturbations in the Neuquen basin, although it remains uncertain to which extent late Maastrichtian climatological changes contributed directly to the K-Pg boundary mass extinction.
Year of Publication: 2016
Research Program: ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Argentina; Atlantic Ocean; Bajada del Jaguel; Cretaceous; Dinoflagellata; Leg 208; Mesozoic; Microfossils; Neuquen Basin; ODP Site 1262; Ocean Drilling Program; Palynomorphs; Sea-surface temperature; South America; South Atlantic; Upper Cretaceous; Walvis Ridge
Coordinates: S271100 S271100 E0013500 E0013400
Record ID: 2018008241
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