Variations in benthic foraminifera biofacies since Mid-Pleistocene (MIS 7) in the Campos Basin slope, Eastern Brazil: Assessing present-day and past controlling factors

Benthic and planktonic foraminifera faunal and stable isotopic (δ18O and δ13C) analyses on foraminiferal tests were carried out on a piston core, collected from the Campos Basin slope at a water depth of 1475 m. The core location is in front of Cape São Tomé and exhibits landslide scars features. Be...

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Bibliographic Details
Main Authors: Gasparini, SP, Vilela, CG, Maslin, M, Ferreira, KF
Format: Article in Journal/Newspaper
Language:English
Published: ELSEVIER 2023
Subjects:
Science & Technology
Life Sciences & Biomedicine
Paleontology
Biofacies
Slope
Productivity
River influence
Isotopes
S Atlantic
DEEP-SEA FORAMINIFERA
DISTRIBUTION PATTERNS
ORGANIC-MATTER
OCEAN-FLOOR
MARGIN
ASSEMBLAGES
COASTAL
SHELF
PALEOPRODUCTIVITY
Planktonic foraminifera
Online Access:https://discovery.ucl.ac.uk/id/eprint/10179306/3/Maslin_Manuscript-1.pdf
https://discovery.ucl.ac.uk/id/eprint/10179306/
Description
Summary:Benthic and planktonic foraminifera faunal and stable isotopic (δ18O and δ13C) analyses on foraminiferal tests were carried out on a piston core, collected from the Campos Basin slope at a water depth of 1475 m. The core location is in front of Cape São Tomé and exhibits landslide scars features. Benthic foraminifera biofacies with ecological indexes and statistics, lithological facies, biostratigraphy and stable isotopic analysis were used to understand the paleoenvironmental evolution of the region by comparison with modern foraminiferal assemblage. Six biofacies were identified between Marine Isotope Stage (MIS) 7 to MIS 1. The main ecological factors controlling the modern assemblages are: bottom currents, slope stability, oxygen concentration, and nutrient input. However, the last two factors are linked to oceanic processes associated with the Paraíba do Sul river, the influence of which has changed in the past. In particular, Biofacies 3, contains infaunal species, points to dysoxic or anoxic periods in the environment, which are interpreted as periods of increased river influence. Changing environmental conditions were observed as the dominant benthic foraminifera species varied down the core, from Epistominella exigua that thrives in stressful conditions, such as sea level oscillations to Globocassidulina crassa, that prefers mild environments during periods of sea level stability.

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