Santonian deep sea benthic foraminifera from IODP Site U1513, Mentelle Basin (SW Australia): Reactions of benthic foraminiferal assemblages to surface water cooling at southern high latitudes

Author(s)

erik wolfgring, Maria Rose Petrizzo, Kenneth G. MacLeod, Brian T. Huber, David K. Watkins

Abstract

International Ocean Discovery Program (IODP) Expedition 369 recovered a stratigraphically complete, Santonian-aged, pelagic sedimentary sequence at Site U1513 on the Naturaliste Plateau (33°47.6084′S, 112°29.1338′E) at ~2800 m water depth. The site was located at ~60°S paleolatitude in Cretaceous times. A total of 59 samples studied from Holes 1513A and 1513B yielded 140 calcareous and nine agglutinated benthic foraminiferal taxa. Gavelinellids (Notoplanulina, Gavelinella, Anomalinoides) and Gyroidinoides spp., are the most abundant taxa overall and also dominate most samples. We also report 382 foraminiferal stable isotopic measurements and infer cooling [of ~5 °C in surface waters and 2 °C at the seafloor] based on changes in δ

¹⁸O values for benthic and planktonic taxa through the Santonian at Site U1513. Inferred cooling was accompanied by changes in planktonic and benthic foraminiferal assemblages. At Site U1513, benthic foraminiferal taxonomic richness declines by 15 species (from 20– 25 to 5–10 taxa) towards the upper Santonian. Within this interval, epifaunal, oxic foraminifera diminish in absolute and relative abundance, and there is a parallel relative increase in opportunistic taxa and infaunal foraminifera. Changes in benthic foraminiferal communities indicate a shift from oligotrophic to eutrophic conditions in the bottom water despite the general cooling trend. This paper explores the causes and effects of the paleoenvironmental changes in the bottom waters.

Organisation(s)

Department of Palaeontology

External organisation(s)

Università degli Studi di Milano-Bicocca, University of Missouri-Columbia, Smithsonian Institution, University of Nebraska-Lincoln

Journal

Marine Micropaleontology

Volume

175

ISSN

0377-8398

DOI

https://doi.org/10.1016/j.marmicro.2022.102152

Publication date

08-2022

Peer reviewed

Yes

Austrian Fields of Science 2012

105107 Geoelectrics

Keywords

ASJC Scopus subject areas

Oceanography, Palaeontology

Portal url

https://ucrisportal.univie.ac.at/en/publications/497e70ef-050c-4c2f-8b64-1a78a2c5b25b