High paleolatitude Cenomanian planktonic Foraminifera from IODP Expedition 369 sites drilled on Mentelle Basin, SE Indian Ocean

Author(s): Goughnour, Rebecca; Huber, Brian T.; Petrizzo, Maria Rose
International Ocean Discovery Program Expedition 369 Scientists
Author Affiliation(s): Primary:
Adrian College, Department of Geology, Adrian, MI, United States
Smithsonian Institution National Museum of Natural History, United States
Universita di Milano, Italy
Volume Title: Geological Society of America, 2018 annual meeting & exposition
Source: Abstracts with Programs - Geological Society of America, 50(6); Geological Society of America, 2018 annual meeting & exposition, Indianapolis, IN, Nov. 4-7, 2018. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0016-7592 CODEN: GAAPBC
Note: In English
Summary: Cenomanian planktonic foraminifera from southern high latitudes have been poorly documented because few austral deep-sea sites have penetrated the Mid-Cretaceous sediment record and, among those, the drilled sequences were incomplete because of poor core recovery and/or presence of unconformities. During 2017, International Ocean Discovery Program (IODP) Expedition 369 recovered biostratigraphically complete late Albian-Cenomanian black claystone and nannofossil-rich claystone at Sites U1513, U1514 and U1516 in the Mentelle Basin, which is located in offshore SW Australia. These sites all were positioned at ∼60°S paleolatitude in the SE Indian Ocean during the mid-Cretaceous. Foraminifera in the mid- to upper Cenomanian cores are moderately to well preserved and are quite rare relative to the sediment volume. The percentage of planktic specimens relative to benthics generally ranges from 70-90%. The planktic assemblages are dominated by small-sized species of Microhedbergella with very rare occurrences of Whiteinella spp. and Schackoina cenomana. Biserial and planispiral planktonic species are surprisingly rare and sporadic in their distribution at the Mentelle Basin sites; these taxa are generally considered as opportunistic and are relatively common at other austral locations during the mid-Cretaceous. Low latitude planktic species that have been traditionally used as biostratigraphic markers occur in very few samples and, where present, there is typically only 1 specimen. Along similar lines, lower Cenomanian foraminiferal assemblages are dominated by agglutinated species, and in some samples calcareous foraminifera are completely absent. The lower Cenomanian sequences show strong apparent changes in the carbonate compensation depth with the percentage of planktic specimens relative to benthics varying from 0-50%. Further study of the Expedition 369 Cenomanian core samples, combined with foraminiferal stable isotopes, will reveal much more about the paleoceanographic factors that influenced the planktic foraminiferal population dynamics and species composition.
Year of Publication: 2018
Research Program: IODP Integrated Ocean Drilling Program
IODP2 International Ocean Discovery Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Assemblages; Biostratigraphy; Carbonate compensation depth; Cenomanian; Cretaceous; Expedition 369; Foraminifera; IODP Site U1513; IODP Site U1514; IODP Site U1516; Indian Ocean; International Ocean Discovery Program; Marine environment; Mentelle Basin; Mesozoic; Microfossils; Paleo-oceanography; Paleoenvironment; Planktonic taxa; Upper Cretaceous
Coordinates: S342055 S330714 E1130529 E1122908
Record ID: 2019046005
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States