T237 Insights from Microfossils and Their Modern Analogs: From Traditional and Emerging Approaches, to Critical Re-Evaluations (Posters)

Wednesday, 18 October 2023
8:00 AM - 5:30 PM
Hall B

LATE EARLY TO EARLY MIDDLE EOCENE FORAMINIFERA FROM IODP EXPEDITION 396 SITE U1574 ON THE ELDHØ OUTER HIGH, VØRING PLATEAU, NORWEGIAN MARGIN

Paper number: T237-6
Program: Technical Sessions
Time: 8:00 AM – 5:30 PM

Authors

Abstract

International Ocean Discovery Program (IODP) Expedition 396 embarked to the Norwegian Margin to study the North Atlantic Igneous Province (NAIP) and to understand the relationship between magmatism and the Paleocene-Eocene paleoclimate. The use of calcareous microfossils aids in our understanding of Early Eocene paleoclimate and paleoceanography (i.e., hothouse and large-scale freshwater incursion into the North Atlantic). Holes U1574A and C were drilled on top of the Eldhø (paleovolcano) located on the northern flank of the Vøring Plateau. Calcareous microfossils were mostly absent from the ~140 m thick late Lower Eocene sediment section of Hole U1574A, except for the lowermost ~20 m directly overlying the igneous basement. This section contained rare moderately well-preserved calcareous microfossils including nannofossils, planktonic and benthic foraminifera, and micro-mollusks, including aragonitic pteropods. The late Early Eocene age of the sediments at Site U1574 were assigned by the presence of dinocyst marker species (Subzone E3a and E3b (~44–49.8 Ma) of Bujak and Mudge, 1994). A tentative basal age placement in subzone E7a (~46–49 Ma) of Wade et al. (2011) was based on broader foraminiferal assemblage characteristics, consistent with the dinocyst biostratigraphy.

Eighty-nine samples from Holes U1574A and U1574C were selected for a more detailed taxonomic study of the foraminifera. Of these silica-rich sand to clay samples, 36 samples yield rare to trace abundances with moderate to good preservation of benthic and planktonic foraminifera with pyritized tests and pyrite framboids. Rare micro-mollusks (including pteropods) and ichthyoliths are noted. Three samples show minor amounts of Paleocene reworking. Among the most abundant planktonic foraminifera are Subbotina sp., S. eocaena, Pseudohastigerina wilcoxensis, Globanomalina sp., and G. australiformis. Benthic assemblages are dominated by species of Cancris, Nonion, and Lenticulina and suggest shallow depths (i.e., outer neritic or upper bathyal). Future work aims to combine our data with other datasets to refine the biostratigraphic and palaeoceanographic interpretation of the late Early to early Middle Eocene environments in the Vøring Plateau, Norwegian Margin.

Geological Society of America Abstracts with Programs. Vol. 55, No. 6

doi: 10.1130/abs/2023AM-392849

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