A mid to late Holocene ultra high-resolution foraminiferal biofacies record from IODP Expedition 318; Wilkes Land, Adelie Trough, Antarctica

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Author(s): Salman, Farah I.; La Courte, Kristine; Hendricks, Elyzabeth I. M.; Pekar, Stephen F.; Decesare, Matthew
Author Affiliation(s): Primary:
Queens College, School of Earth and Environmental Sciences, Flushing, NY, United States
Volume Title: Geological Society of America, Northeastern Section, 49th annual meeting
Source: Abstracts with Programs - Geological Society of America, 46(2), p.88; Geological Society of America, Northeastern Section, 49th annual meeting, Lancaster, PA, March 23-25, 2014. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0016-7592 CODEN: GAAPBC
Note: In English
Summary: An ultra high-resolution foraminiferal biofacies study was conducted using samples from the Integrated Ocean Drilling Program (IODP) Expedition 318: Wilkes Land, Site U1357, which is located in the Adelie Trough, Antarctica. The Adelie Trough is a glacially scoured, ∼1000 meters deep basin, located on the continental shelf off of Wilkes Land. In collaboration with Stanford University, a total of 1,800 samples were taken from the 186-meter long core from Hole U1357A at 10 cm intervals for foraminiferal analysis. For this study, 800 samples were taken from the upper half of the core (<90 meters below sea floor, mbsf), which was dated from ∼6.4 kyr to present. These samples were washed to remove the clay and silt size particles and then were examined using stereo binocular microscopes to pick and identify both planktonic and benthic foraminifers. Thus far, over 300 samples have been examined for foraminiferal biofacies and stable isotope analysis from the foraminiferal tests to investigate paleoceanographic and paleoclimatic changes in the Adelie trough in the middle to late Holocene. Preliminary results show generally low foraminiferal abundances and diversity throughout the study interval. Over 30 species of benthic foraminifers have so far been identified, with Neogloboquadrina pachyderma sinistral representing over 98% of the planktonic foraminifers observed. Planktonic foraminiferal abundances are generally higher below 49.2 mbsf (3.7 kyr). The agglutinated Trochammina spp. species are generally the dominant taxa throughout the samples examined. Cibicides spp. abundances are higher between 27 to 60 mbsf (2.7 to 4.7 kyr) and again above 10 mbsf (<1,000 kyr). Epistominella spp. are more abundant between 47.8 and 75.7 mbsf (3.6 and 5.5 kyr). Globocassidulina and Quinquelculina spp. are also more abundant below 70 mbsf (∼5.2 kyr). The higher abundances of calcareous benthic forms are interpreted to represent higher oxygen levels and less corrosive waters for the bottom waters. This suggests better ventilated bottom waters may have been occurring during the Mid Holocene warming. The high dominance of agglutinated forms in the upper part of the section suggests that bottom waters during the Neoglacial (3.5 kyr-present) were more corrosive and contained lower oxygen content.
Year of Publication: 2014
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Adelie Trough; Antarctica; Assemblages; Biofacies; Cenozoic; Expedition 318; Foraminifera; Holocene; IODP Site U1357; Integrated Ocean Drilling Program; Invertebrata; Marine environment; Microfossils; Paleo-oceanography; Paleoenvironment; Protista; Quaternary; Southern Ocean; Wilkes Land
Coordinates: S662448 S662448 E1402531 E1402531
Record ID: 2014094314
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States