Paleoenvironmental changes during the early Eocene on the South Tasman Rise; Ocean Drilling Program ODP Site 1171

Online Access: Get full text
Author(s): Bandoo, Ardanna L.; Pekar, Stephen F.; Ferrantelli McDonald, Natalie
Author Affiliation(s): Primary:
City University of New York, Queens College, Flushing, NY, United States
Volume Title: Geological Society of America, Northeastern Section, 47th annual meeting
Source: Abstracts with Programs - Geological Society of America, 44(2), p.49; Geological Society of America, Northeastern Section, 47th annual meeting, Hartford, CT, March 18-20, 2012. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0016-7592 CODEN: GAAPBC
Note: In English
Summary: Paleoenvironmental changes were determined by developing an integrated sequence stratigraphic framework in early Eocene sediments obtained from ODP (Ocean Drilling Program) Leg 189 Site 1171 (located on the South Tasman Rise). This was accomplished by using grain size analysis, foraminiferal biofacies and planktonic/benthic foraminiferal ratios. Grain size analysis was used to determine changes in the water depth, foraminiferal biofacies provided information on paleoenvironmental changes (e.g., water depths, bottom water oxygen levels, etc.) and planktonic/benthic foraminiferal ratios were used to estimate water depths. The South Tasman Rise is an ideal location to investigate paleooceanographic and climatic changes around Antarctica, as it was near Antarctica during the early Eocene. Additionally, this foraminiferal study represents among the most southerly early Eocene sites with well-preserved calcareous microfossils. Grain size analysis shows that the percentage of muds ranged from 90 to 95%, indicating low energy environments, with water depths being generally below storm wave base. In the samples examined, foraminiferal taxa alternated between agglutinates and calcareous forms. Dominant benthic calcareous genera include: Lenticulina, Bolivina, Guttulina, Elphidium and Fissurina. Planktonic/benthic foraminiferal ratios ranged from 0 to 12%, which suggest shallow waters on the shelf, although dissolution recognized in some samples may have biased these ratios. Taking together the lithofacies and biofacies data, two sequence boundaries were identified at 51.0 Ma and 52.5 Ma. A possible third sequence boundary occurs at 51.5 Ma. Records from other shallow-water margins and deep-sea oxygen records correlates well with these three sequence boundaries suggesting a global mechanism.
Year of Publication: 2012
Research Program: ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Benthic environment; Cenozoic; Eocene; Foraminifera; Grain size; Granulometry; Invertebrata; Leg 189; Lower Eocene; Marine environment; Marine sediments; Microfossils; ODP Site 1171; Ocean Drilling Program; Pacific Ocean; Paleo-oceanography; Paleoenvironment; Paleogene; Protista; Sediments; South Pacific; South Tasman Rise; Southwest Pacific; Tasman Sea; Tertiary; West Pacific
Coordinates: S483000 S482900 E1490700 E1490600
Record ID: 2012085843
Copyright Information: GeoRef, Copyright 2018 American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States