Larger benthic foraminifers of the Marion Plateau, NE Australia (ODP Leg 194); Miocene faunas from bryozoan and red-algal dominated carbonate platforms

Author(s): Hallock, Pamela; Sheps, Kathryn; Howell, Michael W.
Author Affiliation(s): Primary:
University of South Florida, College of Marine Science, St. Petersburg, FL, United States
Volume Title: Geological Society of America, 2004 annual meeting
Source: Abstracts with Programs - Geological Society of America, 36(5), p.370; Geological Society of America, 2004 annual meeting, Denver, CO, Nov. 7-10, 2004. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0016-7592 CODEN: GAAPBC
Note: In English
Summary: Two Neogene carbonate platforms on the Marion Plateau, off northeastern Australia, were drilled during ODP Leg 194. Approximately 510 m of mixed shelf and slope sediments were penetrated at Site 1193; ∼672 m of shallow-water platform sediments were penetrated at Site 1196. Shallow-water carbonates at Site 1193 were dominated by bryozoans. At Site 1196 coralline red algae dominated, with stony corals common in some intervals. Larger benthic foraminifers (LBF) were abundant at both sites; five LBF assemblages were distinguished using thin sections cut from recovered cores. Assemblage A was found in mixed carbonate-terrigenous clastic, neritic facies (<100 m) following basement flooding. Operculina complanata was most common in terrigenous mud-rich facies, while Lepidocyclina spp. with relatively primitive, non-stellate morphologies dominated carbonate-rich facies. These taxa are characteristic of latest Oligocene to early Miocene ages; consistent with nannofossil dates of 18-24 Ma for units immediately above basement. Assemblage B, found in platform facies at sites 1193 and 1196 and in corresponding slope sediments at sites 1197 and 1198, is characterized by predominantly non-stellate lepidocyclinids and ovate miogypsinids. Units containing this assemblage are interpreted to be late-early Miocene (∼16-18 Ma). Assemblage C, found at Site 1196 (183-326 mbsf), is characterized by Flosculinella, Austrotrillina, soritids, and smaller miliolid foraminifers. The middle Miocene (13.3-15.2 Ma) interpretation is consistent with nannofossil dates from the interval. Assemblage D was found in platform facies at sites 1193, 1194, and 1196 and in corresponding slope sediments at sites 1197 and 1198. This assemblage is characterized by the transition from mixed concentric and stellate lepidocyclinids to predominantly stellate forms. Units containing this assemblage are interpreted to be middle Miocene (∼11.9-16.4 Ma). Assemblage E, dominated by Amphistegina with common stellate Lepidocyclina, was found at Site 1196 in upper platform facies, in corresponding periplatform sediments at sites 1197 and 1198, and also in transported sediments at sites 1193 and 1194. Nannofossil and planktic foraminiferal biostratigraphy in periplatform sediments indicate a late Miocene age for this assemblage.
Year of Publication: 2004
Research Program: ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Algae; Amphistegina; Anthozoa; Assemblages; Australasia; Australia; Benthic taxa; Biostratigraphy; Bryozoa; Carbonate platforms; Carbonate sediments; Cenozoic; Cnidaria; Coelenterata; Coral Sea; Depositional environment; Foraminifera; Invertebrata; Leg 194; Lepidocyclina; Lithofacies; Marine environment; Marion Plateau; Microfossils; Miocene; Nannofossils; Neogene; Northeastern Australia; Nummulites; Nummulitidae; ODP Site 1193; ODP Site 1196; ODP Site 1197; ODP Site 1198; Ocean Drilling Program; Oligocene; Operculina; Orbitoidacea; Pacific Ocean; Paleogene; Plantae; Protista; Rhodophyta; Rotaliacea; Rotaliina; Sediments; Shallow-water environment; Shelf environment; Slope environment; South Pacific; Southwest Pacific; Tertiary; West Pacific
Coordinates: S201500 S201400 E1514800 E1514700
S210100 S210000 E1525200 E1525100
S210500 S210400 E1530500 E1530400
S205800 S205700 E1524500 E1524300
Record ID: 2006006985
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