New interpretations of Late Cretaceous silicoflagellate evolution and biostratigraphy; recent discoveries from the Canadian Arctic

Author(s): McCartney, Kevin; Witkowski, Jakub; Harwood, David
Author Affiliation(s): Primary:
University of Maine at Presque Isle, Department of Environmental Sciences, Presque Isle, ME, United States
Other:
University of Warsaw, Poland
University of Nebraska, United States
Volume Title: Geological Society of America, 2011 annual meeting
Source: Abstracts with Programs - Geological Society of America, 43(5), p.641; Geological Society of America, 2011 annual meeting, Minneapolis, MN, Oct. 9-12, 2011. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0016-7592 CODEN: GAAPBC
Note: In English
Summary: Unusual and well-preserved fossil silicoflagellates are described from marine sediments of the Kanguk Formation on the northern Canada Arctic Margin and Archipelago. These include new taxa (two new genera and many new species) from Santonian and Campanian time intervals not previously studied for silicoflagellates. This work, combined with studies of the late Campanian silicoflagellates of DSDP Site 275 (southwest Pacific Ocean), Maastrichtian of DSDP Site 216 (northeast Indian Ocean) and Albian of ODP Site 693 (Weddell Sea, Antarctica), allow expansion of the Cretaceous silicoflagellate biostratigraphy to comprise seven zones that replaces the previous single Cretaceous zone. This also provides a more detailed interpretation of silicoflagellate evolution, including the timing of first appearances of important genera. The early Campanian record shows the evolution of Corbisema apical plates and unusual morphologies of Arctyocha. The important genus Lyramula makes its first appearance at the beginning of the Campanian. Of particular interest are Santonian sediments preserved in down-faulted grabens on Devon Island. They were deposited in a shallow marine shelf setting that was never deeply buried. This preserved the fragile opal-A structure that is lost with deeper burial, while the footwalls protected the sediments from late Cenozoic glacial erosion. This silicoflagellate flora is the second oldest report for this group and includes the previously enigmatic genera Cornua and Variramus, and new genera Schulzyocha and Umpiocha. These genera lack the basal rings associated with all Cenozoic silicoflagellate skeletal morphologies and require a new descriptive terminology. Discoveries of double skeletons for three genera show a morphological coupling different than known for Cenozoic silicoflagellates.
Year of Publication: 2011
Research Program: DSDP Deep Sea Drilling Project
ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Arctic Archipelago; Biologic evolution; Biostratigraphy; Campbell Plateau; Canada; Cretaceous; DSDP Site 216; DSDP Site 275; Deep Sea Drilling Project; Framework silicates; Indian Ocean; Interpretation; Invertebrata; Leg 113; Leg 22; Leg 29; Mesozoic; Microfossils; Morphology; New taxa; Ninetyeast Ridge; ODP Site 693; Ocean Drilling Program; Opal; Opal-A; Pacific Ocean; Preservation; Protista; Silica minerals; Silicates; Silicoflagellata; South Pacific; Southern Ocean; Southwest Pacific; Upper Cretaceous; Weddell Sea; West Pacific
Coordinates: N012743 N012744 E0901229 E0901228
S502620 S502620 E1761859 E1761859
S704954 S704953 W0143424 W0143425
Record ID: 2013053088
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States