Evolution of the Cretaceous calcareous nannofossil genus Eiffellithus and its biostratigraphic significance

Online Access: Get full text
doi: 10.1016/j.cretres.2009.03.009
Author(s): Shamrock, J. L.; Watkins, D. K.
Author Affiliation(s): Primary:
University of Nebraska at Lincoln, Department of Geosciences, Lincoln, NE, United States
Volume Title: Cretaceous Research
Source: Cretaceous Research, 30(5), p.1083-1102. Publisher: Elsevier, United Kingdom. ISSN: 0195-6671
Note: In English. Based on Publisher-supplied data; includes appendix; illus., incl. charts, 5 plates, 1 table, sketch map
Summary: The calcareous nannofossil genus Eiffellithus is an important taxon of mid- to Upper Cretaceous marine sediments in biostratigraphy and paleoceanography. The definition of species within Eiffellithus have been both broadly interpreted and variably applied by nannofossil workers. This is particularly true for the Eiffellithus eximius plexus. While the taxonomy of mid-Cretaceous Eiffellithus species has recently been well-defined, the remaining 35 m.y. history of the genus has not been closely examined. Our investigation of Cenomanian to Maastrichtian sediments from the Western Interior Seaway, Gulf of Mexico, and Western Atlantic gives rise to six new species of Eiffellithus that can be reliably differentiated. In this paper the hitherto used biostratigraphic markers (E. turriseiffelii and E. eximius) have been redefined in a more restricted sense to increase their utility. These refinements in taxonomy reveal an obvious shift in abundance both within the genus and within the nannofossil assemblage as a whole through the Late Cretaceous. In the Cenomanian and Maastrichtian the genus is composed exclusively of coccoliths bearing an X-shaped central cross, such as E. turriseiffelii, while in the Coniacian through Campanian axial-cross forms such as E. eximius comprise more than 60% of the genus. Within the nannofossil assemblage the genus has low abundances in the Cenomanian but increases to >15% of the assemblage in well-preserved samples in the Santonian. In addition, the pattern of diversification of this genus, whereby a x-shaped, diagonal cross repeatedly gives rise to an axial cross by rotation about the central axis, is an excellent example of iterative evolution that may be related to repetitive shifts in Late Cretaceous climatic and paleoceanographic regimes. Abstract Copyright (2009) Elsevier, B.V.
Year of Publication: 2009
Research Program: DSDP Deep Sea Drilling Project
ODP Ocean Drilling Program
Key Words: 10 Paleontology, Invertebrate; 12 Stratigraphy, Historical Geology and Paleoecology; Algae; Atlantic Ocean; Biostratigraphy; Blake Nose; Blake Plateau; Campanian; Cenomanian; Coniacian; Cretaceous; DSDP Site 95; Deep Sea Drilling Project; Eiffellithus; Greenhorn Limestone; Gulf of Mexico; Kansas; Leg 10; Leg 171B; Maestrichtian; Mesozoic; Microfossils; Nannofossils; New taxa; Niobrara Formation; North America; North Atlantic; Northeastern South Dakota; Northern Kansas; ODP Site 1049; ODP Site 1050; Ocean Drilling Program; Paleo-oceanography; Pierre Shale; Plantae; Revision; Roberts County South Dakota; Santonian; Senonian; Sisseton South Dakota; Smokey Hill; South Dakota; Taxonomy; Turonian; United States; Upper Cretaceous; Washington County Kansas; Western Interior; Western Interior Basin; Western Interior Seaway
Coordinates: N240900 N240900 W0862351 W0862351
N300832 N300832 W0760644 W0760644
N300600 N300600 W0761406 W0761406
Record ID: 2010032374
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands