Distinguishing features:
Parent taxon (Broinsonia): Outer rim of V-units, with slight clockwise obliquity, visible on distal surface and form dark rim in LM; central-area spanned by an axial cross, grill or perforate plate. 3 tiers visible in side view.
This taxon: Large Broinsonia (>8 µm) with broad axial cross bars.
Taxonomy:
Farinacci & Howe catalog pages: A. viriosus *
Distinguishing features:
Parent taxon (Broinsonia): Outer rim of V-units, with slight clockwise obliquity, visible on distal surface and form dark rim in LM; central-area spanned by an axial cross, grill or perforate plate. 3 tiers visible in side view.
This taxon: Large Broinsonia (>8 µm) with broad axial cross bars.
Search data:
LITHS: placolith, elliptical, CA: cross-axial, CROSS-POLARS: R-prominent, V-prominent, rim-bicyclic, |
Lith size: 8->11µm; Data source notes: Bown in Kennedy et al. 2000 |
Geological Range:
Last occurrence (top): within Early Albian Substage (109.70-113.20Ma, top in Albian stage). Data source: Jeremiah 1996
First occurrence (base): in lower part of BC22 zone (30% up, 114.2Ma, in Aptian stage). Data source: Bown et al. 1998 (fig 5.2)
Plot of occurrence data:
Bown, P. R. (2001). Calcareous nannofossils of the Gault, Upper Greensand and Glauconitic Marl (Middle Albian-Lower Cenomanian) from the BGS Selborne boreholes, Hampshire. Proceedings of the Geologists' Association. 112: 223-236. gs Jeremiah, J. (1996). A proposed Albian to Lower Cenomanian nannofossil biozonation for England and the North Sea Basin. Journal of Micropalaeontology. 15(97-129): -. gs Kennedy, W. J. et al. (2000). Integrated stratigraphy across the Aptian-Albian boundary in the Marnes Bleues, at the Col de Pre _-Guittard, Arnayon (Drome), and at Tartonne (Alpes-de-Haute-Provence), France: a candidate Global Boundary Stratotype Section and Boundary Point for the base of the Albian Stage. Cretaceous Research. 21: 591-720. gsReferences:
Broinsonia viriosa compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 8-11-2024
Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=10134 Go to Archive.is to create a permanent copy of this page - citation notes |
This policy contains information about your privacy. By posting, you are declaring that you understand this policy:
This policy is subject to change at any time and without notice.
These terms and conditions contain rules about posting comments. By submitting a comment, you are declaring that you agree with these rules:
Failure to comply with these rules may result in being banned from submitting further comments.
These terms and conditions are subject to change at any time and without notice.
Comments