Nannotax3 - ntax_mesozoic - Calculites percernis

Distinguishing features: Small Calculites with four blocks divided along near axial sutures (extinction lines) at 0˚ and diagonal sutures (extinction lines) at 45˚ to the polarising directions.

Citation: Calculites percernis Jeremiah, 1996

Taxonomic discussion: The coccolith was described as formed of "four blocks divided along near axial sutures (extinction lines) at 0˚ and diagonal sutures (extinction lines) at 45˚ to the polarising directions." This description implies a cocolith with continuous rim not one divided into blocks - as understood here.

Geological Range:
Last occurrence (top): within NC10a subzone (100.45-103.13Ma, top in Cenomanian stage). Data source: Gale et al., 2011
First occurrence (base): within NC9b subzone (103.13-107.59Ma, base in Albian stage). Data source: Gale et al., 2011

References:

Bown, P. R. & Concheyro, A. (2004). Lower Cretaceous calcareous nannoplankton from the Neuquen Basin, Argentina. In, Villa, G., Lees, J. A. & Bown, P. R. (eds) Calcareous Nannofossil Palaeoecology and Palaeocenographic Reconstructions, Proceedings of the INA9 conference, Parma 2002. Marine Micropaleontology. 52(1-4): 51-84. gs

Burnett, J. A. (1998). Upper Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 132-199. gs V O

Gale, A. S., Kennedy, W. J., Burnett, J. A., Caron, M. & Kidd, B. E. (1996). The Late Albian to Early Cenomanian succession at Mont Risou, near Rosans (Drôme, SE France): an integrated study (ammonites, inoceramids, planktonic foraminifera, nannofossils, oxygen and carbon isotopes). Cretaceous Research. 17: 515-606. gs

Gale, A. S. et al. (2011). The uppermost Middle and Upper Albian succession at the Col de Palluel, Hautes-Alpes, France: An integrated study (ammonites, inoceramid bivalves, planktonic foraminifera, nannofossils, geochemistry, stable oxygen and carbon isotopes, cyclostratigraphy). Cretaceous Research. 32: 59-130. 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 V O

Lees, J. A. (2007). New and rarely reported calcareous nannofossils from the Late Cretaceous of coastal Tanzania: outcrop samples and Tanzania Drilling Project Sites 5, 9 and 15. Journal of Nannoplankton Research. 29(1): 39-65. gs V O

Tags	LITHS: holococcolith, elliptical, CA: ca_disjunct, pores, closed, CROSS-POLARS: rim-unicyclic, R-prominent,
Metrics	Lith size: 3->5µm; Segments: 4->4; Data source notes: original description

Calculites percernis

References:

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