Taxonomy:
Distinguishing features: Medium sized; circular; central area with bright central plug crossed by strongly curving swastika-like extinction lines. Shield elements are usually conspicuous in LM.
Farinacci & Howe catalog pages: C. gammation *
Search data:Tags | LITHS: placolith, circular, CA: ca_conjunct, grill, vacant, CSPH: equant, monomorphic, CROSS-POLARS: rim-bicyclic, V-prominent, R-prominent, |
Metrics | Lith size: 5->9µm; |
Geological Range:
Last occurrence (top): within NP14 zone (46.29-49.11Ma, top in Lutetian stage). Data source: Perch-Nielsen 1985b
First occurrence (base): within NP11 zone (53.70-54.17Ma, base in Ypresian stage). Data source: [PRB rough estimate]
Plot of occurrence data:
Bown, P. R. & Dunkley Jones, T. (2012). Calcareous nannofossils from the Paleogene equatorial Pacific (IODP Expedition 320 Sites U1331-1334). Journal of Nannoplankton Research. 32(2): 3-51. gs V O Bown, P. R. & Newsam, C. (2017). Calcareous nannofossils from the Eocene North Atlantic Ocean (IODP Expedition 342 Sites U1403–1411). Journal of Nannoplankton Research. 37(1): 25-60. gs V O Bramlette, M. N. & Sullivan, F. R. (1961). Coccolithophorids and related nannoplankton of the Early Tertiary in California. Micropaleontology. 7(2): 129-188. gs Romein, A. J. T. (1979). Lineages in Early Paleogene calcareous nannoplankton. Utrecht Micropaleontological Bulletin. 22: 1-231. gs V O Self-Trail, J. (2011). Paleogene Calcareous Nannofossils of the South Dover Bridge core, Southern Maryland (USA). Journal of Nannoplankton Research. 32(1): 1-28. gs V O Shamrock, J. L. & Watkins, D. K. (2012). Eocene calcareous nannofossil biostratigraphy and community structure from Exmouth Plateau, Eastern Indian Ocean (ODP Site 762). Stratigraphy. 9(1): 1-11. gs Shepherd, C. L. & Kulhanek, D. K. (2016). Eocene nannofossil biostratigraphy of the mid-Waipara River section, Canterbury Basin, New Zealand. Journal of Nannoplankton Research. 26(1): 33-59. gs V O Varol, O. (1989b). Eocene calcareous nannofossils from Sile (northwest Turkey). Revista Española de Micropaleontología. 21: 273-320. gs V OReferences:
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Toweius gammation compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 14-4-2021
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