Nannotax3 - ntax_cenozoic - Triquetrorhabdulus carinatus

Citation: Triquetrorhabdulus carinatus Martini, 1965

Distinguishing features:
Parent taxon (Triquetrorhabdulus): Elongate, tri-radiate nannoliths formed of a single calcite crystal with the c-axis parallel to the length of the nannolith. Nannolith straight with bilateral or trilateral symmetry. Shows high birefringence.
This taxon: Elongate (up to 50µm). All three blades identical, without ridges.

Geological Range:
Notes: Distribution rather sporadic. Backman et al. (2012) use top common T. carinatus as the boundary between their zones CNM2 and CNM3, occuring near the top of magnetochron C6Bn2n, ca 22.1Ma. In the Neptune data this event appears to be reflected in a marked drop in occurrence frequencies, but the species does persist well above ths level.
The first occurrence is normally recorded in the Oligocene but Eocene occurrences of the species were recorded from the mid Pacific (Leg 198, Shatsky Rise) by Bralower (2005) and from Java by Jones & Dunkley Jones (2020)
Last occurrence (top): within NN3 zone (17.95-19.00Ma, top in Burdigalian stage). Data source: range of common occurrences in Neptune
First occurrence (base): within NP24 zone (26.84-29.62Ma, base in Rupelian stage). Data source: range of common occurrences in Neptune

References:

Backman, J., Raffi, I., Rio, D., Fornaciari, E. & Palike, H. (2012). Biozonation and biochronology of Miocene through Pleistocene calcareous nannofossils from low and middle latitudes. Newsletters on Stratigraphy. 45(3): 221-244. gs

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 O

Bralower, T. J. (2005). Data report: Paleocene-early Oligocene calcareous nannofossil biostratigraphy, ODP Leg 198 Sites 1209, 1210, and 1211 (Shatsky Rise, Pacific Ocean). Proceedings of the Ocean Drilling Program, Scientific Results. 198: 1-15. gs

de Kaenel, E. & Villa, G. (1996). Oligocene-Miocene calcareous nannofossil biostratigraphy and paleoeecology from the Iberian Abyssal Plain. Proceedings of the Ocean Drilling Program, Scientific Results. 149: 79-145. gs O

Jones, A. P. & Dunkley Jones, T. (2020). Middle Eocene to Early Oligocene calcareous nannofossils from the Nanggulan Formation, Java, Indonesia. Journal of Nannoplankton Research. 38(1): 57-79. gs

Martini, E. (1965). Mid-Tertiary calcareous nannoplankton from Pacific deep-sea cores. Colston Papers. 17: 393-411. gs O

Müller, C. (1974). Calcareous nannoplankton, Leg 25 (Western Indian Ocean). Initial Reports of the Deep Sea Drilling Project. 25: 579-633. gs

Perch-Nielsen, K. (1972). Remarks on Late Cretaceous to Pleistocene coccoliths from the North Atlantic. Initial Reports of the Deep Sea Drilling Project. 12: 1003-1069. gs

Perch-Nielsen, K. (1977). Albian to Pleistocene calcareous nannofossils from the Western South Atlantic, DSDP Leg 39. Initial Reports of the Deep Sea Drilling Project. 39: 699-823. gs O

Salomon, R. (1999). The Calcite Palace. Website - https://ina.tmsoc.org/galleries/CalcitePalace/index.htm. -. gs

Theodoridis, S. (1984). Calcareous nannofossil biostratigraphy of the Miocene and revision of the helicoliths and discoasters. Utrecht Micropaleontological Bulletin. 32: 1-271. gs O

Young, J. R. (1998). Neogene. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series . 225-265. gs

Triquetrorhabdulus carinatus

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Sub-taxa & variants (time control age-window is: 0-800Ma)
				Triquetrorhabdulus longus A thin (<2µm), elongate (>25µm) species of Triquetrorhabdulus