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small Gephyrocapsa

Edited by Jeremy Young on Thu, 19/05/2011 - 17:04

small Gephyrocapsa

Description: Gephyrocapsa coccolith <3µm long.

Remarks: Small Gephyrocapsa coccoliths show diverse morphologies and probably include many species. It is not practical to identify them by light microscopy so they are typically simply refered to the informal category "small Gephyrocapsa". Alternatively the names G. aperta, or in the Late Quaternary G. ericsonii are often used in the same sense.

sGeph192-01.JPGsGeph201 (471-0) 16NN14-15.JPG

 

Described species: Small Gephyrocapsa species which have been decribed in the literature include

Extant species

  • Gephyrocapsa ericsonii McIntyre & Bé 1967
  • Gephyrocapsa ornata Heimdal, 1973

Fossil species

  • Gephyrocapsa aperta Kamptner, 1963
  • Gephyrocapsa duoalatus (Martini, 1981) Martini, 1993
  • Gephyrocapsa mediterranea Pirini Radrizzani & Valleri, 1977
  • Gephyrocapsa pelta Samtleben, 1980
  • Gephyrocapsa protohuxleyi Gartner, 1977
  • Gephyrocapsa rota Samtleben, 1980
  • Gephyrocapsa sinuosa Hay & Beaudry, 1973
  • Gephyrocapsa theyeri Pujos 1987
Geological Time Data
Geological Time Periods: 
NN21
NN14
Biblio Reference: 
Young, JR.  1998.  Neogene. Calcareous nannofossil biostratigraphy. :225-265.
Notes on occurrence information: 

Small Gephyrocapsa specimens are usually common in the mid Pliocene (around the NN15/16 boundary) and throughout the Quaternary, but are scarce through much of the Late Pliocene.

Comments

Thu, 19/05/2011 - 21:11 — mstyzen
mstyzen's picture

GOM Pleistocene marker

On the charts I published for the Gulf of Mexico (Styzen 1996, Styzen and Jolley 2008) I have a marker (NP 1.58 in the Shell US nomanclature) based on the first major acme (downhole) of small Gephyrocapsa which also contains common Pseudoemiliania spp. This event features Small Gephyrocapsa in probably it's greatest abundance with literally thousands per field of view.
From the looks of things The age dates assigned to this part of the section on the 2008 chart (available in Time Scale Creator Pro) are a little off. The event falls between the extinctions of Helicosphaera sellii (see my remarks on that too) and that of "large" Gephyrocapsa (which is an event I've never been able to get to work very well). That would put it between 1.34 and 1.46 ma on the Gradstein, Ogg and Smith timescale.

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