RADIOLARIAN
ZONATION
The code numbers for the
Paleogene radiolarian zonation used herein are those introduced by Sanfilippo
and Nigrini (1998a). In that paper we standardized and formally defined 39
radiolarian zones for the tropical Pacific, Indian, and Atlantic Oceans:
RP1-RP22 for the Paleogene and RN1-RN17 for the Neogene. Mean numerical ages for
zonal boundaries were culled from previous literature and converted to the
geomagnetic polarity time scale of Cande and Kent (1995). A chart showing the
correlation between the Paleogene zonal schemes for foraminifers, calcareous
nannofossils, radiolarians, and the geomagnetic polarity time scale is shown in Figure
2. Below is a list of the zonal code numbers used herein, listed from
youngest to oldest, which are equivalent to the previously published named
zones.
- RP22 Lychnocanoma
elongata Zone
- RP21 Dorcadospyris
ateuchus Zone
- RP20 Theocyrtis
tuberosa Zone
- RP19 Cryptocarpium
ornatum Zone
- RP18 Calocyclas
bandyca Zone
- RP17 Cryptocarpium
azyx Zone
- RP16 Podocyrtis
(Lampterium) goetheana Zone
- RP15 Podocyrtis
(Lampterium) chalara Zone
- RP14 Podocyrtis
(Lampterium) mitra Zone
- RP13 Podocyrtis
(Podocyrtoges) ampla Zone
- RP12 Thyrsocyrtis
(Pentalacorys) triacantha Zone
- RP11 Dictyoprora
mongolfieri Zone
- RP10 Theocotyle
cryptocephala Zone
- RP9 Phormocyrtis
striata striata Zone
- RP8 Buryella
clinata Zone
- RP7 Bekoma
bidartensis Zone
- RP6 Bekoma
campechensis Zone
- RP6c Stylotrochus
nitidus-Pterocodon (?) poculum
Subzone
- RP6b Orbula
discipulus Subzone
- RP6a Peritiviator
(?) dumitricai
Subzone
- RP5 Buryella
tetradica Zone
- RP4 Buryella
foremanae Zone
- RP3 Stichomitra
granulata Zone
- RP2 Amphisphaera
kina Zone
- RP1 Amphisphaera
aotea Zone
