New Zealand Journal of Geology and Geophysics abstracts
Distribution and biostratigraphy of latest Eocene to latest Oligocene
Radiolaria from the Mahurangi Limestone, Northland, New Zealand
BARRY O'CONNOR
Department of Geology
Faculty of Agriculture
Utsunomiya University
Utsunomiya 321-8505
Japan
Abstract Radiolaria from the Mahurangi Limestone are
generally common to abundant, well preserved, and the faunas reasonably
diverse. However, all published information concerning these radiolarian faunas
concentrates on the description of new species. This leaves useful data on
location, density, abundance, preservation, biostratigraphy, and distribution
unpublished.
Data on 50 radiolarian-bearing samples from 30 localities spanning the
geographical range of the Mahurangi Limestone are presented. Forty-three of
these samples, from 25 localities, contain radiolarian age index taxa. More
than 179 radiolarian taxa are identified, from over 89 genera, and diversity
ranges up to 136 taxa per sample.
Fifteen radiolarian index species can be identified within the Mahurangi
Limestone, allowing many localities to be dated on radiolarian evidence alone.
For age control, nannofossil age data from samples containing radiolarian age
indicators are also presented. Radiolaria give an age range for the Mahurangi
Limestone of latest Eocene to latest Oligocene.
New or updated information includes a locality map, data on radiolarian
densities, abundances and preservation for each sample, biostratigraphic
information, a full list of radiolarian taxa identified from the Mahurangi
Limestone, and tables of radiolarian distribution within the studied samples. A
diagram correlating international and New Zealand stages with new information
on South Pacific and tropical radiolarian zones for the latest Eocene to
earliest Miocene is also provided, together with stratigraphic ranges for
radiolarian index species used for dating the Mahurangi Limestone.
Keywords Radiolaria; Mahurangi Limestone; Northland; latest
Eocene; Oligocene; biostratigraphy
New Zealand Journal of Geology & Geophysics, 1999, Vol. 42:
489-511
0028-8306/99/4204-0489 $7.00/0 (c) The Royal Society of New Zealand
1999
PDF file of entire paper: medium quality (4581K); (scanned from paper original: notes about this process)
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