New Zealand Journal of Geology and Geophysics abstracts
Integrated biostratigraphy of the Raukumara Series (Cenomanian-Coniacian) at
Mangaotane Stream, Raukumara Peninsula, New Zealand
JAMES CRAMPTON
IAN RAINE
PERCY STRONG
GRAEME WILSON
Institute of Geological & Nuclear Sciences
P.O. Box 30 368
Lower Hutt, New Zealand
email: j.crampton@gns.cri.nz
Abstract The New Zealand Upper Cretaceous Raukumara Series is
divided into three stages: in ascending order, the Arowhanan, Mangaotanean, and
Teratan. The lower boundary stratotypes for all three stages are in Mangaotane
and "Te Rata" streams, in the Raukumara Range, Raukumara Peninsula (the
"Mangaotane section"). Although affected by a number of minor faults, the
section is relatively complete, spans the entire series, and is well exposed.
The lower boundary stratotype of the Arowhanan Stage is within Waitahaia
Formation; the boundary stratotypes of the other two stages are in Karekare
Formation. The section contains abundant inoceramid bivalves and has yielded
poorly to moderately preserved, moderately diverse foraminiferal and
dinoflagellate assemblages. The Mangaotane section is divided into six
inoceramid zones, five dinoflagellate zones, and four informal foraminiferal
assemblage zones. Lower boundaries of the Arowhanan, Mangaotanean, and Teratan
Stages are tied to the lowest occurrences of inoceramid taxa, biostratigraphic
events that can be easily recognised and widely correlated within New Zealand.
Correlations to the international time-scale are more problematic and are
hampered by the lack of reliable or unambiguous biostratigraphic datums and the
lack of absolute ages or other non-biostratigraphic controls in the New Zealand
succession. Based only on biostratigraphic data, the following correlations are
proposed: Arowhanan Stage = upper Cenomanian to lower Turonian; Mangaotanean
Stage = lower-upper Turonian; Teratan Stage = upper Turonian to upper
Coniacian.
Keywords Arowhanan Stage; biostratigraphy; Cenomanian;
Coniacian; correlation; dinoflagellates; foraminifera; inoceramid bivalves;
Karekare Formation; Late Cretaceous; Mangaotane Stream; Mangaotanean Stage;
Raukumara Peninsula; Raukumara Series; Teratan Stage; time-scale; Turonian;
Waitahaia Formation
New Zealand Journal of Geology & Geophysics, 2001, Vol 44: 365-389
0028-8306/01/4403-0365 $7.00/0 (c) The Royal Society of New Zealand
2001
PDF file of entire paper: medium quality (3997K); (scanned from paper original: notes about this process)
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