K-Ar ages of early Miocene arc-type volcanoes in northern New Zealand

Citation
Bw. Hayward et al., K-Ar ages of early Miocene arc-type volcanoes in northern New Zealand, NZ J GEOL, 44(2), 2001, pp. 285-311
Citations number
117
Categorie Soggetti
Earth Sciences
Journal title
NEW ZEALAND JOURNAL OF GEOLOGY AND GEOPHYSICS
ISSN journal
00288306 → ACNP
Volume
44
Issue
2
Year of publication
2001
Pages
285 - 311
Database
ISI
SICI code
0028-8306(200106)44:2<285:KAOEMA>2.0.ZU;2-P
Abstract
Understanding the temporal and spatial development of the early Miocene Nor thland Volcanic Arc is critical to interpreting the patterns of volcanic ac tivity in northern New Zealand through the late Cenozoic. The northwesterly trending are is considered to have developed above a southwest-dipping sub duction system. The distribution of its constituent eruptive centres is des cribed in terms of an eastern belt that extends along the eastern side of N orthland and a complementary broad western belt which includes subaerial an d submarine volcanic edi ices. Critical examination of all 216 K-Ar ages av ailable, including 180 previously unpublished ages, and their assessment ag ainst tectonic, lithostratigraphic, seismic stratigraphic, and biostratigra phic constraints, leads us to deduce a detailed chronology of periods of ac tivity for the various early (and middle) Miocene are-type volcanic complex es and centres of northern New Zealand: Waipoua Shield Volcano Complex (19- 18 Ma, Altonian); Kaipara Volcanic Complex (23-16 Ma, Waitakian-Altonian); Manukau Volcanic Complex (c. 23-15.5 Ma, Waitakian-Clifdenian); North Cape Volcanic Centre (23-18 Ma, Waitakian-Altonian); Whangaroa Volcanic Complex (22.5-17.5 Ma, Waitakian-Altonian); Taurikura Volcanic Complex (22-15.5 Ma, Otaian-Clifdenian); Parahaki Dacites (22.5-18 Ma, Waitakian-Altonian); Kua otunu Volcanic Complex (18.5-11 Ma, Altonian-Waiauan). In general, volcanic activity does not show geographic migration with time, and the western (25 -15.5 Ma) and eastern (23-11 Ma) belts appear to have developed concurrentl y.