--> ABSTRACT: (U-Th)/He Thermochronology as a Potential Petroleum Exploration Tool: An Example from the Taranaki Basin, New Zealand, by P. V. Crowhurst, P. F. Green, and P. J. J. Kamp; #90906(2001)

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P. V. Crowhurst1, P. F. Green2, and P. J. J. Kamp3

1CSIRO Petroleum Resources, PO Box 136, North Ryde, NSW 1670, Australia
2Geotrack International Pty Ltd., 37 Melville Rd., Brunswick West, Victoria 3055, Australia
3Department of Earth Sciences, The University of Waikato, Private Bag 3105, Hamilton, New Zealand

ABSTRACT: (U-Th)/He Thermochronology as a Potential Petroleum Exploration Tool: An Example from the Taranaki Basin, New Zealand

The Taranaki basin, located in central-western New Zealand, contains a predominantly terrigenous Late Cretaceous to Holocene terrestrial to marine succession, with an estimated maximum thickness of ~8 km. This basin is of particular interest because it provides most of New Zealand’s commercial hydrocarbon discoveries.

Previously published AFTA (apatite fission track analysis) results from four wells in the Southern Taranaki Graben revealed and quantified the effects of major cooling as a result of Late Miocene inversion (Kamp and Green, 1990). Combined AFTA and vitrinite reflectance data from the Fresne-1 well (Green et al., 1995) suggest around 2.5 to 3 km of section was eroded from the Fresne-1 structure, which is highly consistent with estimates from reconstructions based on seismic sections.

Subsequent to that work being carried out, significant advances in methodology have been made, particularly in extracting thermal history information from AFTA data and in incorporating the effects of variation in kinetic response between apatites of different chlorine content (Green et al., 1996). Therefore, for this study the samples from the Fresne-1 well originally analysed by Kamp and Green (1990) have been reanalysed using latest methods, in which chlorine contents are measured in every apatite grain analysed. This data was then used to define thermal history solutions using a ‘multi-compositional’ kinetic model, which makes full quantitative allowance for the effect of chlorine content on annealing rates.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado