New Zealand Journal of Geology and Geophysics abstracts
Heat flow through the West Coast, South Island, New Zealand
JOHN TOWNEND
Institute of Geological & Nuclear Sciences
P.O. Box 30 368
Lower Hutt, New Zealand
Abstract Bottom-hole temperature data collected from 24
petroleum exploration wells have been used to calculate conductive heat flow
through the West Coast, South Island. Steady-state modelling suggests a mean
heat flow of 76 +/- 15 mW/m2 (20%, 1 SD), a figure higher
than those obtained previously by Funnell et al. and Funnell & Allis for
the southern Taranaki and southwest South Island regions
(65-70 mW/m2 and 60 +/- 4 mW/m2, respectively).
Pliocene-Quaternary erosion over much of the West Coast has probably caused an
increase in measured surface heat flow of 25-30 mW/m2.
Localised areas of heat flow in excess of 90 mW/m2 exist in
the Lake Brunner region and at the sites of Card Creek-1 and Matiri-1 wells.
Convective effects caused by fluid migration along structural features in these
three areas may be responsible for the highly elevated local heat flows.
However, calculations of the thermal effects of late Neogene erosion in the
southern Taranaki and West Coast regions suggest that the present-day
discrepancy in surface heat flows may be largely due to differing magnitudes
and rates of erosion.
Keywords heat flow; West Coast; temperature; geothermal
gradient; South Island; New Zealand; thermal conductivity
New Zealand Journal of Geology & Geophysics, 1999, Vol. 42: 21-31
0028-8306/4201-0021 $7.00/0 (c) The Royal Society of New Zealand 1999
PDF file of entire paper: medium quality (1651K); (scanned from paper original: notes about this process)
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