Heat flow through the West Coast, South Island, New Zealand

Abstract

2 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.

Shear velocity structure of the Northland Peninsula, New Zealand, inferred from ambient noise correlations

“… Stern et al [1987] demonstrated that a 25 km thick crust would require a hotter than normal mantle lid to generate sufficient buoyancy to lift the Northland Peninsula above sea level. Limited crustal heat flow measurements suggest that the crust is somewhat hotter than normal in Northland (74 ± 4 mW m −2 [ Pandey , 1981]), although heat flow studies conducted elsewhere in New Zealand suggest that those measurements are biased toward higher values by 10–15 mW m −2 due to assumptions about thermal conductivity [ Funnell et al , 1996; Townend , 1999; Goutorbe et al , 2008]. As noted above, P velocities in the uppermost mantle beneath Northland are relatively low (i.e., 7.6 km s −1 at 25 km [ Stern et al , 1987]), and similarly low values are seen farther south in the western North Island in active source [ Stratford and Stern , 2006] and mantle refraction (Pn) studies [ Seward et al , 2009].…”

Low-temperature geothermal reserves in New Zealand

“…8 and plotted against vertical well depths ( Fig. 9) are derived from Allis et al (1995), Funnell et al (1996) and King and Thrasher (1996) for Taranaki; Isaac et al (1994) for Northland; Field et al (1997) for the East Coast of the North Island which includes the Hikurangi Accretionary Prism and parts of the North Island Axial Ranges; Cook et al (1999) for the Great South Basin; Suggate and Waight (1999); Townend (1999) for West Coast of the South Island; Fowke (1987) and Schofield (1972) for shallow wells in the Western Waikato and Hauraki Rift Zone; Studt and Thompson (1969) for parts of the North Island; Boedihardi and Hochstein (1990) There are about 520 abandoned offshore and onshore oil and gas wells in New Zealand, drilled from 1866 to 2005, with total depths of 17-5065 m (Appendix 1). These wells have been abandoned for various reasons including limited, or no, hydrocarbon shows and poor hole conditions.…”

Extreme hydrothermal conditions at an active plate-bounding fault

“…The regional value determined from petroleum boreholes west of DFDP-2B is about 30 °C km −1 (ref. 28).…”