Geophysical reconnaissance of the Red Mountain Ophiolite Complex, southern Westland

(Inc. GST)
(Ex. GST)
Write a Review

Hunt, T.M.; Mumme, T.C. 1978 Geophysical reconnaissance of the Red Mountain Ophiolite Complex, southern Westland. [s.l.]: [s.n.]. Report / Geophysics Division 128 33 p.

Abstract: Serpentinites in the Red Mountain Ophiolite Complex are strongly magnetic with an intensity of magnetisation of about 5 A/m; most other rocks in the Complex are only weakly magnetic (J < 1 A/m). Total force aeromagnetic measurements over the Complex suggest that along the eastern margin the serpentinites extend eastwards for about 4 km beneath rocks of the Haast Schist Group, and that the dip of the contact (Livingstone Fault) is about 40deg. The dip of the western boundary of the serpentinites could not be determined because of the presence of strongly magnetic rocks of the McKay Intrusives and other rocks within, or beneath, those of the Brook Street and Maitai Groups. Reconnaissance gravity measurements indicate a residual gravity anomaly of about 160 micro N/kg is associated with the Complex. A detailed interpretation of gravity measurements over the Complex would be difficult because the density of rocks in the Complex varies widely (2.6 - 3.2 Mg/cubic metre), and because of dense igneous bodies within the sedimentary rock surrounding the Complex. Analysis of the gravity and magnetic measurements suggests that the Complex is about 2-3 km thick