Low-level aeromagnetic data available in
digital form have been combined to produce a new 1:100 000 scale map of total
force anomalies of the Coromandel region, New Zealand. The
map incorporates data from 13 surveys flown between 1977 and 1990 and shows the
regional magnetic pattern as well as more detailed localised anomalies. In
addition to magnetic anomalies, the map also depicts data to aid interpretation,
including small-scale maps of topography, geology, magnetic intensity gradient
and apparent magnetisation. The primary magnetic anomalies of the Coromandel
region are associated with Late Miocene and Pliocene volcanic rocks, but have
been locally modified by intense hydrothermal alteration caused by geothermal
activity. Epithermal gold-silver and porphyry copper deposits are associated
with zones of hydrothermal alteration. The map of magnetic anomalies can be used
as an aid to mineral exploration and the interpretation of the processes that
control the distribution of mineral deposits in the region.