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Photogrammetric methods provide ultimate objectivity with the potential for un-biased reinterpretation
at a later date and are thus particularly desirable for fault-related work. I have
made several trips to Dalethorpe in order to photograph and survey the face at varying
resolutions. After initially exploring in-house camera calibration and image analysis options, I
have now made contact with David Park at the recently-opened Geospatial Research Centre
(GRCNZ, http://www.grcnz.com/) at the University of Canterbury. Photogrammetric face
logging promises to become a useful tool with the aid of David’s team’s expertise and
technology. The cooperation with GRCNZ is also set to produce exciting spin-off benefits in
the form of a DTM of part of the Dalethorpe study area acquired using their unmanned aerial
vehicles. This is a capability they are keen to develop, thus providing mutual benefit to myself
and GRCNZ.
PROTECTING WHAT’S LEFT OF AUCKLAND’S
VOLCANIC HERITAGE
Bruce W. Hayward, Auckland
Over 50 years ago at our Society’s first AGM, there was discussion over what could
be done to protect Auckland’s remaining volcanic cones and craters, as they were rapidly
disappearing at the hands of the quarrying industry (Collins, 1957). At that time the NZ
Historic Places Trust was actively campaigning for further reserves, especially for those with
high archaeological values. These were not the first attempts to protect Auckland’s volcanoes,
there had been a number of one off and concerted campaigns over the preceding 50 or so years
(e.g. Fowlds, 1928).
Now, 50 further years on, your Society’s Geological Reserves Subcommittee still
finds that much of its efforts are directed towards trying to protect what we have left of
Auckland’s volcanic heritage, so it seemed an appropriate time to summarise the situation.
The young Auckland basalt volcanic field has erupted over the last ~250,000 years
from about 50 centres (Fig. 1) and is currently considered dormant. These eruptions have
formed maar craters with surrounding tuff rings, simple or multiple scoria cones, and lava
flows that in several instances have built up sizeable shields. Other volcanic-related features
include lava-flow dammed lakes and swamps, numerous lava caves and several fossil forests
killed and buried by volcanic ash or lava flows.
Today, the majority of the remaining scoria cones and craters are protected in public
reserves, and legal implements for protecting various aspects of the volcanic heritage are
included in the Auckland Regional Plan, Regional Coastal Plan, the District Plans of
Auckland, North Shore and Manukau Cities and the Auckland Conservation Management
Strategy. But still this is not enough. Every year Auckland loses more, and this is not restricted
to private land. Auckland’s growth continues to increase pressure on the remaining landforms,
exposures and views of Auckland’s volcanic heritage through housing infill, construction of
bigger and larger buildings, motorway construction, infrastructure developments, and still
some quarrying.
Of Auckland’s original 17 maar craters, 2 (Styaks Swamp, Ash Hill) have been
completely destroyed, a further 4 reclaimed, with 6 still reasonably intact. Only 3 maar craters
GSNZ Newsletter 143 (2007) Page 36