Landform and Geology
Prior to the formation of the gorge the area was
part of an extensive peneplain extending from Makara to Khandallah. The
present landform developed from earthquake and erosion activity
resulting in the formation of the gorge. A characteristic feature of
the peneplain remnant is the rounded forms of the higher slopes
contrasting quite dramatically with the steeper erosion-formed valley
While the landforms within the park appear to be
typically those of a valley landscape in reality the landforms are
considerabl y more complex and varied. Within the park there are a
series of quite dramatic bluffs, spurs, steep rock faces and outcrops
along with a series of ravine -like side valleys. Some of the more
visually striking landforms and rock outcrops are above and on the
south side of the Kaiwharawhara Stream on l and which is not currently
within the park. However, visually these areas are seen as an integral
part of the park landscape. Generally the landforms in the
Kaiwharawhara Stream valley are more dramatic and visually striking
than those in the Korimako S tream valley.
Geologically the area consists of variably
weathered, fractured and jointed sandstones and argillites. Bedrock
slopes are carved by thin colluvium and solifluction deposits.
The soils are yellow-brown Ngaio, Korokoro and
Makara hill soils, and Ngaio silt loam over greywacke. The soils are
reasonably fertile and very well drained.