The name Warrumbungle is of Aboriginal origin and is believed to
either mean ‘small mountains’ or ‘crooked
mountains’. The Warrumbungle National Park is around 500
kilometres north-west of Sydney, with the nearby town of
Coonabarabran being the most common way to access the park.
The Breadknife itself is a fantastic example of an igneous dyke
which has been left exposed following erosion. It was formed as
part of the eruption of the Warrumbungle volcano. It is estimated
that the Warrumbungle volcano first erupted around 17 million years
ago and then stopped around 13 million years ago. Most of the
volcano has been eroded away, leaving the many geological features
that are contained within the park.
This Warrumbungle volcano was a shield volcano which indicates
that the magma, or molten rock, was very hot and runny. This meant
that eruptions were not as violent as some volcanoes and resulted
in a large amount of magma flowing to the surface.
In order to reach The Breadknife itself a bushwalk is required.
Starting at the Pincham carpark the return walk is around 12km and
you should allow around 4-6 hours return. The Breadknife is found
along the route towards the Grand High Tops. Take plenty of water
and sun protection and note that there is some gain in altitude. If
you continue past The Breadknife to the Grand High Tops you will be
able to observe it at another angle. Note that climbing is
prohibited on The Breadknife.
Along the way there are other interesting geological features to
observe including Belougery Spire which is another feature formed
by the extinct volcano.
In the case of The Breadknife, some magma was extruded through
ash and cinders from the volcano. The magma then cooled and
hardened. As the ash and cinders eroded over time the thin band of
rock reaching up from the surrounding landscape is all that
remains. The ‘blade’ of The Breadknife is quite high in
places and is many hundreds of metres long.
To log your visit at the site you need to email the answers to
the following questions:
1. Estimate how high The Breadknife is at the given co-ordinates
(it might help by having someone stand beside the rock and taking
them as 1.5-2m high).
2. Look at the fault lines (cracks) in the rock. Estimate how
wide a ‘block’ (or square) of rock that comprises The
Breadknife is.
You also need to take a photo of you/ your party standing beside
The Breadknife and upload this with your log.
Logs without corresponding answers and picture may be
deleted.