WEST KIMBERLEY PLACE REPORT - Department of Sustainability ...

In the absence of any major mountain-building events, water, wind and ice work to
wear down the surfaces of a landscape, eventually producing a nearly-flat topography
only broken by isolated hills. Geologists refer to this process as 'planation'. In the
Kimberley, the oldest planation surface – the Kimberley High Surface – is thought to
have formed around 200 million years ago (Wright 1964 and Hays 1967 in Ollier et
al. 1988; Tyler 2000), though some researchers have argued that this surface predates
the Neoproterozoic glaciation, which would make it as much as 700 million years old
(Ollier et al. 1988). The remains of the High Surface can be seen today on the highest
mesas of the plateaus of the north Kimberley, such as Mount Hann at 776 metres.
Peaks within the King Leopold and Durack ranges, including Mount Ord at 937
metres, were once hills which stood above this surface.
Between 200 and 100 million years ago, uplift and then erosion of the Kimberley
High Surface formed a second, lower planation surface – the Kimberley Low Surface.
From 70 to 50 million years ago Australia moved into tropical latitudes, and the
warmer climate and heavy rain leached the soil of the Kimberley Low Surface and led
to the formation of laterite, a hard capping of minerals. Twenty million years ago, as
Australia continued its journey north towards Asia, the Kimberley Low Surface was
uplifted. Fast-flowing water rushing down these newly created steep slopes cut deep
gorges and other features that are visible today in the northern coastal regions of the
Kimberley, including the spectacular cliff walls and waterfalls of the lower reaches of
the King George and King Edward rivers (Maher and Copp 2009). The uplifted
Kimberley Low Surface has been gradually worn down to form the hills and valleys
found in the lower altitude country around the edge of the North Kimberley plateaus,
while the original Low Surface is preserved in the vicinity of Halls Creek. A new
planation surface has not yet developed.
HUMAN ARRIVALS
It is still unknown when and from where humans first appeared in this country. The
contemporary scientific explanation is that, after leaving Sundaland (the southern
extension of south-east Asia drowned by rising seas of the Holocene, with
Sundaland's remnants comprising the Malay Peninsula and islands of Sumatra, Java,
Borneo, and surrounding smaller islands), the first arrivals made short voyages
between islands, mostly remaining in sight of land, before setting off on the longest
stretch of the journey. They navigated sea channels up to 100 kilometres wide to
reach the Sahul, the conjoined landmass of Australia and New Guinea (Mulvaney and
Kamminga 1999; Gillespie 2002). We do not know what sort of craft they travelled
on, or whether the journey was made by accident or intention, once or many times.
Archaeological evidence suggests that by at least 40,000 years ago humans had
occupied all, or nearly all, parts of the Australian continent. Scientists identify the
Kimberley as one of the most likely entry points for the initial migration of people
from Asia to Australia. Archaeological investigations may show the Kimberley to be
the first area in Australia to be inhabited by modern humans (O'Connor 1999).
Archaeological finds from rock shelters indicate that early Kimberley people had a
varied diet. They ate many different plants, shellfish, fish, tortoises, lizards, rodents,
wallabies, possums, bandicoots and goose eggs (McConnell and O'Connor 1997;
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