WEST KIMBERLEY PLACE REPORT - Department of Sustainability ...

Creek orogen is located further inland than sections of the King Leopold orogen. As a
result, the outcrops of this orogen are generally poorer and the structures harder to see
and interpret on the ground (Maher and Copp 2010; Patrick Maher pers. comm.
2009).
There is evidence of much older orogenies preserved in Australian rocks. However,
During the Archaean, Earth was much hotter than present. At the beginning of the
Palaeoproterozoic, about 2,300 Ma, the deep Earth was still about twice as hot as in
the later Phanerozoic, and plate tectonic mechanisms did not function as currently
understood, if at all, so the rocks of Archaean are not referable to modern processes.
Extensive deposits of Proterozoic age, like the King Leopold orogen, document
ancient mountain building events strikingly similar to those at collisional boundaries
today (Stanley 1999; Iain Copp pers. comm. 2009; Maher and Copp 2010).
Other important Australian orogenic belts are younger than the King Leopold
orogeny, and include the remains of the Delamerian orogeny in South Australia, the
rocks of the Lachlan fold belt in Victoria and New South Wales, and ongoing uplift in
the eastern Australian highlands. The Delamerian orogeny occurred in the early
Palaeozoic era, when a huge mountain range spanned southern Australia and
Antarctica which were then joined as part of Greater Gondwana (Giesecke 1999). The
rocks of the Palaeozoic Lachlan orogen occur in a 700 kilometre wide belt of Victoria
and New South Wales, extending into Tasmania, the Australian Capital Territory and
Queensland. The Delamerian and Lachlan orogens are adjacent and follow the
Precambrian margin of eastern Australia. They are considerably younger than the
rocks of the King Leopold orogen, revealing much about the assembling of the eastern
seaboard of Australia during the last 500 million years, while the King Leopold
orogen tells a different story altogether: one that is much older, spans a greater time
period and describes the formation of a much earlier 'Australia', at a period when
modern plate tectonic processes were beginning to operate (Maher and Copp 2010;
Witze 2006).
Uplift in eastern Australia is ongoing. The eastern Australian highlands demonstrate
current processes in an active orogenic belt. However, the remnants of the King
Leopold orogen are eroded, and revealed in dramatic coastal exposures, so as to help
explain much more about the events occurring deeper in the crust, which are only
accessible otherwise to geologists through seismic profiles and modelling (Maher and
Copp 2010).
The King Leopold orogen displays a significant geological record of past orogenic
events which led to the Proterozoic assembly of Rodinia, representing key tectonic
events in the evolution of the Australian continent and a major stage of Earth's
history. This record is displayed in significant fault and fold structures in rocks
exposed along the coast of Yampi Peninsula, in the King Leopold Ranges and the
Fitzroy Uplands. These geological features highlight the powerful tectonic forces and
the physical geological structures formed during orogenic processes (Maher and Copp
2010).
The King Leopold orogen of the west Kimberley has outstanding heritage value
to the nation under criterion (a) for recording pre-Rodinian and Proterozoic
plate tectonic processes, key events in the evolution of the Australian continent.
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