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WEST KIMBERLEY PLACE REPORT - Department of Sustainability ...

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century hydrographers and in particular the survey work <strong>of</strong> Phillip Parker<br />

King, one <strong>of</strong> Australia's most important early marine surveyors.<br />

CRITERION (c) – The place has outstanding heritage value to the nation because<br />

<strong>of</strong> the place's potential to yield information that will contribute to an understanding<br />

<strong>of</strong> Australia's natural or cultural history<br />

ANCIENT LANDSCAPES, GEOLOGICAL PROCESSES<br />

A nominator claimed that the Prince Regent River has outstanding heritage value to<br />

the nation under criterion (c) because 'the sunken coastline' <strong>of</strong> the Prince Regent area<br />

'has the potential to provide information adding to our understanding <strong>of</strong> the changes to<br />

our continent over geological time and in response to changing climate.' This<br />

nominator also claimed that 'the Prince Regent limestone and its relationship with the<br />

Prince Regent River extending over 150 kilometres from south-east to north-west and<br />

the Roe river further north which sites at the interface between two distinct types <strong>of</strong><br />

bedrock – basalt to the East and sandstone to the West… are likely to yield<br />

information that improves our understanding <strong>of</strong> the shaping <strong>of</strong> the north-west <strong>of</strong> our<br />

continent and its movements over geological time.'<br />

These claims cannot easily be demonstrated. Furthermore, the boundaries between<br />

land and ocean are in constant flux. Coasts respond to and record the interaction <strong>of</strong><br />

climate, tectonic, sedimentary and biological (including anthropogenic) processes<br />

over long and short timescales. The geological record provides persuasive evidence<br />

all over the world <strong>of</strong> sea level change over time, driven by a variety <strong>of</strong> processes<br />

including changes in sediment load, climate, continental ice storage and ocean basin<br />

volume. Many <strong>of</strong> these processes continue today (Boyd 2007a).<br />

On its own, the Prince Regent River is unlikely to have outstanding heritage<br />

value to the nation under criterion (c) for its potential to provide information<br />

about geological and climate changes over time, nor for its role in shaping the<br />

understanding <strong>of</strong> the shaping <strong>of</strong> north-western Australia.<br />

ECOLOGY, BIOGEOGRAPHY, CLIMATE AND EVOLUTION<br />

Reef ecology, response to change and resilience<br />

The fossil Devonian reef assemblages <strong>of</strong> the Lennard Shelf, including the Napier,<br />

Oscar, Emmanuel and Pillara Ranges span the Givetian-Famennian stages <strong>of</strong> the<br />

Devonian period from about 390–359 million years ago, including the Frasnian–<br />

Famennian mass extinction. While the causes <strong>of</strong> this extinction are still unclear,<br />

suggested mechanisms include climate change and sea level changes. Sea level<br />

changes occurred rapidly at the end <strong>of</strong> the Frasnian stage and at other reefs around the<br />

world this boundary marks their extinction and burial by deeper-water sediment<br />

(Wood 2000). In the Kimberley, there are records <strong>of</strong> the sea level changes, as well as<br />

the extinction <strong>of</strong> a major component <strong>of</strong> the reef-building organisms, (large, calcified<br />

animals) at this time. Despite this, the Kimberley reef remains, albeit with different<br />

taxa, mostly microbial, taking up the role <strong>of</strong> reef building in the Famennian stage<br />

(Wood 2000).<br />

143

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