Oceania: Geological setting and geoscience research priorities
|Location||International Geological Congress,oslo 2008|
|Author||Lambert, Ian۱; Williams, Neil۱; Darby, Desmond۲|
|Holding Date||11 October 2008|
This presentation will outline the almost continuous geological record in the Oceania region – from the oldest dated minerals and earliest signs of life on Earth, to active volcanoes and pristine coral reefs. It will then review the strategic geoscience research priorities in the region.
Australia lies within the fastest moving crustal plate. Long term geological stability has given the smallest continent its unusually deeply weathered and topographically subdued landscapes. The extensive blanket of weathered rocks and sediments – the regolith – has demanded the development of innovative approaches and technologies for mineral exploration and land and water management in Australia.
Western Australia is dominated by two Archaean cratons. It is home to the oldest identified life forms and is characterised by a remarkable mineral endowment. Major petroleum fields occur on the Northwest Shelf and Holocene stromatolites and coral reefs occur further south.
The spectacularly scenic Proterozoic geology of the Northern Territory and South Australia hosts world class mineral deposits, and widespread high-heat-producing granites which are targets for geothermal energy exploration.
The well mineralised eastern highlands of Australia comprise Phanerozoic fold belts, which are overlain by sedimentary basins that host vast coal resources and well preserved fossils of megafauna unique to Australia. The World Heritage listed Great Barrier Reef is the largest coral reef system in the world and there are offshore petroleum fields in southeast Australia.
Tasmania, the island state, is dominated by late Proterozoic to Mesozoic geology. Jurassic dolerites, with spectacular landforms, are related to those in Antarctica and South Africa. There has been a long history of mining in the west of the state, where scenic wilderness areas abound.
The geological features of other countries of Oceania reflect their locations along the active plate margins, between the Australian and Pacific plates. New Zealand separated from Australia in the Mesozoic and its scenic geology reflects its location astride the boundary between the Australian and Pacific plates. The North Island is noted for its volcanic and geothermal landscapes, and for active faulting. The South Island, has spectacular alpine geology, permanent glaciers, and fiords.
Papua New Guinea also exhibits fascinating alpine and volcanic geology, in a tropical setting. It features major ophiolite belts, active tectonism, volcanism in arcs and back arc basins, uplifted coral terraces, and gold and copper mines. The many smaller islands dotted through Oceania are characterised by volcanics, high level intrusives and coral reefs.
The strategic imperatives for the geosciences in the region include environmental sustainability, discovering new clean energy and mineral resources that fuel the regional economies, and mitigating the risks of geohazards.