The Australian Plate is a major
tectonic plate
Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large te ...
in the
eastern
Eastern may refer to:
Transportation
*China Eastern Airlines, a current Chinese airline based in Shanghai
*Eastern Air, former name of Zambia Skyways
*Eastern Air Lines, a defunct American airline that operated from 1926 to 1991
*Eastern Air Li ...
and, largely,
southern hemispheres. Originally a part of the ancient continent of
Gondwana, Australia remained connected to
India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
and
Antarctica
Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest cont ...
until approximately when India broke away and began moving north. Australia and Antarctica began rifting and completely separated roughly .
The Australian plate later fused with the adjacent
Indian Plate
The Indian Plate (or India Plate) is a minor tectonic plate straddling the equator in the Eastern Hemisphere. Originally a part of the ancient continent of Gondwana, the Indian Plate broke away from the other fragments of Gondwana , began ...
beneath the
Indian Ocean
The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by t ...
to form a single
Indo-Australian Plate. However, recent studies suggest that the two plates have once again split apart and have been separate plates for at least 3 million years and likely longer.
The Australian Plate includes the continent of
Australia, including
Tasmania
)
, nickname =
, image_map = Tasmania in Australia.svg
, map_caption = Location of Tasmania in AustraliaCoordinates:
, subdivision_type = Country
, subdi ...
, as well as portions of
New Guinea
New Guinea (; Hiri Motu: ''Niu Gini''; id, Papua, or , historically ) is the world's second-largest island with an area of . Located in Oceania in the southwestern Pacific Ocean, the island is separated from Australia by the wide Torr ...
,
New Zealand
New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...
and the
Indian Ocean
The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by t ...
basin.
Scope
The continental crust of this plate covers the whole of Australia, the
Gulf of Carpentaria, southern
New Guinea
New Guinea (; Hiri Motu: ''Niu Gini''; id, Papua, or , historically ) is the world's second-largest island with an area of . Located in Oceania in the southwestern Pacific Ocean, the island is separated from Australia by the wide Torr ...
, the
Arafura Sea
The Arafura Sea (or Arafuru Sea) lies west of the Pacific Ocean, overlying the continental shelf between Australia and Western New Guinea (also called Papua), which is the Indonesian part of the Island of New Guinea.
Geography
The Arafura S ...
, the
Coral Sea. The continental crust also includes northwestern
New Zealand
New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...
,
New Caledonia and
Fiji. The oceanic crust includes the southeast
Indian Ocean
The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by t ...
, the
Tasman Sea
The Tasman Sea ( Māori: ''Te Tai-o-Rēhua'', ) is a marginal sea of the South Pacific Ocean, situated between Australia and New Zealand. It measures about across and about from north to south. The sea was named after the Dutch explorer ...
, and the
Timor Sea
The Timor Sea ( id, Laut Timor, pt, Mar de Timor, tet, Tasi Mane or ) is a relatively shallow sea bounded to the north by the island of Timor, to the east by the Arafura Sea, and to the south by Australia.
The sea contains a number of reefs ...
]. The Australian Plate is bordered (clockwise) by the
Eurasian Plate
The Eurasian Plate is a tectonic plate that includes most of the continent of Eurasia (a landmass consisting of the traditional continents of Europe and Asia), with the notable exceptions of the Indian subcontinent, the Arabian subcontinent and ...
, the
Philippine Plate
The Philippine Sea Plate or the Philippine Plate is a tectonic plate comprising oceanic lithosphere that lies beneath the Philippine Sea, to the east of the Philippines. Most segments of the Philippines, including northern Luzon, are part of ...
, the
Pacific Plate, the
Antarctic Plate
The Antarctic Plate is a tectonic plate containing the continent of Antarctica, the Kerguelen Plateau, and some remote islands in the Southern Ocean and other surrounding oceans. After breakup from Gondwana (the southern part of the superconti ...
, the
African Plate
The African Plate is a major tectonic plate that includes much of the continent of Africa (except for its easternmost part) and the adjacent oceanic crust to the west and south. It is bounded by the North American Plate and South American Plate ...
and the
Indian Plate
The Indian Plate (or India Plate) is a minor tectonic plate straddling the equator in the Eastern Hemisphere. Originally a part of the ancient continent of Gondwana, the Indian Plate broke away from the other fragments of Gondwana , began ...
.
Geography
The northeasterly side is a complex but generally
convergent boundary
A convergent boundary (also known as a destructive boundary) is an area on Earth where two or more lithospheric plates collide. One plate eventually slides beneath the other, a process known as subduction. The subduction zone can be defined by a ...
with the
Pacific Plate. The Pacific Plate is subducting under the Australian Plate, which forms the
Tonga
Tonga (, ; ), officially the Kingdom of Tonga ( to, Puleʻanga Fakatuʻi ʻo Tonga), is a Polynesian country and archipelago. The country has 171 islands – of which 45 are inhabited. Its total surface area is about , scattered over in ...
and
Kermadec Trench
The Kermadec Trench is a linear ocean trench in the south Pacific Ocean. It stretches about from the Louisville Seamount Chain in the north (26°S) to the Hikurangi Plateau in the south (37°S), north-east of New Zealand's North Island. Toget ...
es, and the parallel
Tonga
Tonga (, ; ), officially the Kingdom of Tonga ( to, Puleʻanga Fakatuʻi ʻo Tonga), is a Polynesian country and archipelago. The country has 171 islands – of which 45 are inhabited. Its total surface area is about , scattered over in ...
and
Kermadec island arc
Island arcs are long chains of active volcanoes with intense seismic activity found along convergent tectonic plate boundaries. Most island arcs originate on oceanic crust and have resulted from the descent of the lithosphere into the mantle alon ...
s. It has also uplifted the eastern parts of New Zealand's
North Island.
The continent of
Zealandia
Zealandia (pronounced ), also known as (Māori) or Tasmantis, is an almost entirely submerged mass of continental crust that subsided after breaking away from Gondwanaland 83–79 million years ago.Gurnis, M., Hall, C.E., and Lavier, L.L., ...
, which separated from
Australia 85 million years ago and stretches from
New Caledonia in the north to
New Zealand's subantarctic islands in the south, is now being torn apart along the
transform boundary
A transform fault or transform boundary, is a fault along a plate boundary where the motion is predominantly horizontal. It ends abruptly where it connects to another plate boundary, either another transform, a spreading ridge, or a subductio ...
marked by the
Alpine Fault
The Alpine Fault is a geological fault that runs almost the entire length of New Zealand's South Island (c. 480 km) and forms the boundary between the Pacific Plate and the Indo-Australian Plate. The Southern Alps have been uplifted on the f ...
.
South of New Zealand the boundary becomes a transitional transform-convergent boundary, the
Macquarie Fault Zone, where the Australian Plate is beginning to subduct under the Pacific Plate along the
Puysegur Trench. Extending southwest of this trench is the
Macquarie Ridge.
The southerly side is a
divergent boundary with the
Antarctic Plate
The Antarctic Plate is a tectonic plate containing the continent of Antarctica, the Kerguelen Plateau, and some remote islands in the Southern Ocean and other surrounding oceans. After breakup from Gondwana (the southern part of the superconti ...
called the
Southeast Indian Ridge (SEIR).
The subducting boundary through Indonesia is not parallel to the
biogeographical Wallace line
The Wallace Line or Wallace's Line is a faunal boundary line drawn in 1859 by the British naturalist Alfred Russel Wallace and named by English biologist Thomas Henry Huxley that separates the biogeographical realms of Asia and Wallacea, a trans ...
that separates the indigenous fauna of Asia from that of
Australasia
Australasia is a region that comprises Australia, New Zealand and some neighbouring islands in the Pacific Ocean. The term is used in a number of different contexts, including geopolitically, physiogeographically, philologically, and ecologi ...
. The eastern islands of Indonesia lie mainly on the
Eurasian Plate
The Eurasian Plate is a tectonic plate that includes most of the continent of Eurasia (a landmass consisting of the traditional continents of Europe and Asia), with the notable exceptions of the Indian subcontinent, the Arabian subcontinent and ...
, but have Australasian-related fauna and flora. Southeasterly lies the
Sunda Shelf
Geologically, the Sunda Shelf is a south-eastern extension of the continental shelf of Mainland Southeast Asia. Major landmasses on the shelf include the Bali, Borneo, Java, Madura, and Sumatra, as well as their surrounding smaller islands. I ...
.
Origins
Depositional age of the Mount Barren Group on the southern margin of the
Yilgarn Craton and
zircon
Zircon () is a mineral belonging to the group of nesosilicates and is a source of the metal zirconium. Its chemical name is zirconium(IV) silicate, and its corresponding chemical formula is Zr SiO4. An empirical formula showing some of t ...
provenance analysis support the hypothesis that collisions between the
Pilbara
The Pilbara () is a large, dry, thinly populated region in the north of Western Australia. It is known for its Aboriginal peoples; its ancient landscapes; the red earth; and its vast mineral deposits, in particular iron ore. It is also a g ...
–
Yilgarn and
Yilgarn–
Gawler
Gawler is the oldest country town on the Australian mainland in the state of South Australia. It was named after the second Governor (British Vice-Regal representative) of the colony of South Australia, George Gawler. It is about north of the ...
Craton
A craton (, , or ; from grc-gre, κράτος "strength") is an old and stable part of the continental lithosphere, which consists of Earth's two topmost layers, the crust and the uppermost mantle. Having often survived cycles of merging an ...
s assembled a proto-Australian continent approximately (Dawson et al. 2002).
See also
*
List of earthquakes in Australia
This is a list of significant earthquakes recorded in Australia and its territories. The currency used is the Australian dollar (A$) unless noted otherwise.
List of earthquakes
Other earthquakes
* Broome, 16 August 1929, magnitude 6.6, offsho ...
*
List of earthquakes in India
The Indian subcontinent has a history of earthquakes. The reason for the intensity and high frequency of earthquakes is the Indian plate driving into Asia at a rate of approximately 47 mm/year. The following is a list of major earthquakes whic ...
*
List of earthquakes in Indonesia
*
List of earthquakes in New Zealand
*
List of earthquakes in Papua New Guinea
*
List of earthquakes in Samoa
*
List of earthquakes in Tonga
*
List of earthquakes in Vanuatu
*
References
{{Tectonic plates
Tectonic plates
Natural history of Oceania
Plates
Plates