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

basin.

Scope

The continental crust of this plate covers the whole of Australia, the Gulf of Carpentaria, southern

, 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 Caledonia and Fiji. The oceanic crust includes the southeast

, 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

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

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

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

, 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).

References

{{Tectonic plates Tectonic plates Natural history of Oceania Plates Plates

Scope

Geography

Origins

See also

References