The Caroline Plate is a minor

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 ...

that straddles the Equator in the eastern hemisphere located north 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 ...

. It forms a subduction zone along the border with the Bird's Head Plate and the

Woodlark Plate The Woodlark Plate is a small tectonic plate located in the eastern half of the island of New Guinea. It subducts beneath the Caroline plate along its northern border while the Maoke Plate converges on the west, the Australian plate converges on ...

to the south. A transform boundary forms the northern border with the Pacific Plate. Along the border with the

Philippine Sea 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 o ...

is a

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 ...

that transitions into a

rift In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics. Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-grabe ...

. The Caroline Plate was first proposed as a distinct plate by .

Geological setting

A separate

terrane In geology, a terrane (; in full, a tectonostratigraphic terrane) is a crust (geology), crust fragment formed on a tectonic plate (or broken off from it) and Accretion (geology), accreted or "Suture (geology), sutured" to crust lying on another pla ...

with its own tectonic history, the Caroline Plate has been considered part of the Pacific Plate because of sparse seismicity and low velocities along its boundaries. It includes the

West West or Occident is one of the four cardinal directions or points of the compass. It is the opposite direction from east and is the direction in which the Sun sets on the Earth. Etymology The word "west" is a Germanic word passed into some ...

and East Caroline basins and the inactive

Eauripik Rise Eauripik Island is a coral atoll of three islands in the western Caroline Islands in the Pacific Ocean, and forms a legislative district in Yap State in the Federated States of Micronesia. Its total land area is only 23.6 hectares , but it enc ...

separating them, but neither the

Caroline Islands The Caroline Islands (or the Carolines) are a widely scattered archipelago of tiny islands in the western Pacific Ocean, to the north of New Guinea. Politically, they are divided between the Federated States of Micronesia (FSM) in the ce ...

nor the Caroline Ridge. It is subducting under the Bird's Head and

Woodlark The woodlark or wood lark (''Lullula arborea'') is the only extant species in the lark genus ''Lullula''. It is found across most of Europe, the Middle East, western Asia and the mountains of north Africa. It is mainly resident (non- migratory) ...

plates along the

New Guinea Trench New is an adjective referring to something recently made, discovered, or created. New or NEW may refer to: Music * New, singer of K-pop group The Boyz Albums and EPs * ''New'' (album), by Paul McCartney, 2013 * ''New'' (EP), by Regurgitator, ...

to the south. The boundary with the Philippine Sea to the west has two segments: the southern segment, the Ayu Trough was spreading at a rate of 8 mm/yr 25–2 Ma but has been slowing down since. The northern segment, the

Palau Palau,, officially the Republic of Palau and historically ''Belau'', ''Palaos'' or ''Pelew'', is an island country and microstate in the western Pacific. The nation has approximately 340 islands and connects the western chain of the ...

and southern

Yap Yap ( yap, Waqaab) traditionally refers to an island group located in the Caroline Islands of the western Pacific Ocean, a part of Yap State. The name "Yap" in recent years has come to also refer to the state within the Federated States of Micr ...

trenches, is not an active subduction zone as indicated by the lack of active

volcanoes A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates a ...

. The Caroline-

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contine ...

boundary is a complex, evolving system partly and potentially developing into a subduction zone. The south-east boundary, along the

Manus Trench Manus Trench is an oceanic trench in the Bismarck Sea north of Papua New Guinea delineating the plate tectonic boundary between the Caroline Caroline may refer to: People *Caroline (given name), a feminine given name * J. C. Caroline (born 1933), ...

, is a convergent boundary, but in the absence of active volcanoes and earthquakes, is not a subduction zone at present.

Tectonic history

The Caroline Plate moves at velocities very close to those of the Pacific Plate and its age of formation and current status as an independent plate are uncertain. There is a very slow rate of spreading between the Caroline and Philippine plates but the Caroline Plate apparently moved together with both the Philippine and New Guinea plates during the Neogene. The Caroline Ridge, to the north, meets the Caroline Plate at the Sorol Trough at which there some evidence of oblique extension; the Caroline Ridge, however, is, although of uncertain origin, made of oceanic crust and probably the product of a hotspot. The presence of a trench and indications of subduction beneath the Pacific Plate is suggestive but the absence of island arcs, which could be expected from substantial subduction in the past, makes the development along this boundary unclear. The Caroline Plate was, under all circumstances, a separate plate in the past. The boundary along its eastern side, the Mussau Trench, must have been an important boundary since magnetic anomalies on the Caroline Plate are Oligocene but those on the Pacific Plate Cretaceous. There are indications of spreading in the Caroline Sea 34–27 Ma. If the Caroline Plate moved with the Pacific Plate there should be clear evidences of a corresponding subduction beneath New Guinea, of which there is virtually none. The Ayu Trough is a slow spreading zone that opened 15 Ma.

References

Notes

Sources

* * ** * * * {{DEFAULTSORT:Caroline Plate Tectonic plates Geology of the Pacific Ocean