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{{About|the geographic feature|the scientific journal|Island Arc (journal)}}
{{About|the geographic feature|the scientific journal|Island Arc (journal)}}
{{Unreferenced|date=October 2009}}
{{Unreferenced|date=October 2009}}
'''Island arcs''' are long chains of active [[Volcano|volcanoes]] with intense seismic activity found along convergent tectonic plate boundaries (such as [[Ring of Fire|the ring of fire]]). Most island arcs originate on oceanic crust and have resulted from the descent of the lithosphere into the mantle along the [[Subduction Zone|subduction zone]]. They are the principal way by which continental growth is achieved<ref>{{Cite journal|last=Taylor|first=S.R.|date=1967|title=The origin and growth of continents|url=http://dx.doi.org/10.1016/0040-1951(67)90056-x|journal=Tectonophysics|volume=4|issue=1|pages=17–34|doi=10.1016/0040-1951(67)90056-x|issn=0040-1951|via=}}</ref> . [[File:Location of the Ryukyu Islands.JPG|thumb|The [[Ryukyu Islands]] form an island arc.]]
[[File:Location of the Ryukyu Islands.JPG|thumb|The [[Ryukyu Islands]] form an island arc.]]
Island arcs can either be active or inactive based on their seismicity and presence of volcanoes. Active arcs are ridges of recent volcanoes with an associated deep seismic zone. They also possess a distinct curved form, a chain of active or recently extinct volcanoes, a deep-sea trench, and a large negative Bouguer anomaly on the convex side of the volcanic arc. The small positive gravity anomaly associated with volcanic arcs has been interpreted by many authors as due to the presence of dense volcanic rocks beneath the arc. While inactive arcs are a chain of islands which contains older volcanic and [[Volcaniclastic rock|volcaniclastic rocks]]<ref name=":0">{{Cite journal|last=Mitchell|first=Andrew H.|last2=Reading|first2=Harold G.|date=1971|title=Evolution of Island Arcs|url=http://dx.doi.org/10.1086/627627|journal=The Journal of Geology|volume=79|issue=3|pages=253–284|doi=10.1086/627627|issn=0022-1376|via=}}</ref> .
An '''island arc''' is a type of [[archipelago]], often composed of a chain of [[volcanoes]], with arc-shaped alignment, situated parallel and close to a boundary between two [[Convergent boundary|converging tectonic plate]]s.


The curved shape of many volcanic chains and the angle of the descending [[lithosphere]] are related<ref>{{Cite journal|last=FRANK|first=F. C.|date=1968|title=Curvature of Island Arcs|url=http://dx.doi.org/10.1038/220363a0|journal=Nature|volume=220|issue=5165|pages=363–363|doi=10.1038/220363a0|issn=0028-0836|via=}}</ref>. If the oceanic part of the plate is represented by the ocean floor on the convex side of the arc, and if the zone of flexing occurs beneath the [[submarine trench]], then the deflected part of the plate coincides approximately with the [[Wadati–Benioff zone|Benioff zone]] beneath most arcs.
Most of these island arcs are formed as one oceanic tectonic plate [[subduction|subducts]] another one and, in most cases, produces [[magma]] at depths below the over-riding plate. However, this is only true for those island arcs that are part of the group of mountain belts which are called [[volcanic arc]]s, a term which is used when all the elements of the arc-shaped mountain belt are composed of volcanoes. For example, large parts of the Andes-Central American-Canadian mountain chain may be known as a volcanic arc, but they are not islands (being situated upon and along a continental area) and are thus not classified as an island arc. On the other hand, the Aegean or [[Hellenic arc]] in the [[Mediterranean]] area, composed of numerous islands such as [[Crete]], is an island arc, but is not volcanic. Parallel to it is the [[South Aegean Volcanic Arc]], which is the volcanic island arc of the same tectonic system.{{Citation needed|date=December 2010}}


==Classification==
==Location==
Most modern island arcs are near the [[Continental margin|continental margins]] (majorly in the northern and western margins of the [[Pacific Ocean]]). However, no direct evidence from within the arcs shows that they have always existed at their present position with respect to the continents. Though, evidence from some continental margins suggests that some arcs may have migrated toward the continents during the late Mesozoic or early Cenozoic<ref name=":0" /> .
There is some debate about the usefulness of the distinction between island arcs and volcanic arcs.{{Citation needed|date=December 2010}} The term "volcanic island arc" is merely a sub-classification of "island arc." Island arcs are tectonically created arc-shaped mountain belts that are partly below sea level. Essentially, they represent a specific geographic-topographic situation in which a mountain belt is partly submerged in ocean. Many of these are composed of volcanoes, and can thus be further classified as volcanic island arcs.

The movement of the island arcs towards the continent could be possible if, at some point, the ancient Benioff zones dipped toward the present ocean rather than toward the continent, as in most arcs today. This will have resulted in the loss of ocean floor between the arc and the continent, and consequently, in the migration of the arc during spreading episodes<ref name=":0" />.

The fracture zones in which some active island arcs terminate may be interpreted in terms of plate tectonics as resulting from movement along transform faults<ref>{{Cite journal|last=WILSON|first=J. TUZO|date=1965|title=A New Class of Faults and their Bearing on Continental Drift|url=http://dx.doi.org/10.1038/207343a0|journal=Nature|volume=207|issue=4995|pages=343–347|doi=10.1038/207343a0|issn=0028-0836|via=}}</ref> <ref>{{Cite journal|last=Isacks|first=Bryan|last2=Oliver|first2=Jack|last3=Sykes|first3=Lynn R.|date=1968-09-15|title=Seismology and the new global tectonics|url=http://dx.doi.org/10.1029/jb073i018p05855|journal=Journal of Geophysical Research|volume=73|issue=18|pages=5855–5899|doi=10.1029/jb073i018p05855|issn=0148-0227}}</ref>, which are plate margins where the crust is neither being consumed nor generated. Thus the present location of these inactive island chains is due to the present pattern of lithospheric plates. However, their volcanic history, which indicates that they are fragments of older island arcs, is not necessarily related to the present plate pattern and may be due to differences in position of plate margins in the past.


==Tectonic formation==
==Tectonic formation==
{{see also|Subduction}}
{{see also|Subduction}}


Understanding the source of heat that causes the melting of the mantle was a contentious problem. Researchers believed that the heat was produced through friction at the top of the slab. However, this is unlikely because the viscosity of the [[asthenosphere]] decreases with increasing temperature, and at the temperatures required for partial fusion the asthenosphere would have such a low viscosity that shear melting could not occur<ref name=":1">{{Cite journal|last=England|first=Richard W.|date=2009|title=Philip Kearey, Keith A. Klepeis and Frederick J. Vine: Global tectonics|url=http://dx.doi.org/10.1007/s11001-010-9082-0|journal=Marine Geophysical Researches|volume=30|issue=4|pages=293–294|doi=10.1007/s11001-010-9082-0|issn=0025-3235|via=}}</ref>.
In the subduction zone, the dehydration of the subducting slab releases volatiles into the overriding [[mantle wedge]]. The addition of volatile components (e.g., water) induces partial melting by lowering the solidus of the wedge. This process, called [[flux melting]], generates varying degrees of [[calc-alkaline]] [[magma]] that buoyantly rises to intrude and be extruded through the lithosphere of the overriding plate. The resulting [[volcano]] chain has the shape of an arc parallel to the convergent plate boundary and convex toward the subducting plate. One of the theories to explain the arc shape views this as a consequence of the geometry of the spherical plate crumpling along a line on a spherical surface, but only the more broadly shaped arcs can be explained in this way.{{Citation needed|date=December 2010}}

It is now believed that water acts as the primary agent that drives partial melting beneath arcs. It has been shown that the amount of water present in the down-going slab is related to the melting temperature of the mantle<ref>{{Cite journal|last=Stolper|first=Edward|last2=Newman|first2=Sally|date=1994|title=The role of water in the petrogenesis of Mariana trough magmas|url=http://dx.doi.org/10.1016/0012-821x(94)90074-4|journal=Earth and Planetary Science Letters|volume=121|issue=3-4|pages=293–325|doi=10.1016/0012-821x(94)90074-4|issn=0012-821X|via=}}</ref>. The greater the amount of water present, the more the melting temperature of the mantle is reduced. This water is released during the transformation of minerals as pressure increases, with the mineral carrying the most water being [[serpentinite]].

These metamorphic mineral reactions cause the dehydration of the upper part of the slab as the hydrated slab sinks. Heat is also transferred to it from the surrounding asthenosphere. As heat is transferred to the slab, temperature gradients are established such that the asthenosphere in the vicinity of the slab becomes cooler and more viscous than surrounding areas, particularly near the upper part of the slab. This more viscous asthenosphere is then dragged down with the slab causing less viscous mantle to flow in behind it. It is the interaction of this down-welling mantle with aqueous fluids rising from the sinking slab that is thought to produce partial melting of the mantle as it crosses its wet solidus<ref>{{Cite journal|last=Tatsumi|first=Yoshiyuki|date=1989-04-10|title=Migration of fluid phases and genesis of basalt magmas in subduction zones|url=https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/JB094iB04p04697|journal=Journal of Geophysical Research: Solid Earth|language=en|volume=94|issue=B4|pages=4697–4707|doi=10.1029/JB094iB04p04697|issn=2156-2202}}</ref>. In addition, some melts may result from the up-welling of hot mantle material within the mantle wedge<ref>{{Cite journal|last=Sisson|first=T. W.|last2=Bronto|first2=S.|date=1998|title=Evidence for pressure-release melting beneath magmatic arcs from basalt at Galunggung, Indonesia|url=http://dx.doi.org/10.1038/36087|journal=Nature|volume=391|issue=6670|pages=883–886|doi=10.1038/36087|issn=0028-0836|via=}}</ref>. If hot material rises quickly enough so that little heat is lost, the reduction in pressure may cause pressure release or decompression partial melting.

On the subducting side of the island arc is a deep and narrow oceanic trench, which is the trace at the Earth’s surface of the boundary between the down-going and overriding plates. This trench is created by the downward gravitational pull of the relatively dense subducting plate on the leading edge of the plate. Multiple [[Earthquake|earthquakes]] occur along this subduction boundary with the seismic hypocenters located at increasing depth under the island arc: these quakes define the Benioff zone<ref>{{Cite journal|last=Toksöz|first=M. Nafi|date=1975|title=The Subduction of the Lithosphere|url=http://dx.doi.org/10.1038/scientificamerican1175-88|journal=Scientific American|volume=233|issue=5|pages=88–98|doi=10.1038/scientificamerican1175-88|issn=0036-8733|via=}}</ref> <ref>{{Cite journal|last=Hacker|first=Bradley R.|last2=Peacock|first2=Simon M.|last3=Abers|first3=Geoffrey A.|last4=Holloway|first4=Stephen D.|date=2003|title=Subduction factory 2. Are intermediate-depth earthquakes in subducting slabs linked to metamorphic dehydration reactions?|url=http://dx.doi.org/10.1029/2001jb001129|journal=Journal of Geophysical Research: Solid Earth|volume=108|issue=B1|pages=|doi=10.1029/2001jb001129|issn=0148-0227|via=}}</ref>.

Island arcs can be formed in intra-oceanic settings, or from the fragments of continental crust that have migrated away from an adjacent continental land mass or at subduction-related volcanoes active at the margins of continents.

== Features ==
Below are some of the generalized features present in most island arcs.

[[Forearc|Fore-arc]]: This region is comprised of the trench, the accretionary prism, and the fore-arc basin. A bump from the trench in the oceanward side of the system is present (Barbados in the Lesser Antilles is an example). The fore-arc basin forms between the fore-arc ridge and the island arc; it is a region of undisturbed flat-bedded sedimentation.

[[Trench|Trenches]]: These are the deepest features of ocean basins; the deepest being the Mariana trench (~36,000 feet). They are formed by flexing of the oceanic lithosphere, developing on the ocean side of island arcs.

[[Back-arc basin]]: They are also referred to as marginal seas and are formed in the inner, concave side of island arcs bounded by back-arc ridges. They develop in response to tensional tectonics due to rifting of an existing island arc.

[[Benioff zone]] or [[Wadati–Benioff zone|Wadatti-Benioff zone]]: This is a plane that dips under the overriding plate where intense volcanic activity occurs, which is defined by the location of seismic events below the arc. Earthquakes occur from near surface to ~660 km depth. The dip of Benioff zones ranges from 30<sup>o</sup> to near vertical (Condie, 1987).

An ocean basin may be formed between the continental margin and the island arcs on the concave side of the arc. These basins have a crust which is either oceanic or intermediate between the normal oceanic crust and that typical of continents; heat flow in the basins is higher than in normal continental or oceanic areas<ref name=":0" /> .

Some arcs, such as the Aleutians, pass laterally into the continental shelf on the concave side of the arc<ref>{{Cite journal|last=Menard|first=H. W.|date=1967-06-15|title=Transitional types of crust under small ocean basins|url=http://dx.doi.org/10.1029/jz072i012p03061|journal=Journal of Geophysical Research|volume=72|issue=12|pages=3061–3073|doi=10.1029/jz072i012p03061|issn=0148-0227}}</ref>, while most of the arcs are separated from the continental crust.

Movement between two lithospheric plates explains the major features of active island arcs. The island arc and small ocean basin are situated on the overlying plate which meets the descending plate containing normal oceanic crust along the Benioff zone. The sharp bending of the oceanic plate downward produces a trench<ref>{{Cite journal|last=OXBURGH|first=E. R.|last2=TURCOTTE|first2=D. L.|date=1970|title=Thermal Structure of Island Arcs|url=http://dx.doi.org/10.1130/0016-7606(1970)81[1665:tsoia]2.0.co;2|journal=Geological Society of America Bulletin|volume=81|issue=6|pages=1665|doi=10.1130/0016-7606(1970)81[1665:tsoia]2.0.co;2|issn=0016-7606}}</ref>.

== Volcanic rocks in the island arc ==
There are generally three volcanic series from which the types of volcanic rock that occur in island arcs are formed<ref name=":2">{{Cite journal|last=Gill|first=J.B.|date=1982|title=Andesites: Orogenic andesites and related rocks|url=http://dx.doi.org/10.1016/0016-7037(82)90392-1|journal=Geochimica et Cosmochimica Acta|volume=46|issue=12|pages=2688|doi=10.1016/0016-7037(82)90392-1|issn=0016-7037|via=}}</ref><ref>{{Cite journal|last=Hall|first=A.|date=1982|title=R. S. Thorpe, Editor. Andesites: Orogenic Andesites and Related Rocks. Chichester, New York, Brisbane, Toronto, and Singapore (John Wiley and Sons), 1982. xiii+724 pp., 277 figs. Price £59·50.|url=http://dx.doi.org/10.1180/minmag.1982.046.341.31|journal=Mineralogical Magazine|volume=46|issue=341|pages=532–533|doi=10.1180/minmag.1982.046.341.31|issn=0026-461X|via=}}</ref>:

* The ''[[Tholeiitic magma series|tholeiitic]]'' series – basaltic andesites and andesites.
* The [[Calc-alkaline magma series|calc-alkaline]] series – andesites.
* The alkaline series – subgroups of alkaline basalts and the rare, very high potassium-bearing (i.e. shoshonitic) lavas.


This volcanic series is related to the age of the subduction zone and the depth. The tholeiitic magma series is well represented above young subduction zones formed by magma from relative shallow depth. The calc-alkaline and alkaline series are seen in mature subduction zones, and are related to magma of greater depths. Andesite and basaltic andesite are the most abundant volcanic rock in island arc which is indicative of the calc-alkaline magmas. Some Island arcs have distributed volcanic series as can be seen in the Japanese island arc system where the volcanic rocks change from tholeiite—calc-alkaline—alkaline with increasing distance from the trench<ref name=":2" />.
On the subducting side of the island arc is a deep and narrow [[oceanic trench]], which is the trace at the Earth’s surface of the boundary between the downgoing and overriding plates. This trench is created by the gravitational pull of the relatively dense subducting plate pulling the leading edge of the plate downward. Multiple [[earthquake]]s occur along this subduction boundary with the [[seismic]] [[hypocenter]]s located at increasing depth under the island arc: these quakes define the [[Wadati–Benioff zone]]s.{{Citation needed|date=December 2010}}


Several processes are involved in arc magmatism which gives rise to the great spectrum of rock composition encountered. These processes are, but not limited to, magma mixing, fractionation, variations in the depth and degree of partial melting and assimilation. Therefore, the three volcanic series results in a wide range of rock composition and do not correspond to absolute magma types or source regions<ref name=":1" />.
Ocean basins that are being reduced by subduction are called 'remnant oceans' as they will slowly be shrunken out of existence and crushed in the subsequent [[orogeny|orogenic]] collision. This process has happened repeatedly in the geological history of the Earth.{{Citation needed|date=December 2010}}


==List of modern island arcs==
==List of modern island arcs==
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==Ancient island arcs==
==Examples of ancient island arcs==
Remains of former island arcs have been identified at some locations. The table below mention a selection of these.
Remains of former island arcs have been identified at some locations. The table below mention a selection of these.
{{incomplete list|date=November 2018}}
{|class="wikitable"
{|class="wikitable"
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Revision as of 00:49, 12 December 2018

This article is about the geographic feature. For the scientific journal, see Island Arc (journal).

Island arcs are long chains of active volcanoes with intense seismic activity found along convergent tectonic plate boundaries (such as the ring of fire). Most island arcs originate on oceanic crust and have resulted from the descent of the lithosphere into the mantle along the subduction zone. They are the principal way by which continental growth is achieved[1] .

The Ryukyu Islands form an island arc.

Island arcs can either be active or inactive based on their seismicity and presence of volcanoes. Active arcs are ridges of recent volcanoes with an associated deep seismic zone. They also possess a distinct curved form, a chain of active or recently extinct volcanoes, a deep-sea trench, and a large negative Bouguer anomaly on the convex side of the volcanic arc. The small positive gravity anomaly associated with volcanic arcs has been interpreted by many authors as due to the presence of dense volcanic rocks beneath the arc. While inactive arcs are a chain of islands which contains older volcanic and volcaniclastic rocks[2] .

The curved shape of many volcanic chains and the angle of the descending lithosphere are related[3]. If the oceanic part of the plate is represented by the ocean floor on the convex side of the arc, and if the zone of flexing occurs beneath the submarine trench, then the deflected part of the plate coincides approximately with the Benioff zone beneath most arcs.

Location

Most modern island arcs are near the continental margins (majorly in the northern and western margins of the Pacific Ocean). However, no direct evidence from within the arcs shows that they have always existed at their present position with respect to the continents. Though, evidence from some continental margins suggests that some arcs may have migrated toward the continents during the late Mesozoic or early Cenozoic[2] .

The movement of the island arcs towards the continent could be possible if, at some point, the ancient Benioff zones dipped toward the present ocean rather than toward the continent, as in most arcs today. This will have resulted in the loss of ocean floor between the arc and the continent, and consequently, in the migration of the arc during spreading episodes[2].

The fracture zones in which some active island arcs terminate may be interpreted in terms of plate tectonics as resulting from movement along transform faults[4] [5], which are plate margins where the crust is neither being consumed nor generated. Thus the present location of these inactive island chains is due to the present pattern of lithospheric plates. However, their volcanic history, which indicates that they are fragments of older island arcs, is not necessarily related to the present plate pattern and may be due to differences in position of plate margins in the past.

Tectonic formation

See also: Subduction

Understanding the source of heat that causes the melting of the mantle was a contentious problem. Researchers believed that the heat was produced through friction at the top of the slab. However, this is unlikely because the viscosity of the asthenosphere decreases with increasing temperature, and at the temperatures required for partial fusion the asthenosphere would have such a low viscosity that shear melting could not occur[6].

It is now believed that water acts as the primary agent that drives partial melting beneath arcs. It has been shown that the amount of water present in the down-going slab is related to the melting temperature of the mantle[7]. The greater the amount of water present, the more the melting temperature of the mantle is reduced. This water is released during the transformation of minerals as pressure increases, with the mineral carrying the most water being serpentinite.

These metamorphic mineral reactions cause the dehydration of the upper part of the slab as the hydrated slab sinks. Heat is also transferred to it from the surrounding asthenosphere. As heat is transferred to the slab, temperature gradients are established such that the asthenosphere in the vicinity of the slab becomes cooler and more viscous than surrounding areas, particularly near the upper part of the slab. This more viscous asthenosphere is then dragged down with the slab causing less viscous mantle to flow in behind it. It is the interaction of this down-welling mantle with aqueous fluids rising from the sinking slab that is thought to produce partial melting of the mantle as it crosses its wet solidus[8]. In addition, some melts may result from the up-welling of hot mantle material within the mantle wedge[9]. If hot material rises quickly enough so that little heat is lost, the reduction in pressure may cause pressure release or decompression partial melting.

On the subducting side of the island arc is a deep and narrow oceanic trench, which is the trace at the Earth’s surface of the boundary between the down-going and overriding plates. This trench is created by the downward gravitational pull of the relatively dense subducting plate on the leading edge of the plate. Multiple earthquakes occur along this subduction boundary with the seismic hypocenters located at increasing depth under the island arc: these quakes define the Benioff zone[10] [11].

Island arcs can be formed in intra-oceanic settings, or from the fragments of continental crust that have migrated away from an adjacent continental land mass or at subduction-related volcanoes active at the margins of continents.

Features

Below are some of the generalized features present in most island arcs.

Fore-arc: This region is comprised of the trench, the accretionary prism, and the fore-arc basin. A bump from the trench in the oceanward side of the system is present (Barbados in the Lesser Antilles is an example). The fore-arc basin forms between the fore-arc ridge and the island arc; it is a region of undisturbed flat-bedded sedimentation.

Trenches: These are the deepest features of ocean basins; the deepest being the Mariana trench (~36,000 feet). They are formed by flexing of the oceanic lithosphere, developing on the ocean side of island arcs.

Back-arc basin: They are also referred to as marginal seas and are formed in the inner, concave side of island arcs bounded by back-arc ridges. They develop in response to tensional tectonics due to rifting of an existing island arc.

Benioff zone or Wadatti-Benioff zone: This is a plane that dips under the overriding plate where intense volcanic activity occurs, which is defined by the location of seismic events below the arc. Earthquakes occur from near surface to ~660 km depth. The dip of Benioff zones ranges from 30o to near vertical (Condie, 1987).

An ocean basin may be formed between the continental margin and the island arcs on the concave side of the arc. These basins have a crust which is either oceanic or intermediate between the normal oceanic crust and that typical of continents; heat flow in the basins is higher than in normal continental or oceanic areas[2] .

Some arcs, such as the Aleutians, pass laterally into the continental shelf on the concave side of the arc[12], while most of the arcs are separated from the continental crust.

Movement between two lithospheric plates explains the major features of active island arcs. The island arc and small ocean basin are situated on the overlying plate which meets the descending plate containing normal oceanic crust along the Benioff zone. The sharp bending of the oceanic plate downward produces a trench[13].

Volcanic rocks in the island arc

There are generally three volcanic series from which the types of volcanic rock that occur in island arcs are formed[14][15]:

  • The tholeiitic series – basaltic andesites and andesites.
  • The calc-alkaline series – andesites.
  • The alkaline series – subgroups of alkaline basalts and the rare, very high potassium-bearing (i.e. shoshonitic) lavas.

This volcanic series is related to the age of the subduction zone and the depth. The tholeiitic magma series is well represented above young subduction zones formed by magma from relative shallow depth. The calc-alkaline and alkaline series are seen in mature subduction zones, and are related to magma of greater depths. Andesite and basaltic andesite are the most abundant volcanic rock in island arc which is indicative of the calc-alkaline magmas. Some Island arcs have distributed volcanic series as can be seen in the Japanese island arc system where the volcanic rocks change from tholeiite—calc-alkaline—alkaline with increasing distance from the trench[14].

Several processes are involved in arc magmatism which gives rise to the great spectrum of rock composition encountered. These processes are, but not limited to, magma mixing, fractionation, variations in the depth and degree of partial melting and assimilation. Therefore, the three volcanic series results in a wide range of rock composition and do not correspond to absolute magma types or source regions[6].

List of modern island arcs

Island arc Country Trench Basin or marginal sea Overriding Plate Subducting plate
Aleutian Islands United States Aleutian Trench Bering Sea North American Plate Pacific Plate
Kuril Islands Russia Kuril–Kamchatka Trench Sea of Okhotsk North American Plate Pacific Plate
Japanese Archipelago Japan Japan Trench、Nankai Trough Sea of Japan North American Plate, Eurasian Plate Pacific Plate, Philippine Sea Plate
Ryukyu Islands Japan Ryukyu Trench East China Sea (Okinawa Trough) Eurasian Plate Philippine Sea Plate
Philippine Islands Philippines Philippine Trench South China Sea, Celebes Sea Eurasian Plate Philippine Sea Plate
Sunda Islands Indonesia Java Trench Java Sea, Flores Sea Eurasian Plate Australian Plate
Andaman and Nicobar Islands India Northern Java Trench Andaman Sea Eurasian Plate Indo-Australian Plate
Izu Islands and Bonin Islands (Ogasawara Islands) Japan Izu-Ogasawara Trench Philippine Sea Plate Pacific Plate
Mariana Islands United States Mariana Trench Philippine Sea Plate Pacific Plate
Bismarck Archipelago Papua New Guinea New Britain Trench Pacific Plate Australian Plate
Solomon Islands (archipelago) Solomon Islands San Cristobal Trench Pacific Plate Australian Plate
New Hebrides Vanuatu New Hebrides Trench Pacific Plate Australian Plate
Tonga islands Tonga Tonga Trench Australian Plate Pacific Plate
Antilles Puerto Rico Trench Caribbean Sea Caribbean Plate North American Plate, South American Plate
South Sandwich Islands United Kingdom South Sandwich Trench Scotia Sea Scotia Plate South American Plate
Aegean or Hellenic arc Greece Eastern Mediterranean Trench Aegean Sea Aegean Sea Plate or Hellenic Plate African Plate
South Aegean Volcanic Arc Greece Eastern Mediterranean Trench Aegean Sea Aegean Sea Plate or Hellenic Plate African Plate

Examples of ancient island arcs

Remains of former island arcs have been identified at some locations. The table below mention a selection of these.

Island arc Country Fate
Chaitenia Chile, Argentina Accreted to Patagonia in the Devonian.[16]
Insular Islands Canada, United States Accreted to North America in the Cretaceous.
Intermontane Islands Canada, United States Accreted to North America in the Jurassic.

See also

References

  1. ^ Taylor, S.R. (1967). "The origin and growth of continents". Tectonophysics. 4 (1): 17–34. doi:10.1016/0040-1951(67)90056-x. ISSN 0040-1951.
  2. ^ a b c d Mitchell, Andrew H.; Reading, Harold G. (1971). "Evolution of Island Arcs". The Journal of Geology. 79 (3): 253–284. doi:10.1086/627627. ISSN 0022-1376.
  3. ^ FRANK, F. C. (1968). "Curvature of Island Arcs". Nature. 220 (5165): 363–363. doi:10.1038/220363a0. ISSN 0028-0836.
  4. ^ WILSON, J. TUZO (1965). "A New Class of Faults and their Bearing on Continental Drift". Nature. 207 (4995): 343–347. doi:10.1038/207343a0. ISSN 0028-0836.
  5. ^ Isacks, Bryan; Oliver, Jack; Sykes, Lynn R. (1968-09-15). "Seismology and the new global tectonics". Journal of Geophysical Research. 73 (18): 5855–5899. doi:10.1029/jb073i018p05855. ISSN 0148-0227.
  6. ^ a b England, Richard W. (2009). "Philip Kearey, Keith A. Klepeis and Frederick J. Vine: Global tectonics". Marine Geophysical Researches. 30 (4): 293–294. doi:10.1007/s11001-010-9082-0. ISSN 0025-3235.
  7. ^ Stolper, Edward; Newman, Sally (1994). "The role of water in the petrogenesis of Mariana trough magmas". Earth and Planetary Science Letters. 121 (3–4): 293–325. doi:10.1016/0012-821x(94)90074-4. ISSN 0012-821X.
  8. ^ Tatsumi, Yoshiyuki (1989-04-10). "Migration of fluid phases and genesis of basalt magmas in subduction zones". Journal of Geophysical Research: Solid Earth. 94 (B4): 4697–4707. doi:10.1029/JB094iB04p04697. ISSN 2156-2202.
  9. ^ Sisson, T. W.; Bronto, S. (1998). "Evidence for pressure-release melting beneath magmatic arcs from basalt at Galunggung, Indonesia". Nature. 391 (6670): 883–886. doi:10.1038/36087. ISSN 0028-0836.
  10. ^ Toksöz, M. Nafi (1975). "The Subduction of the Lithosphere". Scientific American. 233 (5): 88–98. doi:10.1038/scientificamerican1175-88. ISSN 0036-8733.
  11. ^ Hacker, Bradley R.; Peacock, Simon M.; Abers, Geoffrey A.; Holloway, Stephen D. (2003). "Subduction factory 2. Are intermediate-depth earthquakes in subducting slabs linked to metamorphic dehydration reactions?". Journal of Geophysical Research: Solid Earth. 108 (B1). doi:10.1029/2001jb001129. ISSN 0148-0227.
  12. ^ Menard, H. W. (1967-06-15). "Transitional types of crust under small ocean basins". Journal of Geophysical Research. 72 (12): 3061–3073. doi:10.1029/jz072i012p03061. ISSN 0148-0227.
  13. ^ OXBURGH, E. R.; TURCOTTE, D. L. (1970). "Thermal Structure of Island Arcs". Geological Society of America Bulletin. 81 (6): 1665. doi:10.1130/0016-7606(1970)81[1665:tsoia]2.0.co;2. ISSN 0016-7606.
  14. ^ a b Gill, J.B. (1982). "Andesites: Orogenic andesites and related rocks". Geochimica et Cosmochimica Acta. 46 (12): 2688. doi:10.1016/0016-7037(82)90392-1. ISSN 0016-7037.
  15. ^ Hall, A. (1982). "R. S. Thorpe, Editor. Andesites: Orogenic Andesites and Related Rocks. Chichester, New York, Brisbane, Toronto, and Singapore (John Wiley and Sons), 1982. xiii+724 pp., 277 figs. Price £59·50". Mineralogical Magazine. 46 (341): 532–533. doi:10.1180/minmag.1982.046.341.31. ISSN 0026-461X.
  16. ^ Hervé, Francisco; Calderón, Mauricio; Fanning, Mark; Pankhurst, Robert; Rapela, Carlos W.; Quezada, Paulo (2018). "The country rocks of Devonian magmatism in the North Patagonian Massif and Chaitenia". Andean Geology. 45 (3): 301–317. doi:10.5027/andgeoV45n3-3117.
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