Located in the western Pacific Ocean near Indonesia, the Molucca Sea plate has been classified by scientists as a fully subducted microplate that is part of the Molucca Sea Collision Complex . The Molucca Sea plate represents the only known example of divergent double subduction (DDS), which describes the subduction on both sides of a single oceanic plate.
16-612: The Molucca Sea plate is one of many tectonic features that compose the Molucca Sea Collision Complex, which refers to the tectonic relationship of the Sangihe plate , Halmahera plate , and the Molucca Sea plate, in addition to the volcanic Halmahera and Sangihe Arcs. The southeast moving Sangihe plate is situated along the western boundary of the Molucca Sea plate. The northwest moving Halmahera plate
32-761: A remnant slab subducted below the Halmahera plate, and another broad high-velocity zone beneath the Celebes Sea at 700–1000 km depth is interpreted as a remnant slab below the Sangihe plate, both remnants having originated from a slab subducted beneath the Philippine-Halmahera Arc 45 Ma to 25 Ma ago. In this model, the Bird's Head and Halmahera plates are separated by the Sorong Fault ,
48-814: Is situated along the eastern boundary of the Molucca Sea plate. In the western Pacific Ocean , the Molucca Sea is bordered by the Indonesian Islands of Celebes ( Sulawesi ) to the west, Halmahera to the east, and the Sula Islands to the south. The Molucca Sea borders the Banda Sea to the south and the Celebes Sea to the west. To the north is the Philippine Sea and to the east is the Halmahera Sea . Situated south of Mindanao ,
64-494: Is that Halmahera was part of the Molucca Sea slab subducted during the Neogene between 45 Ma and 25 Ma. Seismicity shows the east-dipping Halmahera reaches a depth of about 200 km. Seismic tomography suggests that the Halmahera goes deeper to at least 400 km. Both Sangihe and Halmahera are exposed to the surface while the Molucca Sea plate is completely subsumed below these two microplates. The southern boundary of
80-669: The Australian plate . This tectonics article is a stub . You can help Misplaced Pages by expanding it . Halmahera plate Halmahera plate has recently (1990s) been postulated to be a microplate within the Molucca Sea Collision Zone of eastern Indonesia . The tectonic setting of the Molucca Sea region is unique. It is the only global example of an active arc-arc collision consuming an oceanic basin via subduction in two directions. The Molucca Sea plate has been subsumed by tectonic microplates,
96-459: The Molucca Sea region is unique. It is the only global example of an active arc-arc collision consuming an oceanic basin via subduction in two directions. The Molucca Sea plate has been subsumed by tectonic microplates, the Halmahera plate and the Sangihe plate. The whole complexity is now known as the Molucca Sea Collision Zone . The existence of Sangihe as a tectonic plate separate from
112-482: The Molucca Sea plate is not yet entirely agreed upon by geologists. Some see Sangihe as a western slab of the Molucca Sea plate, just as they regard Halmahera as an eastern slab of the Molucca Sea plate. What is apparent to date is that Sangihe was part of the Molucca Sea slab subducted during the Neogene between 45 Ma and 25 Ma. Seismicity shows the west-dipping Sangihe reaches a depth of about 650 kilometres (400 mi). Both Sangihe and Halmahera are exposed to
128-416: The Halmahera plate and the Sangihe plate . The whole complexity is now known as the Molucca Sea Collision Zone . The existence of Halmahera as a tectonic plate separate from the Molucca Sea plate is not yet entirely agreed upon by paleogeologists. Some see Halmahera as an eastern slab of the Molucca Sea plate, just as they regard Sangihe as a western slab of the Molucca Sea plate. What is apparent to date
144-409: The Molucca Sea is a narrow basin underlined by a north‐south ophiolitic ridge, which uplifts the central region of the basin. While the scientific community has not come to a consensus as to when the Molucca Sea plate became fully subducted, the dominant theory is that the Molucca Sea plate has been completely subducted beneath the overriding Halmahera and Sangihe plates . When actively subducting,
160-600: The Molucca Sea plate has experienced hundreds of earthquakes ranging in magnitude. The most recent large earthquake occurred in January 2017 when a 7.3 magnitude earthquake deep beneath the Celebes Sea , which the USGS attributed to the “ deep reverse faulting within the inclined seismic zone defining the deep limit of the Molucca Sea microplate beneath the Celebes Sea Basin. ” The geologic characteristics displayed on
176-499: The Molucca Sea plate is also the boundary of the Philippine Sea plate and the Australian plate , and is moving northwards. Since the Sangihe plate and the Halmahera plate are in continuity with the Molucca Sea plate, this implies all three slabs are moving northward in mantle with the Australian plate . A broad high-velocity zone beneath the Bird's Head plate at 400–600 km depth is interpreted by R Hall and W Spakman as indicating
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#1732782559493192-410: The Molucca Sea plate is characterized as a thick, low velocity layer, which is highly variable in density. The variable in density of the Molucca Sea plate led to different subduction velocities on the two sides. Divergent Double Subduction may facilitate various tectonic processes, including closure of ocean basins, accretion and amalgamation of volcanic arcs, and growth of continents. Historically,
208-499: The crustal collision of the Molucca Sea plate was formed by surface intersection of "oppositely dipping Benioff zones ” (also known as divergent double subduction) which results in the Sangihe and Halmahera volcanic arcs . The force exerted by the thick overlying collision complex of the Halmahera and Sangihe plates effectively depressed the crust of the Molucca Sea plate. The plate itself features an asymmetrical morphology, configured in an inverted U-shape. The arc-arc collision zone of
224-405: The submarine Talaud-Mayu Ridge, which bisects the arc-arc collision zone of the Molucca Sea plate; these ophiolites provide insight regarding the relationship between earthquakes and uplift surrounding the plate. Sangihe plate Sangihe plate has recently (1990s) been postulated to be a microplate within the Molucca Sea Collision Zone of eastern Indonesia . The tectonic setting of
240-402: The surface while the Molucca Sea plate is completely subsumed below these two microplates. The southern boundary of the Molucca Sea plate is also the boundary of the Philippine Sea plate and the Australian plate , and is moving northwards. Since the Sangihe plate and the Halmahera plate are in continuity with the Molucca Sea plate, this implies all three slabs are moving northward in mantle with
256-470: The surrounding islands provide insight regarding the complex plate movement of the divergent double subducting plate. Detached ophiolitic series and thick melanges are overlain by forearc deposits; subduction-driven east–west shortening of the Snellius Plateau caused the thrust melanges to reactivate and deform the forearc series. Exposed ophiolitic rocks can be found on the islands of
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