The Samarai Islands archipelago, part of the larger Louisiade Archipelago , is located 50 kilometres (31 mi) southeast of mainland New Guinea island, within the nation of Papua New Guinea .
21-581: The archipelago consists of: 4 larger volcanic islands frequently fringed by coral reefs; and 30 smaller coral islands. The islands stretch over more than 50 kilometres (31 mi), and spread over an ocean area of 1,000 square kilometres (390 sq mi), between the Solomon Sea to the north and the Coral Sea to the south. The aggregate land area of the islands is about 262.1 square kilometres (101.2 sq mi), with Basilaki Island being
42-427: A detachment layer is present. Thrust tectonics is associated with the shortening and thickening of the crust, or the lithosphere. This type of tectonics is found at zones of continental collision , at restraining bends in strike-slip faults, and at the oceanward part of passive margin sequences where a detachment layer is present. Strike-slip tectonics is associated with the relative lateral movement of parts of
63-511: A moist tropical climate , and are largely covered with tropical moist broadleaf forests . Archipelago An archipelago ( / ˌ ɑːr k ə ˈ p ɛ l ə ɡ oʊ / AR -kə- PEL -ə-goh ), sometimes called an island group or island chain , is a chain, cluster, or collection of islands , or sometimes a sea containing a small number of scattered islands. Archipelagos are sometimes defined by political boundaries. For example, while they are geopolitically divided,
84-413: Is associated with the stretching and thinning of the crust or the lithosphere . This type of tectonics is found at divergent plate boundaries, in continental rifts , during and after a period of continental collision caused by the lateral spreading of the thickened crust formed, at releasing bends in strike-slip faults , in back-arc basins , and on the continental end of passive margin sequences where
105-421: Is formed in the process of sea-floor spreading ; transform , where plates slide past each other, and convergent , where plates converge and lithosphere is "consumed" by the process of subduction . Convergent and transform boundaries are responsible for most of the world's major ( M w > 7) earthquakes . Convergent and divergent boundaries are also the site of most of the world's volcanoes , such as around
126-452: Is the study of the motions and deformations of the Earth's crust ( geological and geomorphological processes) that are current or recent in geological time . The term may also refer to the motions and deformations themselves. The corresponding time frame is referred to as the neotectonic period . Accordingly, the preceding time is referred to as palaeotectonic period . Tectonophysics is
147-462: The Aegean Islands (since the sea has a large number of islands). Archipelagos may be found isolated in large amounts of water or neighbouring a large land mass. For example, Scotland has more than 700 islands surrounding its mainland, which form an archipelago. Archipelagos are often volcanic, forming along island arcs generated by subduction zones or hotspots , but may also be
168-661: The San Juan Islands and Gulf Islands geologically form part of a larger Gulf Archipelago. The word archipelago is derived from the Ancient Greek ἄρχι-( arkhi- , "chief") and πέλαγος ( pélagos , "sea") through the Italian arcipelago . In antiquity , "Archipelago" (from Medieval Greek * ἀρχιπέλαγος and Latin archipelagus ) was the proper name for the Aegean Sea . Later, usage shifted to refer to
189-586: The foreland to a collisional belt. In plate tectonics, the outermost part of the Earth known as the lithosphere (the crust and uppermost mantle ) act as a single mechanical layer. The lithosphere is divided into separate "plates" that move relative to each other on the underlying, relatively weak asthenosphere in a process ultimately driven by the continuous loss of heat from the Earth's interior. There are three main types of plate boundaries: divergent , where plates move apart from each other and new lithosphere
210-519: The Earth's outer shell interact with each other. Principles of tectonics also provide a framework for understanding the earthquake and volcanic belts that directly affect much of the global population. Tectonic studies are important as guides for economic geologists searching for fossil fuels and ore deposits of metallic and nonmetallic resources. An understanding of tectonic principles can help geomorphologists to explain erosion patterns and other Earth-surface features. Extensional tectonics
231-466: The Pacific Ring of Fire . Most of the deformation in the lithosphere is related to the interaction between plates at or near plate boundaries. The latest studies, based on the integration of available geological data, and satellite imagery and Gravimetric and magnetic anomaly datasets have shown that the crust of the Earth is dissected by thousands of different types of tectonic elements which define
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#1732802297932252-612: The Samarai Islands archipelago. Malay and Chinese sailors may have visited the islands before European explorers. The islands most likely first sighted by Europeans in 1606, by Luis Váez de Torres . Louis Antoine de Bougainville named them the Louisiades in 1768 for King Louis XV of France . European stops were also paid by Admiral Bruni d'Entrecasteaux in 1793, and Captain Owen Stanley in 1849. The islands have
273-419: The crust or the lithosphere. This type of tectonics is found along oceanic and continental transform faults which connect offset segments of mid-ocean ridges . Strike-slip tectonics also occurs at lateral offsets in extensional and thrust fault systems. In areas involved with plate collisions strike-slip deformation occurs in the over-riding plate in zones of oblique collision and accommodates deformation in
294-676: The largest. Logea Island , Samarai Island and Sariba Island lie closest to mainland New Guinea, while the Kitai Group lies further east. The entire archipelago is within the Bwanabwana Rural LLG (Local Level Government), a part of the Samarai-Murua District in Milne Bay Province , southeastern Papua New Guinea. The seat of the Bwanabwana Rural LLG is Samarai , the population center of
315-404: The processes that result in the structure and properties of the Earth's crust and its evolution through time. The field of planetary tectonics extends the concept to other planets and moons. These processes include those of mountain-building , the growth and behavior of the strong, old cores of continents known as cratons , and the ways in which the relatively rigid plates that constitute
336-465: The result of erosion , deposition , and land elevation . Depending on their geological origin, islands forming archipelagos can be referred to as oceanic islands , continental fragments , or continental islands . Oceanic islands are mainly of volcanic origin, and widely separated from any adjacent continent. The Hawaiian Islands and Galapagos Islands in the Pacific , and Mascarene Islands in
357-670: The shelf. The islands of the Inside Passage off the coast of British Columbia and the Canadian Arctic Archipelago are examples. Artificial archipelagos have been created in various countries for different purposes. Palm Islands and The World Islands off Dubai were or are being created for leisure and tourism purposes. Marker Wadden in the Netherlands is being built as a conservation area for birds and other wildlife. The largest archipelago in
378-432: The south Indian Ocean are examples. Continental fragments correspond to land masses that have separated from a continental mass due to tectonic displacement. The Farallon Islands off the coast of California are an example. Sets of islands formed close to the coast of a continent are considered continental archipelagos when they form part of the same continental shelf, when those islands are above-water extensions of
399-576: The study of the physical processes associated with deformation of the crust and mantle from the scale of individual mineral grains up to that of tectonic plates. Seismotectonics is the study of the relationship between earthquakes, active tectonics, and individual faults in a region. It seeks to understand which faults are responsible for seismic activity in an area by analysing a combination of regional tectonics, recent instrumentally recorded events, accounts of historical earthquakes, and geomorphological evidence. This information can then be used to quantify
420-403: The subdivision into numerous smaller microplates which have amalgamated into the larger Plates. Salt tectonics is concerned with the structural geometries and deformation processes associated with the presence of significant thicknesses of rock salt within a sequence of rocks. This is due both to the low density of salt, which does not increase with burial, and its low strength. Neotectonics
441-483: The world by number of islands is the Archipelago Sea , which is part of Finland . There are approximately 40,000 islands, mostly uninhabited. The largest archipelagic state in the world by area, and by population, is Indonesia . Tectonic Tectonics (from Latin tectonicus ; from Ancient Greek τεκτονικός ( tektonikós ) 'pertaining to building ') are
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