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Microcontinent
Continental crustal fragments, partly synonymous with microcontinents, are pieces of continents that have broken off from main continental masses to form distinct islands that are often several hundred kilometers from their place of origin. Causes Continental fragments and microcontinent crustal compositions are very similar to those of regular continental crust. The rifting process that caused the continental fragments to form most likely impacts their layers and overall thickness along with the addition of mafic intrusions to the crust. Studies have determined that the average crustal thickness of continental fragments is approximately . The sedimentary layer of continental fragments can be up to thick and can overlay two to three crustal layers. Continental fragments have an average crustal density of which is very similar to that of typical continental crust. Strike-slip fault zones cause the fragmentation of microcontinents. The zones link the extensional zones where co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Jan Mayen Microcontinent
The Jan Mayen Microcontinent is a fragment of continental crust within the oceanic part of the western Eurasian Plate lying northeast of Iceland. At the onset of separation between the Greenland and Eurasian plates 55 million years ago, it formed part of the eastern margin of the Greenland Plate. Propagation of a new spreading center from the Reykjanes Ridge separated this microcontinent from the Greenland Plate. For a short period it formed a microplate, until the Aegir Ridge became inactive, after which it formed part of the Eurasian Plate. The island of Jan Mayen is a much younger feature, formed of volcanic rock, built up at the northernmost tip of the microcontinent. Extent The microcontinent extends about 500 km southwards from the Jan Mayen fracture zone. It is up to 160 km wide. The Jan Mayen Ridge separates the Norwegian Sea (the Norway Basin) from the Greenland Sea.C.Michael Hogan. 2011. Norwegian Sea. Eds. P.Saundry & C.J.Cleveland. Encyclopedia of Earth. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Continent
A continent is any of several large geographical regions. Continents are generally identified by convention (norm), convention rather than any strict criteria. A continent could be a single large landmass, a part of a very large landmass, as in the case of Asia or Europe within Eurasia, or a landmass and nearby islands within its continental shelf. Due to these varying definitions, the number of continents varies; up to seven or as few as four geographical regions are commonly regarded as continents. Most English-speaking world, English-speaking countries recognize seven regions as continents. In order from largest to smallest in area, these seven regions are Asia, Africa, North America, South America, Antarctica, Europe, and Australia (continent), Australia (sometimes called Oceania or Australasia). Different variations with fewer continents merge some of these regions; examples of this are merging Asia and Europe into Eurasia, "Most people recognize seven continents—Asia, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Seychelles Microcontinent
The Seychelles microcontinent underlies the Seychelles in the western Indian Ocean made of Late Precambrian rock. The granite outcrops of the Seychelles Islands in the central Indian Ocean were amongst the earliest examples cited by Alfred Wegener as evidence for his continental drift theory. Ridge–plume interactions have been responsible for separating a thinned continental sliver from a large continent (i.e. India). The granites of the Seychelles Microcontinent were emplaced 750 Ma, during the late Precambrian. Thermally-induced rifting in the Somali Basin and transform rifting along the Davie Fracture Zone began in the late Permian, 225 million years ago. The Gondwana supercontinent began to break up in the Middle Jurassic, about 167 million years ago. At that time, East Gondwana, comprising Antarctica, Madagascar, India, and Australia, began to separate from Africa. East Gondwana then began to separate about 115–120 million years ago when India began to move northward ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Kerguelen Plateau
The Kerguelen Plateau (, ), also known as the Kerguelen–Heard Plateau, is an oceanic plateau and large igneous province (LIP) located on the Antarctic Plate, in the southern Indian Ocean. It is about to the southwest of Australia and is nearly three times the size of California. The plateau extends for more than in a northwest–southeast direction and lies in deep water. The plateau was produced by the Kerguelen hotspot, starting with or following the breakup of Gondwana about 130 million years ago. A small portion of the plateau breaks sea level, forming the Kerguelen Islands (a overseas territory (France), French overseas territory) plus the Heard Island and McDonald Islands, Heard and McDonald Islands (an states and territories of Australia, Australian external territory). Intermittent volcanism continues on the Heard and McDonald Islands. Geographical extent Symmetrically across the Indian Ocean ridge and due west of Australia is the Broken Ridge underwater volcanic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Fault Block
Fault blocks are very large blocks of rock, sometimes hundreds of kilometres in extent, created by Tectonics, tectonic and localized stresses in Crust (geology), Earth's crust. Large areas of bedrock are broken up into blocks by Fault (geology), faults. Blocks are characterized by relatively uniform lithology. The largest of these fault blocks are called crustal blocks. Large crustal blocks broken off from tectonic plates are called terranes. Those terranes which are the full thickness of the lithosphere are called microplates. Continent-sized blocks are called variously ''microcontinents, continental ribbons, H-blocks, extensional allochthons and outer highs.'' Because most stresses relate to the tectonic activity of moving Plate tectonics, plates, most motion between blocks is horizontal, that is parallel to the Earth's crust by Fault (geology)#Strike-slip faults, strike-slip faults. However vertical movement of blocks produces much more dramatic results. Landforms (mounta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Gondwana
Gondwana ( ; ) was a large landmass, sometimes referred to as a supercontinent. The remnants of Gondwana make up around two-thirds of today's continental area, including South America, Africa, Antarctica, Australia (continent), Australia, Zealandia, Arabian Peninsula, Arabia, and the Indian subcontinent. Gondwana was formed by the Accretion (geology), accretion of several cratons (large stable blocks of the Earth's crust), beginning with the East African Orogeny, the collision of India and Geography of Madagascar, Madagascar with East Africa, and culminating in with the overlapping Brasiliano orogeny, Brasiliano and Kuunga orogeny, Kuunga orogenies, the collision of South America with Africa, and the addition of Australia and Antarctica, respectively. Eventually, Gondwana became the largest piece of continental crust of the Paleozoic Era, covering an area of some , about one-fifth of the Earth's surface. It fused with Laurasia during the Carboniferous to form Pan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Mascarene Plateau
The Mascarene Plateau is a submarine plateau in the Indian Ocean, north and east of Madagascar. The plateau extends approximately , from Seychelles in the north to Réunion in the south. The plateau covers an area of over of shallow water, with depths ranging from , plunging to to the abyssal plain at its edges. It is the second-largest oceanic plateau in the Indian Ocean after the Kerguelen Plateau. Geography The northern part of the Mascarene Plateau includes the Agaléga Islands and the Seychelles Islands. The southern part of the Mascarene Plateau includes Hawkins Bank, the Mascarene Islands, Nazareth Bank, the Saya de Malha Bank, and the Soudan Banks. The Mascarene Islands are the mountainous islands of the Cargados Carajos Shoals, Mauritius, Réunion, and Rodrigues. Geology The Indian subcontinent was at one time next to the east coast of Seychelles, but seafloor spreading has moved the landmass to its current position, where it has collided and fused w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Borneo
Borneo () is the List of islands by area, third-largest island in the world, with an area of , and population of 23,053,723 (2020 national censuses). Situated at the geographic centre of Maritime Southeast Asia, it is one of the Greater Sunda Islands, located north of Java Island, Java, west of Sulawesi, and east of Sumatra. The island is crossed by the equator, which divides it roughly in half. The list of divided islands, island is politically divided among three states. The sovereign state of Brunei in the north makes up 1% of the territory. Approximately 73% of Borneo is Indonesian territory, and in the north, the East Malaysian states of Sabah and Sarawak make up about 26% of the island. The Malaysian federal territory of Labuan is situated on a small island just off the coast of Borneo. Etymology When the sixteenth-century Portuguese explorer Jorge de Menezes made contact with the indigenous people of Borneo, they referred to their island as ''Pulu K'lemantang'', which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Newfoundland (island)
Newfoundland ( , ; , ) is a large island within the Canadian province of Newfoundland and Labrador. It is situated off the eastern coast of the Northern America, North American mainland and the geographical region of Labrador. The island contains 29 percent of the province's land area, but is home to over 90% of the province's population, with about 60% of the province's population located on the small southeastern Avalon peninsula. The island is separated from the Labrador Peninsula by the Strait of Belle Isle and from Cape Breton Island by the Cabot Strait. It blocks the mouth of the Saint Lawrence River, creating the Gulf of Saint Lawrence, the world's largest estuary. Newfoundland's nearest neighbour is the French overseas collectivity of Saint Pierre and Miquelon. With an area of , Newfoundland is the List of islands by area, world's 16th-largest island, List of Canadian islands by area, Canada's fourth-largest island, and the largest Canadian island outside Northern Can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
British Isles
The British Isles are an archipelago in the Atlantic Ocean, North Atlantic Ocean off the north-western coast of continental Europe, consisting of the islands of Great Britain, Ireland, the Isle of Man, the Inner Hebrides, Inner and Outer Hebrides, Outer Hebrides, the Northern Isles (Orkney and Shetland), and over six thousand smaller islands. They have a total area of and a combined population of almost 72 million, and include two sovereign states, the Republic of Ireland (which covers roughly five-sixths of Ireland), and the United Kingdom, United Kingdom of Great Britain and Northern Ireland. The Channel Islands, off the north coast of France, are normally taken to be part of the British Isles, even though geographically they do not form part of the archipelago. Under the UK Interpretation Act 1978, the Channel Islands are clarified as forming part of the British Islands, not to be confused with the British Isles. The oldest rocks are 2.7 billion years old and are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Caribbean Sea
The Caribbean Sea is a sea of the Atlantic Ocean, North Atlantic Ocean in the tropics of the Western Hemisphere, located south of the Gulf of Mexico and southwest of the Sargasso Sea. It is bounded by the Greater Antilles to the north from Cuba to Puerto Rico, the Lesser Antilles to the east from the Virgin Islands to Trinidad and Tobago, South America to the south from the Venezuela, Venezuelan coastline to the Colombia, Colombian coastline, and Central America and the Yucatán Peninsula to the west from Panama to Mexico. The Geopolitics, geopolitical region around the Caribbean Sea, including the numerous islands of the West Indies and adjacent coastal areas in the mainland of the Americas, is known as the Caribbean. The Caribbean Sea is one of the largest seas on Earth and has an area of about . The sea's deepest point is the Cayman Trough, between the Cayman Islands and Jamaica, at below sea level. The Caribbean coastline has many gulfs and bays: the Gulf of Gonâve, the Gul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Geography Of Iceland
Iceland is an island country at the confluence of the Atlantic Ocean, North Atlantic and Arctic Ocean, Arctic oceans, east of Greenland and immediately south of the Arctic Circle, atop the constructive boundary of the northern Mid-Atlantic Ridge. The island country is the world's List of islands by area#Islands, 18th largest in area and one of the most List of sovereign states and dependent territories by population density, sparsely populated. It is the westernmost European country when not including Greenland and has more land covered by glaciers than continental Europe. Its total size is and possesses an exclusive economic zone of . Statistics Iceland is an island country in Northern Europe, straddling the Eurasian and North American plates between the Greenland Sea and the North Atlantic Ocean, northwest of the British Isles. Extent (locations outside mainland in parentheses) :North: Rifstangi, 66°32′3" N (Kolbeinsey, 67°08,9 N) :South: Kötlutangi, 63°23′6" N ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
