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Yakutat Block
The Yakutat Block is a terrane in the process of accreting to the North American continent along the south central coast of Alaska. It has been displaced about northward since the Cenozoic along the Queen Charlotte-Fairweather fault system. The block subducts between this fault system and the Alaska-Aleutian Subduction Zone. The thickness of the Yakutat Block varies, ranging from approximately 15 km in the west to 30 km in the east. The Yakutat Block is bounded on the northeast by the Fairweather Fault, and on the north by a system of thrust and possibly strike-slip faults in the Chugach Mountains and Saint Elias Mountains. The Yakutat Block is bounded on its southwest side by an as yet undefined underwater geologic feature known as the Transition Zone. Global Positioning System (GPS) measurements indicate that the Yakutat block has a distinctive velocity relative to both the Pacific Plate and the North American Plate. Thus it appears to be a terrane in the process o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terrane
In geology, a terrane (; in full, a tectonostratigraphic terrane) is a crust fragment formed on a tectonic plate (or broken off from it) and accreted or " sutured" to crust lying on another plate. The crustal block or fragment preserves its distinctive geologic history, which is different from the surrounding areas—hence the term "exotic" terrane. The suture zone between a terrane and the crust it attaches to is usually identifiable as a fault. A sedimentary deposit that buries the contact of the terrane with adjacent rock is called an overlap formation. An igneous intrusion that has intruded and obscured the contact of a terrane with adjacent rock is called a stitching pluton. There is also an older usage of the term ''terrane'', which described a series of related rock formations or an area with a preponderance of a particular rock or rock group. Overview A tectonostratigraphic terrane did not necessarily originate as an independent microplate, since it may not contain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Himalayas
The Himalayas, or Himalaya ( ), is a mountain range in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau. The range has some of the Earth's highest peaks, including the highest, Mount Everest. More than list of highest mountains on Earth, 100 peaks exceeding elevations of above sea level lie in the Himalayas. The Himalayas abut on or cross territories of Himalayan states, six countries: Nepal, China, Pakistan, Bhutan, India and Afghanistan. The sovereignty of the range in the Kashmir region is disputed among India, Pakistan, and China. The Himalayan range is bordered on the northwest by the Karakoram and Hindu Kush ranges, on the north by the Tibetan Plateau, and on the south by the Indo-Gangetic Plain. Some of the world's major rivers, the Indus River, Indus, the Ganges river, Ganges, and the Yarlung Tsangpo River, Tsangpo–Brahmaputra River, Brahmaputra, rise in the vicinity of the Himalayas, and their combined drainage basin is home to some 6 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wrangell Volcanic Field
The Wrangell Volcanic Field is a volcanic field stretching from eastern Alaska in the United States to the southwestern Yukon Territory in Canada. The field includes the four highest volcanoes in the United States, Mount Bona, Mount Blackburn, Mount Sanford, and Mount Churchill, all of which exceed 15,000 ft (4,600 m) in elevation. It formed as a result of subduction of the Pacific Plate beneath the North American Plate at the easternmost end of the Aleutian Trench /sup>. The bulk of the Wrangell Volcanic Field lies within the Wrangell Mountains of Alaska, but the field also extends eastwards into the neighboring Saint Elias Mountains and the Yukon Territory. The east–west length of the field is over 200 mile (320 km), while the width reaches up to 80 miles (130 km) in the central Wrangell Mountains. The field includes numerous shield volcanoes, stratovolcanoes, caldera complexes, cinder cones, and extensive lava flows, which have erupted throughout t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oceanic Plateau
An oceanic or submarine plateau is a large, relatively flat elevation that is higher than the surrounding relief with one or more relatively steep sides. There are 184 oceanic plateaus in the world, covering an area of or about 5.11% of the oceans. The South Pacific region around Australia and New Zealand contains the greatest number of oceanic plateaus (see map). Oceanic plateaus produced by large igneous provinces are often associated with hotspot (geology), hotspots, mantle plumes, and volcanic islands — such as Iceland, Hawaii, Cape Verde, and Kerguelen. The three largest plateaus, the Caribbean large igneous province, Caribbean, Ontong Java Plateau, Ontong Java, and Mid-Pacific Mountains, are located on swell (geology), thermal swells. Other oceanic plateaus, however, are made of rifted continental crust, for example the Falkland Plateau, Lord Howe Rise, and parts of Kerguelen Plateau, Kerguelen, Mascarene Plateau, Seychelles, and Arctic ridges. Plateaus formed by larg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Global Positioning System
The Global Positioning System (GPS) is a satellite-based hyperbolic navigation system owned by the United States Space Force and operated by Mission Delta 31. It is one of the global navigation satellite systems (GNSS) that provide geolocation and time information to a GPS receiver anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. It does not require the user to transmit any data, and operates independently of any telephone or Internet reception, though these technologies can enhance the usefulness of the GPS positioning information. It provides critical positioning capabilities to military, civil, and commercial users around the world. Although the United States government created, controls, and maintains the GPS system, it is freely accessible to anyone with a GPS receiver. Overview The GPS project was started by the U.S. Department of Defense in 1973. The first prototype spacecraft was launched in 1978 an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Accretion (geology)
In geology, accretion is a process by which material is added to a tectonic plate at a subduction zone, frequently on the edge of existing continental landmasses. The added material may be sediment, volcanic arcs, seamounts, oceanic crust or other igneous features. Description Accretion involves the addition of material to a tectonic plate via subduction, the process by which one plate is forced under the other when two plates collide. The plate which is being forced down, the subducted plate, is pushed against the upper, over-riding plate. Sediment on the ocean floor of the subducting plate is often scraped off as the plate descends. This accumulated material is called an accretionary wedge (or accretionary prism), which is pushed against and attaches to the upper plate. In addition to accumulated ocean sediments, volcanic island arcs or seamounts present on the subducting plate may be amalgamated onto existing continental crust on the upper plate, increasing the contine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saint Elias Mountains
The Saint Elias Mountains () are a subgroup of the Pacific Coast Ranges, located in southeastern Alaska in the United States, Southwestern Yukon and the very far northwestern part of British Columbia in Canada. The range spans Wrangell-St. Elias National Park and Preserve in the United States and Kluane National Park and Reserve in Canada and includes all of Glacier Bay National Park in Alaska. In Alaska, the range includes parts of the city/borough of Yakutat and the Hoonah-Angoon and Valdez-Cordova census areas. This mountain range is named after Mount Saint Elias, which in turn was named in 1741 by the Danish-born Russian explorer Vitus Bering. Geology The Saint Elias Mountains form the highest coastal mountain range on Earth. It formed due to the subduction of the Yakutat microplate underneath the North American Plate. The Yakutat microplate is a wedge shaped oceanic plateau with a thickness of . Similar to the adjacent Pacific Plate, which has a crustal thickness of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chugach Mountains
The Chugach Mountains of southern Alaska are the northernmost of the several mountain ranges that make up the Pacific Coast Ranges of the western edge of North America. The range is about long and wide, and extends from the Knik and Turnagain Arms of the Cook Inlet on the west to Bering Glacier, Tana Glacier, and the Tana River on the east. It is bounded on the north by the Matanuska, Copper, and Chitina rivers. The highest point of the Chugach Mountains is Mount Marcus Baker, at , but with an average elevation of , most of its summits are not especially high. Even so, its position along the Gulf of Alaska ensures more snowfall in the Chugach than anywhere else in the world, an annual average of over 1500 cm (800 in).Steep, Freeskiing Documentary, 2007 The mountains are protected in the Chugach State Park and the Chugach National Forest. Near to Anchorage, they are a popular destination for outdoor activities. The Richardson Highway, Seward Highway, P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
