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Hannegan Caldera
Hannegan caldera is a 3.72 million year old volcanic collapse structure in the North Cascades of the U.S. state of Washington (state), Washington. The caldera collapsed during two separate volcanic eruptions that produced as much as 140 km3 of rhyolite ash. The caldera is filled with 55-60 km3 of tuff consisting of ignimbrite, wall-rock breccia, and post-caldera sedimentary rocks. Rocks filling the caldera are lumped into a stratigraphic unit called the Hannegan volcanics. This geologic unit is subdivided into the ignimbrite of Hannegan Peak, which is overlain by the slightly younger ignimbrite of Ruth Mountain. Hannegan caldera is centered 8.9 km northeast of Mount Shuksan. Prominent geographic points within the caldera include Hannegan Peak, Hannegan Pass, Ruth Mountain, Icy Peak, the western portion of Copper Ridge and the uppermost reaches of the Chilliwack River. The caldera’s western margin is in Mount Baker-Snoqualmie National Forest but most of the structure is in North ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hannegan Peak
Hannegan Peak is a mountain summit located in the Skagit Range, which is a subset of the North Cascades in Whatcom County of Washington state. It is situated immediately north of Hannegan Pass, and north of Ruth Mountain in the Mount Baker Wilderness, which is managed by Mount Baker-Snoqualmie National Forest. Banning Austin and R.M. Lyle made the first ascent of Hannegan Peak in 1893 while surveying for a possible road across the Cascades over Hannegan Pass to Whatcom Pass. This peak was named in association with Hannegan Pass, which in turn was named for Tom Hannegan, State Road Commissioner at that time. Although no road was built, a four-mile trail leads hikers to the pass, and another one-mile path leads to the summit. Peaks which can be seen from the summit include Mount Shuksan, Ruth Mountain, Mineral Mountain, Mount Baker, Mount Sefrit, Mount Larrabee, Granite Mountain, Mount Chardonnay, Mount Rexford, the Picket Range, and many more. Climate Hannegan Peak is lo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hannegan Pass
Hannigan is a surname. A spelling variant is Hannegan. Notable people with the surname Hannigan include: * Alyson Hannigan, American actress * Barbara Hannigan, Canadian soprano * Ed Hannigan, American comic book writer and artist * James Hannigan, British composer * Lisa Hannigan, Irish singer and songwriter * Ray Hannigan (1927–2020), Canadian ice hockey player * Robert Hannigan, senior British civil servant and author of a report informally known as the ''Hannigan Report'' *Robyn E. Hannigan, American academic in the field of science *Thomas M. Hannigan (1940–2018), American businessman and politician :Fictional characters: *Miss Agatha Hannigan, fictional character in '' Annie'' Hannegan may refer to: *Bryan Hannegan, American scientific administrator * Edward A. Hannegan (1807–1859), American politician from Indiana * Robert E. Hannegan (1903–1949), American politician from Missouri *''Hannegan v. Esquire, Inc.'', 1946 U.S. Supreme Court case *Tom Hannegan (1970–20 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lava
Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or underwater, usually at temperatures from . The volcanic rock resulting from subsequent cooling is also often called ''lava''. A lava flow is an outpouring of lava during an effusive eruption. (An explosive eruption, by contrast, produces a mixture of volcanic ash and other fragments called tephra, not lava flows.) The viscosity of most lava is about that of ketchup, roughly 10,000 to 100,000 times that of water. Even so, lava can flow great distances before cooling causes it to solidify, because lava exposed to air quickly develops a solid crust that insulates the remaining liquid lava, helping to keep it hot and inviscid enough to continue flowing. The word ''lava'' comes from Italian and is probably derived from the Latin word ''labes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magma
Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural satellites. Besides molten rock, magma may also contain suspended crystals and gas bubbles. Magma is produced by melting of the mantle or the crust in various tectonic settings, which on Earth include subduction zones, continental rift zones, mid-ocean ridges and hotspots. Mantle and crustal melts migrate upwards through the crust where they are thought to be stored in magma chambers or trans-crustal crystal-rich mush zones. During magma's storage in the crust, its composition may be modified by fractional crystallization, contamination with crustal melts, magma mixing, and degassing. Following its ascent through the crust, magma may feed a volcano and be extruded as lava, or it may solidify underground to form an intrusion, such as a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dike (geology)
A dike or dyke, in Geology, geological usage, is a sheet of rock that is formed in a Fracture (geology), fracture of a pre-existing rock body. Dikes can be either Intrusive rock, magmatic or Sedimentary rock, sedimentary in origin. Magmatic dikes form when magma flows into a crack then solidifies as a sheet intrusion, either cutting across layers of rock or through a contiguous mass of rock. Clastic dikes are formed when sediment fills a pre-existing crack.Essentials of Geology, 3rd Ed, Stephen Marshak Magmatic dikes A magmatic dike is a sheet of igneous rock that cuts across older rock beds. It is formed when magma fills a fracture in the older beds and then cools and solidifies. The dike rock is usually more resistant to weathering than the surrounding rock, so that erosion exposes the dike as a natural wall or ridge. It is from these natural walls that dikes get their name. Dikes preserve a record of the fissures through which most mafic magma (fluid magma low in silica) reac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Park Service
The National Park Service (NPS) is an agency of the United States federal government within the U.S. Department of the Interior that manages all national parks, most national monuments, and other natural, historical, and recreational properties with various title designations. The U.S. Congress created the agency on August 25, 1916, through the National Park Service Organic Act. It is headquartered in Washington, D.C., within the main headquarters of the Department of the Interior. The NPS employs approximately 20,000 people in 423 individual units covering over 85 million acres in all 50 states, the District of Columbia, and US territories. As of 2019, they had more than 279,000 volunteers. The agency is charged with a dual role of preserving the ecological and historical integrity of the places entrusted to its management while also making them available and accessible for public use and enjoyment. History Yellowstone National Park was created as the first national par ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
US Forest Service
The United States Forest Service (USFS) is an agency of the U.S. Department of Agriculture that administers the nation's 154 national forests and 20 national grasslands. The Forest Service manages of land. Major divisions of the agency include the Chief's Office, National Forest System, State and Private Forestry, Business Operations, and Research and Development. The agency manages about 25% of federal lands and is the only major national land management agency not part of the U.S. Department of the Interior, which manages the National Park Service, the U.S. Fish and Wildlife Service, and the Bureau of Land Management. History The concept of national forests was born from Theodore Roosevelt's conservation group, Boone and Crockett Club, due to concerns regarding Yellowstone National Park beginning as early as 1875. In 1876, Congress formed the office of Special Agent in the Department of Agriculture to assess the quality and conditions of forests in the United States. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North Cascades National Park
North Cascades National Park is an American national park in the state of Washington. At more than , it is the largest of the three National Park Service units that comprise the North Cascades National Park Complex. North Cascades National Park consists of a northern and southern section, bisected by the Skagit River that flows through the reservoirs of Ross Lake National Recreation Area. Lake Chelan National Recreation Area lies on the southern border of the south unit of the park. In addition to the two national recreation areas, other protected lands including several national forests and wilderness areas, as well as Canadian provincial parks in British Columbia, nearly surround the park. North Cascades National Park features the rugged mountain peaks of the North Cascades Range, the most expansive glacial system in the contiguous United States, the headwaters of numerous waterways, and vast forests with the highest degree of flora biodiversity of any American national par ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mount Baker-Snoqualmie National Forest
Mount is often used as part of the name of specific mountains, e.g. Mount Everest. Mount or Mounts may also refer to: Places * Mount, Cornwall, a village in Warleggan parish, England * Mount, Perranzabuloe, a hamlet in Perranzabuloe parish, Cornwall, England * Mounts, Indiana, a community in Gibson County, Indiana, United States People * Mount (surname) * William L. Mounts (1862–1929), American lawyer and politician Computing and software * Mount (computing), the process of making a file system accessible * Mount (Unix), the utility in Unix-like operating systems which mounts file systems Displays and equipment * Mount, a fixed point for attaching equipment, such as a hardpoint on an airframe * Mounting board, in picture framing * Mount, a hanging scroll for mounting paintings * Mount, to display an item on a heavy backing such as foamcore, e.g.: ** To pin a biological specimen, on a heavy backing in a stretched stable position for ease of dissection or display ** To ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chilliwack River
Chilliwack ( )( hur, Ts'elxwéyeqw) is a city in the province of British Columbia, Canada. Chilliwack is surrounded by mountains and home to recreational areas such as Cultus Lake and Chilliwack Lake Provincial Parks. There are numerous outdoor activities in the area in which to participate, including hiking, rock climbing, mountain biking horseback riding, whitewater kayaking, camping, fishing, golf and paragliding. Chilliwack is known for its annual corn harvest, and is home to the Province's second largest independent bookstorebr>The Book Man The Fraser Valley Regional District is headquartered in Chilliwack, which is the Fraser Valley's second largest city after Abbotsford. The city had a population of 93,203 in the 2021 Canadian census, with a census metropolitan area population of 113,767 people. Etymology In Halq'eméylem, the language of the Stó:lō communities around Chilliwack and Sardis, ''Tcil'Qe'uk'' means "valley of many streams". It also lends its name to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
