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Merrill Cave
Merrill Cave is a former ice cave in Lava Beds National Monument in California. It was known for the pool of ice that was found year-round in the lower chamber of the cave, which fully disappeared due to compounding factors by 2005. History The caves found here were created by flows of smooth lava 10,500 to 65,000 years ago. The cave was known Native Americans of the area, but was first recorded in 1888. It was named after the family of Charles H. Merrill, a homesteader whose land was donated to the National Park Service in 1938. Historically, there has been a large perennial ice deposit at the bottom of the cave. The deposit has fluctuated in depth over the last several thousand years. Precipitation from above ground would collect in the lower chamber, and would freeze over the winter. In 1990, the NPS began monitoring the depth of the ice. Using historical photographs, it was known that ice levels had been growing for the preceding 40 years. In 1997, ice levels were first detec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lava Beds National Monument
Lava Beds National Monument is located in northeastern California, in Siskiyou County, California, Siskiyou and Modoc County, California, Modoc counties. The monument lies on the northeastern flank of Medicine Lake Volcano, which is the largest volcano by area in the Cascade Range. The region in and around Lava Beds National Monument lies at the junction of the Sierra-Klamath, Cascade, and Great Basin physiographic provinces. The monument was established as a National monument (United States), national monument on November 21, 1925, and includes more than . Lava Beds National Monument has numerous lava tubes, with 27 having marked entrances and developed trails for public access and exploration. The monument also offers trails through the high Great Basin Deserts and xeric shrublands, xeric shrubland desert landscape and the volcanic field. In 1872 and 1873, the area was the site of the Modoc War, involving a band led by Kintpuash (also known as Captain Jack). The area of Captai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Cave
An ice cave is any type of natural cave (most commonly lava tubes or limestone caves) that contains significant amounts of perennial (year-round) ice. At least a portion of the cave must have a temperature below 0 °C (32 °F) all year round, and water must have traveled into the cave’s cold zone. Terminology This type of cave was first formally described by Englishman Edwin Swift Balch in 1900, who suggested the French term ''glacieres'' should be used for them, even though the term ''ice cave'' was then, as now, commonly used to refer to caves simply containing year-round ice. Among speleologists, ''ice cave'' is the proper English term. A cavity formed ''within'' ice (as in a glacier) is properly called a glacier cave. Types Ice caves occur as static ice caves, such as Peña Castil Ice Cave, and dynamic or cyclical ice caves, such as Eisriesenwelt. Temperature mechanisms In most of the world, bedrock caves are thermally insulated from the surface and so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
California
California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an international border with the Mexico, Mexican state of Baja California to the south. With almost 40million residents across an area of , it is the List of states and territories of the United States by population, largest state by population and List of U.S. states and territories by area, third-largest by area. Prior to European colonization of the Americas, European colonization, California was one of the most culturally and linguistically diverse areas in pre-Columbian North America. European exploration in the 16th and 17th centuries led to the colonization by the Spanish Empire. The area became a part of Mexico in 1821, following Mexican War of Independence, its successful war for independence, but Mexican Cession, was ceded to the U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Park Service
The National Park Service (NPS) is an List of federal agencies in the United States, agency of the Federal government of the United States, United States federal government, within the US Department of the Interior. The service manages all List of national parks of the United States, national parks; most National monument (United States), national monuments; and other natural, historical, and recreational properties, with various title designations. The United States Congress created the agency on August 25, 1916, through the National Park Service Organic Act. Its headquarters is in Washington, D.C., within the main headquarters of the Department of the Interior. The NPS employs about 20,000 people in units covering over in List of states and territories of the United States, all 50 states, the District of Columbia, and Territories of the United States, US territories. In 2019, the service had more than 279,000 volunteers. The agency is charged with preserving the ecological a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lava25
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 often also 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. Etymology The word ''lava'' comes from Italian language, Italian and is probably derived fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lava Tube
A lava tube, more rarely called a pyroduct, is a 'roofed conduit through which molten lava travels away from its vent'. If lava in the tube drains out, it will leave an empty cave. Lava tubes are common in low-viscosity volcanic systems. Lava tubes are important as they are able to transport molten lava much further away from the eruptive vent than lava channels. A tube-forming lava flow can emplace on longer distance due to the presence of a solid crust protecting the molten lava from atmospheric cooling. Lava tubes are often considered when preparing hazard maps or managing an eruptive crisis. Formation A lava tube is a type of lava cave formed when a low-viscosity lava flow develops a continuous and hard crust, which thickens and forms a roof above the still-flowing lava stream. Three main formation mechanisms have been described: (1) roofing over a lava channel, (2) pāhoehoe lobe extension or (3) lava flow inflation. # When it erupts from a vent, lava usually flow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Geological Survey
The United States Geological Survey (USGS), founded as the Geological Survey, is an agency of the U.S. Department of the Interior whose work spans the disciplines of biology, geography, geology, and hydrology. The agency was founded on March 3, 1879, to study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The agency also makes maps of planets and moons, based on data from U.S. space probes. The sole scientific agency of the U.S. Department of the Interior, USGS is a fact-finding research organization with no regulatory responsibility. It is headquartered in Reston, Virginia, with major offices near Lakewood, Colorado; at the Denver Federal Center; and in NASA Research Park in California. In 2009, it employed about 8,670 people. The current motto of the USGS, in use since August 1997, is "science for a changing world". The agency's previous slogan, adopted on its hundredth anniversary, was "Earth Science in the Pub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natural Bridge
A natural arch, natural bridge, or (less commonly) rock arch is a natural landform where an arch has formed with an opening underneath. Natural arches commonly form where inland cliffs, coastal cliffs, fins or stacks are subject to erosion from the sea, rivers or weathering ( subaerial processes). Most natural arches are formed from narrow fins and sea stacks composed of sandstone or limestone with steep, often vertical, cliff faces. The formations become narrower due to erosion over geologic time scales. The softer rock stratum erodes away creating rock shelters, or alcoves, on opposite sides of the formation beneath the relatively harder stratum, or caprock, above it. The alcoves erode further into the formation eventually meeting underneath the harder caprock layer, thus creating an arch. The erosional processes exploit weaknesses in the softer rock layers making cracks larger and removing material more quickly than the caprock; however, the caprock itself continues to erode ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Speleothem
A speleothem (; ) is a geological formation made by mineral deposits that accumulate over time in natural caves. Speleothems most commonly form in calcareous caves due to carbonate dissolution reactions. They can take a variety of forms, depending on their depositional history and environment. Their chemical composition, gradual growth, and preservation in caves make them useful paleoclimatic proxies. Chemical and physical characteristics More than 300 variations of cave mineral deposits have been identified. The vast majority of speleothems are calcareous, composed of calcium carbonate (CaCO3) minerals (calcite or aragonite). Less commonly, speleothems are made of calcium sulfate ( gypsum or mirabilite) or opal. Speleothems of pure calcium carbonate or calcium sulfate are translucent and colorless. The presence of iron oxide or copper provides a reddish brown color. The presence of manganese oxide can create darker colors such as black or dark brown. Speleothems can also b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lavacicle
A stalactite (, ; , ) is a mineral formation that hangs from the ceiling of caves, hot springs, or man-made structures such as bridges and mines. Any material that is soluble and that can be deposited as a colloid, or is in suspension, or is capable of being melted, may form a stalactite. Stalactites may be composed of lava, minerals, mud, peat, pitch, sand, sinter, and amberat (crystallized urine of pack rats). A stalactite is not necessarily a speleothem, though speleothems are the most common form of stalactite because of the abundance of limestone caves. The corresponding formation on the floor of the cave is known as a stalagmite. Formation and type Limestone stalactites The most common stalactites are speleothems, which occur in limestone caves. They form through deposition of calcium carbonate and other minerals, which is precipitated from mineralized water solutions. Limestone is the chief form of calcium carbonate rock which is dissolved by water that contain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rime Ice
Rime ice forms when supercooled water droplets freeze onto surfaces. In the atmosphere, there are three basic types of rime ice: *Soft rime forms when supercooled water freezes under calm wind conditions. It is milky and crystalline, like sugar, and similar to hoar frost. *Hard rime forms by rapid freezing of supercooled water under at least moderate wind conditions. The droplets freeze more or less individually, leaving air gaps. *Clear ice forms by slow freezing of supercooled water. Clear ice is typically transparent and homogeneous. Its amorphous and dense structure makes it adhesive. Soft and hard rime are less dense than clear ice and less adhesive, thus generally cause less damage. Glaze ice is similar in appearance to clear ice, however it is the result of a completely different process, occurring during freezing rain or freezing drizzle, drizzle. Rime ice also forms when icing conditions, ice forms on the surface of an aircraft, particularly on the leading edges and co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hoarfrost
Frost is a thin layer of ice on a solid surface, which forms from water vapor that deposits onto a freezing surface. Frost forms when the air contains more water vapor than it can normally hold at a specific temperature. The process is similar to the formation of dew, except it occurs below the freezing point of water typically without crossing through a liquid state. Air always contains a certain amount of water vapor, depending on temperature. Warmer air can hold more than colder air. When the atmosphere contains more water than it can hold at a specific temperature, its relative humidity rises above 100% becoming supersaturated, and the excess water vapor is forced to deposit onto any nearby surface, forming seed crystals. The temperature at which frost will form is called the dew point, and depends on the humidity of the air. When the temperature of the air drops below its dew point, excess water vapor is forced out of solution, resulting in a phase change directly from wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
