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Valles Caldera
The Valles Caldera (or Jemez Caldera) is a volcanic caldera in the Jemez Mountains of northern New Mexico. Hot springs, streams, fumaroles, natural gas seeps, and volcanic domes dot the caldera landscape. The highest point in the caldera is Redondo Peak, an resurgent lava dome located entirely within the caldera and surrounded by moat-like flows of rhyolitic solidified lavas. Located within the caldera are several grass valleys, or ''valles'', the largest of which is Valle Grande ( ), the only one accessible by a paved road. In 1975, Valles Caldera was designated as a National Natural Landmark by the National Park Service with much of the caldera being within the Valles Caldera National Preserve, a unit of the National Park System. The area has a varied history involving cultural significance, economic resources, scientific studies, and complex geological setting. History Use of Valles Caldera dates back to prehistoric times: spear points dating to 11,000 years ago have been ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhyolite
Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture (geology), texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained matrix (geology), groundmass. The mineral assemblage is predominantly quartz, sanidine, and plagioclase. It is the extrusive equivalent of granite. Its high silica content makes rhyolitic magma extremely viscosity, viscous. This favors explosive eruptions over effusive eruptions, so this type of magma is more often erupted as pyroclastic rock than as lava flows. Rhyolitic ash-flow tuffs are among the most voluminous of continental igneous rock formations. Rhyolitic tuff has been used extensively for construction. Obsidian, which is rhyolitic volcanic glass, has been used for tools from prehistoric times to the present day because it can be shaped to an extremely sharp edge. Rhyolitic pumice finds use as an abrasive, in concrete, and as a soil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hot Spring
A hot spring, hydrothermal spring, or geothermal spring is a Spring (hydrology), spring produced by the emergence of Geothermal activity, geothermally heated groundwater onto the surface of the Earth. The groundwater is heated either by shallow bodies of magma (molten rock) or by circulation through fault (geology), faults to hot rock deep in the Earth's crust. Hot spring water often contains large amounts of dissolved minerals. The chemistry of hot springs ranges from acid sulfate springs with a pH as low as 0.8, to alkaline chloride springs saturated with silica, to bicarbonate springs saturated with carbon dioxide and carbonate minerals. Some springs also contain abundant dissolved iron. The minerals brought to the surface in hot springs often feed communities of extremophiles, microorganisms adapted to extreme conditions, and it is possible that life on Earth had its origin in hot springs. Humans have made use of hot springs for bathing, relaxation, or medical therapy for th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Treaty Of Guadalupe Hidalgo
The Treaty of Guadalupe Hidalgo officially ended the Mexican–American War (1846–1848). It was signed on 2 February 1848 in the town of Villa de Guadalupe, Mexico City, Guadalupe Hidalgo. After the defeat of its army and the fall of the capital in September 1847, Mexico entered into peace negotiations with the U.S. envoy, Nicholas Trist. The resulting treaty required Mexico to cede 55 percent of its territory including the present-day states of California, Nevada, Utah, most of Colorado, New Mexico and Arizona, and a small portion of Wyoming. Mexico also relinquished all claims for Texas and recognized the Rio Grande as the southern boundary of Texas. In turn, the U.S. government paid Mexico $15 million "in consideration of the extension acquired by the boundaries of the United States" and agreed to pay debts owed to American citizens by the Mexico, Mexican government. Mexico, Mexicans in areas annexed by the U.S. could relocate within Mexico's new boundaries or receive Amer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Navajo People
The Navajo or Diné are an Native Americans in the United States, Indigenous people of the Southwestern United States. Their traditional language is Navajo language, Diné bizaad, a Southern Athabascan language. The states with the largest Diné populations are Arizona (140,263) and New Mexico (108,305). More than three-quarters of the Diné population resides in these two states.American Factfinder United States Census Bureau The overwhelming majority of Diné are enrolled in the Navajo Nation. Some Diné are enrolled in the Colorado River Indian Tribes, another federally recognized tribe. With more than 399,494Becenti, Arlyssa [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Knapping
Knapping is the shaping of flint, chert, obsidian, or other conchoidal fracturing stone through the process of lithic reduction to manufacture stone tools, strikers for flintlock firearms, or to produce flat-faced stones for building or facing walls, and flushwork decoration. The original Germanic term ''knopp'' meant to strike, shape, or work, so it could theoretically have referred equally well to making statues or dice. Modern usage is more specific, referring almost exclusively to the free hand percussion process pictured. It is distinguished from the more general verb "chip" (to break up into small pieces, or unintentionally break off a piece of something) and is different from "carve" (removing only part of a face), and "cleave" (breaking along a natural plane). Method Flintknapping or knapping is done in a variety of ways depending on the purpose of the final product. For stone tools and flintlock strikers, chert is worked using a fabricator such as a hammerstone to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Obsidian
Obsidian ( ) is a naturally occurring volcanic glass formed when lava extrusive rock, extruded from a volcano cools rapidly with minimal crystal growth. It is an igneous rock. Produced from felsic lava, obsidian is rich in the lighter elements such as silicon, oxygen, aluminium, sodium, and potassium. It is commonly found within the margins of rhyolite, rhyolitic lava flows known as obsidian flows. These flows have a high content of silicon dioxide, silica, giving them a high viscosity. The high viscosity inhibits the atomic diffusion, diffusion of atoms through the lava, which inhibits the first step (nucleation) in the formation of mineral crystals. Together with rapid cooling, this results in a natural glass forming from the lava. Obsidian is hard, Brittleness, brittle, and amorphous; it therefore Fracture (mineralogy)#Conchoidal fracture, fractures with sharp edges. In the past, it was used to manufacture cutting and piercing tools, and it has been used experimentally as s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Native Americans In The United States
Native Americans (also called American Indians, First Americans, or Indigenous Americans) are the Indigenous peoples of the Americas, Indigenous peoples of the United States, particularly of the Contiguous United States, lower 48 states and Alaska. They may also include any Americans whose origins lie in any of the indigenous peoples of North or South America. The United States Census Bureau publishes data about "American Indians and Alaska Natives", whom it defines as anyone "having origins in any of the original peoples of North and South America ... and who maintains tribal affiliation or community attachment". The census does not, however, enumerate "Native Americans" as such, noting that the latter term can encompass a broader set of groups, e.g. Native Hawaiians, which it tabulates separately. The European colonization of the Americas from 1492 resulted in a Population history of Indigenous peoples of the Americas, precipitous decline in the size of the Native American ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colorado
Colorado is a U.S. state, state in the Western United States. It is one of the Mountain states, sharing the Four Corners region with Arizona, New Mexico, and Utah. It is also bordered by Wyoming to the north, Nebraska to the northeast, Kansas to the east, and Oklahoma to the southeast. Colorado is noted for its landscape of mountains, forests, High Plains (United States), high plains, mesas, canyons, plateaus, rivers, and desert lands. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains. Colorado is the List of U.S. states and territories by area, eighth-largest U.S. state by area and the List of U.S. states and territories by population, 21st by population. The United States Census Bureau estimated the population of Colorado to be 5,957,493 as of July 1, 2024, a 3.2% increase from the 2020 United States census. The region has been inhabited by Native Americans in the United St ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fort Collins
A fortification (also called a fort, fortress, fastness, or stronghold) is a military construction designed for the defense of territories in warfare, and is used to establish rule in a region during peacetime. The term is derived from Latin ("strong") and ("to make"). From very early history to modern times, defensive walls have often been necessary for cities to survive in an ever-changing world of invasion and conquest. Some settlements in the Indus Valley Civilization were the first small cities to be fortified. In ancient Greece, large cyclopean stone walls fitted without mortar had been built in Mycenaean Greece, such as the ancient site of Mycenae. A Greek '' phrourion'' was a fortified collection of buildings used as a military garrison, and is the equivalent of the Roman castellum or fortress. These constructions mainly served the purpose of a watch tower, to guard certain roads, passes, and borders. Though smaller than a real fortress, they acted as a border ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Park System
The National Park Service (NPS) is an agency of the United States federal government, within the US Department of the Interior. The service manages all national parks; most 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 all 50 states, the District of Columbia, and US territories. In 2019, the service had more than 279,000 volunteers. The agency is charged with preserving the ecological and historical integrity of the places entrusted to its management and with making them available for public use and enjoyment. History Artist George Catlin, during an 1832 trip to the Dakotas, was perhaps the first to suggest the concept of a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grass Valley
A grass valley (also vega and valle) is a meadow located within a forested and relatively small drainage basin such as a headwater. Grass valleys are common in North America, where they are created and maintained principally by the work of beavers or browsers feeders. Rarely, they are associated with cienegas. The words vega and valle are loanwords from Spanish. Notable examples * Valles Caldera, New Mexico * Las Vegas Springs Preserve, Nevada See also *Rincon (meadow) A rincón is a grass meadow. The term is in wide use in English in the southwest United States, where it refers specifically to a sloping (usually steep) meadow on the south facing upper slopes of a forested mountain. These characteristic high m ... Wetlands Fluvial landforms {{Topography-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lava Dome
In volcanology, a lava dome is a circular, mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano. Dome-building eruptions are common, particularly in convergent plate boundary settings. Around 6% of eruptions on Earth form lava domes. The geochemistry of lava domes can vary from basalt (e.g. Semeru, 1946) to rhyolite (e.g. Chaiten, 2010) although the majority are of intermediate composition (such as Santiaguito, dacite-andesite, present day). The characteristic dome shape is attributed to high viscosity that prevents the lava from flowing very far. This high viscosity can be obtained in two ways: by high levels of silica in the magma, or by degassing of fluid magma. Since viscous basaltic and andesitic domes weather fast and easily break apart by further input of fluid lava, most of the preserved domes have high silica content and consist of rhyolite or dacite. Existence of lava domes has been suggested for some domed structures on the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
