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Alcove (landform)
Alcove is the geographical and geological term for a steep-sided hollow in the side of an exposed rock face or cliff of a homogeneous rock type, that was water eroded. Alcoves are weathering features common in dissected horizontal strata. Alcoves form where chemical and physical weathering is concentrated along horizontal discontinuities where water and salts concentrate, such as the contact between a sandstone and an underlying shale bed. In the case of layered sandstones, an alcove may later be enlarged by exfoliation of upper layers. This is commonly seen in the sandstone alcoves of the Colorado Plateau, like those in Navajo Sandstone The Navajo Sandstone is a geological formation in the Glen Canyon Group that is spread across the U.S. states of southern Nevada, northern Arizona, northwest Colorado, and Utah as part of the Colorado Plateau province of the United States.Anonymou .... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geography
Geography (from Greek: , ''geographia''. Combination of Greek words ‘Geo’ (The Earth) and ‘Graphien’ (to describe), literally "earth description") is a field of science devoted to the study of the lands, features, inhabitants, and phenomena of Earth. The first recorded use of the word γεωγραφία was as a title of a book by Greek scholar Eratosthenes (276–194 BC). Geography is an all-encompassing discipline that seeks an understanding of Earth and its human and natural complexities—not merely where objects are, but also how they have changed and come to be. While geography is specific to Earth, many concepts can be applied more broadly to other celestial bodies in the field of planetary science. One such concept, the first law of geography, proposed by Waldo Tobler, is "everything is related to everything else, but near things are more related than distant things." Geography has been called "the world discipline" and "the bridge between the human and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geology
Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Earth sciences, including hydrology, and so is treated as one major aspect of integrated Earth system science and planetary science. Geology describes the structure of the Earth on and beneath its surface, and the processes that have shaped that structure. It also provides tools to determine the relative and absolute ages of rocks found in a given location, and also to describe the histories of those rocks. By combining these tools, geologists are able to chronicle the geological history of the Earth as a whole, and also to demonstrate the age of the Earth. Geology provides the primary evidence for plate tectonics, the evolutionary history of life, and the Earth's past climates. Geologists broadly study the properties and processes of E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cliff
In geography and geology, a cliff is an area of rock which has a general angle defined by the vertical, or nearly vertical. Cliffs are formed by the processes of weathering and erosion, with the effect of gravity. Cliffs are common on coasts, in mountainous areas, escarpments and along rivers. Cliffs are usually composed of rock that is resistant to weathering and erosion. The sedimentary rocks that are most likely to form cliffs include sandstone, limestone, chalk, and dolomite. Igneous rocks such as granite and basalt also often form cliffs. An escarpment (or scarp) is a type of cliff formed by the movement of a geologic fault, a landslide, or sometimes by rock slides or falling rocks which change the differential erosion of the rock layers. Most cliffs have some form of scree slope at their base. In arid areas or under high cliffs, they are generally exposed jumbles of fallen rock. In areas of higher moisture, a soil slope may obscure the talus. Many cliffs also fea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exfoliation (geology)
Exfoliation joints or sheet joints are surface-parallel fracture systems in rock, and often leading to erosion of concentric slabs. ''(See Joint (geology)).'' General characteristics of exfoliation joints * Commonly follow topography. * Divide the rock into sub-planar slabs. * Joint spacing increases with depth from a few centimeters near the surface to a few meters * Maximum depth of observed occurrence is around 100 meters. * Deeper joints have a larger radius of curvature, which tends to round the corners of the landscape as material is eroded * Fracture mode is tensile * Occur in many different lithologies and climate zones, not unique to glaciated landscapes. * Host rock is generally sparsely jointed, fairly isotropic, and has high compressive strength. * Can have concave and convex upwards curvatures. * Often associated with secondary compressive forms such as arching, buckling, and A-tents (buckled slabs) Formation of exfoliation joints Despite their common occurrenc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colorado Plateau
The Colorado Plateau, also known as the Colorado Plateau Province, is a physiographic and desert region of the Intermontane Plateaus, roughly centered on the Four Corners region of the southwestern United States. This province covers an area of 336,700 km2 (130,000 mi2) within western Colorado, northwestern New Mexico, southern and eastern Utah, northern Arizona, and a tiny fraction in the extreme southeast of Nevada. About 90% of the area is drained by the Colorado River and its main tributaries: the Green, San Juan, and Little Colorado. Most of the remainder of the plateau is drained by the Rio Grande and its tributaries. The Colorado Plateau is largely made up of high desert, with scattered areas of forests. In the south-west corner of the Colorado Plateau lies the Grand Canyon of the Colorado River. Much of the Plateau's landscape is related to the Grand Canyon in both appearance and geologic history. The nickname "Red Rock Country" suggests the brightly colored ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Navajo Sandstone
The Navajo Sandstone is a geological formation in the Glen Canyon Group that is spread across the U.S. states of southern Nevada, northern Arizona, northwest Colorado, and Utah as part of the Colorado Plateau province of the United States.Anonymous (2011b''Navajo Sandstone''. U.S. Geological Survey, Reston, Virginia. last accessed August 18, 2013 Description The Navajo Sandstone is particularly prominent in southern Utah, where it forms the main attractions of a number of national parks and monuments including Red Rock Canyon National Conservation Area,''Red Rock Canyon National Conservation Area - Rock Climbing.'' Southern Nevada District Office, Bureau of Land Management, Reno, Nevada |
