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The blowholes of Wupatki National Monument are an example of such a phenomenon. It is estimated that the closed underground passages have a volume of at least seven billion cubic feet. Wind speeds can approach 30 miles per hour. [2] Another well-known example of this kind of blowhole is the natural entrance to Wind Cave in South Dakota. [13]
A geo or gio (/ ɡ j oʊ / GYOH, from Old Norse gjá [1]) is an inlet, a gully or a narrow and deep cleft in the face of a cliff. Geos are common on the coastline of the Shetland and Orkney islands. They are created by the wave driven erosion of cliffs along faults and bedding planes in the rock. Geos may have sea caves at their heads. Such sea ...
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 after an arch has formed, which ...
The Pancake Rocks are a heavily eroded limestone formation where the sea bursts through several vertical blowholes during incoming swells, particularly at high tide. The limestone was formed in the Oligocene period (around 22–30 million years old), a period in the geological history of New Zealand where most of the continent of Zealandia was submerged beneath shallow seas. [2]
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exposed in a geographical region (the stratigraphic column).
Transverse dunes and Seif dunes are some alternative examples of the effect of unidirectional air flow on dune formation. Barchan dune schematic. Ripple marks: Ripple marks are small ridges of sediment that form due to wind or water blowing over loose sediment in either a current or wave pattern.
Topography can modify the local climate, for example through orographic precipitation, which in turn modifies the topography by changing the hydrologic regime in which it evolves. Many geomorphologists are particularly interested in the potential for feedbacks between climate and tectonics , mediated by geomorphic processes.
Triangular diagrams showing the aluminium (A), calcium (C) and iron (F) content of the main phases (dark dots) in metamorphic rocks in various facies. Thin grey lines are stable phase equilibria . Triangular diagrams showing the aluminium (A), iron (F) and magnesium (M) content of the main phases (dark dots and, when the composition can vary ...