A vast alluvial fan blossoms across the desolate landscape between the Kunlun and Altun mountain ranges that form the southern border of the Taklimakan Desert in China’s XinJiang Province. The left side is the active part of the fan, and appears blue from water currently flowing in the many small streams. Credit: NASA/GSFC/METI/ERSDAC/JAROS/ASTER An alluvial fan is a fan-shaped deposit formed where a fast flowing stream flattens, slows, and spreads typically at the exit of a canyon onto a flatter plain. A convergence of neighboring alluvial fans into a single apron of deposits against a slope is called a bajada, or compound alluvial fan.[1] Image File history File links Size of this preview: 554 × 600 pixelsFull resolution (3774 × 4086 pixel, file size: 3. ...
Image File history File links Size of this preview: 554 × 600 pixelsFull resolution (3774 × 4086 pixel, file size: 3. ...
Image File history File linksMetadata Download high resolution version (1146x605, 195 KB) Alluvial Fan aerial photo with topo overlay, Copper Canyon, Death Valley, California I (Ethan OConnor) created this image from USGS orthophotos and 24k Topo DRGs. ...
Image File history File linksMetadata Download high resolution version (1146x605, 195 KB) Alluvial Fan aerial photo with topo overlay, Copper Canyon, Death Valley, California I (Ethan OConnor) created this image from USGS orthophotos and 24k Topo DRGs. ...
Death Valley is a valley in the U.S. states of California and Nevada, and is the location of the lowest elevation in North America at -282 ft (86 m). ...
An alluvial fan is a fan-shaped deposit where a fast flowing stream flattens, slows, and spreads, typically at the exit of a canyon onto a flatter plain. ...
Formation
Owing to the slowing of flow, any solid material carried by the water is dropped. As this reduces the capacity of the channel, the channel will change direction over time, gradually building up a slightly mounded or shallow conical fan shape. The deposits are in general poorly-sorted.[1] This fan shape can also be explained with a thermodynamic justification: the system of sediment introduced at the apex of the fan will tend to a state which minimizes the sum of the transport energy involved in moving the sediment and the gravitational potential of material in the cone. It can easily be seen that there will be iso-transport energy lines forming concentric arcs about the discharge point at the apex of the fan. Thus the material will tend to be deposited equally about these lines, forming the characteristic cone shape. Multiple braided streams are usually present and active during water flows. Alluvial fans are most likely to be found in desert areas subject to periodic flash floods from nearby thunderstorms in local hills. Alluvial fans are very common around the margins of the sedimentary basins of the Basin and Range province of southwestern United States and northern Mexico. Thermodynamics (Greek: thermos = heat and dynamic = change) is the physics of energy, heat, work, entropy and the spontaneity of processes. ...
In physics, gravitational potential is the measure of potential energy an object possesses due to its position in a gravitational field. ...
A braided river channel consists of a network of small channels separated by small islands called braid bars. ...
A rolling thundercloud over Enschede, The Netherlands. ...
The term sedimentary basin is used to refer to any geographical feature exhibiting subsidence and consequent infilling by sedimentation. ...
Basin and Range index map - USGS The Basin and Range Province is a particular type of topography that covers much of the southwestern United States and northwestern Mexico that is typified by elongate north-south trending arid valleys bounded by mountain ranges which also bound adjacent valleys. ...
Plants often are concentrated at the base of alluvial fans and many have long tap roots (30-50 feet) to reach water. The long-rooted plants are called phreatophytes by biologists. The water at this level is derived from water that has seeped through the fan and hit an impermeable layer that funneled the water to the base of the fan where it is concentrated and sometimes forms springs and seeps if the water is close enough to the surface. These stands of bushes cling onto the soil at their bases and over time wind action often blows away sand around the bushes which form islands of habitat for many animals. Divisions Green algae Chlorophyta Charophyta Land plants (embryophytes) Non-vascular plants (bryophytes) Marchantiophyta—liverworts Anthocerotophyta—hornworts Bryophyta—mosses Vascular plants (tracheophytes) †Rhyniophyta—rhyniophytes †Zosterophyllophyta—zosterophylls Lycopodiophyta—clubmosses †Trimerophytophyta—trimerophytes Pteridophyta—ferns and horsetails Seed plants (spermatophytes) †Pteridospermatophyta—seed ferns Pinophyta—conifers Cycadophyta—cycads Ginkgophyta—ginkgo Gnetophyta—gnetae Magnoliophyta—flowering plants...
Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ...
A natural spring on Mackinac Island in Michigan. ...
Habitat (which is Latin for it inhabits) is the place where a particular species live and grow. ...
Reference - ^ a b American Geological Institute. Dictionary of Geological Terms. New York: Dolphin Books, 1962.
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