Sink (geography)

A geographic sink is a depression within an endorheic basin where water collects with no visible outlet. Instead of discharging, the collected water is lost due to evaporation and/or penetration (water sinking underground, e.g., to become groundwater in an aquifer). If the sink has karstic terrain, water will sink at a higher rate than the surface evaporation, and conversely if the lakebed or sink bed has a layer of soil that is largely impervious to water (hardpan), evaporation will predominate. Since dry lakes in sinks with hardpan have little penetration, they require more severe aridity/heat to eliminate collected water at a comparable rate as for a similar sink with appreciable penetration.

Depending on losses, precipitation, and inflow (e.g., a spring, a tributary, or flooding); the temporal result of a lake in a sink may be a persistent lake, an intermittent lake, a playa lake (temporarily covered with water), or an ephemeral lake.

LakeBadwater crop
Death Valley, Spring 2005: ephemeral Lake Badwater in the flooded Badwater Basin

List of geographic sinks

See also

  • Endorheic basin – Closed drainage basin that allows no outflow
  • Sinkhole – Depression or hole in the ground caused by collapse of the surface into an existing void space
Aeolian landform

Aeolian landforms are features of the Earth's surface produced by either the erosive or constructive action of the wind. This process is not unique to the Earth, and it has been observed and studied on other planets, including Mars.

Endorheic basin

An endorheic basin (also endoreic basin or endorreic basin) is a limited drainage basin that normally retains water and allows no outflow to other external bodies of water, such as rivers or oceans, but converges instead into lakes or swamps, permanent or seasonal, that equilibrate through evaporation. Such a basin may also be referred to as a closed or terminal basin or as an internal drainage system or interior drainage basin.

Endorheic regions, in contrast to exorheic regions, which flow to the ocean in geologically defined patterns, are closed hydrologic systems. Their surface waters drain to inland terminal locations where the water evaporates or seeps into the ground, having no access to discharge into the sea. Endorheic water bodies include some of the largest lakes in the world, such as the Caspian Sea, the world's largest saline inland sea.Endorheic basins constitute local base levels, defining a limit of erosion and deposition processes of nearby areas.The term comes from the Ancient Greek: ἔνδον, éndon, "within" and ῥεῖν, rheîn, "to flow".

Lahontan Valley

The Lahontan Valley is in Churchill County in the U.S. state of Nevada. The valley is a landform of the central portion of the prehistoric Lake Lahontan's lakebed of 20,000-9,000 years ago. The valley and the adjacent Carson Sink represent a small portion of the lake bed, and Humboldt Lake is to the valley's northeast (Pyramid Lake is west and Walker Lake is south). Aside from the city of Fallon, the railroad junction at Hazen, and the ghost town of Stillwater, the Lahontan Valley is mostly uninhabited desert. During the era of the California trail the Lahontan and adjacent valleys to the northwest were called the Forty Mile Desert.

The valley derives its name from Louis-Armand de Lom d'Arce de Lahontan, Baron de Lahontan, a French soldier.

Sedimentary basin

Sedimentary basins are regions of Earth of long-term subsidence creating accommodation space for infilling by sediments. The subsidence can result from a variety of causes that include: the thinning of underlying crust, sedimentary, volcanic, and tectonic loading, and changes in the thickness or density of adjacent lithosphere. Sedimentary basins occur in diverse geological settings usually associated with plate tectonic activity. Basins are classified structurally in various ways, with a primary classifications distinguishing among basins formed in various plate tectonic regime (divergent, convergent, transform, intraplate), the proximity of the basin to the active plate margins, and whether oceanic, continental or transitional crust underlies the basin. Basins formed in different plate tectonic regimes vary in their preservation potential. On oceanic crust, basins are likely to be subducted, while marginal continental basins may be partially preserved, and intracratonic basins have a high probability of preservation. As the sediments are buried, they are subjected to increasing pressure and begin the process of lithification. A number of basins formed in extensional settings can undergo inversion which has accounted for a number of the economically viable oil reserves on earth which were formerly basins.

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