Pressure ridge

Pressure ridge

A pressure ridge is an ice formation typically found on large frozen lakes during the winter. In the most basic sense, a pressure ridge is a long crack in the ice that occurs because of repeated heating and cooling on the surface of the lake.

In cases of extreme cold, ice will shrink in volume like any other solid, opening up cracks in the surface of lakes that are completely frozen over. The cracks quickly fill with water and freeze again, but when the temperature rises later, the ice expands and forces itself upward along the lines of the crack, in much the same fashion that plate tectonics creates mountain ranges, albeit on a much smaller scale. Pressure ridges can sometimes extend for miles, making an ice road impassable for truckers hauling freight to far northern locations.

Pressure ridges also develop on lava flows when the solid colder top layer is deformed by movements of the underflowing hotter lava.

External links

* [http://planet-terre.ens-lyon.fr/planetterre/objets/img_sem/XML/db/planetterre/metadata/LOM-Img232-2008-04-28.xml Pressure ridges on hawaiian an icelandic lava flows (in french)]


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  • pressure ridge — noun : a ridge produced on floating ice by buckling or crushing under lateral pressure of wind or tide or on a congealing lava flow by the continued movement of its liquid interior * * * 1. a ridge produced on floating ice by buckling or crushing …   Useful english dictionary

  • pressure ridge — 1. a ridge produced on floating ice by buckling or crushing under lateral pressure of wind or ice. 2. Geol. a ridge produced on a congealing lava flow by pressure from the still liquid interior. [1895 1900] * * * …   Universalium

  • pressure ridge — A work hardened edge of a damaged panel area that will often remain, even after the area has been smoothed with hammer and dolly; it must then be dressed with hammer and body spoon …   Dictionary of automotive terms

  • ice pressure ridge —    A rugged, irregular wall of broken floating ice buckled upward by the lateral pressure of wind or current forcing or squeezing one floe against another, or against a shore; it may extend for kilometers in length and up to 30 m in height. Along …   Glossary of landform and geologic terms

  • volcanic pressure ridge —    An elongate uplift of the congealing crust of a lava flow, probably due to the pressure of the underlying, still flowing lava; commonly < 5 m in height (but range up to 15 m) and < 100 m length (but can exceed 500 m).    Compare: tumulus …   Glossary of landform and geologic terms

  • Ridge (disambiguation) — A Ridge can be a number of things in English:* Ridge, a geological feature that features a continuous elevational crest for some distance * Ridge, Dorset, a village in Dorset, England * Ridge, Hertfordshire, a village in Hertfordshire, England *… …   Wikipedia

  • ridge — [1] An edge, ledge, or lip which protrudes beyond the normal face of an object. See rim ridge. [2] The cutting edge of a screw thread above the flanks. [3] See pressure ridge. [4] A hump. See piston ring ridge burr …   Dictionary of automotive terms

  • ridge — [rıdʒ] n [: Old English; Origin: hrycg] 1.) a long area of high land, especially at the top of a mountain ▪ We made our way carefully along the ridge. 2.) a) something long and thin that is raised above the things around it ▪ A small ridge of… …   Dictionary of contemporary English

  • ridge — [rij] n. [ME rigge < OE hrycg, akin to ON hrygr, backbone, Ger rücken, back < IE * (s)kreuk , a hump, mound < base * (s)ker , to bend > L curvus, bent, circus, a ring] 1. Obs. an animal s spine or back 2. the long, narrow top or crest …   English World dictionary

  • ridge — [ rıdʒ ] noun count ** 1. ) the long narrow top of a mountain or group of mountains: The log cabin is set on a ridge in the Blue Ridge Mountains. 2. ) a long narrow raised line along the surface of something: Tires had thrown the mud into ridges …   Usage of the words and phrases in modern English

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