laccolith

laccolith
laccolithic, laccolitic /lak'euh lit"ik/, adj.
/lak"euh lith/, n. Geol.
a mass of igneous rock formed from magma that did not find its way to the surface but spread laterally into a lenticular body, forcing overlying strata to bulge upward.
Also, laccolite /lak"euh luyt'/.
[1875-80; < Gk lákko(s) pond + -LITH]

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      in geology, any of a type of igneous intrusion that has split apart two strata, resulting in a domelike structure; the floor of the structure is usually horizontal. A laccolith is often smaller than a stock, which is another type of igneous intrusion, and usually is less than 16 km (10 miles) in diameter; the thickness of laccoliths ranges from hundreds of metres to a few thousand metres. They can be contrasted with sills (sill), which are sheetlike intrusions oriented parallel to the bedding of the enclosing rock: a laccolith's ratio of diameter to thickness should be less than 10; a larger ratio would make the body a sill. Acidic rocks are more common than basic rocks in laccoliths. Although the lower portions of laccoliths are seldom visible, they usually are interpreted as having a relatively small feeder from a magma source below. A well-known example of a laccolith is found in the Henry Mountains, Utah.

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Universalium. 2010.

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  • laccolith — [lak′ə lith΄] n. [< Gr lakkos, a cistern + LITH] a dome shaped, irregular formation of intrusive igneous rock found between layers of sedimentary rock: cf. BATHOLITH …   English World dictionary

  • Laccolith — A laccolith is an igneous intrusion (or concordant pluton) that has been injected between two layers of sedimentary rock. The pressure of the magma is high enough that the overlying strata are forced upward, giving the laccolith a dome or… …   Wikipedia

  • Laccolith — Laccolite Lac co*lite, Laccolith Lac co*lith, n. [Gr. ? a cistern + lite, lith.] (Geol.) A mass of igneous rock intruded between sedimentary beds and resulting in a mammiform bulging of the overlying strata. {Lac co*lit ic}, a. [1913 Webster] …   The Collaborative International Dictionary of English

  • laccolith — noun Etymology: Greek lakkos pond, reservoir + English lith more at lake Date: 1879 a mass of igneous rock that is intruded between sedimentary beds and produces a domical bulging of the overlying strata • laccolithic adjective …   New Collegiate Dictionary

  • laccolith — noun a) a mass of igneous or volcanic rock found within strata which forces the overlaying strata upwards and forms domes. b) mass similar to lopolith but concave up …   Wiktionary

  • laccolith — mass of igneous rock intruded between two sedimentary beds Stones and Rocks …   Phrontistery dictionary

  • laccolith — n. mass of igneous rock formed beneath the Earth s surface which causes the ground above it to bulge …   English contemporary dictionary

  • laccolith — ALASKA VOLCANO OBSERVATORY GLOSSARY A body of igneous rocks with a flat bottom and domed top. It is parallel to the layers above and below it …   Glossary of volcanic terms

  • laccolith — [ lakəlɪθ] noun Geology a lens shaped mass of igneous rock intruded between rock strata, causing doming. Origin C19: from Gk lakkos reservoir + lith …   English new terms dictionary

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