laccolith

American  

[lak-uh-lith] / ˈlæk ə lɪθ /

Also laccolite

noun

Geology.

1. 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.

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laccolith British  

/ ˈlækəlɪθ, ˈlækəˌlaɪt, ˌlækəˈlɪtɪk /

noun

1. a dome-shaped body of igneous rock between two layers of older sedimentary rock: formed by the intrusion of magma, forcing the overlying strata into the shape of a dome See lopolith

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laccolith Scientific  

/ lăk′ə-lĭth′ /

1. A body of igneous rock intruded between layers of sedimentary rock, resulting in uplift. Laccoliths are usually plano-convex in cross-section, having a flat bottom and a convex top, and are roughly circular in plan. They are usually connected to a dike and are typically up to 8 km (5 mi) in diameter and tens to hundreds of meters thick.

2. See illustration at batholith

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Other Word Forms

• laccolithic
  adjective
• laccolitic
  adjective

Etymology

Origin of laccolith

1875–80; < Greek lákko ( s ) pond + -lith

Example Sentences

A laccolith is a sill-like body that has expanded upward by deforming the overlying rock.

From Textbooks • Jan. 1, 2015

Geologists decided that it was caused by a "laccolith," a mass of molten material that had forced its way toward the surface, raising local rock strata instead of breaking through them.

From Time Magazine Archive