• synonyms


[uhn-kuh n-fawr-mi-tee]
See more synonyms for unconformity on Thesaurus.com
noun, plural un·con·form·i·ties.
  1. lack of conformity; incongruity; inconsistency.
  2. Geology.
    1. a discontinuity in rock sequence indicating interruption of sedimentation, commonly accompanied by erosion of rocks below the break.
    2. the interface between such strata.
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Origin of unconformity

First recorded in 1590–1600; un-1 + conformity
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for unconformity

Historical Examples

  • Either of these events would have produced an unconformity; the two make it more pronounced.

    The Geography of the Region about Devils Lake and the Dalles of the Wisconsin

    Rollin D. Salisbury

  • They are separable into a lower and upper division with an unconformity often occurring between them.

  • At Llandovery they rest unconformably upon Ordovician rocks (Bala), but in many other places no unconformity is traceable.

  • An unconformity thus records movements of the crust and a consequent break in the deposition of the strata.

    The Elements of Geology

    William Harmon Norton

  • Such an erosion surface, called an “unconformity,” marks a gap in the geological record of the district where it occurs.


    William J. Miller

British Dictionary definitions for unconformity


noun plural -ties
  1. lack of conformity
  2. the contact surface between younger and older rocks representing a discontinuity in the geological record. Most commonly it represents an erosional surface
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Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for unconformity


c.1600, from un- (1) "not" + conformity. Geological sense is from 1829.

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Online Etymology Dictionary, © 2010 Douglas Harper

unconformity in Science


  1. A surface between successive strata representing a missing interval in the geologic record of time, produced either by an interruption in deposition or by the erosion of depositionally continuous strata followed by renewed deposition. An unconformity is a type of discontinuity.
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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.