unconformity

[ uhn-kuhn-fawr-mi-tee ]

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.

unconformity

/ ˌʌnkənˈfɔːmɪtɪ /

noun

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

unconformity

/ ŭn′kən-fôr′mĭ-tē /

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.

Word History and Origins

Origin of unconformity¹

First recorded in 1590–1600; un- ¹ + conformity

Example Sentences

The sites include familiar ones, such as the Grand Canyon’s “great unconformity,” a billion-year gap in the rock record erased by erosion.

From Science Magazine

An “unconformity” is the geological term for “a discontinuity in the deposition of sediment,” in Raffles’s words.

From New York Times

It echoes James Playfair’s description of the “abyss of time” he glimpsed while viewing a strata unconformity at Siccar Point in 1788, when geology was first emerging as a science.

From The Guardian

An unconformity: At Mount Stimson, the rover identified from sol 980 a thick sandstone unit overlying the lake deposits, separated by a geological feature called an unconformity.

From BBC

This unconformity represents a time where erosive processes took over after millions of years when the lake had finally dried up - to form a new land surface.

From BBC

Related Words

• abnormality
• alteration
• change
• deviation
• discrepancy
• disparity
• divergence
• diversity
• fluctuation
• innovation
• modification
• mutation
• shift
• variety