unconformity
Americannoun
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unconformities
plural
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lack of conformity; incongruity; inconsistency.
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Geology.
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a discontinuity in rock sequence indicating interruption of sedimentation, commonly accompanied by erosion of rocks below the break.
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the interface between such strata.
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noun
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lack of conformity
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the contact surface between younger and older rocks representing a discontinuity in the geological record. Most commonly it represents an erosional surface
Other Word Forms
Noun Inflected Forms
Etymology
Origin of unconformity
First recorded in 1590–1600; un- 1 + conformity
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
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 ● Apr. 20, 2019
These desert-formed sandstones sit above an unconformity, and this suggests that after a long period with a humid climate, the climate became drier and wind became the dominant agent shaping the environment at Gale Crater.
From BBC ● Mar. 22, 2018
She’s revising a manuscript describing an unconformity in the sedimentary layers of Mount Sharp, within the Gale crater, a record of the alternating wet-dry cycles on the planet.
From Science Magazine ● Jun. 29, 2017
When sea-level fell, the land was exposed to erosion creating an unconformity.
From Textbooks ● Jan. 1, 2017
With few exceptions the Carboniferous strata rest on those of the Devonian without any marked unconformity; the one period passed quietly into the other, with no great physical disturbances.
From The Elements of Geology by William Harmon Norton
There are three types of unconformities, nonconformity, disconformity, and angular unconformity.
From Textbooks ● Jan. 1, 2017
Disconformities are unconformities that occur between parallel layers of strata indicating either a period of no deposition or erosion.
From Textbooks ● Jan. 1, 2017
There are four types of unconformities, as summarized in Table 8.1, and illustrated in Figure 8.9.
From Textbooks ● Jan. 1, 2015
Recognizing unconformities is important for understanding time relationships in sedimentary sequences.
From Textbooks ● Jan. 1, 2015
How geological history may be read in unconformities is further illustrated in Figures 207 and 208.
From The Elements of Geology by William Harmon Norton
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
