THE FIRST OBSERVATIONS. “Of the many unconformities (gaps) observed in geological strata, the term Great Unconformity is applied to either the unconformity observed by James Hutton in 1787 at Siccar Point in Scotland, or that observed by John Wesley Powell in the Grand Canyon in 1869. Both instances are exceptional examples of where the contacts between sedimentary strata and either sedimentary or crystalline strata of greatly different ages, origins, and structure represent periods of geologic time sufficiently long to raise great mountains and then erode them away.”
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linkedin post 2022-06-29 05:12:48
Nigel Fleming
September 21, 2022