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  2. Unconformity - Wikipedia

    en.wikipedia.org/wiki/Unconformity

    An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval of time before deposition of the younger layer, but the term is used to describe any break in the ...

  3. Knox Supergroup - Wikipedia

    en.wikipedia.org/wiki/Knox_Supergroup

    The formation is broken up into two members, the New Richmond and Willow River Members. The Shakopee was deposited in a peritidal setting and is divided by an unconformity. The unconformity left river valleys that were filled with siliciclastic material that was covered by marine deposits.

  4. Hutton's Unconformity - Wikipedia

    en.wikipedia.org/wiki/Hutton's_Unconformity

    Hutton's Unconformity is a name given to various notable geological sites in Scotland identified by the 18th-century Scottish geologist James Hutton as places where the junction between two types of rock formations can be seen. This geological phenomenon marks the location where rock formations created at different times and by different ...

  5. Cross-cutting relationships - Wikipedia

    en.wikipedia.org/wiki/Cross-cutting_relationships

    Cross-cutting relationships can be used to determine the relative ages of rock strata and other structures. Explanations: A – folded rock strata cut by a thrust fault; B – large intrusion (cutting through A); C – erosional angular unconformity (cutting off A & B) on which rock strata were deposited; D – volcanic dike (cutting through A, B & C); E – even younger rock strata (overlying ...

  6. Geology of the Death Valley area - Wikipedia

    en.wikipedia.org/wiki/Geology_of_the_Death...

    Little is known about the history of the oldest exposed rocks in the area due to extensive metamorphism.This somber, gray, almost featureless crystalline complex is composed of originally sedimentary and igneous rocks with large quantities of quartz and feldspar mixed in. [1] The original rocks were transformed to contorted schist and gneiss, making their original parentage almost unrecognizable.

  7. Uniformitarianism - Wikipedia

    en.wikipedia.org/wiki/Uniformitarianism

    Hutton's Unconformity at Jedburgh. Above: John Clerk of Eldin's 1787 illustration. Below: 2003 photograph. Uniformitarianism, also known as the Doctrine of Uniformity or the Uniformitarian Principle, [1] is the assumption that the same natural laws and processes that operate in our present-day scientific observations have always operated in the universe in the past and apply everywhere in the ...

  8. Shinumo Quartzite - Wikipedia

    en.wikipedia.org/wiki/Shinumo_Quartzite

    Their colors and cementation appear to be the result of ground or connate water alteration after their deposition. Finally, the upper member of the Shinumo Quartzite is composed of reddish brown and locally purple sandstone and an overlying well-cemented gray quartzite.

  9. Eparchaean Unconformity - Wikipedia

    en.wikipedia.org/wiki/Eparchaean_Unconformity

    Tirupati Eparchaean Unconformity, a notified National Geo-heritage Monument [1] [2] [3] is a major discontinuity of stratigraphic significance that represents a period of remarkable serenity in the geological history of the Earth i.e. sudden changes and discontinuity in the rock layers in Earth's crust.