When.com Web Search

Search results

  1. Results From The WOW.Com Content Network
  2. Unconformity - Wikipedia

    en.wikipedia.org/wiki/Unconformity

    Angular unconformity. An angular unconformity is an unconformity where horizontally parallel strata of sedimentary rock are deposited on tilted and eroded layers, producing an angular discordance with the overlying horizontal layers. [6] The whole sequence may later be deformed and tilted by further orogenic activity. A typical case history is ...

  3. Hutton's Unconformity - Wikipedia

    en.wikipedia.org/wiki/Hutton's_Unconformity

    An unconformity is a break in the normal progression of sedimentary deposits, where newer deposits are lain on top of older. The example Hutton discovered is known as an angular unconformity in which a sharp change in younging direction can be seen in the orientation of bedding planes .

  4. Nankoweap Formation - Wikipedia

    en.wikipedia.org/wiki/Nankoweap_Formation

    [10] [11] The contact between the overlying Tapeats Sandstone and the folded and faulted Nankoweap Formation is a prominent angular unconformity that is part of the Great Unconformity. [7] Uranium-lead dating of detrital zircons from the Nankoweap Formation indicate the presence of zircon grains in approximately the 800–770 Ma age range. This ...

  5. Great Unconformity - Wikipedia

    en.wikipedia.org/wiki/Great_Unconformity

    The unconformity between the Tonto Group and the Vishnu Basement Rocks is a nonconformity. The break between the Tonto Group and the Grand Canyon Supergroup is an angular unconformity. [2] [3] [4] Powell's Great Unconformity is part of a continent-wide unconformity that extends across Laurentia, the ancient core of

  6. Lithostratigraphy - Wikipedia

    en.wikipedia.org/wiki/Lithostratigraphy

    Angular unconformity: younger sediment lies upon an eroded surface of tilted or folded older rocks. The older rock dips at a different angle from the younger. Disconformity : the contact between younger and older beds is marked by visible, irregular erosional surfaces .

  7. Unkar Group - Wikipedia

    en.wikipedia.org/wiki/Unkar_Group

    The surface of this angular unconformity truncates dipping strata comprising the folded and faulted Unkar Group. Though this surface is typically a plane, differential erosion of the tilted strata of the Unkar Group left resistant beds of the upper layer Cardenas Basalt and the middle layer Shinumo Quartzite as ancient hills, called monadnocks .

  8. Tonto Group - Wikipedia

    en.wikipedia.org/wiki/Tonto_Group

    Throughout the majority of it extent, the Tonto Group lies unconformably on underlying Precambrian rocks forming the Great Unconformity. This contact is either an angular unconformity truncating tilted strata of the Grand Canyon Supergroup or a nonconformity cut into the crystalline Vishnu Basement Rocks. The base of the Tonto Group consists of ...

  9. 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 ...