Diskussion:Bryce Canyon nationalpark

Senaste kommentaren: för 8 år sedan av InternetArchiveBot i ämnet Externa länkar ändrade

Hjälp gärna till att översätta detta!

Geologi

redigera
Huvudartikel: Bryce Canyonområdets geologi
Erosion of sedimentary rocks has created natural arches.

The Bryce Canyon area shows a record of deposition that spans from the last part of the Cretaceous period and the first half of the Cenozoic era. The ancient depositional environment of region around what is now the park varied:

  • The Dakota Sandstone and the Tropic Shale were deposited in the warm, shallow waters of the advancing and retreating Cretaceous Seaway (outcrops of these rocks are found just outside park borders).
  • The colorful Claron Formation that the park's delicate hoodoos are carved from was laid down as sediments in a system of cool streams and lakes that existed from 63 to about 40 million years ago (from the Paleocene to the Eocene epochs). Different sediment types were laid down as the lakes deepened and became shallow and as the shoreline and river deltas migrated.

Several other formations were also created but were mostly eroded away following two major periods of uplift:

  • The Laramide orogeny affected the entire western part of what would become North America starting about 70 million years ago and lasting for many millions of years after. This event helped to build the ancestral Rocky Mountains and in the process closed the Cretaceous Seaway. The Straight Cliffs, Wahweap, and Kaiparowits formations were victims of this uplift.
  • The Colorado Plateaus were uplifted 10 to 15 million years ago and were segmented into different plateaus — each separated from its neighbors by faults and each having its own uplift rate. The Boat Mesa Conglomerate and the Sevier River Formation were removed following this uplift.
Hoodoos can form strange shapes due to random fluctuations in erosion patterns and variations between the rock strata.

Vertical joints were created by this uplift, which were eventually (and still are) preferentially eroded. The easily eroded Pink Cliffs of the Claron Formation respond by forming freestanding pinnacles in badlands called hoodoos, while the more resistant White Cliffs formed monoliths. The pink color is from iron oxide and manganese. Also created were arches, natural bridges, walls, and windows. Hoodoos are composed of soft sedimentary rock and are topped by a piece of harder, less easily eroded stone that protects the column from the elements. Bryce Canyon has one of the highest concentrations of hoodoos of any place on Earth.

The formations exposed in the area of the park are part of the Grand Staircase. The oldest members of this supersequence of rock units are exposed in the Grand Canyon, the intermediate ones in Zion National Park, and its youngest parts are laid bare in Bryce Canyon area. A small amount of overlap occurs in and around each park.

Externa länkar ändrade

redigera

Hej, wikipedianer!

Jag har just ändrat 1 externa länkar på Bryce Canyon nationalpark. Kontrollera gärna mina ändringar. Om du har några frågor, eller vill be boten ignorera vissa länkar eller hela artikeln, läs frågor och svar för mer information. Jag har gjort följande ändringar:

När ändringarna har blivit kontrollerade kan du använda verktygen nedan för att rapportera eventuella problem.

  • Om du har hittat länkar som påstås vara döda men inte är det kan du rapportera det som falskt positivt.
  • Om du har hittat fel i själva ändringen kan du rapportera en bugg.
  • Om du har hittat fel med själva URL:en, som till exempel att den använder en otillförlitlig arkivtjänst, kan du ändra det med URL-verktyget.

Hälsningar.—InternetArchiveBot (Rapportera fel) 20 juni 2018 kl. 07.02 (CEST)Svara