View source for Grand Staircase

{{Short description|Landform in Utah and Arizona, United States}}
{{Other uses}}
{{More footnotes|date=July 2016}}
{{Use mdy dates|date=September 2011}}
[[Image:Grand Staircase Escalante National Monument.jpg|thumb|upright=1.3|View from [[Utah_State_Route_12|Utah Highway 12]] of Grand Staircase–Escalante National Monument]]

The '''Grand Staircase''' is an immense sequence of [[sedimentary rock]] [[stratum|layers]] that stretches south from [[Bryce Canyon National Park]] and [[Grand Staircase–Escalante National Monument]], through [[Zion National Park]], and into [[Grand Canyon National Park]].<ref name=NPS>{{NPS|url=https://www.nps.gov/brca/learn/nature/grandstaircase.htm|title=Grand Staircase|access-date=8 September 2024}}</ref>

==Characterization==
In the 1870s, geologist [[Clarence Dutton]] first conceptualized this region as a huge stairway ascending out of the bottom of the Grand Canyon northward with the cliff edge of each layer forming giant steps. Dutton divided this layer cake of Earth history into five steps from the youngest (uppermost) rocks:<ref name=NPS/>
*[[Pink Cliffs]] 
*[[Grey Cliffs]] 
*[[White Cliffs (Utah)|White Cliffs]] 
*[[Vermilion Cliffs]]
*[[Chocolate Cliffs]]

Since then, modern geologists have further divided Dutton's steps into individual rock [[formation (geology)|formation]]s.<ref name=NPS/>

{{Clear}}
[[Image:Grand Staircase-big.jpg|thumb|900px|center|The Grand Staircase. Red dots from left to right: Pink Cliffs, Grey Cliffs, White Cliffs, Vermilion Cliffs, Chocolate Cliffs (NPS image)]]
{{Clear}}
[[Image:Grand Staircase.jpg|thumb|upright=1.75|alt=Cross section diagram of rock layers | Grand Canyon (A), Chocolate Cliffs (B), Vermilion Cliffs (C), White Cliffs (D), Zion Canyon (E), Gray Cliffs (F), Pink Cliffs (G), Bryce Canyon (H)]]

Formations in the Grand Staircase starting with the youngest (uppermost) rocks:<ref>{{cite web |url=http://www.nature.nps.gov/geology/inventory/publications/reports/brca_gre_rpt_view.pdf |title=Bryce Canyon National Park Geologic Resource Evaluation Report |website=Mature.nps.gov |access-date=2016-07-16 |archive-date=December 15, 2016 |archive-url=https://web.archive.org/web/20161215105136/http://www.nature.nps.gov/geology/inventory/publications/reports/brca_gre_rpt_view.pdf |url-status=dead }}</ref>
*[[Claron Formation]]
*[[Kaiparowits Formation]]
*[[Wahweap Formation]]
*[[Straight Cliffs Formation]]
*[[Tropic Shale]]
*[[Dakota Sandstone]]
*[[Carmel Formation]]
*[[Temple Cap Formation]]
*[[Navajo Formation]]
*[[Kayenta Formation]]
*[[Moenave Formation]]
*[[Chinle Formation]]
*[[Moenkopi Formation]]
*[[Kaibab Limestone]]
*[[Toroweap Formation]]
*[[Coconino Sandstone]]
*[[Hermit Shale]]
*[[Supai Group]]
*[[Surprise Canyon Formation]]
*[[Redwall Limestone]]
*[[Temple Butte Limestone]]
*[[Muav Limestone]]
*[[Bright Angel Shale]]
*[[Tapeats Sandstone]]

==Geology==
{{Further|geology of the Grand Canyon area|geology of the Zion and Kolob canyons area|geology of the Bryce Canyon area}}

The major sedimentary rock units exposed in the Grand Canyon range in age from 200&nbsp;million to 600 million years and were deposited in warm shallow seas and near-shore environments.  The nearly 40 identified rock layers of Grand Canyon form one of the most studied geologic columns in the world. 

The oldest exposed formation in Zion National Park is the youngest exposed formation in the Grand Canyon – the ~240‑million-year-old [[Kaibab Limestone]]. The Bryce Canyon area to the northeast continues where the Zion area leaves off by presenting [[Cenozoic]]-aged rocks that are 100 million years younger. In fact, the youngest formation seen in the Zion area is the oldest exposed formation in Bryce Canyon – the [[Dakota Sandstone]]. There are, however, shared rock units between all three, creating a super-sequence of [[formation (geology)|formation]]s that geologists call the Grand Staircase. Bryce Canyon's formations are the youngest known units in the Grand Staircase. Younger rock units, if they ever existed, have been removed by [[erosion]]. 

These layers have undergone 5000 to 10,000 feet (1500 to 3000 m) of uplift, starting about 66 million years ago with the [[Laramide orogeny]], which has increased the ability of the [[Colorado River (U.S.)|Colorado River]] to cut its channel to make individual plateaus out of the [[Colorado Plateau]]s region. The major canyons of the region did not start to form until about five to six million years ago, when the [[Gulf of California]] opened up and thus lowered the river's [[base level]] (its lowest point).

==Paleontology==
In the 1880s, many large [[dinosaur]] skeletons were excavated from southern [[Utah]] in regions north of the Grand Staircase. Following these discoveries, there was little interest in further exploration. In the late 20th and early 21st centuries, there has been greatly renewed interests in the strata of the Grand Staircase, particularly since the exposure and collection of new fossils in previously unexplored strata has a high probability of revealing fossil remnants of hitherto unseen [[species]].

[[file:FossilBonesMultiple.jpg|thumb|center|700px|{{center|Fossilized skeleton (partial) of a young [[hadrosaur]]<br/>
displayed at the [[Grand Staircase–Escalante National Monument]]<br/>Click image for display placard text}}]]

Southern Utah has continued to reward researchers owing to its climatological "sweet spot" for exposing fossil remnants for observation and collection at the surface. At locations south, in Arizona, the climate is so dry that erosion is relatively slow. Further north, the wetter climates encourage growth of forests, which destroy fossils by the actions of roots and soil bacteria. In southern Utah, there are enough strong and wet storms to cause episodic rapid erosion and the consequent exposure of fossil remains, but with insufficient annual average rainfall to support destructive, deep-rooted plant life.

==Gallery==
(South to north, climbing the staircase)
<gallery widths="200px" heights="120px">
Image:Vermilioncliffsglencanyon.jpg|[[Vermilion Cliffs]]
Image:Navajo SS-Escalante.jpg|[[White Cliffs (Utah)|White Cliffs]]
Image:SEUtahStrat.JPG|The Permian through Jurassic part of the staircase, as seen at [[Glen Canyon NRA]]
</gallery>

==See also==
*[[Grand Staircase–Escalante National Monument]]

==References==
{{Reflist}}
*''The Salt Lake Tribune'', May 21, 2006, p.&nbsp;1: A New Golden Age – "Utah's peak for dinosaur discoveries ended in the 1920s but recent finds have the state on the cusp of another boom"
*[https://archive.today/20030623235425/http://www.nps.gov/brca/geology_grand.html National Park Service: Bryce Canyon National Park Nature and Geology – The Grand Staircase] (public domain text). Not found 4/8/08
* [https://www.blm.gov/programs/national-conservation-lands/utah/grand-staircase-escalante-national-monument Grand Staircase-Escalante National Monument]t

== External links ==
* {{commons-inline}}
*[https://web.archive.org/web/20060520003019/http://3dparks.wr.usgs.gov/escalante2/ USGS.gov: Photo tour of Grand Staircase]


{{Grand Staircase–Escalante National Monument}}
{{Geology of the Grand Canyon area}}


[[Category:Grand Staircase–Escalante National Monument]]
[[Category:Bryce Canyon]]
[[Category:Grand Canyon]]
[[Category:Colorado Plateau]]
[[Category:Geology of Utah]]
[[Category:Geology of Arizona]]
[[Category:Sandstone formations of the United States]]