Grand Staircase

The Grand Staircase (Grand Staircase ) is a arranged in the form of a grand staircase sequence of sedimentary strata in the United States, which extend into the states of Utah and Arizona from Bryce Canyon National Park to the south via the Zion National Park to the Grand Canyon.

Location and Name

Referred to as Grand Staircase area is roughly equal parts in Utah and Arizona in the north to the south. The southern boundary is formed by the Grand Canyon, the northern boundary of Paunsaugunt Plateau in southern Utah. The eastern boundary is formed by the jagged ridge of the Cockscomb ( cockscomb ), which lies in the area of ​​East Kaibab mono Cline, a large Schichtverbiegung, at the streak the further west in the underground layers of rock into the air. The western boundary is the Hurricane Cliffs on the system of the Kolob Canyons.

The originator of the name is unclear, they may be traced back to the geologist Clarence Dutton, the 1870 structured by a series of steep walls and flat terrain climb north from the Grand Canyon and introduced himself as a staircase. Dutton divided the resembles a layer cake sequence from top to bottom into five sections:

• Pink Cliffs
• Grey Cliffs
• White Cliffs
• Vermilion Cliffs
• Chocolate Cliffs

Since then, the levels have been geologically subdivided fine.

Geology

The geology of the Grand Canyon and its surroundings are dominated by five main units whose age is between 2 billion and 600 million years ago, and which are divided into nearly forty subunits. Between the rock units in the Grand Canyon in Bryce Canyon and Zion Canyon, there are numerous links.

The oldest open-minded formation in Zion National Park is the youngest in the Grand Canyon - the 240- million year old Kaibab Limestone. The area of Bryce Canyon in the northeast begins at the point where the rocks of the Zion area stop and is composed of rocks of the Cenozoic, which are about 100 million years younger. Indeed, the recent formation of the Zion area, the Dakota Sandstone, the oldest of Bryce Canyon. Nevertheless, divide the three areas a common layer sequence Grand Staircase.

This layer sequence at the beginning of the Tertiary period began about 65 million years ago to lift, and has a total of 1,500 to 3,000 m raised, and at the same time thereby partially tilted and bent. These movements go back to the mix lara orogeny, and had the incision of the Colorado River and its tributaries in the rock result. However, the large plateau formed is only about five to six million years ago when the Gulf of California opened and put the drain base of the Colorado deeper.

The sequence of scarps and flat pieces goes back to the alternation of different resistant rocks. Hard rocks such as sandstone and limestone are only slowly removed, while soft marl and claystone offer little resistance. For this reason, the plateaus form by clearing away the softer layers on the surfaces of the hard rocks. The steep walls result from a combination of factors: the underlying hard rocks the soft rocks are continually eroded in geologically short periods of time, so that the overlying layers nachstürzen over again and make fresh wastage; while ensuring the stability of the rock for the training steeper walls.

Paleontology

In the eighties of the 19th century, the Grand Staircase were excavated many large dinosaur skeletons in southern Utah north. After these discoveries, only a few further studies were performed. Towards the end of the 20th and beginning of the 21st century, however, interest in the study of long-distance still unexplored fossil content of the layers of the Grand Staircase awoke.

The Southern Utah has not therefore ceased to be due to the interaction of its climatic conditions and its rocks a worthwhile goal for researchers, as always free scent and fossils can be collected at the surface. In the south, in Arizona, the climate is so dry that the removal vonstattengeht slowly. In the north the climate allows the growth of trees and forests, so that not only the erosion is reduced, but also the root growth and activity of benthic bacteria to destroy the fossils leads.

In southern Utah, the climate is too dry, however, for the formation of a vegetation cover, and the episodic occurrence of storms and cloudbursts leads to rapid erosion, which repeatedly exposes new fossils.

White Cliffs