The Big Hollow (Wyoming)
Encyclopedia
The Big Hollow is a wind eroded deflection basin
located to the west of Laramie, Wyoming
in the United States
. It is the second largest wind eroded depression in the world. The Big Hollow is the largest deflation basin in North America. The Big Hollow is younger than the alluvial valley floors which now form its boundaries and is therefore of Late Pleistocene age (less than 250,000 years). During most of the Pleistocene the Big Hollow was actually a hill composed of soft sedimentary bedrock. The material making up this former hill was much more easily eroded than the alluvial valley floors which bounded it to both the north and south. Eventually, the hill was washed and blown away and then the wind continued to erode a deflation basin into the soft bedrock. Eventually the former hill became lower than the river channels which once flowed around it. The geologists call this "topographic reversal".The Qattara Depression
near Cairo, Egypt is the largest. Citation: http://www.akademifantasia.org/middle-east/qattara-depression-worlds-largest-vanish-land The Big Hollow is an undrained basin and is 11 miles (17.7 km) long, 4 miles (6.4 km) wide, and up to 200 feet (61 m) deep. Oil was discovered in 1917 and the basin has been productive since. The basin is listed on the National Natural Landmark
list.
Blowout (geology)
Blowouts are sandy depressions in a sand dune ecosystem caused by the removal of sediments by wind.Blowouts occur in partially vegetated dunefields or sandhills. A blowout forms when a patch of protective vegetation is lost, allowing strong winds to "blow out" sand and form a depression...
located to the west of Laramie, Wyoming
Laramie, Wyoming
Laramie is a city in and the county seat of Albany County, Wyoming, United States. The population was 30,816 at the . Located on the Laramie River in southeastern Wyoming, the city is west of Cheyenne, at the junction of Interstate 80 and U.S. Route 287....
in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. It is the second largest wind eroded depression in the world. The Big Hollow is the largest deflation basin in North America. The Big Hollow is younger than the alluvial valley floors which now form its boundaries and is therefore of Late Pleistocene age (less than 250,000 years). During most of the Pleistocene the Big Hollow was actually a hill composed of soft sedimentary bedrock. The material making up this former hill was much more easily eroded than the alluvial valley floors which bounded it to both the north and south. Eventually, the hill was washed and blown away and then the wind continued to erode a deflation basin into the soft bedrock. Eventually the former hill became lower than the river channels which once flowed around it. The geologists call this "topographic reversal".The Qattara Depression
Qattara Depression
The Qattara Depression is a depression in the north west of Egypt in the Matruh Governorate and is part of the Libyan Desert. It lies below sea level and is covered with salt pans, sand dunes and salt marshes. The region extends between latitudes of 28°35' and 30°25' North and longitudes of 26°20'...
near Cairo, Egypt is the largest. Citation: http://www.akademifantasia.org/middle-east/qattara-depression-worlds-largest-vanish-land The Big Hollow is an undrained basin and is 11 miles (17.7 km) long, 4 miles (6.4 km) wide, and up to 200 feet (61 m) deep. Oil was discovered in 1917 and the basin has been productive since. The basin is listed on the National Natural Landmark
National Natural Landmark
The National Natural Landmark program recognizes and encourages the conservation of outstanding examples of the natural history of the United States. It is the only natural areas program of national scope that identifies and recognizes the best examples of biological and geological features in...
list.
External links
- Big Hollow National Natural Landmark, National Park Service