Table of Contents
What formed the Basin and Range province?
The basins (valleys) and ranges (mountains) are being created by ongoing tension in the region, pulling in an east-west direction. Over most of the last 30 million years, movement of hot mantle beneath the region caused the surface to dome up and then partially collapse under its own weight, as it pulled apart.
When did the Basin and Range form?
The faulting that started the Basin and Range is complex and not very uniform. In some places, extension started before 55 million years ago, and in some places, it is still active, as mentioned above. However, the majority of the extension occurred around 20 ±10 million years ago.
What geologic structures dominate the Basin and Range province?
The dominant physiographic structure of the Basin and Range Province is the result of a series of normal fault-blocks, most of which are tilted either to the east or west.
What is Nevada’s Basin and Range caused by?
Unlike the Cascade or Appalachian mountains, which are “compressional,” meaning they are caused by tectonic plates slamming into each other, Nevada’s many ranges are “extensional:” they are caused by the North American plate stretching out over several million years.
What is unique about the Basin and Range province?
The Basin and Range Province is a vast physiographic region covering much of the inland Western United States and northwestern Mexico. It is defined by unique basin and range topography, characterized by abrupt changes in elevation, alternating between narrow faulted mountain chains and flat arid valleys or basins.
What type of stress is the Basin and Range province?
Basin and range topography is an alternating landscape of parallel mountain ranges and valleys. It is a result of crustal extension/stretching (extensional tectonics) of the lithosphere (crust and upper mantle) due to mantle upwelling, gravitational collapse, crustal thickening, or relaxation of confining stresses.
What does Basin and Range look like?
Basin and Range topography is characterized by alternating valleys and mountainous areas, oriented in a north-south, linear direction. The boundaries between the mountains and valleys are very sharp, both because of the straight faults between them and because many of those faults are still active.
Is the Grand Canyon in the Basin and Range?
A drainage system that flowed through what is today the eastern Grand Canyon emptied into the now lower Basin and Range province. The new river captured the older drainage to form the ancestral Colorado River, which in turn started to form the Grand Canyon.
What is a basin and range?
How old is the Basin and Range province?
around 17 million years ago
It is defined by unique basin and range topography, characterized by abrupt changes in elevation, alternating between narrow faulted mountain chains and flat arid valleys or basins. The physiography of the province is the result of tectonic extension that began around 17 million years ago in the early Miocene epoch.
What type of fault is the Basin and Range province?
normal faulting
It is generally accepted that basin and range topography is the result of extension and thinning of the lithosphere, which is composed of crust and upper mantle. Extensional environments like the Basin and Range are characterized by listric normal faulting, or faults that level out with depth.
What is the basin Range known for?
Where is the basin and Range Province located?
The Basin and Range Province is a vast physiographic region covering much of the inland Western United States and northwestern Mexico. It is defined by unique basin and range topography, characterized by abrupt changes in elevation, alternating between narrow faulted mountain chains and flat arid valleys or basins.
How is the basin and range different from the Great Basin?
Note that the Basin and Range is different from the Great Basin, which is defined as an area of drainage basins that do not flow towards the ocean but drain internally. The Great Basin is within the Basin and Range, and is made up of the northern arm of the Basin and Range geologic province.
What is the crustal thickness of the basin and Range Province?
The average crustal thickness of the Basin and Range Province is approximately 30 – 35 km and is comparable to extended continental crust around the world. The crust in conjunction with the upper mantle comprises the lithosphere.
What are the ages of the basin and range?
Since its formation, the bedrock of the basins has been covered by young deposits such as loose sediment washed down from the mountains and evaporite deposits from dried-out lakes. The ranges, however, expose rocks whose ages span from Precambrian to Cenozoic.