Lunar Crater, Nevada : 無料・フリー素材/写真
Lunar Crater, Nevada / Ken Lund
| ライセンス | クリエイティブ・コモンズ 表示-継承 2.1 |
|---|---|
| 説明 | Lunar Crater volcanic field is a volcanic field in Nye County, Nevada. It lies along the Reveille and Pancake Ranges and consists of over 200 vents, mostly small volcanic cones with associated lava flows but also several maars, including one maar named Lunar Crater. Some vents have been eroded so heavily that the structures underneath the volcanoes have been exposed. Lunar Crater itself has been used as a testing ground for Mars rovers and as training ground for astronauts.The volcanic field has formed on top of older, Oligocene to Miocene age volcanic rocks and calderas, but its own activity commenced only about 6 million years ago. The reasons for the volcanic activity there are not well known. The volcanic field has produced various types of basaltic magma and also trachyte; the most recent eruption was about 38,000 years ago and renewed activity is possible.The volcanic field is named after the Lunar Crater vent, the most distinctive vent in the volcanic field. The area is dry and rugged and thus uninhabited. Owing to its diverse geology and accessibility, Lunar Crater volcanic field was used to test prototype Mars rovers and as a training ground for astronauts for the Moon landings. Parts of the volcanic field lie within the Palisade Mesa wilderness study area, and Lunar Crater is classified as a National Natural Landmark, known as Lunar Crater National Natural Landmark.Lunar Crater itself is almost circular and embedded in basaltic lavas, underlying tuffs and two older volcanic cones including Lunar Cone. A tephra ring (ring of volcanic material) defines a 3,600 feet (1,100 m) wide and 430 feet (130 m) deep crater which is the endpoint of a small canyon that appears to predate the formation of Lunar Crater. An alluvial fan and a playa fill the bottom of the crater, which is the lowest point in this volcanic field, while its margins are surrounded by tephra beds including ash, lapilli, scoria and tuff blocks; it appears that most of these are older rocks that were torn out of the ground and ejected during the formation of Lunar Crater. Cinder cones are found at Lunar Crater; two vents east and southeast from Lunar Crater are known as North Kidney Butte and South Kidney Butte.en.wikipedia.org/wiki/Lunar_Crater_volcanic_fielden.wikipedia.org/wiki/Wikipedia:Text_of_Creative_Commons_... |
| 撮影日 | 2020-04-18 16:45:59 |
| 撮影者 | Ken Lund , Reno, Nevada, USA |
| 撮影地 | |
| カメラ | Canon PowerShot SX720 HS , Canon |
| 露出 | 0.003 sec (1/400) |
| 開放F値 | f/5.0 |
| 焦点距離 | 21159.18367 dpi |