Open access. Karner Don Halvorson Gordon A. Jenne Stanley F. First published: 1 January Copyright American Geophysical Union. Book Series: Field Trip Guidebooks. Free Access.
Summary PDF Request permissions. PDF Request permissions. Regional tectonic map showing location of major Paleocene-Eocene alkalic volcanic centers and associated West-Northwest fault zones. Laramide structural arches shown by brown text and dashed lines. Bouguer gravity anomaly map of South Dakota that shows lateral density variations in the earth.
Black Hills shown by black line. Generalized diagram of the Black Hills Precambrian basement surface structure. Generalized structural cross section of the Black Hills Precambrian basement. Thrust faults do not penetrate through the Phanerozoic cover thus producing monolines at the surface.
Cross section location shown on basement surface map above. Phanerozoic sedimentary rocks shown in green, pink, orange and beige eroding back away from the Precambrian igneous-metamorphic core of the Black Hills shown in purple. Black rectangle shows location of the Tertiary Northern Black Hills alkali magmatic trend.
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Thrust fault trace drawn at Cretaceous Fall River Formation level. Sage Creek lineament shown by red dashed line. The northern Black Hills Eocene alkalic magmatic province. Several smaller domes exist in the area where sedimentary rocks still cover the igneous intrusions white dotted lines.
The folding and doming of sedimentary rocks is caused by igneous intrusion. Gold mineralization occurs in several places along the trend of Eocene intrusive domes, but two Precambrian ore sites dominate the gold recovery. About four miles to the west the majority of the remaining gold ore is found in the Cambrian Deadwood Formation at Bald Mountain Mine.
Hydrothermal replacement during Eocene magmatism and older placer deposits in the basal conglomerate account for these smaller deposits. Minor amounts of ore were recovered from quartz veins in Precambrian quartz-mica schist. Schematic cross section through the northern Black Hills, showing general spatial relationships between the Iron formation-hosted gold Homestead Formation , Cambrian paleoplacers Hidden Treasure , and Tertiary epithermal mineralization e. Gilt Edge and Richmond Hill - intrusion and breccia-hosted deposits; Golden Reward, Annie Creek, and Carbonate — sediment-hosted deposits; various levels of Homestake mine — Precambrian-hosted epithermal mineralization.
Devils Tower - Wikipedia
Precambrian-hosted epithermal veins are inferred to be conduits for fluid migration into Phanerozoic rocks. Ore bodies are in black. Letter symbols refer to Phanerozoic formations that were probably present at the time the Tertiary magmatism began. Melting occurred as upwelling mantle passed through the transition zone and was focused at the edge of the Kula slab western edge and Farallon plate eastern edge.
Devils Tower with its columnar jointing is the most easily recognized of the intrusive bodies in the magmatic province. The jointing is formed by contraction as the magma cools. The joints align perpendicular to the direction of the cooling front. The feature can be separated into four segments based on the nature of the columnar jointing. The upper columns UC extend about feet m from the top.
Vertical columns, over ten feet in diameter are present. The lower columns LC exhibit a smaller diameter beginning with feet at the base and tapering to 4 feet at the transition with the upper columns.
The transition zone may mark a variation in mineralogy. Dark compositional layering separates the two segments. At the shoulder S the lower columns continue down but splay outward as they approach the base. The base B displays more fractures and variability in orientation of columns.
It merges into an extensive scree pile. Fur trappers may have visited Devils Tower, but they left no written evidence of having done so. The first documented Caucasian visitors were several members of Captain William F.
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Raynolds 's expedition to Yellowstone. Sixteen years later, Colonel Richard I. Dodge escorted an Office of Indian Affairs scientific survey party to the massive rock formation and coined the name Devils Tower. The movie Close Encounters of the Third Kind used the formation as a plot element and as the location of its climactic scenes. Similarly, the movie Paul , used the formation at the film's climax as an homage to Close Encounters of the Third Kind.
In recent years, climbing Devils Tower has increased in popularity. The first known ascent of Devils Tower by any method occurred on July 4, , and is accredited to William Rogers and Willard Ripley, local ranchers in the area. They completed this first ascent after constructing a ladder of wooden pegs driven into cracks in the rock face. A few of these wooden pegs are still intact and are visible on the tower when hiking along the 1.
Over the following thirty years many climbs were made using this method before the ladder fell into disrepair. The first ascent using modern climbing techniques was made by Fritz Wiessner with William P. House and Lawrence Coveney in Wiessner led almost the entire climb free , placing only a single piece of fixed gear, a piton , which he later regretted, deeming it unnecessary. In George Hopkins parachuted onto Devils Tower, without permission, as a publicity stunt resulting from a bet.
As the weather deteriorated, a second attempt was made to drop equipment, but Hopkins deemed it unusable after the rope became snarled and frozen due to the rain and wind. Today, hundreds of climbers scale the sheer rock walls of Devils Tower each summer. The most common route is the Durrance Route , which was the second free route established in There are many established and documented climbing routes covering every side of the tower, ascending the various vertical cracks and columns of the rock.
The difficulty of these routes range from relatively easy to some of the most challenging in the world.
All climbers are required to register with a park ranger before and after attempting a climb. No overnight camping at the summit is allowed; climbers return to base on the same day they ascend. Because of this, many Indian leaders objected to climbers ascending the monument, considering this to be a desecration. The climbers argued that they had a right to climb the Tower, since it is on federal land.
A compromise was eventually reached with a voluntary climbing ban during the month of June when the tribes are conducting ceremonies around the monument. Climbers are asked, but not required, to stay off the Tower in June. However, several climbers along with the Mountain States Legal Foundation sued the Park Service, claiming an inappropriate government entanglement with religion. Devils Tower National Monument protects many species of wildlife, such as white-tailed deer , prairie dogs , and bald eagles.
From Wikipedia, the free encyclopedia. For other uses, see Devil's Tower disambiguation. This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Main article: Durrance Route. Retrieved December 14, Geographic Names Information System. United States Geological Survey. September 24, — via Wikisource.