File:Serpentinite with chrysotile asbestos (Archean; Casper Mountain, Natrona County, Wyoming, USA (49145813948).jpg
Original file (3,003 × 1,731 pixels, file size: 4.44 MB, MIME type: image/jpeg)
Captions
Captions
Summary[edit]
.jpg&action=edit§ion=1){kind=link}
| Description |
Serpentinite from the Precambrian of Wyoming, USA. (public display, University of Wyoming Geological Museum, Laramie, Wyoming, USA) Serpentinite forms by metamorphism of olivine-rich peridotites (dunites - ultramafic, phaneritic, intrusive igneous rocks). Metamorphism of olivine in the presence of water results in the formation of the mineral serpentine (Mg3Si2O5(OH)4). A metamorphic rock composed principally of serpentine is thus a serpentinite. Serpentinite has a mottled greenish color, often has the look & feel of hard candle wax, and ranges in texture from crystalline to “foliated”. Many serpentinites have a foliated look to them, but it’s really not due to an planar alignment of crystals. The appearance of “foliated” serpentinites is really the result of extensive development of slickenlined surfaces. Serpentinite can have a small component of magnetite that is usually significant enough to feel a slight tug when a magnet is placed next to the rock. Some serpentinites (see above) have "veins" of white asbestos (= chrysotile serpentine). Many Precambrian greenstone belts have significant occurrences of serpentinites. Slices of dunitic mantle caught up in orogenic belts by obduction (= ophiolites) are often serpentinized. Sometimes, mantle peridotite masses that were caught up in rising magmas have been serpentinized (for example, in kimberlites & lamproites). The sample seen here is from a Precambrian greenstone belt in Wyoming. The rock is from Casper Mountain, where Precambrian basement rocks are exposed. The area was uplifted during the Laramide Orogeny (late Mesozoic to early Cenozoic). Tens of millions of years of weathering and erosion has since removed the Phanerozoic sedimentary cover. Serpentinite at Casper Mountain is composed of antigorite serpentine, clinochrysotile, and lizardite serpentine. Other components include magnetite, chromite, hematite, relict pyroxene, relict olivine, biotite mica, talc, and clinochlore. Locality: unrecorded/undisclosed site on Casper Mountain, south of the town of Casper, southeastern Natrona County, eastern Wyoming, USA Site-specific info. from: Gable et al. (1988) - The Precambrian geology of Casper Mountain, Natrona County, Wyoming. United States Geological Survey Professional Paper 1460. 50 pp. |
| Date | |
| Source | Serpentinite with chrysotile asbestos (Archean; Casper Mountain, Natrona County, Wyoming, USA |
| Author | James St. John |
Licensing[edit]
.jpg&action=edit§ion=2){kind=link}
- You are free:
- to share – to copy, distribute and transmit the work
- to remix – to adapt the work
- Under the following conditions:
- attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
|
This image was originally posted to Flickr by James St. John at https://flickr.com/photos/47445767@N05/49145813948 (archive). It was reviewed on 30 November 2019 by FlickreviewR 2 and was confirmed to be licensed under the terms of the cc-by-2.0. |
File history
Click on a date/time to view the file as it appeared at that time.
| Date/Time | Thumbnail | Dimensions | User | Comment | |
|---|---|---|---|---|---|
| current | 17:09, 30 November 2019 | | 3,003 × 1,731 (4.44 MB) | Ser Amantio di Nicolao (talk | contribs) | Transferred from Flickr via #flickr2commons |
You cannot overwrite this file.
File usage on Commons
There are no pages that use this file.
.jpg&oldid=602013161){kind=link}