File:Peridotite (Dunite) 1 (16788415375).jpg
Original file (981 × 697 pixels, file size: 1.31 MB, MIME type: image/jpeg)
Captions
Summary
[edit]DescriptionPeridotite (Dunite) 1 (16788415375).jpg |
Igneous rocks form by the cooling & crystallization of hot, molten rock (magma & lava). If this happens at or near the land surface, or on the seafloor, they are extrusive igneous rocks. If this happens deep underground, they are intrusive igneous rocks. Most igneous rocks have a crystalline texture, but some are clastic, vesicular, frothy, or glassy. Peridotites are coarsely-crystalline, ultramafic, intrusive igneous rocks. Igneous rocks have an ultramafic chemistry if they are <45% silica (= SiO2 chemistry) and are dominated by the minerals olivine and/or pyroxene. They are often greenish-colored, greenish-black, or brownish-black. Peridotites are scarce in much of the Earth’s crust, but are common in Earth's upper mantle. There are a few places on Earth where mantle rocks have been uplifted to the surface. Examples of localities with exposed mantle peridotites (or metamorphosed peridotites) include Oman, Cyprus, the Shetland Islands, Austria, and Newfoundland. Sometimes, peridotite rocks from the mantle get caught up in rising masses of magma. When erupted from volcanoes at the surface, the lava flows will have mantle peridotite xenoliths. There are four principal varieties of peridotite, based on different percentages of the three main minerals: olivine, clinopyroxene, and orthopyroxene. These four rocks are dunite, harzburgite (formerly saxonite), wehrlite, and lherzolite. Dunite has 90 to 100% olivine, with minor pyroxene. Lherzolite, harzburgite, and wehrlite have decent mixes of olivine & pyroxene. Harzburgite is a mix of olivine and orthopyroxene (40 to 90% olivine & 10 to 60% orthopyroxene). Wehrlite is a mix of olivine and clinopyroxene (40 to 90% olivine & 10 to 60% clinopyroxene). Lherzolite is a mix of olivine (40 to 90% of the rock), plus orthopyroxene and clinopyroxene. The peridotite shown above is a dunite - it's almost exclusively composed of forsterite olivine. The scattered, black specks are small crystals of chromite (FeCr2O4). |
Date | |
Source | Peridotite (Dunite) 1 |
Author | James St. John |
Licensing
[edit]- 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@N05/16788415375 (archive). It was reviewed on 7 December 2019 by FlickreviewR 2 and was confirmed to be licensed under the terms of the cc-by-2.0. |
7 December 2019
File history
Click on a date/time to view the file as it appeared at that time.
Date/Time | Thumbnail | Dimensions | User | Comment | |
---|---|---|---|---|---|
current | 17:54, 7 December 2019 | 981 × 697 (1.31 MB) | Ser Amantio di Nicolao (talk | contribs) | Transferred from Flickr via #flickr2commons |
You cannot overwrite this file.
File usage on Commons
The following page uses this file:
Metadata
This file contains additional information such as Exif metadata which may have been added by the digital camera, scanner, or software program used to create or digitize it. If the file has been modified from its original state, some details such as the timestamp may not fully reflect those of the original file. The timestamp is only as accurate as the clock in the camera, and it may be completely wrong.
Pixel composition | RGB |
---|---|
Orientation | Normal |
Horizontal resolution | 600 dpi |
Vertical resolution | 600 dpi |
Software used | Adobe Photoshop CS2 Macintosh |
File change date and time | 17:56, 11 March 2015 |
Color space | Uncalibrated |
Image width | 981 px |
Image height | 697 px |
Date and time of digitizing | 13:55, 11 March 2015 |
Date metadata was last modified | 13:56, 11 March 2015 |