File:Chlorite schist (Wissahickon Schist, Neoproterozoic to Cambrian; Jarrettsville, Maryland, USA) (16735383710).jpg
Original file (1,087 × 844 pixels, file size: 1.64 MB, MIME type: image/jpeg)
Captions
Captions
Summary
[edit]_(16735383710).jpg&action=edit§ion=1){kind=link}
| Description |
Chlorite schist from the Neoproterozoic to Cambrian of Maryland, USA. (8.2 centimeters across at its widest) Metamorphic rocks result from intense alteration of any previously existing rocks by heat and/or pressure and/or chemical change. This can happen as a result of regional metamorphism (large-scale tectonic events, such as continental collision or subduction), burial metamorphism (super-deep burial), contact metamorphism (by the heat & chemicals from nearby magma or lava), hydrothermal metamorphism (by superheated groundwater), shear metamorphism (in or near a fault zone), or shock metamorphism (by an impact event). Other categories include thermal metamorphism, kinetic metamorphism, and nuclear metamorphism. Many metamorphic rocks have a foliated texture, but some are crystalline or glassy. Schist is an intermediate- to high-grade, foliated metamorphic rock. It is highly variable in appearance, depending on the mineral content, which is a function of the precursor rock and specific temperature-pressure conditions. Garden-variety schists form by metamorphism of phyllites. Schists typically have medium- to large-sized crystals, unlike the microcrystalline nature of slate & phyllite. Schist's foliated texture (= crystals aligned into bands or stripes or layers) is often only seen when specimens are viewed on edge. Chlorite schist is a moderately common metamorphic rock. It is principally composed principally of chlorite, a silicate mineral with a greenish to grayish-green color. The sample of chlorite schist (metapelite) shown above is from the Neoproterozoic- to Cambrian-aged Wissahickon Schist of Maryland, USA. Metamorphism took place during the Taconic Orogeny (Late Ordovician to Silurian), which affected much of eastern North America. Chlorite schist can have a component of magnetite (Fe3O4 - iron oxide) (for example, see above specimen), which usually occurs as black, relatively small, octahedral crystals. Stratigraphy: Wissahickon Schist (a.k.a. Wissahickon Formation), Glenarm Series (Glenarm Supergroup), Neoproterozoic to Cambrian; metamorphism in the Late Ordovician to Silurian Locality: Jarrettsville, western Harford County, northeastern Maryland, USA |
| Date | |
| Source | Chlorite schist (Wissahickon Schist, Neoproterozoic to Cambrian; Jarrettsville, Maryland, USA) |
| Author | James St. John |
Licensing
[edit]_(16735383710).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@N05/16735383710 (archive). It was reviewed on 2 December 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 | 06:23, 2 December 2019 | | 1,087 × 844 (1.64 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.
_(16735383710).jpg&oldid=895801507){kind=link}