Syncline
In structural geology, a syncline is a fold with younger layers closer to the center of the structure, whereas an anticline is the inverse of a syncline. A synclinorium (plural synclinoriums or synclinoria) is a large syncline with superimposed smaller folds.<ref>Synclinorium. (2008). In Encyclopædia Britannica. Retrieved May 03, 2008, from Encyclopædia Britannica Online: http://www.britannica.com/EBchecked/topic/578375/synclinorium</ref> Synclines are typically a downward fold (synform), termed a synformal syncline (i.e. a trough), but synclines that point upwards can be found when strata have been overturned and folded (an antiformal syncline).
CharacteristicsEdit
On a geologic map, synclines are recognized as a sequence of rock layers, with the youngest at the fold's center or hinge and with a reverse sequence of the same rock layers on the opposite side of the hinge. If the fold pattern is circular or elongate, the structure is a basin. Folds typically form during crustal deformation as the result of compression that accompanies orogenic mountain building.
Notable examplesEdit
- Powder River Basin, Wyoming, US
- Sideling Hill roadcut along Interstate 68 in western Maryland, US, where the Rockwell Formation and overlying Purslane Sandstone are exposed
- Forêt de Saou syncline in Saou, France
- Southland Syncline in the southeastern corner of the South Island of New Zealand, including The Catlins and the Hokonui Hills
- Strathmore Syncline, Scotland
- Wilpena Pound, Flinders Ranges, South Australia
- Fort Valley, Shenandoah County, Virginia
- Hondo Syncline in the Picuris Mountains of New Mexico, an example of an overturned syncline<ref>Template:Cite journal</ref>
- Afikpo syncline, Nigeria
GalleryEdit
- Sideling Hill cut MD1.jpg
Syncline exposed in Sideling Hill roadcut
- Provo Canyon syncline.jpg
Snow-dusted syncline in Provo Canyon, Utah
- Syncline.JPG
Road cut near Fort Davis, Texas showing a syncline
- Rainbow Basin.JPG
Rainbow Basin Syncline in the Barstow Formation near Barstow, California
- SynclineCalico.JPG
Syncline in the lower parking lot of Calico Ghost Town; the ductile folding is at the base and the brittle is above.
- Roundtop Hill outcrop1.jpg
Synclinal fold in Silurian Wills Creek Formation or Bloomsburg Formation at Roundtop Hill (Maryland)
- Bear Valley east wall.jpg
East wall of Bear Valley Strip Mine, near Shamokin, Pennsylvania
- Upheaval Syncline campsite.jpg
Syncline in Navajo Sandstone, Upheaval Dome, Canyonlands National Park, Utah
- The Catlins.jpg
Satellite view of part of New Zealand's Southland Syncline, showing parallel folds running northwest–southeast
- Wilpena Pound - Aerial View.jpg
Wilpena Pound, a synclinal basin in the Flinders Ranges of South Australia