Antecline (PSF).png

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.[1] 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).


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 examples

  • 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
  • The 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


See also


  1. ^ Synclinorium. (2008). In Encyclopædia Britannica. Retrieved May 03, 2008, from Encyclopædia Britannica Online:

Media files used on this page

Antecline (PSF).png
line art drawing of an anticline.
Syncline exposed in the lower parking lot of Calico Ghost Town near Barstow, California.
Provo Canyon syncline.jpg
Snow-dusted syncline in Provo Canyon, Utah
The Catlins.jpg
This satellite image shows the Catlins, a region in the southeast of New Zealand's South Island, after a severe blizzard hit the island in July 2003. The dark green areas are forested, while most of the light green and yellow areas are farmed. White patches are covered in snow.
WikiProject Geology.svg
Author/Creator: unknown, Licence: CC BY-SA 2.5
Upheaval Syncline campsite.jpg
en:Syncline in Navajo Sandstone visible from the Syncline Campsite on the northwest side of Upheaval Dome, Canyonlands National Park, Utah, facing south. May 2002.
(c) EricandHolli at the English-language Wikipedia, CC-BY-SA-3.0
Syncline in a road cut-out near Ft. Davis, TX
Sideling Hill cut MD1.jpg
Author/Creator: Acroterion, Licence: CC BY-SA 3.0
The Sideling Hill syncline as exposed in the Interstate 68 roadcut to the west of Hancock, Maryland, USA, from the en:Victor Cushwa Memorial Bridge
Rainbow Basin.JPG
Rainbow Basin Syncline near Barstow, California.
Bear Valley east wall.jpg
View of the east wall of Bear Valley Strip Mine from the Whaleback. 2008.