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Syncline identification and geology

A fold in layered rock in which the strata dip inward toward the fold axis from both sides, forming a trough-like shape. In a syncline that has not been overturned, the youngest rocks are found in the core. Synclines and anticlines typically occur together as complementary fold pairs in regions of compressional deformation. Field: structural geology. Example: The Nittany Valley in central Pennsylvania occupies a broad syncline in Paleozoic sedimentary rocks, with resistant sandstone forming ridges on the fold limbs and softer limestone and shale eroded into the valley floor.. Related terms: Anticline, Fold, Trough, Compression.

Sources, scope & corrections

These authoritative resources support category-level nomenclature, terminology, identification methods, and safety. When a specimen-specific safety warning appears, the public-health source listed here directly supports that precaution. They are not line-by-line citations for every other property on this entry, and natural specimens vary.

Editorial owner
GeoMiner
Last updated
2026-03-30T15:19:42.096023+00:00
Review status
Published; not independently peer-reviewed
  • USGS Thesaurus — U.S. Geological Survey. Controlled earth-science terminology used to describe USGS information resources.
  • Glossary of Geologic Terms — U.S. National Park Service. Geologic definitions prepared by the NPS Geologic Resources Inventory.

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Common questions

What does Syncline mean in geology?
A fold in layered rock in which the strata dip inward toward the fold axis from both sides, forming a trough-like shape. In a syncline that has not been overturned, the youngest rocks are found in the core. Synclines and anticlines typically occur together as complementary fold pairs in regions of compressional deformation.
What is an example of Syncline?
The Nittany Valley in central Pennsylvania occupies a broad syncline in Paleozoic sedimentary rocks, with resistant sandstone forming ridges on the fold limbs and softer limestone and shale eroded into the valley floor.
Which earth-science field uses the term Syncline?
Syncline is used in structural geology.
Which terms are related to Syncline?
Related terms in this reference are Anticline, Fold, Trough, Compression.

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