Synclines

Part of speech: noun

Definitions

1. A structural geological feature characterized by a downward arching fold in rock layers, where the youngest rocks are at the core
2. A type of fold that forms when rock layers are compressed and bent downwards, resulting in a trough-like structure
3. An arrangement of strata that dip inward from both sides toward a central axis, forming a concave upward shape in the Earth's crust

Etymology: "Synclines" is the plural of "syncline," a geological term for a fold in rock layers that dips downward, so the youngest strata sit at its core. The word is built from two Greek-derived pieces. The prefix "syn-" means "together" or "with," and "-cline" comes from the Greek "klinein," meaning "to lean" or "to bend." Put together, the name describes layers that lean or bend toward one another, which is exactly what a syncline looks like in cross-section. The opposite structure, an upward arch with the oldest rock at the center, is called an "anticline," built on the same stem with the prefix "anti-" meaning "against" or "opposite." The pair works as a matched set: a syncline and an anticline sit side by side in folded terrain, and geologists often name them together to describe the folding pattern.

Synonyms: folds, valleys