noun
- large-scale depressions in the Earth’s crust where thick sequences of sedimentary rocks accumulate over long periods of geological time
Usage: geological term; plural of geosyncline
Examples
- The Appalachian Mountains formed from ancient geosynclines that were later compressed and uplifted.
- Geologists study geosynclines to understand how mountain ranges develop over millions of years.
- Thick layers of limestone and sandstone accumulated in these geosynclines during the Paleozoic Era.
- The theory of geosynclines helped explain the formation of major mountain belts before plate tectonics.
- Marine fossils found in geosynclines indicate these areas were once covered by shallow seas.
- Modern geologists have largely replaced the geosyncline concept with plate tectonic theory.