What is geosyneline theory?

Geosyncline theory is a geological concept that describes large-scale depressions in the Earth's crust where significant sediment accumulation occurs over geologic time. These regions, known as geosynclines, are characterized by thick sequences of sedimentary rocks that can eventually undergo tectonic processes, leading to mountain building, or orogeny. The theory was pivotal in the early understanding of plate tectonics and the formation of mountain ranges, although it has since been largely replaced by more comprehensive models of tectonic activity.