geosynclinal
(noun)
noun
1. (geology) The downward bend or subsidence of the Earth's crust, which permits the gradual accumulation of sediment and hence forms the first step in the formation of a mountain range.
(noun)
1. (geology) The downward bend or subsidence of the Earth's crust, which permits the gradual accumulation of sediment and hence forms the first step in the formation of a mountain range.