Epeiric

Epeiric refers to things related to an epeiric sea, an inland or epicontinental sea that forms when sea level rises high enough to cover large portions of continental crust. In such settings, a shallow sea bathes broad areas of a continent rather than existing as a separate ocean basin. The term is primarily used in geology and paleogeography to describe sedimentary environments and paleoenvironments rather than current oceanography.

Geologically, epeiric seas are characterized by their shallow depths and extensive geographic reach across continental interiors. They develop during transgressive episodes when sea level stands above the elevations of a continent, allowing marine conditions to prevail far from true ocean margins. Sedimentary deposits from epeiric seas are often thick and widespread, including limestones, shales, and chalk, and they can yield important fossil and hydrocarbon records. The concept helps explain large, continent-spanning sequences formed in a relatively restricted, inland setting.

Notable historical examples include several Paleozoic and Mesozoic occurrences in North America, Europe, and elsewhere. In North America, the Mississippian to Pennsylvanian periods saw widespread east-to-west epeiric seas, while the Cretaceous period featured the Western Interior Seaway that split the continent. In Europe, the Permian Zechstein Sea and related inland basins are often described as epeiric. Today, the term remains a traditional descriptor for ancient inland seas and is often used alongside or replaced by the broader concept of epicontinental seas in scientific literature.