protoNorthSea

ProtoNorthSea is a paleo-geographic concept used to describe the early phase of the basin that would evolve into the modern North Sea. It refers to a network of rifted margins and subsiding basins along the northwest European continental shelf during parts of the Mesozoic and earlier, preceding the establishment of the clearly defined North Sea basin in the Cenozoic. The term is not a formal stratigraphic stage, but a way to discuss the pre-basin geometry and sedimentation that set up later aquatic connections and fill.

Geologically, proto-North Sea arrangements are tied to regional crustal extension and basin formation that followed earlier tectonic events in the North Atlantic realm. Through the late Paleozoic to early Mesozoic, regional basins developed as margins pulled apart, with sediments recording shifts between continental, nearshore, and marine conditions. Later, during the Jurassic to Cretaceous, continued subsidence and sea-level fluctuations contributed to the establishment of a more continuous seaway that would become the modern North Sea. The area also hosts a variety of petroleum-relevant sequences, including thick marine and deltaic deposits and, on some margins, evaporitic units associated with surrounding basins.

Research on protoNorthSea helps explain the prelude to current hydrocarbon systems, paleogeographic connections to the Atlantic, and the evolution of sediment routing into the central North Sea region. It is mainly used in regional syntheses and sequence-stratigraphic frameworks, rather than as a formal stage in the geological timescale. Doggerland—a later land connection during glacials—exists in a different temporal context but is often discussed alongside discussions of the North Sea’s ancient geography.

See also: North Sea, Doggerland, NW Europe geology.