Geologic and geophysical data acquired on the northwest European shelf, mainly resulting from the search for oil and gas, reveal a fundamental system of tensional rifts and horsts which form the framework controlling post-Paleozoic deposition. Deep grabens filled with Mesozoic and Tertiary strata can be traced from the northernmost North Sea through the North Netherlands trough into Holland, to link up with the Rhine and Rhone grabens. Another rift system, west of Britain includes the West Scotland, Hebridean, Irish Sea, Celtic Sea, and Western Approaches basins. Similar thick sedimentary basins occur in the Porcupine Seabight and Rockall troughs. Selected geophysical profiles illustrate the basic rift framework. The rift system is considered to be a response to crustal s resses in the northwest European plate, related to the opening of the southern part of the North Atlantic, which began in the Triassic. The Celtic Sea-Hebridean, Porcupine Seabight and Rockall basins represent abortive attempts to extend the spreading ridge northward.

The tensional rifting and faulting of the northwest European shelf control the distribution and facies of the infilling sediments and the location of several of the large oil and gas fields recently discovered in the northern North Sea.

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