More than three decades after Norway opened parts of the Norwegian Sea to petroleum exploration, potentially significant oil and gas resources remain hidden beneath thick layers of volcanic rock. Now, advances in exploration technology and renewed industry interest could bring one of Europe's least explored offshore frontiers back into focus. Norway may still hold substantial undiscovered oil and gas resources in areas that have remained virtually untouched by exploration drilling for more than 30 years. According to the Norwegian Offshore Directorate,…