The oklahoma Geological Survey will prepare a map of the State at a scale of 1:500,000 to show karst terrains and associated environmental problems in Oklahoma. Surface and near-surface carbonates (limestone and dolomite) comprise about 6% of the surface area of the State, whereas sulphates (gypsum and anhydrite) comprise about 4% of the State. Areas of carbonates and sulphates will be differentiated and mapped separately as two zones: in zone 1 they are 0-6 m deep, and in zone 2 they are 6-30 m deep. Areas underlain by bedded salt (halite) within 300 m of the surface comprise 14.6% of the State, and they will be mapped as zone 3.