isopach map

Map of the areal extent and thickness variation of a stratigraphic unit; used in geological exploration for oil and for underground structural analysis.

Related terms:

• lithofacies map
• stratigraphic map
• rate-of-change map
• isofacies map
• residual map
• ratio map
• facies map
• structural contour map
• isolith map
• paleotectonic map