The Permian-Triassic boundary located near Haftad Gholleh is an erosional unconformity
or disconformity, as in other parts of Iran, where Permian sequences contain dolomitic limestone, shale and sandstone situated below the Triassic sequence at a disconformity.
The Athabasca Basin uranium mines produce from deposits that occur at an erosional unconformity
marking the contact of sediments with underlying basement crystalline rocks.
This boundary of erosional unconformity
contains dolomitic limestone and shale and sandstone disconformably located below the Triassic sequence and represents a hiatus of about 10 million years.