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 1835 deposits were unfruitful for correlations, as this eruption buried all previous sequences over an erosional unconformity
and therefore offer the only information that all other deposits are older.
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.