The southeast is located at the southern rim of the Taurus belt. The geologic units are marginal folds and stable platforms. In the folds are karstified units of Eozene Midyat limestone, underlied by impermeable rocks of the Gercüs unit. At some places carbonates of the Cretaceous Mardin group crop out.
The limestones are karstified, but large caves as in the Taurus belt are rare.