Fig. 5

Overview field photographs of the Ab-Haji Formation in east-central Iran. a Overview of the Ravar–Abkuh section; view to the east from the top of the Upper Triassic Nayband to the Lower Jurassic Ab-Haji formations; note the conspicuous increase in slope angle at the formational contact caused by a distinct increase in grain size and weathering resistance. b Interbedded siltstones and shales of the uppermost part of the Ab-Haji Formation are overlain by the ammonite-rich marls and limestones of Badamu Formation (Ravar–Abkuh section). View is to the west. c Sharp, erosional contact of the fine-grained siltstones and sandstones of the Nayband Formation and coarse-grained sandstones of the Ab-Haji Formation (Zarand–Chenaruyeh section). View to the east. d Overview of the Zarand–Eshkeli section; view to the south from the top of the Upper Triassic Nayband to the Lower Jurassic Ab-Haji formations. At the top, fluvial, coal-bearing strata of the Hojedk Formation are underlain by limestones and marls of the Badamu Formation