Tectonic provenance of the Upper Red Formation sandstonesin the Hesar section, Mahneshan Basin (west Alborz)

The Mahneshan Basin is one of the syntectonic Neogene sub-basins of the Central Iran. The basin is filled by about 4 km of the Miocene Upper Red Formation deposits, showing a combination of halokinetic and growth strata patterns. To assess the provenance evolution of sediments in north of the Mahneshan basin named the Hesar section, we conducted remote sensing mapping, field survey, as well as petrographical and modal analyses of sandstones. Our results reveal that the sandstones are fine to medium-grained sedarenites (Q46F10Rf44) and mainly derived from fine-grained siliciclastics, metamorphic, carbonate, chert and andesitic volcanic rocks, which were exposed in an orogenic tectonic setting (Qm34F10Lt56 and Qt49F10L41). The combination of provenance data and northeastward paleocurrent direction, reflect that the sediments mainly supplied from basement rocks of the Takab Complex and Qom Formation in southwest of Mahneshan Basin. The unchanged provenance of sediments along the studied succession, indicate that regional shortening and uplift of parent rocks has begun before deposition of the Upper Red Formation (Miocene) and continued during deposition of these sediments. This is in agreement with previous age assumption for exhumation of Takab Complex during Oligocene time.