عنوان مقاله [English]
نویسندگان [English]چکیده [English]
In this research, petrography and geochemistry of the sandstones of Padeha Formation (Early-Middle Devonian) in Asu section, 40 km eastern Gonabad, located in Lut Block have been studied. In this section, the thickness of Padeha Formation is 210 m which is composed of siliclastic rocks. After field studies, 30 medium-grained sandstone samples were selected for point-counting and 10 sandstone samples were selected for geochemical analysis. The results of mineralogical studies show that monocrystalline quartz is the main phase and zircon and tourmaline minerals are the secondary phase. Based on the calculated percentages of point counting data, the composition of these sandstones has been detected as quartzarenites. Petrographical evidence, such as, well rounded monocrystaline quartzs with straight extinction, lacking of plagioclase and ferromagnesian minerals, overgrowth silic cement, existence of rounded zircon and tourmaline imply craton interior and sediment recycling provenance. Moreover, using modal analysis data and (Qm95.5, F0.8, Lt3.6) and (Qt99.1, F0.8, L0) diagrams support this provenance. Based on chemical analysis of 10 samples which were taken from the surface the average SiO2 content is 96.77%, TFeO 0.6% and TiO2 is 0.45%. Based on geochemical data in discriminating tectonic diagrams, Padeha Formation sandstones are deposited on a continental passive margin.