Diagenetic history and provenance of Devonian terrestrial sandstones at the margin of Gondwana: Padeha Formation, Eastern Alborz, Iran

Abstract The northern margin of Gondwana in Iran rifted in the Devonian, forming a passive continental margin to the Paleotethys Ocean, the details of which are obscured by later collision. A record of the early phase of opening of Paleotethys is preserved in the 600-m thick Padeha Formation, a Middle Devonian terrestrial rift basin succession. The sandstones are quartz arenite, sub-arkose and arkose and contain minimal detrital matrix (∼1%). Bulk-rock geochemistry, according to major elements, suggests a source to the sandstones that was dominated by I-type granite, but also, based on trace elements, included small amounts of intermediate or mafic rocks. Low Zr and HREE contents suggest little or no sandstone in the source area and thus low abundance of fine-grained heavy minerals (