Preliminary assessment of the petrology of the Hopeman Sandstone (Permo-Triassic), Moray Firth Basin, Scotland

Abstract

The Hopeman Sandstone is a cross-bedded sandstone of Permo-Triassic age that crops out in coastal exposures in northeastern Scotland. Although the unit has traditionally been interpreted as an aeolian deposit, partly on the assumption of well-sorted, well-rounded quartz sand and lack of micas, no detailed thin-section studies have been published to confirm these conclusions. The following report employs petrographical analysis to quantify the sorting, rounding and mineral composition of the Hopeman Sandstone. Our results indicate that the formation is not as well sorted or well rounded as previously suggested and that it contains significant orthoclase and trace amounts of muscovite, which may suggest that depositional models for at least some facies within the unit need to be revised. This report serves as a preliminary analysis of unusual textural trends across the Hopeman Sandstone and should prompt additional research to further characterize and interpret the sedimentology of the formation.