Geology of the Lower Triassic Jakabhegy Sandstone Formation, Hungary, SE Transdanubia

Abstract

The Jakabhegy Sandstone Formation, known for a long time at surface in the western part of the Mecsek Mts, SE Transdanubia, was encountered by several boreholes in the second half of the 20th century in a large part of SE Transdanubia, during exploration for uranium ore in the Upper Permian formations in its subcrop. The formation is made up of five informal lithologic units, from the base upward the main conglomerate, the gravelly sandstone, the pale sandstone with conglomerate 2 at its base, then the red-brown siltstone and sandstone and at the top the variegated sandstone (units a, b, c, d, e). Grain size becomes finer upsection, the grains are medium-rounded, and sorting generally improves upward. Planar cross-bedding of varying size is characteristic. The Jakabhegy Sandstone Formation occurs in two types of development. In the case of complete development, all the lithologic units are present, but the lower two (a+b) do not overlap the Late Permian-Early Triassic Kővagoszőlős Sandston...