Provenance and Compositional Variance of the Carboniferous Manhang Sandstones, Central Eastern Korea

Abstract

The Carboniferous Manhang sandstones in Mungyeong, Danyang, Samcheog, Jeongseon, and Gangreung coalfields were investigated to examine their composition and provenance. Sandstones are composed mostly of quartz, subordinate rock fragment, and minor heavy minerals and mica. Only sedimentary and low-grade metamorphic rock fragments occur as lithic grains. The provenance was probably composed of sedimentary and low-grade metamorphic rocks as evidenced by modal composition (quartzose to lithic, absence of feldspar), rock fragment types, characteristics of polycrystalline quartz (>25% Qp with >3 crystal units per grain), rounded heavy minerals, and textural inversion. The five coalfields seem to have shared a common provenance based on similar paleocurrent directions, similar modal and chemical composition, and close geographic proximity. The compositional variance between quartzose sandstones in Mungyeong, Jeongseon, and Gangreung coalfields and lithic sandstones in Danyang and Samcheog coalfields seem to have resulted from combination of slightly different source rock types (proportion of sedimentary vs. metamorphic rock) and transport distance.