Mineralogical evidence for red coloration of sandstones at the Chilgok Formation of the Cretaceous Hayang Group, Southeastern Korea

다국어 초록 (Multilingual Abstract)

The present study was focused on red sandston bedsoccurring in the Chilgok Formation, lower Hayang Group of Cre-taceous age. Red sandstones consist mainly of plagioclase, quartz,and volcanic rock fragment, with accessory minerals such asbiotite, chlorite, pyroxene, hornblende, leucoxene, ilmenite, sphene,pyrite, and hematite. Volcanic rock fragments composed of pyrox-ene, plagioclase, and glass material are intensively altered. Red-dening of sandstones was preferentially attributed to the presenceof hematite, Fe- and Ti-bearing minerals. Hematite pigmentationwas largely caused by post-depositional disolution of Fe-silicatessuch as chlorite, biotite, and amphibole. Diagnostic alteration ofmafic minerals as wel as Ti-bearing minerals, together with clayminerals, indicates that pigmentary materials in the red bedsinherited from diagenetic sources in the depositional basin, possi-bly during early diagenesis.