Compaction and cementation control on bleaching in Triassic fluvial red beds, S-Germany

This study focusses on bleaching phenomena the pore scale in an Olenekian (Upper Buntsandstein) sandstone quarry. The area exposes a 10 m thick red body with up to cm-sized, greyish-white laminae sandstones. Analyses focus bleached and unbleached zones same cm-sized samples. Bleached show larger grain size (by 27 μm), less compaction higher porosity 3 %). They also exhibit stronger cementation by all observed authigenic phases of quartz, illite, K-feldspar minor extent dolomite. Calculated intergranular volumes cementational loss correlate positively bleaching. Meanwhile contain more ductile grains (e.g. micas, detrital clay, rock fragments like phyllites plutonic fragments) are affected major via compaction. Bleaching is related primary features size-selective lamination associated permeability coarse-grained laminae. It reliant onto early framework stabilising cement phase, which keeps pathways open for uplift-related leaching detritus few dolomite cements.