Fig. 6 Scanning electron microscopy–energy-dispersive x-ray analyzer analyses from biotite weathering products in M2 saprolite. (A) Qualitative chemical analysis of prismatic weathering products in coating sites (same site as in Fig. 5, Photo 2); (B) Qualitative chemical analysis of prismatic weathering products perpendicular to 001 planes in kaolinite and gibbsite pseudomorph after biotite (same material as in Fig. 5, Photo 4)