Fig. 3. Thin section micrographs. (A) Richfield dryland Bt2 (38–57 cm). Plasmic fabric is ma-skelsepic, or granostriated. This micrograph shows a biotite grain weathering, a process which releases 2:1 clays. (B) Richfield irrigated Bt2 (35–53 cm). Plasmic fabric is skel-masepic (or parallel striated), with a larger proportion of oriented clay in the matrix as well as coating skeleton grains. Cross-polarized light, long-axis frame length = 665 µm.