Figure 3.
Illustration of porosity types in granitic saprock of the San Jacinto Mountains, California. (A) Joint fractures bound matrix blocks. (B) Joint fractures stained by preferential flow of blue dye tracer; note wetting front in matrix lags behind that in joints (photo credit: S. Frazier). (C) Thin section micrograph (plane light) of saprock matrix showing porosity in blue. Note mesofractures, partially expanded biotite (b), and dissolution-pitted plagioclase (dp). (D) Close-up of outlined area in (C), showing dissolution pitting (dp) following albite twin planes and clay films (cf) lining the mesofracture wall.