AOAC SPADA Meeting

Soil profile includes the Picacho inceptisol that is underlaid by 4 ‐ 8 m of saprolite

One of the fastest weathering granodiorite in  the world.  Forms a unique soil profile  Quick percolation so a well drained soil

Granodiorite exposed road cut demonstrates that bedrock undergoes spheroidal  weathering to saprock

Bedrock Minerals: Quartz (20‐24%) Plagioclase (50%) Biotite (9%)  Hornblende (6%) K‐feldspar (2%) Fe, Ti oxides (2%) Apatite (0.6%)

Saprolite Minerals: Mica Iron oxides – Goethite and Hematite Halloysite Kaolinite Quartz

Saprock (Cr)

White et al. 1998; Buss et al., 2008