Derry, LA, JC Pett-Ridge, AC Kurtz, and JW Troester. 2006. Ge/Si and sr-87/Sr-86 tracers of weathering reactions and hydrologic pathways in a tropical granitoid system. Journal of Geochemical Exploration 88 (1-3) (JAN-MAR): 271-4.
Ge/Si and 87Sr/86Sr data from primary and secondary minerals, soil waters, and stream waters in a tropical granitoid catchment
quantitatively reflect mineral alteration reactions that occur at different levels within the bedrock–saprolite–soil zone. Near the
bedrock–saprolite interface, plagioclase to kaolinite reaction yields low Ge/Si and 87Sr/86Sr. Higher in the regolith column,
biotite weathering and kaolinite dissolution drive Ge/Si and 87Sr/86Sr to high values. Data from streams at base flow sample the
bedrock–saprolite interface zone, while at high discharge solutes are derived from upper saprolite–soil zone. Coupled Ge/Si and
87Sr/86Sr can be effective tools for quantifying the importance of specific weathering reactions, and for geochemical hydrograph