Geochemical samples characterization

The following SR methods are useful in characterization of environmental and low temperature geochemical samples. More thorough reviews of some of these SR methods are given in the other chapters in this RiMG volume. 

While a number of techniques are now available for elementary analyses of environmental and geochemical samples, very few can characterize the chemical states of elements in such systems. However, it is obvious that knowledge of the chemical states rather than the mere contents of particular elements is often indispensable for a complete imderstanding of their behaviors and roles in the environment or in the mechanisms of environmental and geochemical processes. 

In both instances, samples of the fluids in the zone are collected at intervals to characterize the nature of geochemical reactions and to track changes over time. 

Backflushing of injected wastes can also be a good way to observe waste/reservoir geochemical interactions. Injected wastes are allowed to backflow (if formation pressure is above the elevation of the wellhead) or are pumped to the surface. Backflowed wastes are sampled periodically (and reinjected when the test is completed) the last sample taken will have had the longest residence time in the injection zone. Keely165 and Keely and Wolf166 describe this technique for characterizing... 

A strong positive correlation exists between Cu, Ag, Co, Au, W, and Se in the B and C horizon soil and suggests that these elements are geochemical pathfinders for sulfide mineralization at the Shiko Lake mineral occurrence. Glacial dispersal of Cu and Co in C horizon soil samples is characterized by the shape of geochemical profiles. These typically... 

Figure 12.1 Map showing locations of sites (squares) used for the soil profiles and boreholes (C and B), and contents of arsenic in the leach fractions of the top layer of the soil profiles. Squares with stars denote samples used for the Pb isotope study other squares are locations of profiles used in a geochemical study (Ayuso, unpublished data). Dashed lines enclose areas containing wells characterized by Lipfert and Reeve (2004) and Lipfert et al. (2007) as containing high-arsenic groundwater (As >1.3 pmol L ), medium arsenic groundwater, and low arsenic groundwater in the Mount Percival recharge area (most wells have <0.13 jimol L-1). Solid line encloses the drainage basin in this study.

VanPut, A. et al., Geochemical characterization of suspended matter and sediment samples from the Elbe River by EPXMA, Water Res., 28, 643, 1994. 

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