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Figure 3. Map showing the distribution of marine sedimentary rocks of Cretaceous and Tertiary ages, plus the study areas and results of evaluation of selenium contamination from the Department of the Interior (DOI) National Irrigation Water Quality Program (Seiler et al, 1999). Some of these marine rocks contain high total organic carbon and high trace element content. For example, see figure 4 which shows a subsurface perspective of the Tertiary marine rocks in part of California. Geology from King and Beikman (1974). |
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