The problem is compounded by the failure to interpret some of the data reported in the paper (e.g., 13 C-enrichment of calcite) and the failure to discuss relevant information reported elsewhere (e.g., the reducing character of gases trapped in fluid inclusions). For a number of postulated processes rational models are not proposed (e.g., the transport of Mg from Amargosa Desert springs to Yucca Mountain secondary calcite). Although a number of partial models, addressing separate aspects of the data, are proposed in the paper, many of these models are problematic, ranging from ambiguous (e.g., the linkage of the Mg oscillatory zonation of calcite with climate) to unjustifiable (e.g., the interpretation of the δD water data as an indicator of the meteoric character of mineral forming fluids). Our evaluation of the paper by Wilson and others has identified a serious problem, the absence of a rational explanation for the origin of the Yucca Mountain secondary minerals. We critically evaluate the data and interpretations reported in the paper. A phenomenological model envisaging the deposition of secondary minerals by meteoric fluids infiltrating downward though the vadose zone was proposed in the paper " Origin, timing, and temperature of secondary calcite–silica mineral formation at Yucca Mountain, Nevada " by N. Mineralogical, isotopic and fluid inclusion studies have been carried out in order to determine the origin of these minerals as well as the physico-chemical parameters of aqueous fluids that deposited them. Hydrogenic secondary minerals from the vadose zone of Yucca Mountain are being studied as paleohydrogeological indicators. For licensure purposes an adequate treatment of the issue will require detailed paleohydrogeological information. A reliable assessment of the future performance of the repository will necessarily be a licensing issue. – In advance of a licensing proceeding to be conducted by the United States Nuclear Regulatory Commission in 2004-2007, Yucca Mountain in southern Nevada continues to be evaluated as a potential site for the construction of a facility for the geological disposal of high-level nuclear waste and spent nuclear fuel.
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