Meteoric water flushing

Presently, in the view of numerous subsequent studies, (i.e., Hitchon and Friedman 1969 Kharaka et al. 1974 Banner et al. 1989 Connolly et al. 1990 Stueber and Walter 1991), it is obvious that basin subsurface waters have complicated histories and frequently are mixtures of waters with different origins. As was proposed by Knauth and Beeunas (1986) and Knauth (1988), formation waters in sedimentary basins may not require complete flushing by meteoric water, but instead can result from mixing between meteoric water and the remnants of original connate waters. 

Small secondary pores are frequent in feldspars of modem sediments (Passaretti and Eslinger, 1987 Brantley et al., 1999). Additional dissolution of detrital feldspars proceeds through the earliest stages of diagenesis (Milliken, 1988). Sandstones flushed with large quantities of meteoric water are especially prone to loss of feldspars through dissolution (Mathisen, 1984). 

At shallow depths carbonate cements may cause sands to become brittle and hard. Carbonate which precipitates on the sea floor may also form hard grounds in dominantly clastic sequences. Sandstones may become calcite cemented due to dissolution of biogenic aragonite at relatively shallow depth (less than a few hundred meters). Calcareous sediments flushed by meteoric water at shallow depth or exposed during regression may become rapidly ce-... 

On a regional scale, there is an apparent correlation between the extent of mixing and the gross permeability of individual units. For example, Mississippian units and the Sawtooth Formation have a relatively high permeability as compared to the Bow Island Formation. Indications from the SD data (Fig. 10) are that these deeper units also have a higher proportion of meteoric water. Thus, it appears that the pattern of basin flushing depends upon the broad-scale features of hydraulic conductivity. The higher conductivity elements of the flow system represent pathways for initial and continued introduction of meteoric water to the basin. 

Wilmoth, B.M. (1972) Salty groundwater and meteoric flushing of contaminated aquifers in West Virginia. Ground Water 10, 99-105. 

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