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The composition, morphology, and distribution of vadose diagenetic features are related to extrinsic and intrinsic factors. Extrinsic factors include the total yearly precipitation, and its seasonal distribution, evapotranspiration, and temperature. These influence the total carbon dioxide supplied, and the relative time during which input (by vadose percolation) and loss (by degassing and evapotranspiration) occur. Intrinsic factors include rock type and composition, porosity and permeability, soil cover, and topography. These influence the rate of water infiltration, and the resulting rate at which descending waters become saturated. The interaction of the two factor groups determines the final character of the zones of vadose diagenesis. There results a land surface-, joint-, or fr cture-related zone beneath which descending waters are generally saturated and little solution occurs. Also a zone exists beneath which pore fluids and gasses are unaffected by degassing or evapotranspiration, and within which vadose precipitational fabrics are confined.

As such, the zone of active vadose diagenesis may constitute only a small part of the total zone of percolation, much of the zone being characterized by fluids which pass through without altering their composition (i.e., causing no diagenetic alteration of rock fabric or mineralogy). Furthermore, because of the high wettability of most carbonate grains (in the absence of adsorbed organics), pores in the zone of slow degassing and high relative humidity may not display "typical" vadose meniscus cements, but may instead display coatings and fills of euhedral crystals. Consequently, the absence of vadose diagenetic features is probably the more common case (without indicating a lack of exposure). As such, periods of exposure may only be patchily recorded by the presence of vadose diagene ic zones.

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