Illite conversion from smectite

The observed freshening with depth and distance from the prism toe is consistent with enhanced conversion of smectite to illite, driven by increase in... 

Mixed-layered illite/smectites from cores in geologic areas where there has been substantial erosion of the overlying stratigraphic section give no evidence of the conversion of illite interlayers back to smectite. 

The values used for the wt% conversion term in the above equation were estimated from the calculated curves of Surdam and Crossey (1985). The redox calculation was made for acetic and malonic acids, assuming a conversion efficiency for malonic acid equivalent to that reported for the production of oxalic acid. This calculation was applied only to source rocks undergoing the smectite-illite transformation. The potential volume of plagioclase dissolved was calculated using the relationship ... 

The Michigan Basin brines very low pH helps to explain their ability to leach and react with other rocks, as is indicated by their high contents of strontium, barium and other metals, although much of the Sr and Ba probably came from the reaction with calcite. Geothermal water also probably mixed with some of the formations, as indicated by the variable presence of iodine, boron, lithium, cesium, rubidium and other rare metals. With most of the brines, the calcium concentration is somewhat higher than its magnesium equivalent in seawater end liquor from a potash deposit, and the potassium a little lower. Wilson and Long (1993) speculated that this occurred by the conversion of the clays kaolinite and smectite to illite ... 

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