Nuclear logging and mineral inversion in sedimentary consequences

The inversion of nuclear-derived chemistry into quantitative mineralogy is considered. The techniques, problems, and philosophy of the inversion process are discussed. The roles of mineral choice and individual mineral composition are shown to be important in estimating an accurate modal mineralogy. Compositional colinearity in which three or more of the phases sought lie on, or close to, the same compositional plane can produce unstable mathematical solutions. The absence of water and carbon dioxide data together with the inability to measure Na and Mg individually contribute additional difficulties to the inversion process. Despite these concerns, a geologically meaningful mineralogy may be produced, though adequate validation of a particular solution still remains