Procedures for Petrophysical, Mineralogical and Geochemical Characterization of Fine-Grained Clastic Rocks and Sediments

摘要

The methods result from about four years of study of shales and recent fine-grained muds and are suitable for rapidly processing large numbers of samples cheaply and quickly with very good precision. Density and porosity measurements sufficient to provide good between-sample comparisons of shales with only about 1 or 2% porosity are possible using equipment found in most laboratories providing that attention is given to sources of small errors and suitable immersion fluids are used. Mineralogical composition can be precisely characterized by x-ray diffraction, providing that a careful sample preparation scheme is adhered to. Such precision can be maintained on samples as small as 20mg in size. Elemental analyses are better performed on high-temperature ash remaining after loss-on-ignition than on original whole sample. Complete chemical analyses of major, minor, and many trace elements can be obtained on sample sizes as small as 20mg of ash. Precision afforded by mineralogical and chemical methodology is sufficient to allow merging of data from these two sources for statistical analyses. Presence of significant amounts of x-ray-amorphous mineraloids is now thoroughly documented in recent muds and is possibly present in many shales. (ERA citation 05:000186)