The application of X-ray and thermoanalytical techniques to the mineralogical analysis of an interbasaltic horizon

The use of XRD as a diagnostic technique for deeply weathered samples (8) suggested the occurrence of gibbsite and geothite, the presence of cristobalite and lepidocrocite was not recognized and the presence of chlorite was highly questionable. The XRD traces in this study give sparse observations and background interference from the high iron concentration of the samples let to difficulties in interpretation of the minerals.The use of thermoanalytical techniques produced the mineral assembly: gibbsite, lepidocrocite, goethite, kaolinite, cristobalite, and possibly chlorite. It has brought to light the factors such as pretreatment, texture of the sample, sample:diluent ratio and heating rate, must be carefully considered when mineralogical identification of these type of deeply weathered samples is undertaken by the methods studied.