QUANTITATIVE-DETERMINATION OF MINERAL ABUNDANCE IN GEOLOGICAL SAMPLESUSING COMBINED CATHODOLUMINESCENCE MICROSCOPY AND IMAGE-ANALYSIS

The abundance of certain mineral phases is often difficult to quantify in rock samples using conventional analytical methods such as polariz ing microscopy, X-ray diffraction or chemical bulk analysis. This is e specially true if samples consist of fine-grained material and/or of m inerals with similar optical or crystallographic properties. The prese nt study shows that high-contrast images of several minerals can be pr oduced using hot-cathode luminescence (CL) microscopy, leading to subs equent quantification by image analysis. Certain minerals can be disti nguished and quantified due to their luminescence properties in sample s of Lower Turonian sandstone (e.g. quartz, feldspar, kaolinite and ca rbonates). The advantages of the method presented are: (1) CL and opti cal microscopy images can be compared directly; (2) the method can be readily automated; and (3) additional information (grain-size distribu tion, roundness, pore space) can be obtained simultaneously using comp uter-aided image analysis.