Quantitative Analysen magmatischer Gesteine mittels reflexionsspektroskopischer Infrarot-Messungen

Abstract

The objective of this research is the quantification of modal composition of magmatic rocks using infraredspectra and based on spectral analysis of individual minerals. For that purpose a new, model-based spectralunmixing method was developed. This method is based on thermal infrared reflection spectroscopy at a wave-lenght between 8 - 14 æm since silicates and magmatic rocks show their strongest spectral features(Reststrahlen bands) in this range of the electromagnetic spectrum. Rock samples from the precambrian igne-ous complex Mt. Timna in Southern Israel were analyzed. The samples include different granitoid rocks andone ultrabasic rock unit. This research was part of preparatory investigations to develop new approaches ofdata analysis for a new thermal hyperspectral sensor (ARES) which is scheduled for operation in 2005 by GFZand DLR. Before the modal composition of the magmatic rock samples was quantified, extensive spectral analysis wasperformed to identify and study the spectral behavior of silicates within their original rock context. The mostimportant rock-forming minerals were measured for the first time in thin sections using a microscope and bidi-rectional reflection spectroscopy methods in the thermal infrared. For quantitative mineral analysis a methodwas developed that calculates the correlation of automatically extracted spectral features and chemical com-position or solid solution of different minerals and selects the best suited results ...