Mapping of an ophiolite complex by high-resolution visibleinfrared spectrometry

Abstract

The Sumail massif of the Oman peridotite has been surveyed by the high spectral resolution imager HyMap. The field measurements have been taken simultaneously to the HyMap campaign with a GER 3700 spectrometer. To compare the two data sets, further calibration and a t mospheric correction are made through empirical line corrections. A continuum removal by a modified Gaussian model on reflectance is then performed for each pixel to minimize atmospheric scattering and shadowing effects. Classification from spectral dista n ce is established using field observations and comparisons at full spectral resolution to identify peridotite subunits (harzburgites and dunites) and to distinguish plagioclase-wehrlites from gabbros. Detections of hydrothermal transformations of olivine i n serpentines and their alteration in carbonates along fracture networks, characterized by narrow spectral signatures, validate the classification. This demonstrates the utility of the high spectral resolution and the development of appropriate processing methods for geological identifications.