FTIR spectroscopy, widely used for measuring trace OH in nominally anhydrous minerals (NAMs), requires accurate crystal orientation for precise OH content determination. Current strategies—pre-orienting crystals or taking multiple measurements on random orientations—are time-consuming, sometimes unfeasible, or assume random crystal orientation, which is often untrue for important NAMs like olivine in deformed mantle peridotites. We present a novel method to determine olivine crystallographic orientation using FTIR. Unlike previous approaches (e.g. Asimov et al. 2006), our method uses a single frequency within the silicate overtone region, measured at various angles to the polarizer. Our preliminary tests, considering factors such as the number of measurements at different angles, minimization algorithms, and accuracy, reveal that this method can significantly enhance the precision and efficiency of crystal orientation determination using FTIR. This advancement holds potential for broader application in mineralogical studies, improving the precision of OH content measurements.

Government of the Principality of Asturias and the Foundation for the Promotion of Applied Research in Asturias (FICYT) (grant SV-PA-21-AYUD/2021/57163) under the Asturias Plan for Science, Technology and Innovation 2018-2022 (PCTI-Asturias).

Póster presentado en The 7th Orogenic Lherzolite Meeting, del 30 de septiembre al 6 de octubre de 2024, celebrado en Oviedo (España)

Peer reviewed