Skip to Main content Skip to Navigation
Conference papers

Nitrogen determination in micas of metamorphic rocks

Abstract : Micas are minerals that provide large amounts of information regarding geological processes, because of the sensitivity of their chemical composition to temperature, pressure and deformation of rocks in which they form. Rocks under analysis are formed of different minerals with variable grain size. Mica grain size may vary between 5 and 10 μm and approximately correspond to the chemical formula (Si3.2Al0.8)O10(Al1.9Fe0.05Mg0.1)(OH)2(K0.75Na0.05), being distinguishable from other minerals because of their composition and their morphology in secondary electron images and specially backscattered electron (BSE) images. NH4, when present, would partially substitute K in the previous formula. In some cases NH4-rich micas (tobelites) have been described coexisting with the corresponding K-rich micas, but the actual NH4 content of normal K-rich micas is still unknown. Low N content makes necessary to use nuclear reactions such as 14N(d, pγ)15N at 1.4 MeV and its cascade of intense γ-rays. For the quantification and localization of nitrogen on the surface of the samples, PIGE analysis was carried out in the vacuum microprobe line of the CNA, together with simultaneous micro-RBS and micro-PIXE analyses, giving a more comprehensive picture of sample structure and composition.
Complete list of metadata
Contributor : Dominique Girod Connect in order to contact the contributor
Submitted on : Thursday, September 7, 2006 - 11:44:24 AM
Last modification on : Monday, March 28, 2022 - 10:44:05 AM

Links full text




F.J. Ager, M.P. Mata, M.D. ynsa, M.A. Respaldiza, B. Goffé, et al.. Nitrogen determination in micas of metamorphic rocks. Seventeenth International Conference on Ion Beam Analysis, Jun 2005, Séville, Spain. pp.642-645, ⟨10.1016/j.nimb.2006.03.072⟩. ⟨in2p3-00091797⟩



Record views