Staircase 40/Ar39Ar spectra of fine-grained white mica: Timing and duration of deformation and empirical constraints on argon diffusion

Abstract

Research Article| August 01, 1996 Staircase 40/Ar39Ar spectra of fine-grained white mica: Timing and duration of deformation and empirical constraints on argon diffusion David L. Kirschner; David L. Kirschner 1Institut de Minéralogie et Pétrographie, Université de Lausanne, CH-1015 Lausanne, Switzerland Search for other works by this author on: GSW Google Scholar Michael A. Cosca; Michael A. Cosca 1Institut de Minéralogie et Pétrographie, Université de Lausanne, CH-1015 Lausanne, Switzerland Search for other works by this author on: GSW Google Scholar Henri Masson; Henri Masson 1Institut de Minéralogie et Pétrographie, Université de Lausanne, CH-1015 Lausanne, Switzerland Search for other works by this author on: GSW Google Scholar Johannes C. Hunziker Johannes C. Hunziker 1Institut de Minéralogie et Pétrographie, Université de Lausanne, CH-1015 Lausanne, Switzerland Search for other works by this author on: GSW Google Scholar Geology (1996) 24 (8): 747–750. https://doi.org/10.1130/0091-7613(1996)024<0747:SAASOF>2.3.CO;2 Article history first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation David L. Kirschner, Michael A. Cosca, Henri Masson, Johannes C. Hunziker; Staircase 40/Ar39Ar spectra of fine-grained white mica: Timing and duration of deformation and empirical constraints on argon diffusion. Geology 1996;; 24 (8): 747–750. doi: https://doi.org/10.1130/0091-7613(1996)024<0747:SAASOF>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Staircase 40Ar/39Ar spectra of 2 to 6 μm white micas in ductile carbonate mylonites (Morcles-Doldenhorn nappe, Switzerland) record ages between 32 and 13 Ma. These ages are within independent geochronologic and biostratigraphic time limits for the beginning and ending of deformation of this fold-thrust nappe. We interpret these data to record protracted white mica neocrystallization and growth during low-temperature ductile deformation, such that the differences between the maximum and minimum ages in the 40Ar/39Ar spectra record the time span over which mica formed and grew. We have modeled the argon concentrations in these micas, taking into account the thermal history of the nappe, mica growth, and diffusional loss of argon. Our results indicate that available experimental data underestimate the activation energy for argon diffusion in muscovite, and that the retentivity of argon in white mica is greater than generally thought. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.