Rayleigh fractionation of heavy rare earths and yttrium during metamorphic garnet growth

Abstract

Research Article| February 01, 2002 Rayleigh fractionation of heavy rare earths and yttrium during metamorphic garnet growth Juan E. Otamendi; Juan E. Otamendi 1Departamento de Geología, Universidad Nacional de Río Cuarto, 5800 Río Cuarto, Argentina Search for other works by this author on: GSW Google Scholar Jesús D. de la Rosa; Jesús D. de la Rosa 2Departamento de Geología, Universidad de Huelva, 21819 Palos de La Frontera, Spain Search for other works by this author on: GSW Google Scholar Alberto E. Patiño Douce; Alberto E. Patiño Douce 3Department of Geology, University of Georgia, Athens, Georgia 30602, USA Search for other works by this author on: GSW Google Scholar Antonio Castro Antonio Castro 4Departamento de Geología, Universidad de Huelva, 21819 Palos de La Frontera, Spain Search for other works by this author on: GSW Google Scholar Author and Article Information Juan E. Otamendi 1Departamento de Geología, Universidad Nacional de Río Cuarto, 5800 Río Cuarto, Argentina Jesús D. de la Rosa 2Departamento de Geología, Universidad de Huelva, 21819 Palos de La Frontera, Spain Alberto E. Patiño Douce 3Department of Geology, University of Georgia, Athens, Georgia 30602, USA Antonio Castro 4Departamento de Geología, Universidad de Huelva, 21819 Palos de La Frontera, Spain Publisher: Geological Society of America Received: 04 Jun 2001 Revision Received: 01 Oct 2001 Accepted: 24 Oct 2001 First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2002) 30 (2): 159–162. https://doi.org/10.1130/0091-7613(2002)030<0159:RFOHRE>2.0.CO;2 Article history Received: 04 Jun 2001 Revision Received: 01 Oct 2001 Accepted: 24 Oct 2001 First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Juan E. Otamendi, Jesús D. de la Rosa, Alberto E. Patiño Douce, Antonio Castro; Rayleigh fractionation of heavy rare earths and yttrium during metamorphic garnet growth. Geology 2002;; 30 (2): 159–162. doi: https://doi.org/10.1130/0091-7613(2002)030<0159:RFOHRE>2.0.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 We present laser-ablation microprobe inductively coupled–mass spectrometry analyses of Y, Yb, Er, Dy, and Gd in garnet crystals from high-grade metamorphic and migmatitic rocks from the Sierras Pampeanas of Argentina. These rocks contain large garnet porphyroblasts (≥4 mm) that are compositionally zoned. Rare earth element concentrations in the rims are typically one order of magnitude lower than those in the cores. A notable feature of this zonation is the inversion of Yb/Er and Yb/Dy ratios, from >1 in the cores to <1 in the rims. We show quantitatively that the spatial distribution of these trace elements in garnet can be most simply and effectively explained as arising from Rayleigh fractionation during garnet growth. We also analyzed a small garnet crystal (<2 mm) representative of a garnet population that is associated with migmatitic leucosomes. This crystal displays uniformly low concentrations of all trace elements that are virtually identical in both absolute and relative magnitudes to those in the rims of the larger garnet porphyroblasts. The small crystals, and perhaps part of the porphyroblast rims, are likely to be peritectic products of incongruent melting reactions. We argue that melts formed from garnet-bearing sources may generally be unable to equilibrate with metamorphic garnet cores and may thus be more strongly depleted in heavy rare earth elements and Y than modeling based on bulk source-rock abundances of these elements would indicate. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.