Title: Nb-Ta fractionation in peraluminous granites: A marker of the magmatic-hydrothermal transition
Abstract: Research Article| March 01, 2016 Nb-Ta fractionation in peraluminous granites: A marker of the magmatic-hydrothermal transition Christophe Ballouard; Christophe Ballouard 1Géosciences Rennes, UMR CNRS 6118, OSUR, Université Rennes 1, 35042 Rennes Cedex, France Search for other works by this author on: GSW Google Scholar Marc Poujol; Marc Poujol 1Géosciences Rennes, UMR CNRS 6118, OSUR, Université Rennes 1, 35042 Rennes Cedex, France Search for other works by this author on: GSW Google Scholar Philippe Boulvais; Philippe Boulvais 1Géosciences Rennes, UMR CNRS 6118, OSUR, Université Rennes 1, 35042 Rennes Cedex, France Search for other works by this author on: GSW Google Scholar Yannick Branquet; Yannick Branquet 1Géosciences Rennes, UMR CNRS 6118, OSUR, Université Rennes 1, 35042 Rennes Cedex, France2Institut des Sciences de la Terre d’Orléans (ISTO), UMR 6113 CNRS, Université d’Orléans, BRGM, Campus Géosciences, 1A rue de Férollerie, F-45071 Orléans Cedex 2, France Search for other works by this author on: GSW Google Scholar Romain Tartèse; Romain Tartèse 3Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Muséum National d’Histoire Naturelle, Sorbonne Universités, CNRS, UPMC, IRD, 75005 Paris, France4Department of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK Search for other works by this author on: GSW Google Scholar Jean-Louis Vigneresse Jean-Louis Vigneresse 5Université de Lorraine, UMR 7539 GéoRessources, BP 23, F-54501 Vandoeuvre Cedex, France Search for other works by this author on: GSW Google Scholar Geology (2016) 44 (3): 231–234. https://doi.org/10.1130/G37475.1 Article history received: 29 Oct 2015 rev-recd: 26 Jan 2016 accepted: 27 Jan 2016 first online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Christophe Ballouard, Marc Poujol, Philippe Boulvais, Yannick Branquet, Romain Tartèse, Jean-Louis Vigneresse; Nb-Ta fractionation in peraluminous granites: A marker of the magmatic-hydrothermal transition. Geology 2016;; 44 (3): 231–234. doi: https://doi.org/10.1130/G37475.1 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 In their late stages of evolution, peraluminous granitic melts exsolve large amounts of fluids which can modify the chemical composition of granitic whole-rock samples. The niobium/tantalum (Nb/Ta) ratio is expected to decrease during the magmatic differentiation of granitic melts, but the behavior of both elements at the magmatic-hydrothermal transition remains unclear. Using a compilation of whole-rock geochemical data available in the literature, we demonstrate that fractional crystallization alone is not sufficient to explain the distribution of Nb-Ta in most peraluminous granites. However, we notice that most of the granitic samples displaying evidence of interactions with fluids have Nb/Ta < 5. We propose that the decrease of the Nb/Ta ratio in evolved melts is the consequence of both fractional crystallization and sub-solidus hydrothermal alteration. We suggest that the Nb/Ta value of ∼5 fingerprints the magmatic-hydrothermal transition in peraluminous granites. Furthermore, a Nb/Ta ratio of ∼5 appears to be a good marker to discriminate mineralized from barren peraluminous granites. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.