Daniel Vielzeuf

Axe

nanomatériaux

E-mail

vielzeuf@cinam.univ-mrs.fr

Phone

+33(0)6 62 92 28 41

Fax

+33(0)4 91 41 89 16

Localisation

R3

Grade

DR1

Fonction

chercheur

vielzeuf.jpg

Activité

Pétrologie, Minéralogie, Biominéralogie, Biomatériaux

Thèmes

Scientific Interests (in chronological order) Granulites, Evolution of the continental crust, Pyrenees, Hercynian belt, Exhumation of orogenic peridotites, Theoretical phase relationships, Partial melting in the continental crust, Garnet, Chemical and isotopic heterogeneities in minerals, Oxygen isotopes in garnet, Chemical diffusion in garnet, Solitary waves, Biomineralogy, Red coral

Recherche

Two last fields of interest Calcium diffusivity in garnet: Concentration gradients in calcium are common in metamorphic or magmatic garnets and can be used to determine the timescales of geological processes. However, the kinetics of Ca diffusion in garnet is poorly constrained and experimental studies have to date yielded widely varying diffusion coefficients. In this paper, we describe a new method for generating diffusion profiles in garnet. We incorporated polished and compositionally homogeneous garnet seeds in a finely ground powder of clinopyroxene and garnet. During the experiments (1.3 GPa, 1050-1250°C, and ƒO2 ≤ the graphite-O2 buffer), the mineral powder partially melted, recrystallized, and formed a 10 to 50 µm wide overgrowth zone of compositionally distinct garnet around the seeds. Long duration experiments generated measurable relaxation profiles at these seed/overgrowth interfaces. We performed analytical transmission electron microscope traverses across interface in each experiment. Thirteen usable compositional profiles were obtained with characteristic distances of diffusion ranging from 300 to 1000 nm. From these profiles, Ca-(Fe, Mg) interdiffusion coefficients were retrieved using an analytical solution for the diffusion equation and the data were cast in an Arrhenius relation. Linear regression of the data yields an activation energy Q(Ca-Fe, Mg) equal to 188 ± 48 kJmol-1 and a frequency factor Do equal to 6.6×10-14 m2s-1. Within the compositional range studied, the composition of garnet has no major effect on the Ca-(Fe, Mg) interdiffusion coefficient. The very slow diffusion rate of Ca is in agreement with natural observations indicating that Ca diffuses more slowly than Fe and Mg. The Ca diffusion coefficients derived from this study are not model-dependent and can be used to determine the durations of geological events from Ca relaxation profiles in natural garnets. Nano to macroscale biomineral architecture of red coral: Different techniques have been used to characterize the physical and chemical structure of the red coral calcitic skeleton. A section normal to the axis shows a medullar zone surrounded by a circular domain composed of concentric rings. Growth rings are revealed by the cyclic variation of organic matter (OM) and Mg/Ca ratio. These growth rings are annual; thus, both OM and Mg/Ca ratio can be used to date red coral colonies. Growth rings display wavelets. The internal structure of each wavelet results from the stacking of strata with tortuous interfaces. Tortuosity is due to the presence of micro protuberances. Interfaces between strata may display sharp discontinuities indicative of interruption of the mineralizing process. SEM and TEM studies show that each stratum is made of (i) fibers, organized or not in fan-shaped structures, and (ii) submicron (apparently mono-) crystalline units. Fibers are superstructures made of submicron units possibly assembled by an oriented aggregation mechanism. HRTEM studies show that in spite of displaying single crystal scattering behavior, the submicron crystalline units are made of 2-5 nm nanograins again possibly aggregated by a mechanism of oriented attachment. Thus, sub micron crystalline units and polycrystalline fibers can be both defined as mesocrystals. The red coral skeleton is a hierarchically organized organic-inorganic composite that exhibits porosity, structural and compositional order on length scales from the nm to the macroscale.

Parcours

Employment history - 1978-1980 - Allocataire DGRST - October 1980 - Chargé de recherche de 2ème classe at CNRS - Clermont. - December 1985 - Chargé de recherche de 1ère classe, Clermont. - January 1991 - Directeur de recherche de 2ème classe, Clermont. - October 1998 – Directeur de Recherche de 1ère classe, Clermont - January 2004 - Directeur de Recherche de 1ère classe, Marseille Long stays in foreign countries 1980 : Edinburgh University – Grant Institute, Scotland (3 months) 1984-1985 : Visiting Assistant Professor, Arizona State University, USA (1 year) 1991-1992 : Visiting Associate Professor, Arizona State University (1 year) 1996-1997 – Visiting Professor, Arizona State University (1 year) 2004-2005 – Visiting Professor, CalTech (1 year) 2008 - Visiting scientist, Caltech (3 months)

Publications


The coordination of sulfur in synthetic and biogenic Mg calcites: The red coral case

J. Perrin, C. Rivard, D. Vielzeuf, D. Laporte, C. Fonquernie, A. Ricolleau, M. Cotte, N. Floquet

Geochimica et Cosmochimica Acta 197 226-244 (2017)

Raman characterization of synthetic magnesian calcites

J. Perrin, D. Vielzeuf, D. Laporte, A. Ricolleau, G.R. Rossman, N. Floquet

American Mineralogist 101 11 2525-2538 (2016)

Thermally Induced Modifications and Phase Transformations of Red Coral Mg-Calcite Skeletons from Infrared Spectroscopy and High Resolution Synchrotron Powder Diffraction Analyses

N. Floquet, D. Vielzeuf, D. Ferry, A. Ricolleau, V. Heresanu, J. Perrin, D. Laporte, A.N. Fitch

Crystal Growth and Design 15 8 3690-3706 (2015)

'Distribution of sulphur and magnesium in the red coral

D. Vielzeuf, J. Garrabou, A. Gagnon, A. Ricolleau, J. Adkins, D. Günther, K. Hametner, J.-L. Devidal, E. Reusser, J. Perrin, N. Floquet

Chemical Geology 355 13-27 (2013)

Ordered Misorientations and Preferential Directions of Growth in Mesocrystalline Red Coral Sclerites

N. Floquet, D. Vielzeuf

Crystal Growth and Design 12 10 4805-4820 (2012)

Mesoscale twinning and crystallographic registers in biominerals

N. Floquet, D. Vielzeuf

American Mineralogist 96 1228-1237 (2011)

Uphill diffusion, zero-flux planes and transient chemical solitary waves in garnet

D. Vielzeuf, A. Saul

Contributions to Mineralogy and Petrology 161 5 683-702 (2011)

Multilevel Modular Mesocrystalline Organization in Red Coral

D. Vielzeuf, N. Floquet, D. Chatain, F. Bonneté, D. Ferry, J. Garrabou, E.M. Stolper

American Mineralogist 95 242-248 (2010)

Titanium in phengite : a geobarometer for high temperature eclogites

E. Auzanneau, M.W. Schmidt, D. Vielzeuf, J.A.D. Connolly

Contributions to Mineralogy and Petrology 159 1 1-24 (2010)

An experimental determination of the effect of bulk composition on phase relationships in metasediments at near-solidus conditions

F. Ferri, S. Poli, D. Vielzeuf

Journal of Petrology 50 5 909-931 (2009)

Nano to macroscale biomineral architecture of red coral (Corallium rubrum)

D. Vielzeuf, J. Garrabou, A. Baronnet, O. Grauby, C. Marschal

American Mineralogist 93 11-12 1799-1815 (2008)

Zoning of phosphorus in igneous olivine

M.S. Milman-barris, J.R. Beckett, M.B. Baker, A.E. Hofmann, Z. Morgan, M.R. Crowley, D. Vielzeuf, E. Stolper

Contributions to Mineralogy and Petrology 155 6 739-765 (2008)

Calcium diffusivity in alumino-silicate garnets : an experimental and ATEM study

D. Vielzeuf, A. Baronnet, A.L. Perchuk, D. Laporte, M.B. Baker

Contributions to Mineralogy and Petrology 154 2 153-170 (2007)

Experimental evidence of decompression melting during exhumation of subducted continental crust

E. Auzanneau, D. Vielzeuf, M.W. Schmidt

Contributions to Mineralogy and Petrology 152 2 125-148 (2006)

SIMS analysis of oxygen isotopes : matrix effects in Fe-Mg-Ca garnets

D. Vielzeuf, M. Champenois, J.W. Valley, F. Brunet, J.L. Devidal

Chemical Geology 223 4 208-226 (2005)

Uphill diffusion and zero flux planes in garnets: an experimental and ATEM study.

D. Vielzeuf, A. Lupulescu, A.L. Perchuk, D. Laporte, A. Baronnet, A. Addad

TMS Letters 2/3 89-90 (2005)