ANR-JC MONA

Emilie JANOTS — 2014-07-29T11:50:41Z

This project is funded by one ANR-JC grant (Mona, 2012). The project started in november 2012 with the recruitment of Alexis Grand'Homme, as PhD student co-supervised with Anne-Magali Seydoux-Guillaume (GET, Toulouse). This project requires a large panel of analytical facilities available in ISTerre, GET, or in other institutes. It implies therefore numerous collaborations in France and other international institutes.

Aims and context

Abstract

Dating hydrothermal mineralization is challenging because most chronometers are commonly reset in open system. Although monazite is rare in hydrothermal deposits, it is very attractive to date mineralization because it has a very robust isotopic system (U-Th-Pb) that retains the age of its precipitation. In presence of successive fluid circulations, monazite (re)crystallizes sporadically. Growth episodes are identifiable from zoning in trace elements composition (REE+Y, Th, U and Pb). Using in-situ high resolution techniques (spot size 5µm), it is possible to date these distinct domains and to obtain the age of the successive mineralization stages. In monazite taken from Alpine clefts (Central Alps), preliminary SIMS U-Th-Pb dating gave very promising results. Results show that Miocene monazite can be dated with a resolution of 0.2 Ma. Within a single grain, it is possible to distinguish episodic growth stages separated by an interval <2Ma. Furthermore, monazite is zoned with extreme trace elements fractionation (Th/U up to 600), which remains to be understood.

The aim of this project is to investigate the potential of monazite as chronometer and geochemical tracer of fluid mineralization via detailed characterization of natural samples and hydrothermal experiments. The objectives are two-fold : (1) Obtaining monazite growth ages and growth duration for different areas of the Alps and to link them with the local deformation and exhumation history, (2) trying to understand chemical and isotopic behaviour of the REE+Y, Th, U and Pb during monazite/fluid interaction.

Related papers and conference abstract

2014

Papers
Janots E., Rubatto D., (2014). U-Th-Pb dating of collision in the external Alpine domains (Urseren zone, Switzerland) using low temperature allanite and monazite. Lithos, 184-187, 155-166

Conference Abstracts
Emilie Janots, Edwin Gnos, Alfons Berger, and Martin Whitehouse ; High spatial resolution dating of hydrothermal monazite from Alpine clefts ; EGU 2014

2013

Papers

Berger A., Gnos E., Janots E., Whitehouse M., Soom M., Frei R., Waight T. E., (2013). Dating brittle tectonic movements with cleft monazite : Fluid-rock interaction and formation of REE minerals. Tectonics, Vol. 321176–1189
De Ascenção guedes R., Meisser N., Janots E., Grand'homme A.*, de Parseval P. et Schaub L. (2013).Thorite, dessauite-(Y), hingganite-(Y) et monazite-(Ce) au Mont-Cenis, Lanslebourg, Savoie. Le Règne Minéral 112
Gnos E., Janots E., Berger A. (2013) Quand les petits deviennent les stars : la monazite. Le cristallier Suisse 2/2013

2012

Papers
Janots E., Berger A., Gnos E., Whitehouse M., Lewin E., Pettke T. (2012). Constraints on fluid evolution during metamorphism from U–Th–Pb systematics in Alpine hydrothermal monazite Chemical Geology 326–327, 61-71

CV

Emilie JANOTS — 2013-01-09T14:52:26Z

Position

2013-2015 : Delegation CNRS between ISTerre and the LMU (Munich)
Since 2009 : Assistant professor, UJF, Grenoble (permanent position)
Responsability : Mineral and rock collections
Teaching : 200 hours/ year
2008-2009 : Junior Professor, University of Münster
Responsability : Hydrothermal laboratory
Teaching : 4 hours weekly
2005-2007 : Post-Doctorat, University of Bern, Switzerland
Project 1 : Petrology and dating of accessory minerals in metasediments from Central Alps
Project 2 : Classification of Omani meteorites

Education

10 juillet 2014 : Habilitation à diriger les recherches/ UGA
Titre : « La redistribution des terres rares lors des interactions fluide/roche, du métamorphisme et de la déformation »
2001-2004 : PhD, funding by the CEA-CNRS, ENS Paris, France
Title : Thermodynamic properties and phase relations of REE-bearing minerals : Stability in natural system and application to waste actinide storage in geologic disposal.
Supervisors : F. Brunet (ENS), B. Goffé (ENS), C. Poinssot (CEA, Saclay)
1999-2001 : Master - ENS Paris, France
Title : Phases relations of apatite LaCa4(PO4)2(SiO4)F and TPD Th4(PO4)4P2O7 under isothermal and thermal gradient conditions
Supervisors : F. Brunet (ENS) & B. Goffé (ENS)

ISTerre - Institut des Sciences de la Terre

ANR-JC MONA

Aims and context

Abstract

Related papers and conference abstract

2014

2013

2012

CV

Position

Education