↑ Revenir à Moyens analytiques

Imprimer ce Page

Thermochronologie Traces de Fission

La thermochronologie par les traces de fission dans les cristaux d’apatite est une méthode de reconstitution de l’histoire thermique et des mouvements verticaux des roches des premiers kilomètres de la croûte.

Cette technique est basée sur l’effacement progressif de défauts cristallins lié à la fission naturelle des atomes de 238U pour des températures comprises entre 60 et 110°C. Elle permet de déterminer les paléotempératures dans cette intervalle et de préciser à quelle époque ces températures ont régné.

Nous disposons au sein du laboratoire d’un microscope LEICA DLML muni d’une surplatine à déplacement automatique en X-Y permettant de faciliter la détermination de l’âge traces de fission et d’une chambre à dessin permettant de mesurer la longueur des traces confinées. Le laboratoire dispose en outre du matériel nécessaire pour séparer les cristaux d’apatite (broyeur, tamis, séparation densimétrique et magnétique) et pour la réalisation des montages (polissage).

Projet – EFTAN project

Since the 1970’s when Wagner and co-workers made the first FT analyses on samples from the Alps, there has been a huge increase in the number of fission track studies across Europe with much of the data remaining unpublished or buried in student theses.

At the European FT network (EFTAN) meeting in Lautenbach last in november 2004 it was decided to establish a database of results from these different European studies to facilitate further studies and as an impetus for co-operative research. The data may also be used to compile large-scale summary maps that show sample locations and ages as well as denudation and thermal histories. The database will provide an important resource to support collaborative research proposals between scientists and as well as an aid to future research projects. It will eventually be web-based and accessible to all participants.

A first call has been launched to synthetise all data from published or unpublished sources and 17 laboratories have submitted their data. Published studies have been also added. This preliminary information has been summarised as a map that shows which parts of Europe have FT data. The map has been presented at the Cadiz FT meeting in June 2002.

Members of the EFTAN have decided to make available this first version of that database. Download here the database (PDF format).

Feedback on this table is welcome (error, omission) at jocelyn.barbarand@u-psud.fr.

If you want to participate to this synthesis, please provide for each area studied by fission track the following basic informations :

Lab Name, Contact, Area of study (geographical area, geological unit, country) Mineral used, Number of samples, Method used, i.e. EDM or POP, Length Data Y/N, If data are published: References.

Lien Permanent pour cet article : http://hebergement.u-psud.fr/reliefetbassin/index.php/moyens-analytiques/thermochronologie-traces-de-fission/