Skip to Main content Skip to Navigation
Theses

THERMOCHRONOLOGIE PAR LA METHODE DES TRACES DE FISSION DANS L'APATITE. APPLICATION AUX MASSIFS DE L'ARGENTERA-MERCANTOUR (ALPES OCCIDENTALES) ET DES JEBILET (MESETA MAROCAINE)

Abstract : In apatite from plutonic and metamorphic rocks Uranium 238 Fission Tracks (FT) recording starts when the temperature decreases below 130°C. They become quantitatively stable under 60-70°C. We have used this property for the study of the cooling history of two hercynian massifs: the Argentera-Mercantour (Western Alpes) and the Jebilet (Moroccan Meseta). The first part of this work displays the present status, applications and limits of FT dating. Results from a calibration work done on three nuclear reactors: Mélusine (CEN-Grenoble), RHF (ILL-Grenoble) and Orphée (CEN-Saclay) is discussed. Sixteen samples collected from a NW-SE transect in the Argentera massif are analysed. Their apatite FT ages shows that the massif started to cool down the 130°C isotherm 10 Ma ago with an apparent denudation rate of about 0.15-0.20 mm/yr, constant between 10 Ma and 2.8 Ma. This rate increases at 0.6±0.1 mm/yr for the SW side and 0.9± 0.2 mm/yr for the NE side between 2.8 and 0.3 Ma. This is in agreement with differential mouvements deduced from the geologic data. In the Jebilet, the 7 samples studied shows concordant FT ages. The beginning of tracks recording, at 186±6 Ma, is in agreement with the age of Central Atlantic rifting. It involves a paleogeothermal gradient, at lower Jurassic, of about 55-60°C/km. The last thermal event recorded on these apatites, at 38±3 Ma, refers to the major atlasic tectonic phase.
Complete list of metadatas

Cited literature [112 references]  Display  Hide  Download

https://tel.archives-ouvertes.fr/tel-00452094
Contributor : Pascale Talour <>
Submitted on : Monday, February 1, 2010 - 2:58:16 PM
Last modification on : Thursday, November 19, 2020 - 3:54:26 PM
Long-term archiving on: : Wednesday, November 30, 2016 - 12:36:59 PM

Identifiers

  • HAL Id : tel-00452094, version 1

Collections

Citation

El Mehdi Mansour. THERMOCHRONOLOGIE PAR LA METHODE DES TRACES DE FISSION DANS L'APATITE. APPLICATION AUX MASSIFS DE L'ARGENTERA-MERCANTOUR (ALPES OCCIDENTALES) ET DES JEBILET (MESETA MAROCAINE). Géologie appliquée. Université Joseph-Fourier - Grenoble I, 1991. Français. ⟨tel-00452094⟩

Share

Metrics

Record views

1746

Files downloads

186