Relations spatiales et génétiques entre uranium, sulfures et matières organiques : application aux shales et schistes noirs

Abstract : In many metallic deposits, especially in sedimentary context and particularly in black shales, spatial or genetic relationships are described between organic matter and metals. Several black shales/schists affected by increasing thermo barometric conditions were selected to study the behavior and fate of uranium from sedimentation to high grade metamorphism. In shallow buried cambro ordovician Alum Shales (Sweden), uranium is dispersed and is not detectable as a particular mineralogical expression. Thermal maturation of the Alum Shales and hydrocarbon generation did not cause any identifiable remobilization of primary concentration, since migrated hydrocarbons did not carry uranium. In contrast, greenschist facies metamorphism associated with the Caledonian orogeny resulted in a re expression of uranium mineralization as uraninite or urano titanate crystals, which may evolve into U Ti Zr Y phospho silicates. In the case of Talvivaara, amphibolite facies metamorphism caused remobilization of synsedimentary uranium and synmetamorphic crystallization, during Svecofennian orogeny at 1880 1870 Ma, of uraninite crystals that are frequently included in carbonaceous nodules. This study shows that uranium, which is preconcentrated during sedimentation, remains immobile in the early stages of burial but is remobilized with increasing PT conditions and crystallizes as uranium oxides and/or uranium (phospho-)silicates
Document type :
Theses
File URL :
http://docnum.univ-lorraine.fr/prive/DDOC_T_2014_0019_LECOMTE.pdf
Complete list of metadatas

https://hal.univ-lorraine.fr/tel-01750677
Contributor : Thèses Ul <>
Submitted on : Thursday, March 29, 2018 - 12:52:20 PM
Last modification on : Friday, April 5, 2019 - 8:21:42 PM

Identifiers

  • HAL Id : tel-01750677, version 1

Citation

Andreï Lecomte. Relations spatiales et génétiques entre uranium, sulfures et matières organiques : application aux shales et schistes noirs. Sciences de la Terre. Université de Lorraine, 2014. Français. ⟨NNT : 2014LORR0019⟩. ⟨tel-01750677⟩

Share

Metrics

Record views

11