Characterization of supergene ore deposits of the Moroccan High Atlas, and (U-Th)/He dating of iron (hydr-)oxides: implications to decipher the causes of weathering processes.

Project: Research

Project Details

Description

The weathering processes transform the physicochemical properties of the
hypogene ores and rocks, and generate the formation of their supergene
homologues, depending on several parameters (climate, nature of the
protolite, geodynamics, …) that are still poorly established. The supergene
ore deposits are mined all over the world, because their ores have
competitive advantages in regard to their hypogene homologues:
enrichment in metals and rare elements, accessibility and ease of mining,
no release of sulfuric acid or heavy metals. However, these mineralizations
are still relatively poorly studied.
This PhD project follows two aims: the characterization of supergene ores of
deposits located in the Moroccan High Atlas, and the (U-Th)/He dating of
iron (hydr-)oxides. For each deposit/occurrence, various observations and
analyses (petrography, mineralogy, geochemistry), on the field and in
several laboratories, will provide 1) an inventory of the various mineral
phases 2) the location of these minerals in the weathering profile, 3) the
timing of formation of these minerals (paragenetic sequences), and 4) the
genetic links between the minerals. This detailed characterization will allow
us to perform (U-Th)/He dating on iron oxy-hydroxides from the studied
deposits. This dating method has been recently applied to supergene
environments, and current studies show promising results. Then, these
results will be compared to ages established by using the 40Ar/39Ar method
on K-rich manganese oxides also associated to weathering. On the High
Atlas scale, these new temporal constraints to the supergene
mineralizations will be major chronologic clues in order to evaluate the roles
of the various parameters in the weathering processes.
Short titleCARACT-ERE POUR SUPERGENES
StatusFinished
Effective start/end date1/10/1631/12/17

Attachment to an Research Institute in UNAMUR

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