Mineralogy and Geochemistry of the Guenfouda Clay Deposit, Jerada Province, Northeastern Morocco

The Guenfouda clay deposit is located at about 36km to the southwest of Oujda city
and 6km to the south of Guenfouda village. It belongs to the Jerada Province of the
northeastern Morocco and hosted within the Upper Visean calc-alkaline dacite lava
interbedded within a schisto-volcanic complex. This deposit is mined for more than 15
years and the product being mainly used for refractories and industrial ceramics.
This clay deposit is funnel or trough-like in form, narrowing downwards and
display a E–W trend, which follows the major dextral strike-slip fault that passes through
the south of the deposit. Based on mineral assemblages, four lateral alteration zones were
defined from the north to south parts of the deposit: the Illite zone, the Pyrophyllite-illite
zone, the Pyrophyllite zone and the Quartz zone.
The presence of high-temperature minerals such as pyrophyllite, diaspore, the
alteration zonation pattern and the chemical characteristics are diagnostic of hypogene
origin. However, the variation diagrams, Zr vs TiO2 and P2O5 vs SO3 as well as the values
of the chemical Index of Weathering (CIW) and the Alteration Index (AI) revealed a mixed type. It seems that the genesis of Guenfouda clay deposit was first controlled by the eastwest
strike-slip faults, which brought ascending hydrothermal solutions that led to clay
formation and finally, the weathering processes have continued and extended the
argillization.