Geology Reference
In-Depth Information
Fig. 1
Administrative
subdivision of Doukkala-Abda
region showing the locations of
the geosites described in the paper
coastline; but is absent in the southern part of the area near
Abda; (3) A belt of unconsolidated coastal dunes along the
coastal strip; and (4) the fossil escarpments, especially
dominating in the south-west part, that were formed during
numerous hydrodynamic cycles (Ouadia
1998
).
The region also displays a wealth of karst landforms, the
products of its geology, geography and climate and the
prevailing, hydrological conditions. Karst topography,
limestone pavements, caves, sinkholes, and uvalas (a col-
lection of multiple smaller individual sinkholes that coalesce
into a compound sinkhole) are all represented. From the
geological point of view, the Doukkala-Abda region belongs
to the Coastal Block, de
ned by Michard et al. (
1989
)asa
stable Variscan zone in the coastal part of the western
Moroccan Meseta. The Coastal Block comprises subtabular
Mesozoic and Cenozoic formations overlying folded Palae-
ozoic rocks, the Mesozoic succession representing the
northern part of the El Jadida-Agadir basin (Bouaouda
2004
). The region as a whole, however, is characterized by a
wide variety of volcanic, sedimentary and metamorphic
rocks that range in age from Precambrian to Miocene, and
the older formations are covered by Plio-Quaternary trans-
gressive deposits (Fig.
2
) (Ferr
é
and Ruhard
1975
; Gigout
1965
; Khatmi
1999
).