Geology Reference
In-Depth Information
deformed and metamorphosed during the Eburnian Orogeny
(
interest. Four large zones (geozones) of exceptional value
have been selected on the basis of their representativeness
and the diversity of their geological con
2.000 Ma) and the Eburnean magmatic rocks, mostly
granitoids, are considered to be emplaced synchronically
with this tectonometamorphic event (Charlot
1978
).
(2) Several sedimentary (mainly quartzites) and volcanic
sequences of lower to mid-Neoproterozoic age, which are
locally affected by the Pan-African orogeny and intruded by
Pan-African granitoids (known as PII, of ages ranging
between 630 and 550 Ma, Gasquet et al.
2008
). The Pa-
leoproterozoic basement rocks were also heterogeneously
affected by the Panafrican deformations (folds and shear
zones) and metamorphism.
(3) An upper Neoproterozoic (known as PIII) to Paleo-
zoic cover which unconformably overlies the earlier units
(PI and PII). These cover rocks are disposed sub-horizon-
tally, although they are locally affected by Variscan folds.
*
gurations. Their
locations and approximate boundaries are outlined in
Fig.
1
b. Each geozone may include several smaller spots or
geotopes. These four geozones are described below.
3.1
Granite Landforms of Tafraoute, South
of Tafraoute Village (GLT)
The arid and semi-arid landscapes, surrounding Tafraoute
village (Fig.
1
b), are characterized by magni
cent landforms
which are being developed on the Neoproterozoic granitic
pluton of Tafraoute. Also known as the Tafraoute granites,
these intrusive rocks represent the youngest rocks of the Pan-
African episode (549
6 Ma according to Pons et al.
2006
).
While the Tafraoute granites are relatively homogeneous
from the petrologic point of view, their geomorphologic
scope makes them more interesting and famous. Particularly
remarkable are the forms that result from weathering along
joints (Figs.
2
a and
3
c, d), dome-shaped inselbergs (Fig.
3
a,
b) and tafoni. These features resulted from wind and water
weathering. Some of these natural sculptures have become
part of the popular heritage, such as the
±
3
Sites of Significant Geoheritage Value
in the Kerdous Region
The Kerdous massif includes outstanding landscapes which
largely re
ect a variety of geological components. Besides
the contribution of the geology to the design of magni
cent
landscapes, the outcropping rocks in the area and their
intrinsic characteristics comprise a unique record of multiple
processes in the Earth geological evolution. Obviously
because of the prevalence of basement rocks, most (if not
all) existing peer-review international publications devoted
to the Kerdous inlier are dealing with structural, igneous and
metamorphic features and with their geodynamic aspects
(see references in the previous section). These studies evi-
dence that the area is of great local, national and interna-
tional scienti
“
Chapeau de
Nap
s Hat, Fig.
2
b) or the Elephant. A
proof of the relevance of this geozone is the science pro-
motional video by L
ó
leon
”
(Napoleon
'
ning and Geiger (
2005
) on the geology
and geological history of Morocco, in which a section is
dedicated to the Tafraoute granites. A photograph of
“
ü
Napoleon
appears in the video front cover.
Also famous but controversial are the
'
s Hat
”
”
(Painted Rocks or Blue Rocks), a group of granitic small
hills and boulders located at 4 km south of Tafraoute village
(Fig.
3
). In 1984, the Belgian artist Jean Verame lead a
project to spray these landforms with several tonnes of blue,
red, violet and white paint (Fig.
3
b). With time passing, the
“
Roches Peintes
c interest.
As a precursory step in the compilation of a more com-
plete and systematic inventory of the study area, we present
here a
rst list of sites of geological and geomorphological
Fig. 2
Granite landforms.
a
Prismatic shapes resulting from
erosion along the jointed
Tafraoute granite.
b
The
emblematic granitic gure
“
Chapeau de Nap
ó
leon
”
(Napoleon
s hat) in the village of
Aguerd Oudad, 2 km south of
Tafraoute
'
