Geology Reference
In-Depth Information
3.4.1 Footprints Sites Around the Town of El
Bayadh
Around the locality of El Bayadh, three dinosaur track sites
have been found. Two sites (sites 1 and 2) are located 2 km
northeast of El Bayadh, and a third (site 3) 1 km west of that
locality.
Site 1 is located near the road that connects El Bayadh to
the village of Rogassa. At this site, two track levels were
recognized on lumachel limestone slabs of Valanginian age,
in an area of about 1 km
2
. About 100 tridactyl footprints
with clawed digits of theropod dinosaurs forming 12 sepa-
rate trackways were discovered (Figs.
10
and
11
). The tracks
are in a good state of preservation and their average
dimensions are 50 cm in length and 40 cm in width (Fig.
10
).
About twenty half-moon-shaped footprints related to
sauropod dinosaurs, 22 cm in length and 25 in width on
average were also found at this site.
Site 2 is located 500 m east of the site 1 and shows two
track levels on greenish micritic limestone slabs of Valan-
ginian age. About 50 isolated footprints, including about
thirty tridactyl tracks with clawed imprints of small sizes,
and about 40 half-moon-shaped footprints were found
(Fig.
12
).
Site 3 is located 1 km west of locality of El Bayadh, on
the left bank of Oued Merires. In this site, about 10 tridactyl
footprints of theropod dinosaurs were found on the surface
of a steeply dipping limestone slab.
Fig. 9
Prehistoric rupestrian carvings that are the oldest known in
North Africa in the oasis of Tiout
that consist of dolomites and vermicular limestone, whereas
the Upper Triassic strata are composed of 300 m of red
sandstones and conglomerate (red beds formation) (Flandrin
1952
). In the uppermost part of the vermicular limestone of
Middle Triassic there are 2
-
3 m of continental sediments
(
ne-grained quartz sandstones) containing tracks of small
reptiles (Kota
ski et al.
2004
). These footprints were dis-
covered in 1983 preserved on the underside of a small slab
of
ñ
ne-grained grey-yellowish sandstone. A total of 12
footprints were observed with an average length of 2 cm.
The tracks at this site are pentadactyl with the impressions of
four clawed digits in addition to a reverted digit. These
footprints are assigned to Rotodactylus which is regarded as
one of the earliest members of the dinosaur lineage (e.g.
Kota
3.4.2 Ouafeg el Hamra Footprints Site
Ouafeg El Hamra track site is situated 30 km south of the
locality of El Bayadh. The track level is on a steeply dipping
bedding surface of sandstones of the Continental Intercalaire
(Barremian-Aptian-Albian) (Fig.
13
). At least 40 footprints,
including oval-shaped and tridactyl tracks (Figs.
14
and
15
),
are gathered on an area of about 30 m
2
ñ
ski et al.
2004
).
(Mammeri et al.
2009
). The
footprints
are
in an excellent
state of
3.4
El Bayadh Footprints Sites
El Bayadh city is located about 380 km southwest of
Algiers, in Djebel Amour, central Saharan Atlas. The region
of Djebel Amour consists of a series of NE-SW trending
tight anticlines separated by broad
at-bottomed synclines.
The El Bayadh area constitutes one of these synclines with
thick sedimentary layers of Early Cretaceous age. The suc-
cession includes marly limestone formation (Valanginian-
Hauterivian) and predominantly sandstones series (Barre-
mian-Aptian) (Cornet
1952
). In the last 10 years, large
numbers of dinosaur footprints of Early Cretaceous age have
been found around and south of El Bayadh town (Bensalah
et al.
2005
; Mahboubi et al.
2007
; Regagba et al.
2007
;
Bessedik et al.
2008
; Mammeri et al.
2009
). The main sites
are described below.
Fig. 10
Theropod footprint at El Bayadh track site 1
