THE MEDITERRANEAN LOWER CRETACEOUS

Together with the ammonites, the Albian sediments from Tarfaya are also characterized
by concurrent foraminifera zones, as well as by many bivalvs and gastropods.
Their thickness varies between 300 and 820 m, tending to increase from
east to west. The development of the Lower Cretaceous in this basin is characterized
by the numerous intraformational hiatuses. Upwards the Albian sediments
are connected with the Cenomanian ones by means of a gradual transition.
The Agadir-Essaouira (Haha) Basin comprises two sedimentation zones. In the
southern Agadir zone the Lower Cretaceous is very well exposed in the coastal strip
between Arhoud, Tarhazoute and Aourir, north of Agadir.
The Berriasian is represented at its base by limestones and dolomitized limestones
with remains of neritic fauna (oysters, gastropods, algae and bryozoans),
followed upwards by aleuritic marls and clayey limestones with ammonites: Pomeliceras
(M.) broussei (M a z.), Tirnovella occitanica (P i с t.), T. alpillensis (M a z.)
and Spiticeras (К.) damesiforme Djan. (Wiedmann et al., 1978). The foraminifera
are represented by benthonic nodosarids and agglutinated forms of Haplophragmidium,
Dorothia praeoxycona M о u 1 1., Lenticulina nodosa R e u s s, L.
eichenbergi Bart., В г., L. ouachensis S i g. and Vaginulina sp. (Butt, 1982).
The Lower Berriasian carbonates are typical shallow-sea deposits; they contain
calcareous algae, bivalvs, gastropods and neritic foraminifera, which demonstrate
subreefogenic conditions in the inner shelf zone. The upper part of the Berriasian
built of alternation of marls and clayey limestones with ammonites and benthic
foraminifera, is formed under the conditions of the middle shelf area with gradual
increase in the depth (Butt, 1982).
The Valanginian is represented by varied, predominantly aleuritic marls with
Thurmanniceras thurmanii (P i с t., Cam p.), Sarasinella longi (Say n), Olcostephanus
beticus (W i e d m.), oysters, Trigonia, Pinna, corals, brachiopods and
echinoderms. The distribution of the macrobenthos is very uneven, with strong
local fluctuations. The foraminifera are benthic: Vaginulina sp., Lenticulina ouachensis
S i g., L. eichenbergi ! L. guttata, Spirilina neocomiana M о u 1 1., Epistomina caracolla
I E. ornata, etc. (Wiedmann et al., 1978).
The Hauterivian is represented by a thick complex of aleuritic marls and claystones
with a limestone-dolomite formation in the middle part. The Lower Hauterivian
is characterized by Endemoceras noricum (Roe m.), Acanthodiscus vaceki
N e u m., U h 1. and Crioceratites strombecki (Кое п.), typical benthic foraminifera,
such as Planularia crepidularis (Roem.), Dorothia hauteriviana
(M о u 1 1.), Vaginulinopsis sp. Higher up there are Crioceratites duvali L é v., C.
hildesiensis (Кое п.), С. maghrebiensis I m m e 1 and Crioceratites sp., as well
as the first plankton foraminifera (Wiedmann et al., 1978).
The development of dolomites and reef limestones in the middle part of the Hauterivian
sections demonstrates local shallowing.
The Upper Hauterivian is represented by aleuritic marls and claystones with
Pseudothurmannia angulicostata (d'O r b.), Exogyra sp., brachiopods, planktonic
foraminifera, which are associated with benthos forms. The bio- and lithofacies indicate
a relatively deep middle shelf with open sea connections to the northwest
(Butt, 1982).
The Barremian is also represented by aleuritic marls with claystones with Crioceratites
fissicostatus (Roem.), Nicklesia pulchella (d'Orb.), Heteroceras sp.,
Hedbergella sigali M о u 1 1., H. infracretacea (G 1 a e s s п.) and Clavihedbergella
aff. simplex (M о г г.).
The Lower Aptian is represented by dolomite limestones and sandstones containing
Procheloniceras albrechtiaustriae (H о h.) and Deshayesites callidiscus Cas.
Higher up (in the Middle and Upper Aptian) the beds are condensed. Cheloniceras
(E.) martini (d'O r b.), Ammonitoceras sp., Hypacanthoplites nolani S e u п.,
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