GEOLOGICA CARPATHICA, FEBRUARY 2007, 58, 1, 3—18
www.geologicacarpathica.sk
Introduction
The Ghadames Basin (Fig. 1) is a large intracratonic basin
on the North African Platform, with NE-SW lineaments it
extends over three countries: Hamadah al Hamra of NW
Libya, southern Tunisia and east-central Algeria; formed
during Early Paleozoic times. This platform has under-
gone a complex and polyphase history. Its effect on the
Ghadames Basin has been the production of a series of
fault-bounded structural highs surroundings a central de-
pression.
The basin is bounded by the Amguid El Abiod Uplift in
Algeria in the West, by the Hoggar Massif in Algeria in the
South, and the Qarqaf Arch in Libya, and by the Nefusah
and Dahar Uplifts in the North. To the east the basin wedges
out beneath the western part of the Sirt Basin (Fig. 1).
These main tectonic elements have undergone a complex
history beginning during the Late Precambrian Pan-African
orogeny, and continuing throughout the Phanerozoic with
repeated reactivation of older structures. The current archi-
tecture of the Ghadames Basin is the result of successive ef-
fects by several unconformities including intra/Ordovician,
Late Silurian (Caledonian), Carboniferous-Permian (Her-
cynian), Early Cretaceous (Austrian), Late Senonian (Lara-
mide), Late Eocene (Illyrian) and Early Oligocene
(Pyrennean) phases (illustrated in the stratigraphic column
Fig. 2). This complex evolution can be summarized in three
main stages:
Upper Jurassic—Lower Paleogene lithostratigraphy and facies
development in the Al Hamadah al Hamra area (Libya)
YOUSEF M. SHIREF
1
and
JOSEPH SALAJ
2
1
Charles University in Praque, Faculty of Science, Institute of Hydrogeology, Engineering Geology and Applied Geophysics, Albertov 6,
128 43 Praha 2, Czech Republic; y_shiref@yahoo.com
2
Geological Institute, Slovak Academy of Sciences, Dúbravská cesta 9, P.O. BOX 106, 840 05 Bratislava, Slovak Republic
(Manuscript received March 7, 2006; accepted in revised form June 22, 2006)
Abstract: The 1
st
sedimentary complex of the Triassic to Upper Jurassic (up to Oxfordian) was deposited after long
continental period of the uppermost Permian to lowermost Triassic ( = about 8 Myr). This large sedimentary complex is
divided by three hiatuses; two of them short only situated in the Upper Triassic sediments and by one long, corresponding
to the Upper Jurassic—Barremian. After sedimentation of the continental Aptian to Albian strata of the Kiklah Formation, a
new large Cenomanian to Eocene shallow marine sedimentary cycle with many gypsum lagoonal passages was deposited.
They are represented by the Qasr Tigrinnah Member (Upper Turonian—Coniacian) and the Thala Member (Santonian to
Upper Campanian). On the top of the Thala Member a hardground formed under arid conditions of sedimentation. The
Upper Campanian/Maastrichtian Al Gharbiyah Formation was deposited in warm but humid conditions confirmed by the
Fe-oxides and glauconitic levels. The Al Gharbiyah Formation with three neritic Members: the Bi’r Bu al Ghurab, the Lawdh
Allaq (alternating with the Bi’r Az Zamilah Pelagic Member) and the Tar Member is represented and situated below the
Upper Paleocene Tabaqah Formation, a new name. The boundary between the Maastrichtian and Danian is defined by last
occurrence of Omphalocyclus macroporus Lamarck and by appearance of the Postrugoglobigerina daubjergensis
(Broennimann) and Eoglobigerina danica (Bang). The Shurfah Formation is represented at its base by lagoonal sediments,
higher up by pelagic chalky limestones and by the neritic Ammur Limestones at the top. The Kheir Formation and Gir
Formation of the Ypresian and the Gedari Formation of the Lutetian are proved by planktonic foraminifers.
Key words: Libya, Ghadames Basin, Jurassic—Paleogene, paleogeography, biostratigraphy, foraminifers.
1. The Hercynian orogeny of the North African Platform
resulted in one large subsiding depositional basin, dis-
playing little regional differentiation, and formed through
reactivation of the Pan-African fault system (Van de We-
erd & Ware 1994).
2. Uplift and erosion of the basin during the Hercynian
phase resulted in large parts of the Paleozoic section being
removed in most areas.
3. Subsequently there was an episode of north-west tilt-
ing, resulting in the superimposition of a Mesozoic exten-
sional basin on the eroded remains of the Paleozoic basin
(Van de Weerd & Ware 1994; Echikh 1998).
They represent different types of depositional environ-
ments ranging from continental to transitonal and marine
facies. Most of the Paleozoic sequence is thick in the cen-
ter of the Ghadames Basin and thins gradually towards the
southern edge of the basin which flanks (the Qarqaf Arch)
and provided viable evidence of the existence of this arch
as a positive feature throughout Paleozoic time. The se-
quence consists of thick sandy and calcareous beds with
clay intercalations.
After a long stratigraphical hiatus (Salaj & M’Zoughi
1997) the Triassic sedimentary complex (Fig. 2) was laid
down on continental sediments of the uppermost Permian.
Some continental passages are documented on the basis of
palynology with paleogeographical interpretation (Adloff
et al. 1986; Bouaziz et al. 1987; Mello & Bouaziz 1987;
Kamoun et al. 1994; Dridi & Maazaoui 2004; Hammuda
4
SHIREF and SALAJ
2004). Large lagoonal gypsum passages are present in the
Carnian-Norian sequence. The Norian-Rhaetian (Salaj &
Stráník 1970) and Jurassic sediments (Castany 1951; Bu-
rollet 1956; Bonnefous 1972; Chandoulet al. 1993) are
proved only in Northern and Central Tunisia. The Jurassic
facies development in Northwestern Libya (Fig. 2), as in
Southern Tunisia is predominantly characterized by a la-
goonal sedimentary complex (El Hinnawy et al. 1975; No-
vović 1977) and in the southern part of the Al Hamadah al
Hamra area by continental Upper Jurassic to middle Creta-
ceous sediments. The Upper Cretaceous/Paleogene se-
quences consist mostly of marine carbonates and
evaporites, representing very shallow shelf and restricted
nearshore marine environments.
Material and methods
The samples for microbiostratigraphical evaluation on
the basis of foraminifers come from measured profiles men-
Fig. 1. Tectonic sketch map of Libya and Tunisia (after Burollet 1967, modified).
*Note to Fig. 2:
The authors do not use the new Geological Time
Scale by Gradstein et al. (2004) in Paleogene terminology, because ac-
cording to our opinion, Montian does not coincide with Danian and
Selandian. We do not use Selandian, because there is a hiatus in the re-
gion of Denmark (Thomsen & Heilmann-Clausen 1983, p. 351) be-
tween Danian and Selandian: i) the base of Selandian includes
important conglomerates with glauconite; ii) the index species of the
NP4 Zone – Ellipsolithus macellus, and NP5 Zone – Fasciculithus
tympaniformis as well as foraminifers are missing.
5
UPPER JURASSIC—LOWER PALEOGENE LITHOSTRATIGRAPHY (LIBYA)
Fig. 2. Generalized stratigraphy chart of Mesozoic and Cenozoic rocks in Northwest Libya. * Note see on the previous page.
6
SHIREF and SALAJ
tioned in the Explanatory Booklets edited in the Industrial
Research Centre, Tripoli, as well as from individual Meso-
zoic—Paleogene samples taken by one of us (Y.Sh.).
The samples were washed (with H
2
O
2
) on a 0.008 mm
sieve. Some solid rocks (limestones, dolomitic limestones,
calcareous sandstone) were evaluated from thin sections
( 2 3.5 cm
2
) for the purpose of microbiofacial analysis,
and to find their type of porosity from some Upper Creta-
ceous and Paleogene horizons as well as for the purpose of
proving and documenting some regression and transgres-
sion processes.
Stratigraphy
A composite stratigraphic column of the Mesozoic-Pa-
leogene rock (Fig. 2) is based on exposures along the
study area (Figs. 3—4), which encompasses nine sheets of
the Geological Map of Libya on a 1 : 250,000 scale: name-
ly, the Tarabulus Sheet (NI 33/13), the Mizdah Sheet (NH
33-1), the Nalut Sheet (NH 32/4), Bani Walid Sheet (NH
33-2), Al Qaryat Al Gharbiyah Sheet (NH 33-5), Al Qaryat
Ash Sharqiyah Sheet (NH 33-6), Hun Sheet (NH 33-11), Al
Washkah Sheet (NH 33-15), Bani Walid Sheet (NH 33-2),
Ghadames Sheet (NH 32-7), Al Khums Sheet (Ni 33-14)
and Ra’s Jdeir Sheet (N 32-16). In terms of lithostratigra-
phy, a stratigraphic column has been constructed on the
basis of field measurements carried out in the type section
of the Al Gharbiyah Formation (Al Qaryat Al Gharbiyah
area), the geological map, with laboratory studies (on Bu
Ra’s Member) coupled with studies of thin sections. The
obtained results helped to define the paleoenvironments
of the area between NW Libya and SE Tunisia.
The stratigraphical assignment of these units to the Upper
Senonian and Paleocene has been carried out on the basis of
detailed micro- and macropaleontological investigations.
In the following, we discuss and provide the general
sedimentological description of the beds forming sedi-
mentary cycles and their main fauna. The lithological de-
scriptions of features are discussed in the following.
Middle Jurassic to middle Cretaceous
Dogger
Khashm az Zarzur Formation (Upper Bathonian)
It consists of two lithological units, lower lacustrine
clays with minor sandstone and conglomerate interbeds
and of an upper continental cross-bedded sandstone se-
quence with clay intercalations. The lower shales contain
salt and gypsum in the western part. Fresh water fauna, si-
licified wood and marine fauna occur in these beds indi-
cating variable depositional environments, shallow water
to lagoonal and marine (Banerjee 1980).
Fig. 3. General formations age and locality names in Northwestern Libya.
7
UPPER JURASSIC—LOWER PALEOGENE LITHOSTRATIGRAPHY (LIBYA)
Fig. 4. Topographic map of study area in NW Libya.
Shakshuk Formation (Callovian)
It consists of alternating limestones and of highly fossil-
iferous clays with occasional sandy and conglomerate
beds, which indicate fluctuating environmental condi-
tions (Banerjee 1980). According to their mineral compo-
sition and to chemical analyses these rocks may be
regarded as transitional from sandstone into sandy lime-
stone (Novović 1977).
Ar Rajban Formation (Upper Jurassic to Lower Creta-
ceous, probably until the beginning of the Cenomanian)
It consists of two lithological units: lower conglomerat-
ic cross-bedded sandstone with clay intercalations and up-
per red unit made up of alternating clays and sandstone
beds, with minor carbonate bands, containing thin gyp-
sum beds and veinlets (Novović 1977). This formation is
highly fossiliferous. Numerous fossil brachiopods, bi-
valves, and gastropods were found. This formation is inter-
preted by us as Oxfordian in age.
Lower to middle Cretaceous
Kiklah Formation
(Aptian—Albian)
The term was first introduced by Christie et al. (1955) after
the Kiklah village (Fig. 4). It is a complex of clastic sequenc-
es with minor non-clastic intercalations with thickness vary-
ing from 0 to 65 m between the Ain Tobi Limestone at the
top and the Bi’r al Ghanam Gypsum Member below in the
Kiklah area. The Kiklah
Formation and its members
are introduced by El Hin-
nawy et al. (1975) and
Smetana (1975). It stretch-
es from the Tunisian bor-
der in the West to Ras At
Tahuna in the East (3 km
west of Wadi Ghan) where
it pinches out. The age is
correlable with that of the
Ar Rajban Member in the
western facies, to post-Ox-
fordian to pre-Cenomanian
according to El Hinnawy
et al. (1975).
In Tunisia, the Kiklah For-
mation is equivalent to the
Budinar, Bouhedma, Gafsa
and the lower part of the
Fahdene Formations (Hallett
2002). The dasycladal algae
reported by Salaj et al.
(1998, pp. 207—210) from
dolomitic limestones of Bu-
dinar Formation in Tunisia
was not found at the base of
Kiklah Formation in the Libyan areas.
The Kiklah Formation in some areas of Northwestern
Libya including the Libyan Offshore is assigned to the
Bathonian-Albian by Banerjee (1980), and its Jurassic part
is subdivided from bottom to top into the Khashm Az Zar-
zur Member, the Shakshuk Member, and the Ar Rajban
Member.
The Kiklah Formation, predominantly with its lower
part in some places is included to the Upper Jurassic. It is
subdivided into the members which are valid only for the
Upper Jurassic. The subdivision of the Kiklah Formation
from bottom to top into the Khashm Az Zarzur Member,
the Shakshuk Member, and the Ar Rajban Member is not
correct and in many areas, where they are present a new re-
vision is inavoidable.
Middle—Upper Cretaceous
Sidi as Sid Formation
(Cenomanian)
The term has been introduced by El Hinnawy et al.
(1975). It is one of the most widely distributed rock units
of Jabal Nefusa occurring from the Tunisian border east to
the Mediterranean coast near Al Khums (see Fig. 3).
It is mainly a carbonate sequence with marly bands in the
upper part. Lateral changes to gypsum beds alternating with
marly bands are noticed at places as in the Nalut sheet area.
The formation thickens eastwards. It is about 60 m thick in
the western part, about 100 m in the Nalut sedimentation
area, about 170 m in the Tarabulus sheet area, 180 m in the
reference section at Az Zintan in the Mizdah area, and attains
8
SHIREF and SALAJ
up to 380 m in the Al Khums area in the eastern end (Baner-
jee 1980).
It should also be noted that the gypsum accumulations
in the Sidi as Sid Formation increase eastwards. The deep-
er marine sediments increase westwards with rare remnants
of planktonic foraminifers of genera Hedbergella div. sp.
and Praeglobotruncana div. sp. (Banerjee 1980). The age
is almost certainly Cenomanian with depositional enviro-
ment ranges from lagoonal in the west through littoral to
low energy neritic with rare remants of planktonic fora-
minifers of genera Hedbergella div. sp., Heterohelix div.
sp. and Praeglobotruncana div. sp. in the east.
Nalut Formation (Cenomanian—Lower Turonian)
The term was firstly introduced by Zaccagna (1919) after
the Nalut town on the western part of Jabal Nefusa near the
Tunisian border where these rocks widely occur. During the
recent regional geological mapping in Tripolitania, El Hin-
nawy et al. (1975), Mann (1975), Antonović (1977) and
Novović (1977), confirmed the name of this rock unit as the
Nalut Formation (Banerjee 1980).
It consists of light grey to yellow and whitish, hard,
compact and massive thick-bedded, finely recrystallized
dolomitic limestone and dolomite, irregular or cross-bed-
ded and marly in some parts. Cherty nodules and concre-
tions are common in the upper part of the sequence which
is sometimes red in colour. The top is marked by softer
beds, sometimes containing gypsum. The carbonates (mi-
crites, microsparites, occasionally containing pellets) are
throught to be recrystallized. Organodetrital (presumed
initially algal, coral and crinoidal) nature indicated depo-
sition in the deeper fore-reef zone to shallow circa-littoral
zone influenced by pelagic sedimentation (in the North)
with Cenomanian Rotalipora div. sp. and Praeglobotrun-
cana stephani (Gandolfi) (Mann 1975, p. 33).
The Upper Cenomanian to Lower Turonian Pseu-
dorhapydionina dubia De Castro (Novović 1977, p. 28)
in the dolomitic limestones prove (in the South) the ma-
rine restraint to lagoonal, evaporitic, intertidal to supratid-
al environment with low energy, as in Central Tunisia
(Salaj & Maamouri 1998, p. 375).
Qasr Tigrinnah Formation (Upper Turonian—Coniacian)
The term was introduced by Christie (1955). It extends
from the Tunisian border east to the Wadi Suf al Jin (West),
and from behind the Jabal Nefusa escarpment south to the
Al Hamadah al Hamra plateau region (Banerjee 1980).
The Qasr Tigrinnah Formation has been studied by numer-
ous authors, and it has been described in several publications
(Christie 1955; Desio et al. 1963; Jordi & Lonfat 1963; El
Hinnawy et al. 1975; Röhlich 1979; Banerjee 1980).
The formation could be divided into three broad litho-
logical units. The lower part consists of soft, friable unbed-
ded or thinly bedded slope-forming marls, buff to grey,
yellow and greenish, with less abundant clay and with thin
interbeds of limestone. The middle part consists of marls
and clays with conspicuous thin bands of red to pink, yel-
low or whitish hard limestone, marly chalky or calcarenitic
in places and generally fossiliferous (Banerjee 1980). The
upper part consists of porous, white chalky limestone, dolo-
mitic or sandy with thin marl or clay interbeds. Chert bands
and nodules are common in this horizon, with occasional
thin layers of sandstone at the base. Gypsum and anhydrite
are reported from the western side of the Hamadah Basin.
The carbonates are mostly micrites, and sparite and sparry
allochemical limestones are rather rare. The formation con-
tains a rich fossil assemblage of gastropods, brachiopods,
bivalves, echinoids, ostracods and a few benthic foramini-
fers (Banerjee 1980). These sediments and the contained
fauna indicate lagoonal (evaporitic) to shallow, warm ma-
rine subtidal to quiet neritic environment with Boueina
pygmea Pia (Codiacea) and Dissocladela ondulata Reineri
(Dasycladacea) (Energoproject 1975).
Antonović (1977) and Novović (1977) agreed that most
of the fossils reported from the Qasr Tigrinnah are of Late
Turonian—Coniacian age.
Mizdah Formation (?Upper Coniacian—Santonian—Cam-
panian)
The name was introduced by Burollet (1960), after the
Mizdah village. The Mizdah Formation is assumed to be
the lateral equivalent of the upper and middle part of the
Aleg Formation of Tunisia (Burollet 1956; Banerjee 1980).
Most of the Al Hamadah al Hamra surface is occupied
by this formation. During the recent regional geological
mapping, El Hinnawy et al. (1975), Antonović (1977), No-
vović (1977) and Živanović (1977) divided the Mizdah
Formation into the following two members only: the Tha-
la Member and the Mazuzah Member.
– Mazuzah Member (Upper Coniacian—?Santonian)
It occurs over a wide area from the Tunisian border east
(about 5—15 m thickness) to about 25 m in the Bani Walid
area, and from behind the Jabal Nefusa escarpment south
to an extensive area in the Al Hamadah al Hamra plateaus.
This member is mainly composed of hard, dense, massive
crystalline limestone, dolomite (dolosparite) and dolomitic
limestone, light grey to yellow, blue or pinkish in colour,
medium- to thick-bedded, it consists of very fossiliferous
limestone particularly rich in inoceramids (Röhlich 1979;
Röhlich & Youshan 1992), some of which are of consider-
able size. Oolites were also observed in some places. Due to
its lithology, the Mazuzah Member is resistant to erosion
and it covers a wide area from Al Hamadah al Hamra.
The indicated sedimentation environment was shallow
water in barrier shoal with high energy, occasionally con-
nected with the open sea (presence of ammonites). The pale-
ocurrent is determined from the northern and northwestern
direction (Banerjee 1980).
– Thala Member (?Upper Santonian—Campanian)
The Thala Member was defined by Jordi & Lonfat
(1963) and described in detail by Antonović (1977). It is
9
UPPER JURASSIC—LOWER PALEOGENE LITHOSTRATIGRAPHY (LIBYA)
represented by regressive sediments and belongs to the
upper part of the Mizdah Formation (Jordi & Lonfat 1963;
Chaloupsky 1979; Čepek 1979; Röhlich 1979; Salaj
1979; Megerisi & Mamgain 1980).
In general, the lithological development of the Thala
Member is fairly uniform. It is characterized as a “sandwich-
like” alternation of marls and clays (frequently gypsiferous)
and calcilutite to fine-grained calcarenite, frequently chalky
and finely laminated.
Two types of sediments are present, gypsiferous and
marly limestone beds. The lower part consists of grey to
reddish grey or yellow green thin-bedded limestone, marly
and sandy at places. The upper calcareous part is a porous,
sandy or chalky limestone (calcarenite, calcirudite) or do-
lomite, yellow to white, black stained on the surface. The
environment was shallow water environment, with clean
water of low energy, fairly mobile, of normal salinity open
sea and then changed to shallow sea of subtidal to lagoon-
al environment in the Al Hamadah area.
“Zimam Formation” (Upper Campanian—Maastrichtian)
In the original definition, the Zimam Formation was in-
troduced by Jordi & Lonfat (1963) after Wadi Zimam. In
their subdivision of the formation they identified three
members of which the Lower Tar was at the base; Salaj &
Nairn (1987) showed that the formation section was made
up of beds belonging to three sedimentary cycles. The cy-
cles are separated by the presence of phosphate horizons,
which provide indications of regressive phases.
Nairn & Salaj (1992) proved a revision to the Upper
Cretaceous stratigraphy of Northwestern Libya, between
the Thala and the “Upper Tar” Members. They studied the
Qarayat al Gharbiyah area southeast of Mizdah and they
provided a general sedimentological description of the
“Lower Tar Member” in measured type sections; and they
proposed a new formation name to the Al Gharbiyah For-
mation with a type section. They introduced the formation
with three sedimentary cycles characterized by Upper
Campanian to Maastrichtian microfauna. Three shallower
neritic sequences are represented by the Bi’r Bu al Ghurab,
the Lawdh Allaq (or Bi’r az Zamilah Member with pelagic
facies) and the Tar Member s.s. Members.
In the following, we provide a general sedimentological
and environmental description:
– Al Gharbyiah Formation ( = syn. Lower Tar Marl
Member s.l.; Nairn & Salaj 1992)
It has an average thickness of about 120 m in the NW Al
Hamadah al Hamra. The thickness ranges from as little as
60 m in the West (Chaloupsky 1979), to as much as 190 m
in the east (Čepek 1979), the Lower Tar Member attains
a great thickness rapidly increasing from the West (90 to
120 m) to the East (160 to 180 m) Salaj (1979). There is
a considerable variety of predominantly shallow-water de-
posits, which show both lateral and vertical changes. The
member has a more or less uniform lithological composi-
tion of thin-bedded marl, shale, calcareous mudstone and
limestone, sandy, gypsiferous, chalky and dolomitic in
places. The lower part is formed by glauconitic white or-
ganodetrital
(allochemical)
marly
limestone,
slightly
gypsiferous, exposed in the Mizdah and Bani Walid areas.
Upward is the shaly and marly sequence, dark green to
white, grey, yellowish and reddish, with occasional nests
of celestite crystals as found in the Bani Walid area, hav-
ing rich fossiliferous levels and limestone interbeds.
This limestone, sometimes hard, massive or saccharoi-
dal, reddish or pinkish forms prominent plateaus in the
western part of the Al Hamadah al Hamra Basin and be-
comes more gypsiferous, dolomitic and chalky in the up-
per part in the western region (Energoproject 1975).
This horizon is extremely rich in Campanian macrofauna
represented predominantly by Lopha (Actinostreon) villei
(Coquand), Lopha Actinostreon dichotoma (Bayle), Cera-
tostreon spinosum (Matheron), Pycnodonte (Phygraea)
vesicularls (Lamarck), Nicaisolopha nicaisei (Coquand]
and Tudicla bussoni Collignon, and Bryozoa (Cheilosto-
mata) represented by the species: Woodipora disparilis
(d’Orbigny) (see Fig. 5.1—4). The uppermost rocks are marl
and chalky marl with dominant macrofossils as Lopha (Ac-
tinostreon) dichotoma (Bayle) and Pycnodonte (Phygraea)
vesicularis (Lamarck).
This important fossiliferous horizon attaining a maximum
thickness of 4 m and lying about 10 to 15 m above the base
of the Al Gharbiyah Formation, marks the end of the var-
ied development of the basal sequence of this unit.
The lower sequence of the Al Gharbiyah Formation may
be divided into three parts of unequal thicknesses:
The lower part terminates by a prominent bed of fossil-
iferous limestone or dolomitic limestone, forming a mor-
phologically conspicuous ledge.
The middle part consists mainly of marls and/or clay-
stone. In the eastern part of the area, this marl horizon
contains innumerable shells of oysters (Agerostrea ungu-
lata, Amphidonte overwegi).
The upper part: A thin (10—20 cm) interbed of biocal-
carenite in the marl layer is crowded with poorly preserved
inoceramid shells and their fragments.
The upper part contains locally frequent inoceramid
shells and represents the uppermost inoceramid-bearing lay-
er in this member. Salaj (1979) spread the member in the
eastern and north western parts of the Al Qaryat al Ghar-
biyah area and distinguished the following lithofacies de-
velopments of the Al Gharbiyah Formation as follows:
I – Al Gharbyiah Formation in the eastern area:
a – The basal part of this formation (0.8 to 3 m) is
mainly formed by calcirudites with layers of greenish
gypsiferous marls. The calcirudites are rich in fine detritus
of molluscs, bryozoans and sponge spicules, mainly
monaxone and triaxone. The lower part of the sequence in
places consists mainly of chalky calcilutites with layers of
chalk, which microsopically correspond to clayey biomi-
crite rich in benthic and planktonic microfauna. This hori-
zon of the Upper Campanian is extremely rich in
macrofauna represented predominantly by Lopha (Acti-
nostreon) dichotoma (Bayle).
10
SHIREF and SALAJ
Fig. 5. Photomicrograph of thin sections. 1—4 – Photomicrograph showing thin section of bioclastic packstone of the Al Gharbiyah Fm
with Woodipora disparilis (d’Orbigny). Al Qaryat Al Gharbiyah area. Lower Maastrichtian. 5—8 – Photomicrograph showing thin sec-
tion of microbiosparite with very good porosity after the microfossils Laffiteina bibensis Marie and Rotalia trochidiformis (Lambert)
with a partial to complete dolomitization in the Bu Ra’s Mb.
11
UPPER JURASSIC—LOWER PALEOGENE LITHOSTRATIGRAPHY (LIBYA)
b – In the middle part of the Al Gharbiyah Formation se-
quence (120 to 130 m) which is mainly formed by marls,
calcarenites, and calcirudites, rich in Lower Maastrichtian
macrofauna and chiefly represented by species such as:
Agerostrea ungulata (Schlotheim), Amphidonte overwegi
(Buch), Inoceramus (Cataceramus) regularis (d’Orbigny),
Plicatula hirsuta var. sparsicosta Pervinquiere and Bacu-
lites anceps Lamarck.
c – In the uppermost part of the Al Gharbiyah Forma-
tion calcarenites with Upper Maastrichtian Omphalocy-
clus
macroporus
Lamarck
predominate
often
with
cross-bedding, thickness of which is often 10 to 20 m.
II– Al Gharbiyah Formation in the northwestern area:
a – The lower part of the Upper Campanian sequence is
formed by gypsum-bearing, in places glauconitic marls
(15 to 20 m in thickness), with an assemblage of abun-
dance of the large valves of Lopha (Actinostreon) dichoto-
ma (Bayle), and some other bivalves (see Salaj 1979).
b – The middle part of the Lower Tar Member (45 to
50 m in thickness), calcarenites and calcirudites of the
Lower Maastrichtian with abundant representatives of the
Lopha and Inoceramus predominate. They are represented
by the species: Lopha (Actinostreon) villei (Coquand) and
Inoceramus (Cataceramus) goldfussianus d’Orbigny also
Orbitoides media (d’Archiac), with the last layers (1 to 2 m
in thickness); interformational conglomerates and breccias
are present.
c – The upper part (28 to 35 m in thickness) is represent-
ed by vari-coloured marls and clays with layers of calcareni-
tes, dolocalcirudites and calcirudites with Omphalocyclus
macroporus Lamarck (Chaloupsky 1979). At the base an
about 50 to 70 cm thick calcarenite and phosphatic bed is
present.
In general the macrofauna is represented by mass occur-
rence of bivalves (see Fig. 6), from which the following
species were determined by Zaruba: Lopha (Actinostreon)
villei (Coquand), Lopha (Actinostreon) dichotoma (Bay-
le), Pycnodonte (Phygraea) vesicularis (Lamarck) and
Ceratostreon spinosum (Matheron).
The depositional sequence of the Al Gharbiyah Forma-
tion may be divided into three sedimentary cycles. The
cycles are separated by phosphate horizons, which pro-
vide indications of regressive phases, as follows:
– Deposition of marls and clays with intercalations of
calcarenites in the open sea near the barrier or on the barrier.
– Deposition of basal transgressive calcarenites to cal-
cirudites-bedding on the eroded surface of the Thala
Member (Fig. 7).
Bed sequence of shelly calcarenites to calcirudites of
Upper Campanian was deposited evidently in the barrier
zone and in the subtidal zone with high energy. The
chalky calcilutites developing laterally from shelly cal-
carenites and calcilutites with planktonic microfauna are
predominant, deposited in open sea.
– Deposition of these Upper Campanian sediments
was followed by accumulation of sediments, which prob-
ably originated in a lagoon. In this phase, gypsiferous
and ferruginous phosphatic calcarenites are formed. They
were deposited in a subtidal zone with low energy to la-
goonal area.
The shelly phosphatic calcarenite deposition took place
in a subtidal to barrier zone with high energy.
Clays and marls with thick layers of shelly calcarenites
and calcirudites in an open sea zone near the barrier. It is
proved by plentiful macrofauna and with benthic and
planktonic foraminifers of the Globotruncana ventricosa
Zone. The varied colouring of beds is due to the transport
of terrigenous material from a near emerged zone under
the influence of the warm and humid paleoclimate.
Calcarenites to dolomitic calcarenites with cross-bed-
ding were deposited in the pre-barrier zone of open sea
and on the barrier. From the faunal viewpoint it is impor-
tant that besides a plentiful Maastrichtian macrofauna,
a microfauna is also abundant. It is represented by both
the planktonic and benthic species of the Globotruncana
falsostuarti, Gansserina gansseri and Omphalocyclus
macroporus Zones.
Denomination of the Lower Tar Formation on the Al
Gharbiyah Formation was carried out on all sheets of the
studied area (we now propose to cancel the term the Zi-
mam Formation).
The distinct new transgressive cycle of the Bi’r Bu al
Ghurab Member is characterized by an about 80 cm thick
passage of thin layered 2—5 cm thick, slacking calcareni-
tes crowded with bryozoans (Salaj 1979; Salaj & Megerisi
1984) rich in bivalves, mainly represented by Lopha (Ac-
tinostreon) villei (Coquand), the moulds of embryonal
stages of which are also found at the base of the first cal-
carenite bryozoan thin bed of the transgressive cycle men-
tioned. Rare specimens of Ceratostreon (Actinostreon)
villei (Coquand) are also found in this part.
Concentrations of Fe-oxides and Fe-hydroxides (goet-
hite), are found in some lower layers of bryozoan calcaren-
ites, but predominantly this basal part of the Bi’r Bu al
Ghurab Member is without them.
The regression phase at the boundary of the Bu al
Ghurab and the Lawdh Members and/or at the boundary
of the Bi’r al Ghurab and the Bi’r Az Zamilah Members
(with pelagic facies of chalks and marls) is characterized
by the phosphatic level and rarely by the presence of glau-
conitic grains (influence of redeposited organogenic phos-
phatized grains, probably from freshwater lakes and as
a consequence of a new transgression also connected with
the formation of glauconite, under the action of a warm
but humid paleoclimate, together with high iron concen-
tration (Fe
2
O
3
), up to as much as 20.5 % (Nairn & Salaj
1992, p. 1625).
These, but particularly glauconitic horizons also origi-
nated in the course of sedimentation in the Lawdh Allaq
Member (horizon 10/8; in Nairn & Salaj 1992, Fig. 5,
page 1631) as well as in the course of pelagic sedimenta-
tion in the Bi’r Az Zamilah Member. They are the hori-
zons (samples nos, 7/2, 7/4, 7/7, 7/8; in Salaj & Megerisi
1984) predominantly with Upper Campanian planktonic
foraminifers, and dated as Upper Campanian also with
Baculites anceps (Lamarck) and Curvostrea thomasi
(Peron) (in Salaj & Megerisi 1984, Fig. 5, p. 212).
12
SHIREF and SALAJ
Fig. 6. Fossil assemblages. 1—2 – Lopha (Actinostreon) dichotoma (Bayle), Al Gharbiyah Fm, s.s., Upper Campanian. 3—4 – Am-
phidonte overwegi (Buch), Al Gharbiyah Fm, Lower Maastrichtian. 5, 6, 7 – Agerostrea ungulata (Schlotheim), Tar Mb, s.s., Upper
Maastrichtian. 8, 9, 10 – Ceratostreon aff. spinosum (Matheron). Tar Member s.s., Upper Maastrichtian.
13
UPPER JURASSIC—LOWER PALEOGENE LITHOSTRATIGRAPHY (LIBYA)
Fig. 7. Borings of infauna (cirripods and bivalves) on the last bank of the Thala Mb in Wadi Wasiq area at Lat. 30º38
’04”N, Long.
13º20
’48”E. 1 – Borings of infauna (cirripods and lithofags of bivalves) on the last bank of the Thala Mb (siliceous crystalline light
grey) in Wadi Wasiq at Lat. 30º38
’04”N, Long. 13º20’48”E. 2—3 – On the lower part of the boundary bed (at profile) with distinct
borings of in fauna, transgressively on its eroded surface, the basal thin beds set on. They are formed by fine-grained calcareous organ-
odetrital micro-conglomerates. They fill up surficial unevennesses and partly solidified borings of infauna, which are not present in the
basal thin bed of the Bi’r Bu al Ghurab Mb of the Al Gharbiyah Fm.
The middle and upper part of the Bi’r Az Zamilah Mem-
ber corresponds to the Globotruncana stephensoni Zone
(younger than the zone with Radotruncana calcarata). It
underlies the Lower Maastrichtian strata where the micro-
fauna of the Globotruncana falsostuarti Zone (level 7/7)
and Globotruncana gansseri Zone (level 7/8) was proved
(Salaj & Megerisi 1984).
The
phosphate,
weakly
glauconitic
horizon
with
a relatively high iron concentration Fe
2
O
3
from the
boundary of the Bi’r Az Zamilah and the “Lower” Tar s.s.
Members, in places at the base was replaced by conglom-
erates (Nairn & Salaj 1992, p. 1963). The upper part of the
Al Gharbiyah Formation ( = now only the Tar Member in
the new taxonomic conception) corresponds in the con-
ception of Nairn & Salaj (1992) to the Middle to Upper
Maastrichtian with Omphalocyclus macroporus (Lamarck)
(level No. 7/9 Fig. 5, p. 213) (Salaj & Megerisi 1984).
From macrofauna Amphidonte overwegi von (Buch) and
Meretrix tripolitensis (Baroni) are found. From planktonic
foraminifers additionally it was possible to prove the very
rarely found Gansserina gansseri (Bolli) (in the levels 7/9
and 7/10).
It should be remarked that practically at all localities
where the formation of the Lower Tar Member occurs, sev-
14
SHIREF and SALAJ
eral Fe-oxides horizons are found, often accompanied by
more or less scattered glauconite (Nairn & Salaj 1992).
Paleocene
Tabaqah Formation, new proposed name
Type locality: Wadi Tabaqah.
Coordinates: 30º26
’13”N lat. and 13º13’06”E long.
We divided the Tabaqah into two members: the Umm al
Kifan Member, new proposed name, and the Had Member,
corresponding to the former middle and upper parts of the
Zimam Formation.
Danian
Umm al Kifan Member, new proposed name ( = former
Upper Tar Marl Member)
The type locality: Wádí Umm Kifan (see Salaj 1979,
p. 31); coordinates: 30º34
’30”N lat. and 13º12’31”E long.
The Umm al Kifan Member, new proposed name, is re-
stricted in occurrence to the central and eastern parts of
the Al Hamadah al Hamra Basin, and extends south to the
northern Dor el Gussa area; it represents the first transgres-
sive-regressive sedimentary cycle of the Tabaqah Forma-
tion (a new proposed name) for the middle part of the
former Zimam Formation. The Umm al Kifan Member was
deposited most likely in the pre-barrier zone to open sea
zone as suggested by the nature of rocks and by presence
of brackish species.
It is composed of yellowish green marl and calcareous
mudstone with shaly intercalations, particularly thick and
numerous in the middle part of the sequence. The inter-
bedded limestone is of microcrystalline calcite. The tick-
ness: 6—10 m. In the Al Qaryat al Gharbiyah area the
lithology of this member is formed by light-coloured to
white, in places dolomitic calcilutites scarcely laminated
and slightly silicified. Intracalcilutites to chalky calcilu-
tites and calcarenites are represented subordinally. Local-
ly in the bottom of this sequence greenish gypsiferous
clays are present in the northeastern area.
The Umm al Kifan Member was originally described as
the Upper Tar Marl by Jordi & Lonfat (1963), Antonović
(1977), Chaloupsky (1979), Čepek (1979), Röhlich
(1979), Nairn & Salaj (1992), who explained this differ-
ence in thickness due to regression of the sea from the
edges where the Maastrichtian fauna lies directly below
the Had Limestone, but towards the centre of the basin.
The carbonates are sometimes fossiliferous and they
may show features of current activity particularly towards
the top where cross-bedding occurs and where an oolitic
horizon has been described. Towards the south, the clastic
content of the upper beds increases and a red colour is de-
veloped; these are interpreted as being due to the ap-
proaching to shoreline.
The Danian age of the Umm al Kifan Member is deter-
mined by the planktonic foraminifers (Salaj 1979, p. 33)
represented by specimens of the Postrugoglobigerina
daubjergensis/Eoglobigerina danica Zone with Pos-
trugoglobigerina hariana Salaj and Eoglobigerina dani-
ca (Bang). The macrofauna, occurring very scarcely, is
represented by a group of bivalves with the species:
Arca tinrhentensis Collignon, Pseudomiltha (Zorrita) cha-
vani Colignon and Lima sp. and small indeterminable and
recrystallized gastropods. The Tar/Umm al Kifan Member
boundary and thus also the Maastrichtian/Danian boundary
is determined by the disappearance of the Upper Maastrich-
tian orbitoids, represented by Omphalocyclus macroporus
Lamarck, which do not pass to the Danian and to the Umm
al Kifan Member either.
Montian
Had Limestone Member
Antonović (1977), Živanović (1977), Čepek (1979),
Röhlich (1979) and Salaj (1979) have described the mem-
ber in a different type section through the Al Hamadah al
Hamra. This member is a highly resistant bed of carbonate
rocks-forming the second sedimentary cycle of the
Tabaquah Formation and the extensive plateau of Al Ha-
madah al Hamra (Banerjee 1980). The most widespread se-
quence of all the sedimentary units in the studied area
contributes to geological composition of the very exten-
sive Hamadah al Hamra plateau. It consists mainly of do-
lomitic limestone and dolomite with many dasycladacean
algae represented by the species: Cymopolia elongata
(Defrance), Cymopolia paronai (Reineri), Cymopolia ed-
wardsi L. and G. Morellet and others. We find it in Wadi
Tabaqah, Hamadah al Hamra, with a restricted subtidal to
intertidal marine environment with low energy.
The lower part of the Had Member consists of siliceous
crystalline to microcrystalline limestone and calcilutite,
both in places dolomitized, with a characteristic amount
of grey coloured nodular cherts which predominate. The
intercalations of endostratic breccia, calcarenite and dolo-
mite are also present.
Dasycladacea characteristic of this facies, are present
abundantly. From the microscopic point of view, gastro-
pod biomicrosparite, sparite, dolomitic sparite to do-
losparite dominates with frequent siliceous and dolomitic
foraminiferal biomicrites with Elphidiella prima (Ten
Dam) (loc.: NE of Al Ulaymát) together with fragments of
dasycladal algae.
Thanetian
Shurfah Formation
Established by Jordi & Lonfat (1963) for a Paleocene se-
quence of shales, marl and limestones exposed near Wadi Tar
(Hun area). It is divided into three members (Orbilolites or
Operculina or Operculinoides Limestone, Galta Chalk and
Bu Ra’s Marl) (Banerjee 1980), of which the last member
outcrops in the Mizdah, Nalut and most of Al Qaryat al Ghar-
biyah area, other members are present in the Eastern area.
15
UPPER JURASSIC—LOWER PALEOGENE LITHOSTRATIGRAPHY (LIBYA)
Bu Ra’s Member (Thanetian)
The Bu Ra’s Member, established by Jordi & Lonfat
(1963) and studied in detail by Goudarzi (1970), by report
of the Energoproject (1975), and Živanović (1977), repre-
sents the lower member of the Shurfah Formation. It consists
mainly of marls with layers of calcilutites, calcarenites and
sparitic to dolomitic limestone (loc.: Shatíb al Máqitah)
with Operculina aff. heberti (Munier et Chalmas) to dolo-
mite with very good porosity (see Fig. 6.5—8) after the fos-
sils Laffiteina bibensis Marie and Rotalia trochidiformis
(Lambert). The gypsiferous chalky marl with a conspicuous
finely silty disintegration is the chief lithological type of
the Bu Ra’s Member. The calcilutites and calcarenites lo-
cally also containing nodular cherts, clays, sometimes also
with gypsum, are found in the basal part of the member.
Čepek (1979) reported that clays with gypsum become
the basal part of the member in the eastern part at Al Qary-
at ash Sharqiyah.
In the westernmost part of the same stratigraphic unit,
conglomerates to breccias and sandstones with calcilutite
matrix are equivalent to these clays, in which quartz
grains as intraclasts are quite distinctly represented in the
lower layers of the Bu Ra’s Member. They are subangular
and appear as intraclast-bearing biomicrite to biosparite
under the microscope.
The sedimentary petrography of the detailed constitu-
ents and texture of the Bu Ra’s Member was studied in
thin sections by high power optical microscopy. Petro-
graphically, original particles of the rocks are of two
types: skeletal and non-skeletal. These particles are usual-
ly embedded in a calcite matrix or calcite cement.
1. Skeletal particles: the skeletal elements composition
shows a relative abundance of foraminifers, molluscs, bra-
chiopods fragments and Ostracoda. Pellets, peloids are
also present. The foraminifers increase with higher water
depth and more open circulation, but molluscs and brachi-
opods commonly occur in rock types deposited in normal
shallower marine environments.
2. Dolomite, sparry calcite and anhydrite in crystals and
as micrite supported elements are most commonly associ-
ated with it and they constitute about 60 to more than
85 % of the rocks
The thin section petrographic studies of the Bu Ra’s
Member rocks show that the porosity consists mainly of
vuggy texture (after dissolution of the foraminiferal tests)
also developed as a result of leaching out of void-filling
and replacement by anhydrite and dissolution, but the
rock texture is affected by solution processes and dolo-
mitization to different degrees. However, all the pore spac-
es are composed predominantly of fine crystalline fabrics
with a common occurrence of bioclastic lithofacies.
The limestone framework consists of a relatively wide
range of particles ranging from muds, pellets, peloids, intrac-
lasts and a diversity of bioclasts. These particles are usually
embedded in calcite matrix or in calcite cement. Diagenesis
seems to have been very effective as is shown by the almost
complete obliteration of the original textures through recrys-
tallization of both the particles and their matrix.
Strong diagenesis and recrystallization of the rocks is
largely due to dolomitization and makes their microscopic
identification difficult. Gypsum crystals often enhance the
destructional effect so that primary sedimentary texture be-
comes completely obliterated or is preserved in relics only.
The prevailing sparite and microsparite contain abundant
lighter lenticular shapes. Diagenetic processes caused almost
complete obliteration of the sedimentary textures in most
cases. These processes included cementation, compaction, re-
crystallization and dolomitization. The latter was selective in
some cases and pervasive in others. The thickness varies from
33 m near Wadi Tar to about 5 m in the area between the
Wadi Zamzam and As Sadadah in the Bani Walid sheet area.
The lithological, petrographical and paleontological
characteristics of the Bu Ra’s Member are indicative of
shallow to very shallow water, and a neritic to littoral en-
vironment of deposition. Salaj (1979) confirmed that the
environment is shallow water with low energy supratidal
to intertidal parts of the basin. The Bu Ra’s Member has
been assigned to Thanetian in age, corresponding thus to
the dating of Barr & Weegar (1972).
Qaltah (Galta) Member (Thanetian)
The name was introduced by Burollet (1960) after the Al
Galta spring, on the eastern margin of the Hun Graben. Later
it was ranged as the middle member of the Shurfah Forma-
tion by Jordi & Lonfat (1963). It is composed of white and
greenish, soft, friable, chalky limestone and marl.
Sandy limestone with gypsum interbeds and limestone
with interbeds and irregular nodules of chert occur in the
Al Qaddahiyah area.
South of the type locality, extending over a wide area,
the upper part of the sequence 10—15 min thickness is de-
veloped as yellow fossiliferous, soft, dolomitic marls and
marly chalky limestone. The thickness is about 48 m in
the Wadi Tar area, about 40—45 m south of Jabal as Soda
and 40—50 m in the Bani Walid-Qaddahiyah area.
The sediment was deposited in a relatively quiet shallow
to very shallow marine environment. Čepek (1979) and
Salaj (1979) assigned the Qaltah Member to Thanetian age
by using the faunal evidence. The age is proved by miliolid
foraminifers such as Idalina sinjarica Grimsdale.
Ammur Member (Upper Paleocene)
“Orbitolites Limestone Member”. The Ammur Member
was introduced by Burollet (1960), or by Jordi & Lonfat
(1963) as the ‘Operculinoides or Operculina Limestone’. Lat-
er, the Ammur Member, was applied again according to the
new type section established in the Wadi Ammur (Shakoor &
Shagroni 1984).
It is a grey, yellow to greenish or dark brown cavern-
ous weathering limestone and dolomite with marls and
chalky marls containing Orbitolites complanatus Lamarck
and Lockhartia sp. (Banerjee 1980). The depositional en-
vironment of the Ammur Member is characterized by
presence of algae, abundance of the diverse miliolid fora-
minifers and rare Operculina canalifera d’Archiac (Jordi
16
SHIREF and SALAJ
& Lonfat 1963), as a typically shallow water restraint
back-reef – subtidal to intertidal environment (protect-
ed shelf, with low energy; Barnolas et al. 1990), corre-
sponding probably to the Upper Thanetian.
Upper Paleocene—Lower Eocene
Kheir Member the lower part of the Bishimah Formation
This formation was defined and subdivided by Jordi &
Lonfat (1963) into the Kheir Marl Member, Rouaga and
Gir Gypsum Member. Only the Kheir Member was studied.
The Kheir Member consists of grey, dense, hard, and
thick-bedded to massive micritic limestone with nodules
of green chert in the upper part and interbeds of calcaren-
ite and marly limestone. The thickness varies between 30
to 40 m, but increasing to 150—200 m in (Al Qaddahiyah
area) the type area where the rock types are mainly chalky
limestone and chalky marl with pelagic foraminifers. In
the Sirte Basin Barr & Weegar (1972) described the Upper
Paleocene Morozovella velascoensis Zone from the lower
part and the Lower Eocene Morozovella subbotitina Zone
from the upper part of the Kheir Member.
This age of the Kheir Member is confirmed by the fact
that the lower part of the Rouaga Member on Hun Sheet
(Shakoor & Shagroni 1984) and in the Al Washkah area
(Woller 1978) contains representatives of the alveolines
from the Alveolina oblonga Zone (Hanzlikova in Woller
1978; Salaj 2003), which already corresponds to the high-
er part of the Lower Ypresian.
The Al Hamadah al Hamra facies is characterized by fri-
able greenish yellow and ochrous marl and dolomitic
marlstone, richly inter-layered with green clay and associ-
ated with gypsum abounding throughout the whole verti-
cal extent, especially in the middle and upper part of the
Bishimah Formation.
The middle part of the Bishimah Formation is present-
ed by thin to thik intercalations.
Conclusions and discussion
Our results on the Upper Jurassic to Lower Paleogene
lithobiostratigraphy contribute to the regional geology of
Northwestern Libya, with application for geological map-
ping and for the oil exploration industry. Especially we
were studying the sedimentology and facies characteristics
of the Al Gharbiyah, the Tabaqah. We propose a new name
for the Shurfah Formation with the redefinition of the Tar
Member ( = formerly the Lower Tar Member), the upper part
of the Al Gharbiyah Formation and the Umm al Kifan (for-
merly the Upper Tar Member), the upper part of the
Tabaqah Formation. However, the high porosity of these
formations in the deeper zone or below the Shurfah Forma-
tion in the western part of the Al Hamadah al Hamra is im-
portant from the point of view of oil accumulation.
Our results are also good for stratigraphic interpretations
and applications, especially throughout the Campanian to
the Lower Eocene sedimentary formations, for finding cri-
teria of sedimentary conditions in correct application of
the knowledge on the archipelago zone facies in the Cam-
panian to Lower Eocene, represented by the Al Gharbiyah
and the Shurfah Formations. In the Upper Senonian this ar-
chipelago zone was connected with other Upper Senonian
to Lower Eocene formations in the Libyan offshore zone
and with the Cyrenaica Platform in Eastern Libya.
This archipelago zone in its stratigraphic development
and sedimentary interruptions is very similar to the Gosau
facies in the Western Carpathians and Eastern Alpine belts.
In the both areas the Inoceramus Marls, Orbitoides Lime-
stones are existing and in places the pelagic red marls with
planktonic foraminifers are present. These facies correspond
to the shallow neritic facies, with slight influence of pelagic
sedimentation and many stratigraphical hiatuses. The tec-
tonic evolution in both areas was totally different, the Al-
pine in the northern areas in the Alps and Western
Carpathians, and the epeirogenetic in the South on the Sa-
harian Platform, in the Al Hamadah al Hamra areas.
The application of our knowledge to the humid paleocli-
matic events during the Campanian and Early Paleogene
successions on the basis of the presence of red marls and fer-
rugineous concretions in many stratigraphical levels, which
are especially studied in the Cyrenaica Platform (Salaj 2004),
is also possible in lithofacies development of the Al Ghar-
biyah Formation and all Paleogene rock units of Western
Libya.
To improve the precision of our knowledge on the fa-
cies development and stratigraphy of the Mesozoic and
Paleogene sequences it is necessary to carry out new geo-
logical research to resolve some important problems:
– Precision on the age of the very shallow marine to
continental-fluviatile sediments (well BM1-1) below the
uppermost Dinerian foraminiferal Meandrospira cheni
Zone at the base of the Bir al Jaja Formation.
– The precision on the age of the Norian—Rhaetian—
Sinemurian sediments of the Abu Shayban Formation and
the Bi’r al Ghanam Gypsum Member and determination of
the duration of its hiatuses.
– Detailed study of the lagoonal Pliensbachian—Toar-
cian sediments of the Bu en Niran Member (upper part of
the Bi’r al Ghanam Formation) and paleontological re-
search to find the possibility of approving the age of some
important fossil levels corresponding to the marine incur-
sion in these lagoonal sediments.
– The pebbles of detrital conglometatic sediments of
Tigi Group and the Kiklah Formation, considered herein,
as Aptian—Albian in age.
– The paleomicrobiofacies of carbonate sediments with
the detailed paleontological (macro-, microfauna, nanno-
plankton and palynomorphous) studies of post-tectonic
Cenomanian to Coniacian lagoonal sediments (Sidi as Sid
Formation, Nalut Formation, Qasr Tigrinnah Marl Member
and the Mizdah Formation).
Acknowledgment: This study of Upper Jurassic—Lower
Paleogene lithostratigraphy, facies development and its
problems was supported by the Project MSM 0021620855
on Geophysical Department, Faculty of Sciences, Charles
17
UPPER JURASSIC—LOWER PALEOGENE LITHOSTRATIGRAPHY (LIBYA)
University, Prague. We thank the former Head of this De-
partment Prof. RNDr. M. Kobr, CSc for his help in our
work and for remarks to Prof. RNDr. P. Čepek. CSc (Dept.
of Geology, Faculty of Sciences, Prague), Assoc. Prof. Dr.
J. Michalík (Geol. Institute of the SAS, Bratislava) and
Ph.D. Ahmed Muftah (Garyounis University, Faculty of
Sciences, Dept. of Earth Sciences, Benghazi). We also
thank the Industrial Research Centre, Tripoli for permis-
sion to publish this note.
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