Deltaic sedimentation in the Devonian of Western Libya

Vos, Richard G.

doi:10.1016/0037-0738(81)90057-9

Cited by 25 publications

(12 citation statements)

References 9 publications

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“…This correlates with findings from other authors who investigated Palaeozoic flow directions in this area (e.g. Selley, 1997;Vos, 1981). If the Murzuq Basin was a syndepositional basin during the Carboniferous, as suggested by a palaeogeographic reconstruction of Carr (2002), it would be expected that fluvial channels would have a dominant palaeoflow direction from the basin margins towards the centre to the south-east.…”

Section: Palaeogeographic Implicationssupporting

confidence: 60%

Sedimentological and sequence stratigraphic analysis of Carboniferous deposits in western Libya: Recording the sedimentary response of the northern Gondwana margin to climate and sea-level changes

Fröhlich

Petitpierre

Redfern

et al. 2010

Journal of African Earth Sciences

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a b s t r a c tDetailed sedimentological and sequence stratigraphic analysis of Carboniferous (Tournaisian to Moscovian) strata exposed in the north-western Murzuq Basin and southern Ghadames Basin, western Libya, provides new insights into the sedimentary response of the northern Gondwana margin to climate and sea-level change.The Lower Carboniferous Marar and Assedjefar Formations can be divided into five depositional sequences of 3rd order. In total 27 facies types are defined, grouped into four facies associations: offshore shales, shallow marine clastics, fluvial sandstones and marine carbonates.The bulk of the Lower Carboniferous interval is dominated by an alternation of offshore shales and shallow marine clastics, which were deposited during the transgressive and highstand systems tracts. The clastic deposits mostly consist of laterally persistent coarsening and thickening upward cycles with a common succession from basal hummocky cross-stratified sandstones to ripple-laminated sandstones, capped by multidirectional cross-stratified sandstones.Within the lowstand systems tracts, lenticular sandbodies have been identified, which vary in thickness from 1.5 m (ca. 40 m wide) to 50 m (ca. 1.5 km wide). These are interpreted to be fluvial channel complexes based on their geometry, erosive base, and presence of thick stacked sandstones with unidirectional planar and trough cross-bedding, the absence of bioturbation and occurrence of land plant fragments. These channel complexes mostly cut down into offshore shales, and are interpreted to be bound at the base by sequence boundaries. Palaeogeographic maps generated for each lowstand system show the location and palaeoflow direction of these fluvial channel complexes. They are interpreted to represent large incised valleys filled with thick fluvial sandstones. Their identification and distribution indicates repeated exposure of large areas of western Libya, most-likely controlled by major eustatic sea-level changes.The Assedjefar Formation exibits a gradual decrease in coarse clastic sediment supply throughout the Serpukhovian and by the Bashkirian and Moscovian during the deposition of the Dembaba Formation a carbonate depositional system was established. Limestones are dominantly made up of a heterozoan fauna (brachiopods, crinoids, bryozoans, gastropods) and are mostly preserved as shallow marine storm and coastal deposits. It is hypothesised that a local increase in aridity and/or the gradual erosion and decreasing topography of the hinterland mountains, with the resulting reduction in discharge, controlled this shift from clastic to carbonate deposition.Available data indicate that the Murzuq Basin was interconnected with the Ghadames Basin at this time and is a postdepositional basin with respect to the Carboniferous interval. The sedimentological and sequence stratigraphic data from the present study offer new insights into the depositional setting and facies distribution in the Carboniferous, and the recognition of major incised fluvial systems has signifi...

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Section: Palaeogeographic Implicationssupporting

confidence: 60%

Sedimentological and sequence stratigraphic analysis of Carboniferous deposits in western Libya: Recording the sedimentary response of the northern Gondwana margin to climate and sea-level changes

Fröhlich

Petitpierre

Redfern

et al. 2010

Journal of African Earth Sciences

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“…Palaeocurrents measured in outcrops in the Cambrian and Ordovician sediments show north -NW flow directions (Vos 1981;Massa 1988;Ramos et al 2006), which are the ones observed regionally by Beuf et al (1971). The Ordovician succession presents a rather complex geometry in outcrops.…”

Section: Summary Of the Stratigraphic Architecture Of The Cambrian Tomentioning

confidence: 69%

Palaeohighs: their influence on the North African Palaeozoic petroleum systems

Eschard

Braik

Bekkouche

et al. 2010

PGC

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We present new insights for the characterization of the petroleum system evolution in North Africa based on a review of the stratigraphic architecture description of some selected North African Palaeozoic basins. During Palaeozoic time, the Gondwana platform was divided into sub-basins bounded by structural highs. Most of the highs were inherited from north-south and SW-NE Pan-African crustal faults which were reactivated during the Palaeozoic and later, in the Austrian and Alpine tectonic phases. We studied the stratigraphic architecture of the Palaeozoic succession around four main highs showing a clear tectonic activity during the Palaeozoic sedimentation. The Gargaff Arch, in Libya, is a major SW-NE broad anticline which slowly grew up during the Cambrian and Ordovician and stopped rising during the Silurian. The activity resumed during Late Silurian and early Devonian and during the Late Devonian. The Tihemboka High is a north-south anticline in between Libya and Algeria. The uplift started during the Cambro-Ordovician then stopped during most of the Silurian. The activity resumed during the Late Silurian and continued until the Lower Carboniferous. The Ahara High, separating the Illizi and Berkine basins in Algeria, has continuously grown during the Cambro-Ordovician, stopped rising during the Silurian, and grew again continuously during the Devonian. The Bled El-Mass High is a part of the Azzel-Matti Ridge separating the Ahnet and Reggane basins in Algeria. The high mostly rose during the Cambro-Ordovician then subsided relatively less quickly than the surrounding basins during the Silurian and Devonian. The uplift timing and chronology of each palaeohigh partly controlled the petroleum systems of the surrounding basins. Topographic lows favoured the occurrence of anoxic conditions and the preservation of Lower Silurian and Frasnian source rocks. Complex progressive unconformities developed around the palaeohighs form potential complex tectonostratigraphic traps. Finally, hydrocarbons could have been trapped around the highs during pre-Hercynian times, preserving reservoir porosity from early silicification. Mixed stratigraphic-structural plays could then be present today around the highs.

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“…Fluvial intervals are minor but present. The direction of sediment transport was generally towards the northwest and west (Vos 1981).…”

Section: Geological Settingmentioning

confidence: 97%

“…Wave ripples, low angle parallel lamination, and trough and hummocky cross-stratification are common features. The sediments of the Awaynat Wanin Group were deposited in a shallow marine deltaic environment within the storm wave base, with prodelta silty clay/claystone beds passing upward into distributary channel sandstones (Vos 1981. Fluvial intervals are minor but present.…”

Section: Geological Settingmentioning

confidence: 99%

An unusual occurrence of Pedinopariops (Trilobita: Phacopidae) within siliciclastic facies in the Devonian of Awaynat Wanin, Libya

McKellar¹,

Chatterton²,

Meinhold³

et al. 2011

Bull. Geosci.

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A new phacopid trilobite is described from the Givetian sequence of the Awaynat Wanin Group in the southern Ghadamis Basin, Libya. The specimen displays most of the eye and sculpture features necessary for a determination and can be restricted to Pedinopariops (Hypsipariops) Struve, 1982. The new specimen does not belong to any taxon known so far and hence is considered to be a new species. The specimen remains in open nomenclature and is assigned to Pedinopariops (Hypsipariops) sp. nov. A. This is the first Devonian trilobite described from Libya, and represents an unusual occurrence of Phacopidae in a relatively coarse siliciclastic facies.•

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Deltaic sedimentation in the Devonian of Western Libya

Cited by 25 publications

References 9 publications

Sedimentological and sequence stratigraphic analysis of Carboniferous deposits in western Libya: Recording the sedimentary response of the northern Gondwana margin to climate and sea-level changes

Sedimentological and sequence stratigraphic analysis of Carboniferous deposits in western Libya: Recording the sedimentary response of the northern Gondwana margin to climate and sea-level changes

Palaeohighs: their influence on the North African Palaeozoic petroleum systems

An unusual occurrence of Pedinopariops (Trilobita: Phacopidae) within siliciclastic facies in the Devonian of Awaynat Wanin, Libya

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