Northeast Libya Research Articles

Sequence stratigraphic architecture and depositional evolution of the early Eocene-early Miocene Al Jabal Al Akhdar carbonate successions, N Cyrenaica Promontory, NE Libya – Interplay of tectonics and eustasy

The interactions of tectonics and eustasy on the stratigraphic architectural evolution of the early Eocene-early Miocene Al Jabal Al Akhdar carbonate sedimentary successions were evaluated. This evaluation was achieved through detailed analyses of microfacies, depositional interpretation, and sequence stratigraphic framework of five measured sections located within the Al Jabal Al Akhdar Uplift, northeast Libya. The study interval was subdivided into distinct microfacies based on lithological changes, grain size and components, sedimentary texture and structures, fossil contents, color, and vertical stacking pattern. Six major depositional settings were delineated: restricted lagoon, open marine lagoon, platform margin and shoals, platform-margin reefs, foreslope, and middle to lower slope. Four third-order unconformity-bounded depositional sequences were identified based on vertical and lateral facies distribution, variations in fossil contents, and diagenetic features. Each sequence is composed of a transgressive-regressive interval, except for the younger sequence, which only contains a transgressive unit. Four evolutionary stages are recognized: initiation, growth, high-relief platform, and subaerial exposure. Subsidence resulting from tectonism and sediment loading, coupled with rising sea-level, created the accommodation space for the sedimentation of the studied carbonates. Repeated eustatic sea-level fluctuations controlled the internal stratigraphic heterogeneity and sequence development. Tectonic uplift caused a major sea-level retreat, resulting in the emersion of the carbonate sequences. The pre-existing Mesozoic and Paleocene sequences that underwent major uplift during the Late Cretaceous-early Eocene formed a shallow-water positive-antecedent topography for the formation of the carbonate sediments. This study establishes a carbonate sequence stratigraphic hierarchy of different cyclic sedimentation orders and improves our knowledge of sedimentary and stratigraphic architectural evolution and depositional mechanisms of carbonate platforms in an inverted basin setting. This knowledge can aid in predicting the distribution of lithofacies and depositional systems of economic importance.

Geological, physiochemical, mineralogical, and rheological characterizations of clay deposits in Northeast Libya

ABSTRACT This study was conducted on bentonite deposits in Um Al Rozm and Ain Al Ghazala areas that lie between Latitudes º32 “00 ‘30 and º32 “33 ‘30 N and Longitudes º23 “00 ‘30 and º23 “20 ‘30 E in Northeast Libya. The objective of this study is the assessment of geological, physiochemical, mineralogical, and rheological properties and the potentiality of utilizing these rocks as drilling fluids for oil and gas wells. Chemical and mineralogical analyses were performed by XRF and XRD, respectively. Rheological properties are investigated before and after the treatment process by adding additive materials such as Na2CO3 and CMC. The chemical analysis results of bentonite showed a discrepancy in the proportions of the major components. The results after the treatment process for bentonite in Um Al Rozm exhibit rheological properties consistent with those stipulated by API and other standard bentonites, but for Ain Al Ghazala, the results are unsatisfactory. Mineral analysis of bentonite from the two areas revealed a difference in the mineral composition. The bentonite of the Um Al Rozm area is Na-bentonite, while the bentonite of the Ain Al Ghazala area is Ca-bentonite, whose rheological properties aren’t acceptable as drilling fluid properties stipulated by API.

Ancient Olive Presses and Oil Production in Cyrenaica (North-East Libya) by Ahmed M. A. Buzaian (review)

Ancient Olive Presses and Oil Production in Cyrenaica (North-East Libya) by Ahmed M. A. Buzaian (review)

Recent Benthic Foraminifers from the Coast of Susa Area, North East Libya: Taxonomic Notes and Environmental Implications

Recent Benthic Foraminifers from the Coast of Susa Area, North East Libya: Taxonomic Notes and Environmental Implications

First record of Pluchea dioscoridis (Asteraceae) in Northern Libya

Pluchea dioscoridis (L.) DC. is a species native to Eastern Africa that has been recorded for the first time in northern Libya. It was discovered growing around the city of Benghazi in populations of more than 100 plants beside roads and inside city gardens, and also on the edge of the salt marshes in a typical wet habitat of halophyte plants about five kilometres east of Benghazi and not far from the shoreline in north-east Libya. Populations of this plant were first noticed in 2018 once the civil war was over in Benghazi and confirmed during an investigative research project that aimed to evaluate the state of vegetation four years after the evacuation of the city.

Geomorphosite Inventory of Apollonia and Cyrene in Northeast Libya: involvement in Geotourism Promotion

Libya is located on the southern shore of the Mediterranean Sea in the northern part of Africa. Geomorphological landforms known as geomorphosites are those that have been seen or exploited by humans as having scientific, cultural/historical, aesthetic, or social/economic significance. Various geomorphosites transverse Libya and can be found in other parts of the world. United Nations Educational Scientific and Cultural Organization (UNESCO) geoparks need to conduct a comprehensive inventory of such geomorphosites to protect, promote, and geoconserve these sites for future generations. Geotourism promotion in Libya offers a great opportunity for the local community to grow and prosper. Additional African and developing countries with attractive geosites and landforms that can be promoted as geotourism destinations should be included in this initiative. The present study evaluates and assesses the geomorphosites in Cyrene and Apollonia. These sites are considered to possess regional importance, whose particular archeological and world heritage sites are indexed in UNESCO World Heritage, which makes the region a unique study subject. The area is highly recommended to be a geopark. Libya’s substantial geological assets, notably geoheritage, are enhanced in this study. These resources can promote local, sustainable development through scientific research, educational initiatives, geotourism expansion, and diversification of Libya’s isolated desert areas.

Microfacies Analysis and Depositional Environment of the Middle-Late Oligocene Al Abraq Formation, N Cyrenaica Promontory, Northeast Libya

Microfacies Analysis and Depositional Environment of the Middle-Late Oligocene Al Abraq Formation, N Cyrenaica Promontory, Northeast Libya

Pollution impact on recent mollusks along the Mediterranean coast between Abu Traba and Al Kuwifia, NE Libya

The current study assessed the levels of pollution on recent mollusks along the Mediterranean coast from Abu Traba to Al Kuwifia, Northeast Libya. Twenty-five molluskan species have been documented in total. However, only thirteen taxa were chemically analyzed in this study. The chemical analysis showed that the Cerastoderma glacum and Venus sp. are good accumulators for Zinc (Zn), Lead (Pb) and Thorium (Th), while Cerithium sp. A and Cerithium sp. B are fine collectors for Uranium (U). Most of the analyzed metals have Enrichment Factor (EF)>2 suggesting that they are mainly of anthropogenic origin. We recommend treating the pollution levels of Lead (Pb), Arsenic (As) and Selenium (Se) in different localities of the study area, especially in Abu Traba and Al Kuwifia localities.

Hydro-geochemical review of groundwater and rain waters from Al Jabal Al Akhdar, Northeast Libya

Groundwater recharge and age dating using stable and carbon isotopes in northern Cyrenaica have been performed during the seventies of the last century. Twenty-eight groundwater samples (springs and wells), as well as sixty rain water samples, were collected from four hydrogeological units in Al Jabal Al Akhdar that have been analyzed in order to determine the composition of the stable isotopes (δ2H, δ18O, 14C, and 13C). Tritium is used herein to determine if there is any direct infiltration of modern water to the existed aquifers in the study area. The range of compositions for each rainwater sample is: δ2H (–28.3‰ to 0.3‰) and δ18O (-5.32‰ to 0.33‰) for Benghazi rain samples whereas δ2H (-35‰ to -22.6‰) and δ18O (-6.5‰ to -4.43‰) for Al Marj rain samples which show apparently oceanic and continental effects on the studied samples to the Global Meteoric Water Line (GMWL). The Miocene water samples have δ2H and δ18O values indicated an increasing in aridity as the deuterium excess is reduced due to evaporation effects. Given this result, the isotopic values indicate that the groundwater pumped from wells in Benghazi – Al Marj region resulted from the mixing of at least two groundwater systems. Seawater intrusion should be considered in the Ayn Zayanah-Al Coeffiah karstic system. Additionally, the δ2H/δl8O ratios show that most of the Ayn Zayanah spring discharges contain evaporated waters due to enrichment in isotopic values

Potential and perspectives for establishing protected areas in El-Jabal El-Akhdar region, northeast Libya; an overview and example from ‘El-Abyar area’

This study was conducted in El-Abyar area in El-Jabal El-Akhdar region, northeast Libya. The aim was to study the environmental settings and the potential and possibility of establishing a protected area in this important region from a historical, biological, social, and economic point of view. The methodology included an intensive literature review, distribution of 300 questionnaires, soil and water analysis, fauna and flora survey, in addition to extensive field observation during the period from 2011 to 2021. The study highlighted the significant representative state of the study area for the whole El-Jabal El-Akhdar region in terms of environmental conditions and inappropriate anthropogenic pressure. Although the area has been severely degraded due to the arid climate coupled with decades of mismanagement, it still has remarkable ecological and environmental features and there is a feasible possibility of being converted into an effective protected area for biodiversity conservation with sustainable use of its natural resources by the local population (Category VI on the International Union for Conservation of Nature Classification for protected areas). The remaining barriers for which drastic solutions need to be implemented are a lack of awareness, a lack of protected areas guidelines and national perspectives, interest conflict with local people, a lack of constant funding, and failure of legislation enforcement.

Paleocurrent Analyses of the Sahabi and Wadi al Farigh Areas, Southeast Ajdabiya, Sirt Basin, Libya

Cross-beddings paleocurrents recorded from the Neogene sediments in the Sahabi and Wadi Al Farigh areas, northeast Libya were analyzed. The exposed rocks contained cross-bedding in the Sahabi area belonging to the upper Miocene "upper member" (Units 1, 2, 3) and the Pliocene lower part Member "V" of the Sahabi Formation. Cross-beddings in Unit 1 and Member "V" are represented by a paleocurrent towards the southwest direction, whereas in Units 2 and 3, the paleocurrent is towards the northeast direction. Cross-bedded strata in the Wadi Al Farigh area belongs to Wadi Al Farigh Member of the Sahabi Formation. Cross-beddings were originated by a paleocurrent flow that oscillated between northwest and southeast. Based on this data from both areas, sediments of the Wadi Al Farigh Member originated from the northwest probably due to the Mediterranean Sea, whereas sediments of Units 1, 2, 3, and Member “V” originated from the south and southwest most likely due to the Eosahabi River supply. Wadi Al Farigh Member may have acted as a migrated barrier bar of lime-sand shoal, which isolated the inland the Sahabi area at the south from the coastal area at the north. The isolation that occurred in the Sahabi area has restricted the depositional environments to sabkhas and lagoons, which are responsible for evaporitic deposits in the area.

Molecular characterization and genetic diversity of four undescribed novel oleaginous Mortierella alpina strains from Libya

Background: A large number of undiscovered fungal species still exist on earth, which can be useful for bioprospecting, particularly for single cell oil (SCO) production. Mortierella is one of the significant genera in this field and contains about hundred species. Moreover, M. alpina is the main single cell oil producer at commercial scale under this genus. Methods: Soil samples from four unique locations of North-East Libya were collected for the isolation of oleaginous Mortierella alpina strains by a serial dilution method. Morphological identification was carried out using light microscopy (Olympus, Japan) and genetic diversity of the isolated Mortierella alpina strains was assessed using conserved internal transcribed spacer (ITS) gene sequences available on the NCBI GenBank database for the confirmation of novelty. The nucleotide sequences reported in this study have been deposited at GenBank (accession no. MZ298831:MZ298835). The MultAlin program was used to align the sequences of closely related strains. The DNA sequences were analyzed for phylogenetic relationships by molecular evolutionary genetic analysis using MEGA X software consisting of Clustal_X v.2.1 for multiple sequence alignment. The neighbour-joining tree was constructed using the Kimura 2-parameter substitution model. Results: The present research study confirms four oleaginous fungal isolates from Libyan soil. These isolates (barcoded as MSU-101, MSU-201, MSU-401 and MSU-501) were discovered and reported for the first time from diverse soil samples of district Aljabal Al-Akhdar in North-East Libya and fall in the class: Zygomycetes; order: Mortierellales. Conclusions: Four oleaginous fungal isolates barcoded as MSU-101, MSU-201, MSU-401 and MSU-501 were identified and confirmed by morphological and molecular analysis. These fungal isolates showed highest similarity with Mortierella alpina species and can be potentialistic single cell oil producers. Thus, the present research study provides insight to the unseen fungal diversity and contributes to more comprehensive Mortierella alpina reference collections worldwide.

Molecular characterization and genetic diversity of four undescribed novel oleaginous Mortierella alpina strains from Libya.

Background: A large number of undiscovered fungal species still exist on earth, which can be useful for bioprospecting, particularly for single cell oil (SCO) production. Mortierella is one of the significant genera in this field and contains about hundred species. Moreover, M. alpina is the main single cell oil producer at commercial scale under this genus. Methods: Soil samples from four unique locations of North-East Libya were collected for the isolation of oleaginous Mortierellaalpina strains by a serial dilution method. Morphological identification was carried out using light microscopy (Olympus, Japan) and genetic diversity of the isolated Mortierella alpina strains was assessed using conserved internal transcribed spacer (ITS) gene sequences available on the NCBI GenBank database for the confirmation of novelty. The nucleotide sequences reported in this study have been deposited at GenBank (accession no. MZ298831:MZ298835). The MultAlin program was used to align the sequences of closely related strains. The DNA sequences were analyzed for phylogenetic relationships by molecular evolutionary genetic analysis using MEGA X software consisting of Clustal_X v.2.1 for multiple sequence alignment. The neighbour-joining tree was constructed using the Kimura 2-parameter substitution model. Results: The present research study confirms four oleaginous fungal isolates from Libyan soil. These isolates (barcoded as MSU-101, MSU-201, MSU-401 and MSU-501) were discovered and reported for the first time from diverse soil samples of district Aljabal Al-Akhdar in North-East Libya and fall in the class: Zygomycetes; order: Mortierellales. Conclusions: Four oleaginous fungal isolates barcoded as MSU-101, MSU-201, MSU-401 and MSU-501 were identified and confirmed by morphological and molecular analysis. These fungal isolates showed highest similarity with Mortierella alpina species and can be potentialistic single cell oil producers. Thus, the present research study provides insight to the unseen fungal diversity and contributes to more comprehensive Mortierella alpina reference collections worldwide.

Mineralogical and Geochemistry Study of Darnah Formation in Wadi Al Kharsha, Northeast Libya

This paper has been carried out to determine the mineralogical and geochemical characteristics of Eocene Darnah limestone which outcrops at Wadi Al Kharsha as an example of the Darnah Formation. The most conspicuous phenomenon is the upward increase of the dolomitization process, whereas, the dolomite content ranges from 4.34 to 15.48 % with an average value of 8.99%. The lime (CaO) represents the major predominant with a high content (48.08%), it can be blend with other carbonates to improve its quality to meet the specifications of raw material for cement manufacture. The relationship between calcium (CaO) and magnesium (MgO) exhibits a significantly strong negative linear correlation coefficient (R2 = 0.967), which emphasizes the dolomitization process, while the relationship between SiO2 and Al2O3 is a positive linear significant relationship with a strong correlation coefficient (R2 = 0.98), whereas, the SiO2 increases with increasing of Al2O3. The calculated mineralogical composition revealed that halite, gypsum, and hematite are considered to be minor constituents, almost less than 1.0%. Keywords: Limestone; Darnah Formation; Mineralogy; Geochemistry; Dolomitization; Characterizations; Cement

Facies analysis and depositional environments of the lower Eocene–lower Miocene succession in Northeast Libya

Facies analysis and depositional environments of the lower Eocene–lower Miocene succession in Northeast Libya

Origin of cherts in Al Jabal al Akhdar, northeast Libya: petrographical and paleontological evidences

This paper discusses the petrographical and paleontological characteristics of the exposed siliceous (chert nodules) at Al Jabal al Akhdar in northeast Libya. Cherts are found in four rock units and at four superimposed horizons: Al Athrun Formation (Campanian–Maastrichtian) is the oldest one which is overlain by Apollonia Formation (Early–Middle Eocene), then Darnah Formation (Middle–Late Eocene) and Wadi al Qattarah Formation (Late Miocene) the youngest formations. This study is based on field observation and petrographical and paleontological examinations of both chert nodules and hosting limestone rock. Petrographically, the source of the silica in the chert nodules of the Al Athrun Formation is proved to be from silica-rich fluid due to the radiolarian. However, in Apollonia Formation, the sponges seem to be the source. Meanwhile, Darnah Formation and Wadi al Qattarah Formation are suggested to be secondary in origin (i.e., diagenetically is evidenced in the silica replacement to shells). Therefore, further study using more petrographical and paleontological samples will be demanded in order to confirm the biogenic source of Darnah and Wadi al Qattarah formations.

Quality assessment of the surface and underground water in the region of Al Jabal Al Akhdar, Libya

Surface and groundwater are the main sources of water supply in Libya. This study aims to assess the water quality index for drinking and irrigation purposes. 15 surfaces and 47 groundwater samples are collected in an area where lies in Al Jabal Al Akhdar region, northeast Libya. Water quality parameters such as temperature (T), pH levels, EC, TDS, TH, TAK, major cations ( Ca2+, Mg2+, Na+, K+ and NH4+) and major anions (Cl-, PO43-, HCO3-, NO3-, SO42- and NO2-) were measured. Water quality indices including SAR, % Na, RSC, PI, MH, Kelly’s Ratio and PS were also computed. Main water types were classified based on Piper trilinear diagram. The results revealed a basic pH level for surface water with a maximum level of 7.88. In addition, it is also exhibited a basic pH level for groundwater in the wet season and changed from acidic to basic in the dry season with a maximum level of 8.1. This indicates high-level concentrations of bicarbonate in water samples as measured. It observed that the ratio between TDS and EC increased with the decrease of pH levels, which indicates more releasing inorganic matter. Calcium and sodium are the dominant cations while Bicarbonate and sulfate are the dominant anions in water samples. Based on the U.S salinity, the Wilcox, and the Doneen classifications, the obtained results revealed that the surface water is suitable for drinking and irrigation purposes. Meanwhile, the groundwater is classified between excellent and doubtful except for some samples that were classified as unfit for irrigation purposes. Furthermore and based on the Piper diagram, the water types are classified as calcium sulfate, sodium chloride and as calcium bicarbonate. The water statuses categorization, based on the computational method of water quality index for drinking and irrigation agree with that concluded by US salinity, the Wilcox, and the Doneen diagram.

Evaluation of groundwater quality along al-abyar area, northeast libya

Worldwide, the stress on the freshwater resources is increasing due to population growth and rapid industrialization. Libya is considered as one of the countries which suffer from limited water resources availability. Groundwater is an important water resource in both the urban and rural areas of Libya. To evaluate the quality of groundwater for multiple purposes in the Abyar aera with regard to Physical, Chemical, Heavy Metals and Microbiological. The study conducted in Al-Abyar Regin on seven wells; duration from July 2018 to July 2019, for the following’s parameters, Physical pH, Electrical Conductivity (EC), Temperature (0C), Total dissolved Solids (TDS), Chemical Total Hardness (TH), Total Alkalinity (T. Alk), Sulphate (SO4), Nitrate (NO3), Chloride (Cl), Calcium (Ca), Magnesium (Mg), Potassium (K), Sodium (Na), Bicarbonate (HCO3), Heavy Metals Cadmium (Cd), Copper (Cr), Lead (Pb), Iron (Fe), and Microbiological total coliforms and Total Bacterial counts, and analysis of Results done with Excel as well as spss. Results showed that; Electrical Conductivity, Total Dissolved Solids, total hardness, Calcium, Chloride and total bacterial count were higher than WHO standard. Bicarbonate level was higher than WHO standard in most of the wells. Most of wells were higher than WHO standard with regard of Nitrate. all wells were higher than WHO as well as Libyan standard with regard cadmium, Iron and lead. While temperature, Ph, potassium was normal. All wells were very good for animal consumption, good for domestic purposes, and very acceptable for poultry, some wells may be used in paper industry, Textile, canning and drinks industry. Repair and maintain the wells should be one of the most priority to improve socioeconomic status in Al-Abyar region, and monitor the water quality periodically in essential.

Impact of Edaphic Factors on Vegetation Composition in Al-Jabal Al-Akhdar, Libya

AL JABAL Al Akhdar region is a typical mountainous ecosystem, North East Libya characterized by unique environment in the Middle East. The aim of this study was to examine the spatial pattern of vegetation composition and its relationship with environmental variables in Al Jabal Al Akhdar. Vegetation sampling was carried out using 63 stands on studied seven wadis, distributed at Al Jabal Al Akhdar. The results showed that the study area is the home of 91 species, belonging to 85 genera and 44 families. Twelve of the recorded species are endemic and endangered plants. Application of TWINSPAN program and (DCA) resulted in identification of seven vegetational groups (from A to G) at cut level three of the TWINSPAN classification. Using Canonical Correspondence Analysis (CCA) against the soil variables revealed that the most important correlation of environmental variables with species distribution in Al Jabal Al Akhdar are chloride content, pH value, silt content and major cations (Na+ , Ca+2, Mg+2 and K+).

Surface runoff estimation of Wadi Ba Al-Arid watershed North East Libya, using SCS-CN ,GIS and RS data

The aim of this study is to estimate runoff in Wadi Ba Al Arid watershed for a period of ten years 2009-2018 by Soil Conservation Service Curve Number (SCS-CN) method in combination with the GIS techniques using remote sensing data. The used data are the daily rainfall data from NASA Prediction of Worldwide Energy Resource (POWER), digital elevation data (DEM) from ALOS PALSAR RTC , satellite imagery from the European Space Agency (ESA) Sentinel, and soil data represented in soil maps of a scale 1: 50,000 and some local studies carried out by several Libyan institutions. The overall area of the watershed is about 136.4 km2 and perimeter107.3 Km. The watershed upstream and downstream is well recognized due to the topographical difference as a result of the tectonic geology. Soil maps were processed and classified into hydrologic soil groups (HSG), where the dominant HSG in the study area are C and D. The Landcover/Land use (LULC) was classified into five classes (forest, shrubs, agriculture, barren land) and built up. The HSG and LULC layers were intersected and the CN values and the weighted curve number for each Antecedent Moisture (AMC) condition were assigned. Furthermore, the runoff depth was estimated and the average runoff volume for ten years during 2009–2018 in the study area was estimated by 1.67 Mm3 which represents 4.6 % of the observed average annual rainfall as 264.3 mm during 2009-2018. The rainfall-runoff relationship has shown a strong correlation with the value of 0.75.