Geochemistry, mineral paragenesis and geothermal conditions of oreforming fluids from the Ain El Bey Cu–Fe deposit: potential occurrence of native gold and precious metal traces (North African orogenic belt, Northern Tunisia)

The Ain El Bey abandoned mine, in North-West Tunisia, fits into the geodynamic context of the European and African plate boundary. Ore deposit corresponds to veins and breccia of multiphase Cu–Fe-rich mineralization related to various hydrothermal fluid circulations. Petromineralogical studies indicate a rich mineral paragenesis with a minimum of seven mineralization phases and, at least, six pyrite generations. As is also the case for galena and native silver, native gold is observed for the first time as inclusion in quartz which opens up, thus, new perspectives for prospecting and evaluating the potential for noble metals associated with the mineralization. Scanning Electron Microscope--Energy Dispersive Spectroscopy and Transmission electron microscopy analyses show, in addition, a large incorporation of trace elements, including Ag and Au, in mineral structures such as fahlores(tetrahedrite-tennantite) and chalcopyrite ones. The mineral/mineral associations, used as geothermometers, gave estimated temperatures for the mineralizing fluids varying from 254 to 330 ℃ for phase Ⅲ, from 254 to 350 ℃ for phase Ⅳ, and from 200 to 300 ℃ for phases Ⅴ and Ⅵ. The seventh and last identified mineralization phase, marked by a deposit of native gold, reflects a drop in the mineralizing fluid’s temperature(< 200 ℃) compatible with boiling conditions. Such results open up perspectives for the development of precious metal research and the revaluation of the Cu–Fe ore deposit at the Ain El Bey abandoned mine, as well as at the surrounding areas fitting in the geodynamic framework of the Africa-Europe plate boundary.

Profiles of the Headspace Volatile Organic and Essential Oil Compounds from the Tunisian Cardaria draba (L.) Desv. and Its Leaf and Stem Epidermal Micromorphology

In this work, we investigated aroma volatiles emanated by dry roots, stems, leaves, flowers, and fruits of Cardariadraba (L.) Desv. growing wild in Tunisia and its aerial part essential oils (EOs) composition. A total of 37 volatileorganic compounds (96.7%–98.9%) were identified;4 esters, 4 alcohols, 7 hydrocarbons, 12 aldehydes, 5 ketones,1 lactone, 1 organosulfur compound, 2 organonitrogen compounds, and 1 acid. The hydrocarbons form the maingroup, representing 49.5%–84.6% of the total detected volatiles. The main constituent was 2,2,4,6,6-pentamethylheptane(44.5%–76.2%) reaching the highest relative percentages. Forty-two compounds were determined in thetwo fractions of EOs, representing 98.8% and 97.2% of the total oil composition, respectively. The principal componentswere hexadecanoic acid (34.6%), 6-methyl-5-hepten-2-one (18.3%), decanal (15.0%), 6,10,14-trimethyl-2-pentadecanone (13.2%), and n-pentacosane (13%). Micromorphological details of the leaf and stem epidermisusing light microscopy revealed polygonal cells with sinuous walls in the adaxial and abaxial leaf surfaces andnearly rectangular and long ones with linear and thick walls for the stem epidermis. The stomata complexes wereanisocytic in the leaf epidermis and mainly anisocytic and rarely paracytic in the stem epidermis. Non-glandulartrichomes were unbranched and long with an acute apex or short with a convex apex. The glandular ones wereidentified for the first time in this species. They were short-stalked with a large secretory head. The highest stomatalindex (17.02%) was recorded in the abaxial leaf surface. The identification of headspace volatiles and essentialoil compounds can be used to characterize this species, and the various epidermis micromorphologicalfeatures are very useful for biosystematics taxonomic studies within Brassicaceae.

Potential risk of soil irrigation with treated wastewater over 40 years:a field experiment under semi-arid conditions in northeastern Tunisia

In Tunisia,water scarcity is only adding pressure on water demand in agriculture.In the context of sustainable development goals,Tunisia has been reusing treated wastewater(TWW)as a renewable and inexpensive source for soil fertigation and groundwater(GW)recharge.However,major risks can be expected when the irrigation water is of poor quality.This study aims for evaluating the potential risk of TWW and GW irrigation on soil parameters.Accordingly,we evaluated the suitability of water quality through the analysis of major and minor cations and anions,metallic trace elements(MTEs),and the sodium hazard by using the sodium adsorption ratio(SAR)and the soluble sodium percentage(SSP).The risk of soil sodicity was further assessed by SAR and the exchangeable sodium percentage(ESP).The degree of soil pollution caused by MTEs accumulation was evaluated using geoaccumulation index(Igeo)and pollution load index(PLI).Soil maps were generated using inverse spline interpolation in ArcGIS software.The results show that both water samples(i.e.,TWW and GW)are suitable for soil irrigation in terms of salinity(electrical conductivity<7000μS/cm)and sodicity(SAR<10.00;SSP<60.00%).However,the contents of PO_(4)^(3-),Cu^(2+),and Cd^(2+)exceed the maximum threshold values set by the national and other standards.Concerning the soil samples,the average levels of SAR and ESP are within the standards(SAR<13.00;ESP<15.00%).On the other hand,PLI results reveal moderate pollution in the plot irrigated with TWW and no to moderate pollution in the plot irrigated with GW.Igeo results indicate that Cu^(2+)is the metallic trace element(MTE)with the highest risk of soil pollution in both plots(Igeo>5.00),followed by Ni^(2+)and Pb^(2+).Nevertheless,Cd^(2+)presents the lowest risk of soil pollution(Igeo<0.00).Statistical data indicates that Ca^(2+),Na+,Ni^(2+),and Pb^(2+)are highly distributed in both plots(coefficient of variation>50.0%).This study shows that the use of imagery tools,such as ArcGIS,can provide important information for evaluating the current status of soil fertility or pollution and for better managing soil irrigation with TWW.

Inventory, Systematic and Biogeography of Brachyuran Crabs (Crustacea: Decapoda: Brachyura) on the Tunisian Coast

Several prospects on the northern, central and southern Tunisian coasts were carried out for the sake of a better interpretation of Brachyuran species distribution. Animals were either, captured by hand, caught with a fine mesh net or brought back by fishermen in nets or dredges. A total of 21 species belonging to twelve families and inhabiting different substrates were collected and divided into littoral species and species of depth. Five species were reported for the first time, in Tunisia. The littoral species are Carcinus aestuarii, Liocarcinus corrugatus, Liocarcinus vernalis, Pachygrapsus marmoratus, Pachygrapsus maurus, Brachynotus sexdentatus, Eriphia verrucosa, Maja squinado, Maja crispata, Acanthonyx lunulatus and Pisa tetraodon. The species of depths are Portunus hastatus, Euchirograpsus liguricus, Xantho granulicarpus, Ilia nucleus, Inachus dorsettensis, Lissa chiragra, Pisa corallina, Pisa armata, Calappa granulata and Dromia personata. All these species are reported in the Mediterranean. Some are reported for the first time in Tunisia: P. maurus, A. lunulatus, P. hastatus, E. liguricus, L. chiragra and P. corallina. In order to know the frequency of each species, the presence index was calculated. Carcinus aestuarii present in 91% of prospected stations is the most frequent and wide-distributed brachyuran species along Tunisian coasts.

Intelligent Parking Management System by Multi-Agent Approach:The Case of Urban Area of Tunis

By coordination and cooperation between multi-agents, this paper proposes the network of intelligent agents which can reduce the search time needed to finding a parking place. Based on multi-agent model, the fined solution is designed to help drivers in finding a parking space at anytime and anywhere. Three services are offered: the search for a vacant place, directions to a parking space and booking a place for parking. The results of this study generated by the platform MATSim transport simulation, show that our approach optimizes the operation of vehicles in a parking need with the aim of reducing congestion, and improve traffic flow in urban area. A comparison between the first method where the vehicles are random and the second method where vehicles are steered to vacant parking spaces shows that the minimization of time looking for a parking space could improve circulation by reducing the number of cars in the morning of 2% and 0.7% of the evening. In addition, the traffic per hour per day was reduced by approximately 4.17%.

Fluoride in Tunisian Drinking Tap Water

This paper presents a fluoride health risk characterization approach to identify the hyper-sensitive population of adverse effect like tooth decay, dental fluorosis and skeletal fluorosis. In this context, a sampling campaign has been done over 100 Tunisian water consumption points (tap). Laboratory analysis results show that the quality of drinking water is affected by high fluoride concentration level exceeding 2 mg·L-1. Over these samples, 7% of them present non-compliant with the Tunisian national standard (NT09.14) and the international guidelines (World Health Organization recommendations, WHO). The overtake cases are located essentially in southern Tunisian areas, i.e. Medenine, Gabes, Gafsa and Tataouine. One can highlight that groundwater, in these southern Tunisian areas, are naturally rich of fluoride. This is because of the aquifers geological and fossil nature. However, commonly northern and central Tunisian areas are characterized by low fluoride concentration level below 0.1 mg·L-1. These undertaken cases don’t meet the water quality requirement defined by WHO.

Geochemical Record of the Cenomanian-Turonian Anoxic Event in Tunisia:Is it Correlative and Isochronous to the Biotic Signal?

In Tunisia, five Bahloul spaced sections, Bargou, Jerisa, Guern Halfaya, Kherij and Gafsa were analyzed for biostratigraphy （foraminifera and radiolarians） and major and trace elements. This high-resolution biostratigraphic and chemostratigraphic integrated analyses for the Late Cenomanian-Early Turonian Bahloul Formation provide new insight into the palaeoceanographic evolution of the southern Tethyan margin. Relative low abundance of related terrigenous Ti/Ai and K/ Al ratios and enrichment of some productivity proxies such as Ba, Cu, and Ni （organic matter related trace elements） suggests that the Bahloul, deposited during a relatively short period （0.5 Ma）, was of relatively elevated primary productivity and minimal detrital input. While higher D＊ values concurrent with lower Ti/AI ratios are interpreted as caused by enhanced fluvial material contribution, due to more humid climate during the OAE-2. Enhanced humidity triggered probably fluvial influxes, resulted in a sluggish water circulation and consequent anoxic/euxinic conditions favoring the preservation of organic matter at the bottom. Enrichments in redox-sensitive trace metals U, V, and Mo in the Bahloul Formation deposits and redox indices, such as V/（V＋Ni）, U/Th, V/Cr, and Ni/Co, indicate that oxygen-restricted conditions prevailed during the Late Cenomanian to earliest Turonian times and correlate well with relative abundances of some foraminiferal and radiolarian paleo- environmental relevant indicators. High Ba~ values and Uauth may indicate anoxic conditions at least at the water-sediment interface during the Bahloul Formation deposition and provide information about low to moderate sulfate-reduction reactions.

Integrating multiple electromagnetic data to map spatiotemporal variability of soil salinity in Kairouan region, Central Tunisia

Soil salinization is a major problem affecting soils and threatening agricultural sustainability in arid and semi-arid regions,which makes it necessary to establish an efficient strategy to manage soil salinity and confront economic challenges that arise from it.Saline soil recovery involving drainage of shallow saline groundwater and the removal of soil salts by natural rainfall or by irrigation are good strategies for the reclamation of salty soil.To develop suitable management strategies for salty soil reclamation,it is essential to improve soil salinity assessment pro cess/mechanism and to adopt new approaches and techniques.T his study mapped a recovered area of 7200 m2 to assess and verify variations in soil salinity in space and time in K airouan region in Central Tunisia,taking into account the thickness of soil materials.Two electromagnetic conductivity meters(EM38 and EM31)were used to measure the electrical conductivity of saturated soil-paste extract(ECe)and apparent electrical conductivity(E Ca).Multiple linear regression was established between ECe and ECa,and it was revealed that ECa-EM38 is optimal for E Ce prediction in the surface soils.Salinity maps demonstrated that the spatial structure of soil salinity in the region of interest was relatively unchanged but varied temporally.Variation in salinity at the soil surface was greater than that at a depth.These findings can not only be used to track soil salinity variations and their significance in the field but also help to identify the spatial and temporal features of soil salinity,thus improving the efficiency of soil management.

Sea-level rise impact on the evolution of a microtidal Mediterranean coastline without human-made structures——a case of the Port aux Princes-Sidi Daoued coastline,Gulf of Tunis,NE-Tunisia

The evolution of the natural and pristine Mediterranean coastline Port aux Princes-Sidi Daoued(Gulf of Tunis,NE-Tunisia) is studied during the period of 1887–2010 on the basis of an ancient minute of bathymetry(1887) and aerial photographs treated by numerical photogrammetric methods. Morphological changes of the coastline shows a general retreat despite the absence of the various anthropogenic actions. Adding to the drift currents and the currents of high energy that are generated by the N-W dominant waves along steeply sub-marine funds, the erosion is mainly due to the sea level rise which increased since the beginning of the 2000 s. The Port aux PrincesSidi Daoued coastline works as a single littoral cell limited by Jbel Korbous to the SW and the fishing harbor of Sidi Daoued to the N-E.

Hourly and monthly variations in the surface activity patterns of Hemilepistus reaumurii in arid environments of Tunisia

Life in desert ecosystems drives animals to adapt their surface locomotor activity according to environmental conditions. In this study, the hourly and monthly variations in the surface activity patterns of the terrestrial crustacean Hemilepistus reaumurii were investigated. The surface activity of H. reaumurii at the population scale was observed by collecting the hourly active individuals from the sunrise to the sunset of the studied day in each month of 2013 in the Bchachma locality, Tunisia. The collected active individuals were put in perspex boxes（on which we labeled the hourly time interval in which the individuals were collected） in the field and then transported to the laboratory for analysis. Individuals were counted, sexed, and measured in the laboratory. Despite desert conditions in the studied site, H. reaumurii was characterized by a diurnal surface activity, showing a bimodal pattern during the warm months（i.e., May to October）. However, it exhibited a unimodal surface activity pattern in the cold months（i.e., February, March, and November）. The surface activity was significantly correlated with sunrise and sunset. Moreover, a significant quadratic effect of temperature on the surface activity of H. reaumurii was observed. Furthermore, the study showed that the most important surface activity was recorded in March. The daily exploitation of the temporal niches was significantly different as a function of months. The body size of males was larger than that of females, and the body size of active individuals changed with months. All these behavioural changes in the surface activity represent an adaptive strategy of life in the arid environment.

Nitrogen and Organic Matter Mineralization in the Tunisian Cork Oak Forest: A Laboratory Study

The mineralization of the organic matter is a very important phenomenon which leads to the release of nutriments used by plants. The rate of transformation of the organic matter depends on several factors and parameters such as climatic factors and biological and physicochemical properties of the soil and the litter. In this study, we investigate the effect of the addition of litter of various species as well as the effect of soil moisture on mineralization of organic matter and on mineral nitrogen release in three soils sampled in three cork oak stands during a period of 41 days under the same laboratory conditions. Carbon mineralization was determined using CO2 respiration method, whereas the mineral nitrogen content was measured at the last day of incubation both in soil samples with added plant leaf material, and in control soil samples without addition under two treatments of moisture (40% and 80% WHC—water holding capacity). Our results show that the addition of leaf litter causes an increase in the microbial activity. Soils without addition were significantly different from the plant leaf added soils in respect to carbon mineralization at the end of the incubation period. Moreover, it is noted that the mineralization of carbon is more marked with moisture at 80% than that of 40%, contrary to that of the nitrogen, which is not influenced by the variation of moisture.

Breeding biology of a relictual Maghreb Magpie(Pica mauritanica)population in Tunisia

Background:The Maghreb Magpie(Pica mauritanica)is an endemic North African species.Available knowledge on this species is limited to historic descriptive data with no ecological information provided.Populations continue to dramatically decline in Tunisia,where only one relic population survives.Investigating the breeding biology of this species is essential for conservation purposes.The purpose of this study was to increase our understanding of the Tunisian relic population and provide detailed data on breeding biology over two breeding seasons(2017 and 2018).Methods:This study occurred on a private farm of 650 ha,located 10 km from Dhorbania village at Kairouan Governorate,in central Tunisia.Active nests were monitored weekly during egg laying period and twice a week during hatching period.The Ivlev's electivity index was used to assess whether the frequency of use of nesting trees and bushes matched their availability in the study area.We recorded nest measurements and positions,and compared them using Wilcoxon signed-rank test.Variations of breeding parameters as number of eggs laid,hatchlings,and fledglings over years were performed using Mann–Whitney U-test andχ^(2) tests.We used a Generalized Linear Mixed Model(GLMM)to investigate how egg volume varied with clutch size and laying date.Results:We investigated clutch size,egg size,hatching and fledging success,and evaluated how these parameters varied according to laying date and nest characteristics.Clutch size averaged 5.00±0.19 but was significantly greater nest.Causes of nest failure included the depredation of nestlings by shrikes,cobras and rats(e.g.Lanius meridionalis,Naja haje and Rattus rattus),death of parents by the Black-shouldered Kite(Elanus caeruleus)and nest parasitism by the Great Spotted Cuckoo(Clamator glandarius).Clutch size,brood size and fledgling success were unaffected by laying date,nest volume and nest elevation.Egg volume decreased with laying date but was unaffected by clutch.Conclusion:Our study provides the first and only detailed data on reproductive parameters of the Maghreb Magpie in its entire geographic range(North Africa).Information gleaned from this study provides valuable information for monitoring and long-term conservation plans of the endangered Tunisian Magpie population.Additionally,our data provide an avenue of large-scale comparative studies of the reproductive ecology of the magpie complex.

Strain Partitioning Controlled by Oblique Ramp in Intracratonic Chains in Tunisia: Example of Gafsa Basin

The aim of this contribution is the interpretation of intracratonic chains in African plates, but it is important to verify some parameters such us the oblique convergence between Africaand Europa plates. Particularly In southern central of atlassic Tunisian belts, the slickenside examination of directional preexisting faults of N120 direction shows the coexistence of thrusting and strike-slip faults striation. In the limits of these faults principally in some tectonics lens we distinguish abnormal contacts with Triassic facies. The kinematic evolution of Gafsa basin resumed in the geometry of strike-slip faults connected in the thrusting system, this movement resulted from the oblique convergence on Ben Younes, Bou Ramli and Attig chains during compressive phases. This deformation style requires a shortening axis oblique to the NW-SE accidents (N120). The strain partitioning model verify the geometry of faults and equivalent evolution of folds and confirms the Triassic decollement level but without integrated of basement structures in the deformation. It permeated a passive transport of deformation observed in cover structure.

A GIS Approach Using Morphometric Data Analysis for the Identification of Subsurface Recent Tectonic Activity. Case Study in Quaternary Outcrops—North West of Tunisia

The combination of structural and lithological data with morphometric indicators in a GIS environment constitutes a methodological approach with high added value to identify neotectonic deformations, in particular in the Quaternary outcrops where faults are generally masked by thick recent sediments. This approach, based on the crossing of multisource data, is used in this work to understand the mechanisms that generate landscape forms in the Quaternary outcrop of Oued Lahmar, which belongs to the northwest of Tunisia. In fact, the databases of various morphometric indicators, extracted from the hydrographic network, have been generated using remote sensing data and open sources applications. This database has been enriched by lithological and tectonic data extracted from the regional geological map, to understand the results of the morphometric analysis. The results obtained provide valuable information on the identification of subsurface activity in Oued Lahmar and large vicinity areas with heterogeneous geomorphic and structural characteristics. Indeed, this study revealed the existence of an E-W subsurface tectonic control covered by the Quaternary sedimentary series not indicated on the geological map of the region. This tectonic direction, which follows most of the magmatic outcrop edge in the region, may allow the intrusion of magma and the rejuvenation of ancient deep faults.

DEM-Based GIS Algorithms and 3D Geospatial Mapping for Creation of Hydrogeological Models Data in Foussana Basin (Central Tunisia)

There are many factors which affect the hydrological, geomorphologic and hydrogeological condition of the area. In order to better comprehend all processes, a Digital Elevation Model (DEM) was developed based on Geographical Information System. This latter appears as an essential tool to facilitate the decision support and can provide very important geological information. In fact, the use of the DEM is growing dramatically with the use of the GIS and the improvement of information extracted from elevation data such as mapping of floods, forest areas, erosion, and lineaments. The spatial distribution of topographic attributes can often be used as an indirect measure of the spatial variability of these processes and allows them to be mapped using relatively simple techniques. The main purpose of this study is to model the natural surface of the earth as the most accurate and the most precise. For this end we have tried in this work to develop various types of Digital Elevation Models DEM of the Foussana rift in Central Tunisia and to demonstrate the role of these models in geological, hydrogeological and hydrological study. The 3D model is also coupled in this study with piezometric and hydrochemistry study, so a new information’s plan was mapped by multiple GIS techniques like Spatial analysis and interpolation;in order 1) to comprehend the hydrodynamic of the aquifer, 2) to quantify surface and subsurface water resources and 3) to generate water management scenarios in the study area. To this end, several groundwater samples were collected and analyzed from wells and piezometers. Examining the corresponding physical and chemical parameters showed an increase in the concentrations of hydraulic conductivity in the center of the study area and it coincided with zones with high nutrient concentration. Recommendations are proposed in this zone.

Hauterivian-Barremian Bivalves from the Boulouha Formation of the Dahar Escarpment, Southern Tunisia: Stratigraphy and Regional Correlation

The Lower Cretaceous mixed siliciclastic-carbonate successions of the Boulouha Formation at the type locality in the Dahar escarpment of southern Tunisia have yielded a new discovered assemblage of bivalves which contains Anomia laevigata (Sowerby);Modiolus sp. cf. M. dahuashuensis (Yu et Li);Astarte sp.;and ?Mytilus sp.. The temporal distribution of the Anomia laevigata (Sowerby) and Modiolus sp. cf. M. dahuashuensis (Yu et Li) is limited to the Aptian formations of northeastern China, Japan and Korea, thus we suggest a Hauterivian-Barremian age for the Boulouha Formation. Henceforth, the new biostratigraphic data are used to improve a regional chronostratigraphic correlation between the lower Cretaceous strata of the Saharan Platform domain and those coeval from the Chotts domain.

Gamma Radiation Measurements in Tunisian Marbles

The radioactivity of 15 kinds of different granites collected in Tunisia was determined by gamma-ray spectrometry using hyper-pure germanium (HPGe) detector. The average activity concentrations for primordial radionuclides 238U, 232Th and 40K were respectively 33.24, 8.01 and 116.98 Bq/kg. The activity concentrations ranged from 3.59 to 87.37 Bq/kg for 238U, from 0.45 to 25.34 Bq/kg for 232Th and from 24.06 to 380.23 Bq/kg for 40K. The measured activity concentrations were used to assess of the radium equivalent activity ranged from 22.2 to 995.8 Bq/kg, the absorbed dose rate in air from 7 to 1209 nGy/h and the internal (0.1 to 2.8) and external (0.1 to 2.7) hazard indices. The data obtained in this study may be useful for natural radioactivity mapping.

Validation Approach of the Tectonic Lineament Extraction Enhancement Using Sentinel 2A Images and Modified 3 ×3 Bidirectional Prewitt Filters. Case Study: Grombalia, Tunisia

In this study, filters are used to extract directional tectonic lineaments and, thus, to reveal the presence of faults or fractures in the satellite images. The extraction process consists first in eliminating other different types of lineaments (e.g. the lithological limit, ridgelines, hydrographic network, roads, etc.). Besides, a comparative and quantitative approach is applied to show that when the directional Prewitt filter has a zero setting of the opposite of the assumed direction, as is the case of the N-S direction, the East-West direction is also set to zero. This research work, based on a bidirectional filter (N-S;E-W), shows satisfactory results especially concerning the quantitative fluctuation of lineament directions by interval. This fluctuation is in perfect agreement with the lineaments provided by the digitizing of the different tectonic accidents directions extracted in a GIS environment from the geological map of Grombalia. In this research work, a quantitative approach was used to evaluate the result of the lineament extraction methodology based on one direction analysis and by an interval of directions. Indeed, the N45 lineament direction, well documented in the geological study of the region, was more clearly distinguished by applying the Prewitt filter than by using the Sobel filter. The result was validated by comparison with the results obtained by the digitization of the tectonic accidents mapped on the geological map.

New Structural Elements in Tellian Foreland Domain of the Northeastern Tunisia(Mateur Plain)after Integrating Geological and Geophysical Data

The following paper presents an integrated geological (field observations, wells data) and geophysical data (Gravity measurements and seismic profiles) in Tellian foreland domain of the northeastern Tunisia (Mateur plain) served for a new proposed structural map with many faults already recognized or supposed by traditional structural studies and highlights major regional accidents.