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(a) foliated grey argillite with intercalated siltstone at Tazakourt, (b) black, carbonaceous argillite with thinly laminated siltstone (light) at Tazakourt, (c) disseminated (synsedimentary) chalcopyrite (cp) within siltstone bed intercalated with grey argillite immediately above rhyodacitic volcanic rocks, (d) typical sericite schist at Sidi M'Barek, cross polarized light, (e) quartzitic sandstone, cross polarized light, (f) dark green chloritized argillite (footwall) showing deformed sulphide nodules, and (g) black carbonaceous argillite typical of the hanging wall strata, with calcite layers parallel to S 1 .
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Draa Sfar is a siliciclastic–felsic, volcanogenic massive sulphide (VMS) Zn–Pb–Cu deposit located 15 km north of Marrakesh within the Jebilet massif of the western Moroccan Meseta. The Draa Sfar deposit occurs within the Sarhlef series, a volcano-sedimentary succession that hosts other massive sulphide deposits (e.g., Hajar, Kettara) within the dom...
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... footwall argillite-siltstone lithofacies consists of black carbonaceous argillite, green to light grey argillite with intercalated siltstone, and rare sandstone beds that are moderately to highly schistose (now phyllites and fine-grained schists with S 1 and S 2 well developed; Fig. 6a, b). The mineralogy is dominated by a quartz-chlorite-muscovite-albite assemblage in microcrystalline layers. The proportion of chlorite and muscovite is variable resulting in chlorite-dominated or muscovite-dominated beds (Fig. 6d, f). Disseminated sulphides and flattened, cm-sized sulphide nodules are common in the argillite and ...
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... beds that are moderately to highly schistose (now phyllites and fine-grained schists with S 1 and S 2 well developed; Fig. 6a, b). The mineralogy is dominated by a quartz-chlorite-muscovite-albite assemblage in microcrystalline layers. The proportion of chlorite and muscovite is variable resulting in chlorite-dominated or muscovite-dominated beds (Fig. 6d, f). Disseminated sulphides and flattened, cm-sized sulphide nodules are common in the argillite and siltstone (Fig. 6f). Siltstone and rare sandstone occur as thinly bedded to laminated layers that are often boudinaged and range from 10 to 60 cm in thickness. These layers are composed of quartz grains (up to 80%), chlorite, muscovite, and ...
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... 6a, b). The mineralogy is dominated by a quartz-chlorite-muscovite-albite assemblage in microcrystalline layers. The proportion of chlorite and muscovite is variable resulting in chlorite-dominated or muscovite-dominated beds (Fig. 6d, f). Disseminated sulphides and flattened, cm-sized sulphide nodules are common in the argillite and siltstone (Fig. 6f). Siltstone and rare sandstone occur as thinly bedded to laminated layers that are often boudinaged and range from 10 to 60 cm in thickness. These layers are composed of quartz grains (up to 80%), chlorite, muscovite, and smaller grains of epidote, calcite, opaques, titanite, leucoxene, and zircon (Fig. 6a, b, e). The siltstone beds are ...
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... common in the argillite and siltstone (Fig. 6f). Siltstone and rare sandstone occur as thinly bedded to laminated layers that are often boudinaged and range from 10 to 60 cm in thickness. These layers are composed of quartz grains (up to 80%), chlorite, muscovite, and smaller grains of epidote, calcite, opaques, titanite, leucoxene, and zircon (Fig. 6a, b, e). The siltstone beds are locally interstratified with siltstone laminae containing disseminated sulphides or with laminae of massive sulphide (Fig. 6c). The siltstone and sandstone beds are more common in the southern part of the mine, closer to the underlying coherent rhyodacite and volcaniclastic lithofacies. Beauchamp et al. (1991) ...
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... from 10 to 60 cm in thickness. These layers are composed of quartz grains (up to 80%), chlorite, muscovite, and smaller grains of epidote, calcite, opaques, titanite, leucoxene, and zircon (Fig. 6a, b, e). The siltstone beds are locally interstratified with siltstone laminae containing disseminated sulphides or with laminae of massive sulphide (Fig. 6c). The siltstone and sandstone beds are more common in the southern part of the mine, closer to the underlying coherent rhyodacite and volcaniclastic lithofacies. Beauchamp et al. (1991) interpreted the coherent rhyodacitic to have acted as a topographic "barrier" separating sediments derived from the south and depositing detritus near ...
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... argillite-siltstone unit that is similar to the footwall argillite-siltstone lithofacies. This, in turn, is conformably overlain by a black to dark grey, carbonaceous argillite-minor siltstone lithofacies that displays rhythmic laminations of calcite as beds 2 mm to 1 cm in thickness (20 to 60% of the rock), which are transposed parallel to S 1 (Fig. 6g). The carbonaceous argillite consists of a fine-grained assemblage of muscovite, calcite, quartz and minor chlorite and leucoxene. This facies is a distinct marker that defines the top of the sulphide-bearing argillite-siltstone-volcaniclastic succession that is host to the Draa Sfar deposit (Fig. 3). The carbonaceous argillite ...
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... is accompanied by the breakdown of feldspar, a decrease in the abundance of muscovite, and a substantial increase in the abundance of calcite and quartz. Dark, Mg-rich chlorite is typical of the chloritized inclusions within the ore (e.g., samples DS220, DS128M5; Table 1a), which also contain up to 40 to 80% talc (see Fig. 6b in Marcoux et al., 200X). Primary textures and mineralogy are poorly preserved in the chloritized, talc-altered inclusions, but the protolith is interpreted to be the argillite-siltstone lithofacies. XRD analysis indicates that away from the massive sulphide lens the feldspar is dominantly albite with rare andesine or orthoclase, ...
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... a marked enrichment in Fe, Mg, V and depletion of K, Ca, Na, Ba, Be, Bi and Nb with chlorite alteration. Losses in K and gains in Mg and Fe account for the relative decrease of sericite and enrichment in chlorite. Like the volcaniclastic rocks, the footwall argillites show the same gains and losses for Fe, Mg, K, and Ca with chloritization (Fig. 16). Si addition in both rock types is ...
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... the sericitic footwall to upper Sidi M'Barek orebody (Hole DS125) the altered sediments plotted against the least-altered precursor indicate minimal mass change. The major elements Fe total , Na, P, Al, Si, and Mn and trace elements S, Cu, Th, Sr, Yb, Zr, Cr, and Nb define the isocon line (Fig. 16d). Potassium, Mg, Rb, Y, Ni and La are added, whereas Pb and Ga are lost, which is consistent with compositional changes associated with sericite ...
Citations
... To characterize the rocks from the study area and to identify their role in groundwater salinization, 31 rock samples were collected from the mine for leach testing and to provide petrophysical parameters (porosity and grain density). All lithologies were sampled, namely tuff, lava, sandstone and black pelite, also referred to as black schist by [20] or black argillite by [24]. Sampling was conducted at various mine levels at depths ranging from 110 m to 700 m. ...
In the Marrakech region of Morocco, where water resources are particularly limited, excessive salinity has been measured in the water from some wells intended for human consumption and irrigation. Moreover, the start-up of a mine for the exploitation of a polymetallic sulfide deposit and the progress of the exploitation work have revealed the existence of very saline deep groundwater with a total mineralization of over 80 g/L. The hydrogeochemical study using conservative elements has helped to understand the origin of the groundwater salinity in the Draa Sfar mine and to assess the contribution of the deep salinity source to the high salinities observed in the mine. The groundwater of the shallow aquifer shows almost constant Br−/Cl− and Na+/Cl− ratios, independent of the chloride content. The constant ratios of these conservative elements indicate a single autochthonous origin of Cl−, Br− and Na+, and groundwater salinity is diluted by recharge water containing low concentrations of these elements. Regarding the mine groundwater, the high Li+/Cl− ratio and Br−/Cl− ratios in the range measured on the leachates of the rocks extracted from the mine indicate that the pore water is the reservoir for dissolved chloride and the salinity of the mine’s groundwater results from a mixture between these pore waters and fresh meteoric water that seeps in from the surface and recharges the entire aquifer. This porewater would be a remnant of the hydrothermal fluids that formed the sulfide deposit.
... Microdioritic dikes correspond to the youngest intrusive rocks, dated from ca. 255 -241 ± 5 Ma (K-Ar and 40 K- 40 Ar on kaersutite [36][37][38]) to ca. 235 Ma (SHRIMP U-Th-Pb on zircon [27]). Before these intrusive magmatic rocks, a volcanic rock has been described in Central Jebilet, associated with pyrrhotite-rich massive sulphide deposits, attributed to Upper Visean (e.g., [22,29,[39][40][41]). ...
... The Jebilet massif hosts have many metalliferous deposits, mainly represented by massive sulphides, followed by pyrometasomatic deposits and mineralised veins [22]: (i) massive sulphide deposits are the most studied ones. They are base metal pyrrhotite rich (Kettara, Koudiat Aicha, Draa Sfar, etc.) and are differently considered by authors as syngenetic or epigenetic mineralisation (e.g., [29,39,40,44,49,50] 3 Geofluids mineralisation, according to the recent biostratigraphic reconsiderations [25]. (ii) The pyrometasomatic mineralisation (e.g., Frag El Maa) is linked to syntectonic felsic intrusion emplacement [22]. ...
The Roc Blanc Pb-Zn-Ag-Au vein deposit is located in the NW of Marrakech, in the Central Jebilet massif. It is spatially related to Bramram-Tabouchennt-Bamega (BTB) granodioritic pluton (ca. 330 Ma) metamorphism aureole. The main veins hosted in black shales are oriented N-S to NNW-SSE. Pb-Zn-Ag-Au ore is associated with quartz, chlorite, sericite, and carbonate gangue minerals. Two major stages of ore deposition were distinguished. The preore stage (stage I) comprises two quartz-mineralised vein generations with Fe, As, Zn, and Cu ores (vg1 and vg2). The main ore stage (stage II) consists mainly on Ag, Au, Pb, Zn, Cu, and Sb ores, which is hosted by carbonaceous vein (vg3) and by two late quartz generations veins (vg4 and vg5 with a geodic quartz). Three types of fluid inclusions have been recognized in silver mineralisation bearing quartz veins according to petrographic investigations, microthermometry, and Raman spectroscopy studies: (i) liquid-rich H2O-N2-CH4±CO2-(salt) fluid inclusions (type 1), (ii) vapour-rich H2O-CO2-CH4-N2-(salt) fluid inclusions (type 2), and (iii) aqueous H2O-(salt) fluid inclusions (type 3). The interpretation of fluid inclusion data shows a mixing of two fluids that are metamorphic and surface to subsurface origin, trapped at boiling state. The first mineralised stage was deposited at 350 ± 20 ° C (this temperature of ore deposition was supported also by chlorite geothermometry) with salinity of 13.7 wt% NaCl equiv., while the deposition of the argentiferous stage, which consists of the main economic mineralisation of the Roc Blanc deposit, occurs during decreasing temperature at 150°C with a salinity of 12.1 wt% NaCl equiv. The all-mineralised ore was deposited at relatively low pressure, below ~1-1.1 kbar. So, fluid dilution and cooling are probably the main factor for silver deposition in the Roc Blanc polymetallic vein deposit. In addition, fluid inclusion studies reveal that the mineralising fluid corresponds to a mixture of metamorphic fluid (H2O-CH4-N2-CO2) with surface to subsurface aqueous gas-free fluids (H2O-salt, meteoric, or brine).
... The Central Jebilet Variscan massif contains several massive sulfide deposits that are interpreted as volcanogenic massive sulfide (VMS)-type deposits and which have been mined for Zn-Pb-Cu commodities, making the province an important base metal source region [1][2][3][4][5][6]. The Draa Sfar, Kettara and Koudiat Aïcha (Figure 1) deposits are the ones that have been most exploited in recent decades. ...
... Central Jebilet is dominated by the Carboniferous Sarhlef metasedimentary series (Upper Visean-Namurian: presence of Posidonomya becheri Bronn [29]). This series constitutes a thick succession (≥1000 m) of argillites alternating with siltstone, sandstone and locally felsic and mafic tuff, overlain by carbonaceous argillites and limestones [2,4,6,30]. The Sarhlef series is intruded by pre-orogenic bimodal magmatic rocks and calc-alkaline granodioritic plutons [1,2,30,31]. ...
The Koudiat Aïcha Zn-Cu-Pb deposit (3–Mt ore @ 3 wt.% Zn, 1 wt.% Pb, 0.6 wt.% Cu) in the
Jebilet massif (Morocco) comprises stratabound lenticular orebodies and crosscutting sulfide-bearing
quartz ± carbonate veins in the lower Carboniferous Sarhlef volcano sedimentary succession. The
veins are characterized by abundant pyrrhotite, sphalerite, subordinate chalcopyrite and galena
and rare Ag and Au minerals. The stratabound massive sulfide ores are attributed to a “VMS”
type, whereas the origin of the sulfide–quartz ± carbonate veins remains poorly understood. New
mineralogical and microanalytical data (SEM, EPMA and LA-ICP-MS) combined with fluid inclusion
results point to two-stage vein formation. The early stage involved C–H–O–N Variscan metamorphic
fluids which percolated through fractures and shear zones and deposited pyrite at >400 ◦C, followed
by the formation of pyrrhotite and sphalerite (300 ± 20 ◦C) in quartz veins and in banded and
breccia ores. The pyrrhotite–sphalerite mineralization was overprinted by aqueous brines (34 to
38 wt% eq. NaCl + CaCl2
) that precipitated carbonate and Cu-Pb sulfides (±Ag-Au) at ~180–210 ◦C
through mixing with low-salinity fluids during tectonic reworking of early-formed structures and
in late extension fractures. The latter ore fluids were similar to widspread post-Variscan evaporitic
brines that circulated in the Central Jebilet. Overlapping or successive pulses of different ore fluids,
i.e., metamorphic fluids and basinal brines, led to metal enrichment in the quartz–carbonate veins
compared to the massive sulfide ores. These results underscore that even a single deposit may record
several distinct mineralizing styles, such that the ultimate metal endowment may be cumulative over
multiple stages.
... Furthermore, SWIR results confirm that the mica compositions show systematic trends from phengite muscovite in proximal zones to paragonitic muscovite in distal areas surrounding the main sericite zone at Bukit Botol. Similar relationships are recognized in other VHMS deposits like Prince Lyell (Hendry 1981), Hellyer (Yang 1998), Salgandinho (Plimer and Carvalho 1982), and Draa Sfar (Belkabir et al., 2008), but contrast with the observations at other VMS deposits, such as Myra Falls (Jones et al., 2005) and Western Tharsis Herrmann et al., 2001;Gifkins et al., 2005). In addition, at Bukit Ketaya, minor pyropyhllite and kaolinite spectral profile was identified by SWIR from both alterations, as also supported by XRD data. ...
The volcanic-hosted massive sulphide (VHMS) deposits of the Tasik Chini area, Peninsular Malaysia are hosted by Permian felsic volcanic rocks (¬ 290 Ma) of rhyolitic to rhyodacitic composition and comprise two deposits (Bukit Botol and Bukit Ketaya). Although the ores and the felsic volcanic host rocks of these deposits have metamorphosed to greenschist facies and were affected by a complex deformation history, the hydrothermal alteration zones associated with mineralization are preserved and show systematic mineralogical and geochemical changes with increasing proximity to the ore bodies. The geometry of alteration assemblages of the Bukit Botol and Bukit Ketaya deposits shows they occur as semi-conformable or stratabound zones around the ore lenses. According to petrography study and short wavelength infrared (SWIR) spectra measurements supported by X-Ray diffractometer (XRD), the Bukit Botol deposit is characterised by proximal quartz-sericite-pyrite and distal quartz-sericite alteration zones, whereas distal quartz-chlorite-sericite-pyrite-pyrophyllite ± kaolinite and proximal quartz-chlorite-pyrite ± carbonate ± pyrophyllite form the alteration assemblages of the Bukit Ketaya deposit. The geochemical data is coherent with the mineralogical characteristics, using the Ishikawa alteration (AI) and chlorite-carbonate-pyrite (CCPI) indexes, showing the important of chlorite and sericite formation in the ore proximal and ore distal zones. In addition, the molar elemental ratios of Na2O/Al2O3 versus K2O/Al2O3 and MgO/Al2O3 versus K2O/Al2O3 support that the abundance of muscovite (sericite) and chlorite controlled the intensity of alteration at the both deposits. The results of this study indicate that the combination of mineralogy and geochemistry studies help in defining specific alteration styles and related mineral geochemical variations of the VHMS deposits in Tasik Chini area.
... Acidic magmatic rocks outcrop in a large Hercynian granitic body (El Kamel et al., 1998). As the most of Western Meseta massifs, where known mineralization (gold, silver, copper, iron oxide, sulphur, zinc, lead) are economically exploitable (Diot, 1989;Nerci, 2006;Belkabir et al., 2008;Benhamou & Moumou, 2015;Nshimiyimana et al., 2018). The Jbilet Massif, is located directly to the south of the Rehamna, and characterized by copper-auriferous and argentiferous vein deposits (El Arbaoui et al., 2015;Benchekroun & Essarraj, 2015), which are trending toward NW-SE, N-S, and NE-SW (Yahyaoui & Essaifi, 2011;Nshimiyimana et al., 2018). ...
The analysis of the magnetic signatures and gravity gradient values of the Rehamna Massif south of the Moroccan Western Meseta by using Geosoft Oasis Montaj 7.0.1 software, allowed us to detect several useful anomalies to be exploited and which are related to magmatic bodies and structural features within the study area. These data were analyzed by applying several techniques, including the horizontal gradient filters combined with the first vertical derivative. Subsurface structures; such as geological boundaries, faults, dykes and folds, were visualized as lineaments on geophysical maps, then results were compared with structural features provided by previous studies in the region. Thus, the Rehamna Massif structural map shows sets of linear features which may represent faults or boundaries of geological structures, which can be either faults or boundaries of geological structures, and they are mostly oriented in the directions: N-S, NNE-SSW, NE-SW, E-W with the predominance of the NNE-SSW to NE-SW directions. In addition, the super position of the minerals bearing beds or formations were distinguished from gravity and magnetic data processing results. Some of the recognized anomalies are related to the existence of precious metals which belong to the granitic bodies within the study area.
... e main reason for this is that construction and production are restricted by the inclined mining method and gently inclined medium-thick ore bodies [1][2][3][4]. At present, most mines mainly adopt the shallow hole room-pillar method of underground mining, followed by the pillarless sublevel caving method and the bottom ore structure. ...
In this study, the No. 6 pit in the eastern mining area of the Jinning phosphate mine in China was taken as the research background. In order to reduce the cost of filling, an improved pillarless sublevel caving method is proposed. This method greatly improves the ore recovery rate by adding a recovery route. In addition, the combination of similar material simulation experiments and numerical simulations (discrete element and universal distinct element code) revealed the deformation and failure laws of the surrounding roof rock and the characteristics of the surface subsidence. The results indicate the following. (1) The similar simulation experimental results indicate that the deformation of the overlying rock layer originated from the direct roof of the goaf and gradually developed into the deep part of the rock layer. An irregular stepped caving zone formed in the goaf. The maximum surface subsidence was located above the phosphorus orebody, and it gradually decreased toward both sides. As the stope approached propulsion, the location of the maximum subsidence gradually moved toward the propulsion direction. (2) The numerical results revealed that the displacement of the overlying strata was nonlinear, and it decreased with increasing roof height. A support pressure concentration area was formed within a certain range of the stope roof. The numerical simulation results are basically consistent with the similar simulation experimental results.
... Location of the three drill cores within the Sarhlef Formation. Geological map of the Draa Sfar mine area according toBelkabir et al. (2008). ...
The Sarhlef Formation, which hosts the massive sulphide deposits of the Moroccan Meseta, has been considered as Carboniferous in age. Moreover, palynological analysis of the black shales hosting the Draa Sfar deposit (Central Jebilet) has allowed to restrict the age of the Sarhlef Formation to the late Visean (Asbian). However, this age is not compatible with geochronological data of various magmatic intrusions present in Central Jebilet. New biostratigraphic results based on metamorphosed conodonts from 34 samples (three cores, DS170, DF306 and DS125) of the Draa Sfar deposits provide a new biostratigraphic framework of the Sarhlef Formation. The collected fauna is affected by pyritization, silicification and tectonic deformation. Some non-pyritised or partially pyritized conodonts show a conodont color alteration (CAI) change varying from black to translucent (CAI 5 to CAI 8). The conodont fauna comprise representatives of the genera Icriodus, Polygnathus, Ancyrodella, Palmatolepis, Ancyrognathus, Ancyroides, and Palmatolepis showing that age spans from the Frasnian to Late Famennian. This age is more compatible with the radiometric data of the intrusive magmatic rocks. In core DS170, the Upper Kellwasser Horizon at the Frasnian-Famennian boundary has been identified by lithological characteristics and stratigraphy. The proposed Late Devonian age of the Sarhlef Formation provides new insights on the geological evolution and stratigraphy of the entire region.
... Le gisement de Draa Sfar appartient à la province métallogénique des amas sulfurés à pyrrhotite dominante du massif hercynien des Jebilet-Guemassa (Huvelin, 1977 ;Bernard et al., 1988 ;Souaré,1988 ;Hibti, 2001 ;Rziki, 2006 ;Belkabir et al., 2008 ;Moreno et al., 2008 ; Les corps minéralisés de Draa Sfar sont encaissés dans la série de Sarhlef qui couvre la majeure partie des Jebilets centrales ( fig. 2), Cette série est composé d'une séquence sédimentaire gréso-pélitique (Huvelin, 1977 ;Bordonaro,1983 ;Rziki, 2006 ;Moreno et al., 2008) avec des intercalations des roches volcaniques et volcanosé-dimentaires acides et basiques (Aarab,1995 ;Essaifi, 1995 ;Gibson et al., 2005) (Fig.3). Le gisement de Draa Sfar est de type amas sulfuré volcanogène (Huvelin, 1977 ;Bernard et al.,1988 ;Hibti, 2001 ;Rziki, 2006 ;Belkabir et al., 2008 ;Moreno et al., 2008) étendu ...
... Le gisement de Draa Sfar appartient à la province métallogénique des amas sulfurés à pyrrhotite dominante du massif hercynien des Jebilet-Guemassa (Huvelin, 1977 ;Bernard et al., 1988 ;Souaré,1988 ;Hibti, 2001 ;Rziki, 2006 ;Belkabir et al., 2008 ;Moreno et al., 2008 ; Les corps minéralisés de Draa Sfar sont encaissés dans la série de Sarhlef qui couvre la majeure partie des Jebilets centrales ( fig. 2), Cette série est composé d'une séquence sédimentaire gréso-pélitique (Huvelin, 1977 ;Bordonaro,1983 ;Rziki, 2006 ;Moreno et al., 2008) avec des intercalations des roches volcaniques et volcanosé-dimentaires acides et basiques (Aarab,1995 ;Essaifi, 1995 ;Gibson et al., 2005) (Fig.3). Le gisement de Draa Sfar est de type amas sulfuré volcanogène (Huvelin, 1977 ;Bernard et al.,1988 ;Hibti, 2001 ;Rziki, 2006 ;Belkabir et al., 2008 ;Moreno et al., 2008) étendu ...
... Indeed, in order to know the details of the geological and structural context of this targeted zone, the objective of this study is to highlight the effectiveness of images in lithological, structural and hydrothermal alteration mapping. The Hercynian massif of Jebilet-Gemassa is a metallogenic sulphide province with pyrrhotite dominance 3,4,11,12,15 Sarhlef series that covers most of the Central Jebilets. This series is composed of a sandstone and pelitic sedimentary sequence 5 with intercalations of acidic and basic volcanic along with volcano sedimentary rocks. ...
The Jebilet massif is part of the Paleozoic Hercynian
chain located in the western meseta of Morocco. It
conceals several polymetallic mines and several
mining indices (Copper, Lead and Zinc). The most
important mines such as Draa Sfar, Koudiat Aicha,
Laachach, Bir Enhass and Kettara. Mineralisation are
attributed to Volcanic Massive Sulphide (VMS) types.
These types of genetic model are accompanied by
hydrothermal alteration with a very particular
mapping zonation of minerals alteration. These
minerals including chlorite, sericite, illite as well as
iron oxides are accompanying mineralization in the
majority of cases.
To understand the contribution of Geographic
Information System (GIS) and remote sensing for
mapping the spatial distribution of hydrothermal
alteration minerals, geological mapping, lineament
extraction (structural) at the Central Jebilet scale, we
used GIS and satellite image processing software
ArcGIS and ENVI, PC Geomatica 2016. The ENVI
software allowed us to extract the alteration minerals
namely the silicate group by band ratio. The methods
of supervised classification showed us that basic
magmatic bodies from the North East are acidic bodies
following the application of the Spectral Angle Mapper
(SAM) classification which is based on the spectral
signatures of the samples. PC Géomatica 2016 has also
allowed the extraction of lineaments in the study area
following treatments carried out on the digital field
model STRM with a spatial resolution of 30 meter. In
addition, the ArcGIS software was used to
georeference and overlap data from different sources
and to lay out the maps. The mapping results obtained
by GIS and remote sensing provide an input to the
exploitation in the central jbilets. They could also
provide metallotects for the exploration of similar
deposits in the metallogenic province of Jebilets
Guemassa.
Keywords: GIS, Aster, Central jebilets, Geological
mapping, Lineaments maps, Hydrothermal alteration.
... The differences between the Tazakourt and the Sidi M'Barek deposits are also recorded in the hydrothermal alteration of the host rocks, characterized by the dominance of chlorite in the footwall and sericite in the hanging wall of the Tazakourt orebody, while the Sidi M'Barek orebody is characterized by a sericitedominated alteration in both the footwall and the hanging wall . These differences led Belkabir et al. (2008) to interpret the Tazakourt and Sidi M'Barek orebodies as representing, respectively, the proximal and the distal volcanic environments of the Draa Sfar VMS deposit. ...
... These deposits are aligned along three major lineaments trending north-south to NE-SW (Bernard et al. 1988;Essaifi and Hibti 2008;Maacha et al. 2017). They are typically pyrrhotite-dominated, vertical or steeply dipping, and most of them have been classified as VHMS (Bernard et al. 1988;Zouhry 1998;Belkabir et al. 2008;Lotfi et al. 2008;Marcoux et al. 2008;Moreno et al. 2008). They are affected by Variscan deformation (Bernard et al. 1988;Marcoux et al. 2008;N'diaye et al. 2016;Admou et al. 2018) and show a polyphase mineralization (Lusty et al. 2015;Essaifi et al. 2019). ...
... In the zones where the Zn-rich lens pinches out, the sulfides remain as disseminated minerals within the host metapelites. This thickness variation is similar to that described in the Tazakourt orebody, and related to a 'swell and pinch geometry' by Belkabir et al. (2008) and Marcoux et al. (2008). ...
In addition to a Zn-rich lens representing the northern prolongation of the Draa Sfar volcanogenic massive sulphide deposit, the Sidi M’Barek deposit includes Cu-rich lenses in which gold is being recovered profitably as a by-product. The Cu-rich mineralization is composed of numerous structurally controlled veins whose morphology suits that of a lode rather than that of a stratiform orebody. Although the Cu-rich and Zn-rich orebodies are dominated by pyrrhotite, pyrrhotite is coarser grained in the Cu-rich lenses and mineralization is polyphase. Pyrrhotite is deformed and recrystallized; it is crosscut and replaced by pyrite infilling veins. Pyrite crystallizes also along the S1 cleavage and in pressure shadows around bioclasts in the disseminated ore. Chalcopyrite veins postdate both the pyrrhotite and pyrite phases.
The concentration of Co and Au is higher in the Cu-rich lenses relative to the Zn-rich lenses, which have higher concentrations in Pb, Ag and As. Pyrite and pyrrhotite have distinct sulphur and lead isotopic signatures. We propose a polygenetic model in which a pre-existing syngenetic pyrrhotite-rich mineralization is remobilized in shear zones during a major ductile deformation event allowing deposition of pyrite. The shear zones were reopened during a late ductile-brittle deformation event allowing deposition of chalcopyrite.
Keywords: Massive sulphide; Pyrrhotite; Draa Sfar; Hercynian; Morocco
