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The Imourkhssen porphyry Cu±Mo±Au±Ag deposit is located at the Ouzellagh-Siroua Salient (OSS) straddling the boundary between the central Anti-Atlas and the central High Atlas. It is characterized by a typical porphyry-style mineralization. The volcanic rocks are intruded by numerous magmatic rocks of the Ouarzazate Group (580–539 Ma), referred to as the Late Ediacaran magmatic suites (LEMS). Of these, the Askaoun, Imourkhssen, and Imourgane granites are the most significant as they are related to the porphyry mineralization. The entire set is intruded by the Zaghar mafic dyke swarms. Zircon U-Pb dating of the Imourkhssen granite and the ore-bearing granite porphyry shows that these intrusive rocks were emplaced at 558 ± 1 and 550 ± 2 Ma, respectively. Moreover, the whole-rock major and trace element geochemistry reveal a high-K calc-alkaline I-type composition, consistent with an emplacement in a post-collisional setting under a trans-tensional tectonic regime. Ore bodies are hosted by the Askaoun granodiorite as well as the Imourgane granite. The mineralization occurs as fine-grained dissemination and infills of hydrothermally altered NNE–SSW to N–S trending veins and veinlets. Ore-related hydrothermal alteration consists of potassic, chlorite-sericite, serecitic, and propylitic mineral assemblages along with pervasive silicification and pyritization, providing a porphyry-style alteration pattern. The ore periods comprise supergene and magmatic-hydrothermal periods. The latter includes primary dissemination and secondary NNE–SSW to N–S ore-bearing system stages. The occurrence of molybdenite is either restricted to the potassic and chlorite-sericite alteration zones of the ore-bearing granite as fine disseminations or alternatively as veinlet infills within the propylitic halos. The molybdenite occurrences along with pyrite, chalcopyrite, galena, and tennantite dissemination are assigned to the primary ore stage, while the NNE–SSW to N–S ore-bearing system is related to the secondary ore stage. It consists of pyrite, chalcopyrite, bornite, covellite, diagenite, sphalerite, hematite, galena, gold, and chenguodaite. The predominance of cockade and crack-and-seal textures suggest multiple episodes of ore-forming fluid circulations under epithermal conditions. The supergene stage is achieved by subordinate malachite, azurite, barite, hematite, epsomite, and chrysocolla. From the descriptions above, we argue that the Imourkhssen Cu±Mo±Au±Ag mineralization shares many mineralogical and paragenetic attributes of porphyry-copper deposits. [ABSTRACT FROM AUTHOR]

Introduction Modeling mineral potential based on the precise collection and processing of geological, geophysical, and satellite data enables us to predict the potential presence of mineral substances in a specific area. This process involves constructing complex mathematical models that, utilizing machine learning algorithms and thorough data analysis, assist authorities and decision-makers in the mining sector. It helps identify mineral-rich zones for optimal extraction and manage land resources in the best possible way. Given the diverse geological units present in the Saqez sheet, this sheet is considered one of the most promising areas for the formation of metallic deposits. The host rock for most Pb-Zn deposits in Iran is sedimentary, known as Sedimentary-Hosted Pb-Zn deposits. According to conducted surveys, it has been determined that the Pb-Zn mineralization occurring in the Saqez sheet is also of this type. Typically, calcite, dolomite, shale, sandstone, and igneous rocks serve as hosts for these deposits. Materials and Methods In this research, the exploratory layers of lithology, dolomite alteration, and geochemical of Pb-Zn were used to prepare a map of the prediction of Pb-Zn mineralization in the turpentine sheet. Utilizing the singularity technique on sediments stream, using various exploratory layers performing laboratory spectroscopy, and applying the spectral behavior curves obtained on Sentinel-2A images in this innovative and creative research. It shows its existence compared to another similar research. After fuzzification of exploration layers in GIS software, the prediction map of Pb-Zn mineralization was obtained by Fuzzy-Gamma function and gamma value of 0.85. The results of XRF and ICP-MS analysis on the discovered Pb-Zn samples showed a grade between 3 and 7%, which indicates the correct selection of the studied area and the exploratory layers and their correct integration. Further, by conducting laboratory spectroscopy in a dark room with a halogen lamp and obtaining the spectral behavior curve of the sphalerite mineral related to the samples of the study area, the SAM matching algorithm was applied to the Sentinel-2A satellite images. Results and Discussion According to the Pb-Zn mineralization prediction map of the Saqez sheet, this map is classified into four categories of low, moderate, high, and extreme mineralization potential. It is evident from this map that the northern, central, and southeastern regions have the highest potential for Pb-Zn mineralization. Upon examining the topography and road identification of the Saqez sheet, six areas were selected for exploratory drilling of Pb-Zn. Samples were collected for analysis and validation of identified points. XRF and ICP-MS analysis results indicated that the total Pb-Zn content ranged from 2 to 7% and 70,000 to 20,000 ppm. Finally, high-grade Pb-Zn samples were selected for petrographic examination. Petrographic studies revealed that minerals such as sphalerite, galena, and pyrite were predominant in the collected samples, with their texture filling the pore spaces. Specifically, sphalerite replaced galena, and galena replaced pyrite. The results obtained from laboratory spectral analysis and the application of spectral behavior curves for sphalerite minerals on Sentinel-2A satellite images were utilized to assess the accuracy of the work and identify promising new mineralized areas. By comparing the corrected spectra from the laboratory experiments with the USGS spectral library, it was determined that the obtained spectral behavior is similar to the USGS spectral library. Therefore, the predictive map of Pb-Zn mineralization resulting from the application of spectral behavior curves for sphalerite on Sentinel-2A satellite images indicates the correct selection of imagery, appropriate spectral analysis, and all processing steps. Conclusion Due to the fact that the host rocks of most Pb-Zn deposits in Iran are of sedimentary origin, the first step in modeling the mineral potential of these deposits is to accurately recognize the ore deposit type. Based on the evidence and samples observed in the study area, the ore deposit type in the study area can be considered as the Irish type. Therefore, based on this, modeling and prediction of Pb-Zn mineralization on the one hundred thousand scale map of Saqez were carried out according to the Irish type Pb-Zn mineralization. After evaluating the Pb-Zn mineral potential map, seven final areas were selected for exploration. Based on the exploration conducted in six areas (S1, S2, P, Q-Pb-Zn, Polygon12, and Polygon13), samples containing Pb-Zn mineralization were discovered, while Polygon5 was identified as lacking Pb-Zn mineralization, indicating the reliability of the exploration layers and integration method. XRF and Aqua Regia analysis results showed that the discovered Pb-Zn samples had grades ranging from two to seven percent, indicating economicgrade content for these metals. [ABSTRACT FROM AUTHOR]

Geothermal energy is one of the most valuable and preferable renewable energy sources, given that it produces sustainable, dependable, and clean energy. Understanding the geothermal systems, parameters such as heat, fluids, and structures help to identify potential geothermal systems. These parameters are manifested as hot springs, fumaroles, and alteration minerals. Hydrothermal alteration minerals are often used in geothermal system exploration to evaluate factors such as temperature, fluid, and structures. This study employed GIS and remote sensing in the investigation of hydrothermal mineral alterations and delineating geological structures which provided invaluable information for identifying prospective geothermal resource zones. ASTER was utilised to map phyllic, argillic, and propylitic minerals using SPCA, whereas ISO cluster classification was used to detect kaolinite, smectite, calcite, chlorite, and muscovite/illite-rich areas. DEM was used to extract and map geological lineaments. Results have revealed that the regions that were mapped with indicator hydrothermal alteration minerals were also associated with geological structures. The field work, XRD, and ASD laboratory analysis results indicated a good match with the findings from the remote sensing data. The approach applied in this study may be used along with other techniques during the early phases of geothermal exploration to define geothermal potential targets. [ABSTRACT FROM AUTHOR]

Throughout the Flinders Ranges of South Australia, the red bed Brachina sequence comprises the lower of two regressive, coarsening-upward successions that together constitute the Ediacaran-aged Wilpena Group. Detailed examination of the Brachina sequence has identified evidence of ice-rafting, supporting the contention that frigid climatic conditions continued well after cessation of the Marinoan Glaciation, as well as features postulated to be harbingers of the macroscopic metazoans that occur in abundance higher in the local stratigraphy. Although tuffaceous and lying stratigraphically between deposits of the Marinoan Glaciation and the Acraman Impact/Gaskiers Glaciation, no absolute age dates exist for the sequence. However, through correlation to the global carbon isotope profile, the timespan of Brachina sequence deposition can be constrained to between 635 and 586 Ma, when the regression climaxed with terrestrial deposition upon a local disconformity. The tuffaceous input is timed to have begun at 620 Ma, essentially coincident with initial formation of the passive volcanic continental margin of southeastern Australia and initiation of both the Volyn Large Igneous Province and activity within the Central Iapetus Magmatic Province, all components marking the demise of Rodinia and initial amalgamation of Gondwana. Correlation to the global carbon isotope profile dates the early Ediacaran Brachina sequence of the Flinders Ranges to between 635 and 586 Ma. The ABC Range Quartzite in the central Flinders Ranges is derived from, and hence younger than, the deltaic ABC Range Quartzite in the southwestern Flinders Ranges. Several volcanic outpourings across the Ediacaran globe during the final breakup of Rodinia and initial assembly of Gondwana, including that associated with the development of the eastern Australian passive margin, produced an abundance of atmospheric ash that settled during and beyond deposition of the Brachina sequence. [ABSTRACT FROM AUTHOR]

We explore the connections between crustal shortening, volcanism, and mantle dynamics in the Atlas of Morocco. In response to compressional forces and strain localization, this intraplate orogen has evolved far from convergent plate margins. Convective effects, such as lithospheric weakening and plume‐related volcanism, contributed in important ways to the building of high topography. We seek to better understand how crustal and mantle processes interacted during the Atlas' orogeny by combining multiple strands of observations, including new and published data. Constraints on crustal and thermal evolution are combined with new analyses of topographic evolution, petrological, and geochemical data from the Anti‐Atlas volcanic fields, and a simple numerical model of the interactions among crustal deformation, a mantle plume, and volcanism. Our findings substantiate that: (a) crustal deformation and exhumation accelerated during the middle/late Miocene, contemporaneous with the onset of volcanism; (b) volcanism has an anorogenic signature with a deep source; (c) a dynamic mantle upwelling supports the high topography. We propose that a mantle plume and the related volcanism weakened the lithosphere beneath the Atlas and that this favored the localization of crustal shortening along pre‐existing structures during plate convergence. This convective‐tectonic sequence may represent a general mechanism for the modification of continental plates throughout the thermo‐chemical evolution of the supercontinental cycle. Key Points: Crustal thickening is limited and cannot account for the topography elevation of the Atlas systemResumption of volcanism is contemporaneous with the acceleration of crustal deformation and topography growingThe erosion and weakening of the lower lithosphere, as a consequence of mantle plume, may enhance crustal deformation and exhumation [ABSTRACT FROM AUTHOR]

This work investigates the transition limit between autoignition front and deflagration in hot and premixed conditions. In particular, the objective is to analyze the sensitivity of the combustion regime to the temperature gradient, mixture composition and thermodynamical conditions, which is first analyzed numerically. The results are then compared to experimental data obtained in an optical RCM, fitted with a flat piston and a multi-zone heating system. Temperature gradient after compression is measured in the hot core region using two thin wire thermocouples of about 7.6 µm diameter. The chemiluminescence records confirm that the dynamics of autoignition fronts is strongly dependent on (i) the gaseous mixture composition and the thermodynamical conditions, and (ii) on thermal gradients in the unburned mixture. In particular, the authors evidence experimental conditions for which a steeper gradient or a change in mixture composition leads to a transition from autoignition to deflagration. [ABSTRACT FROM AUTHOR]

Geological mapping undoubtedly plays an important role in several studies and remote sensing data are of great significance in geological mapping, particularly in poorly mapped areas situated in inaccessible regions. In the present study, Principal Component Analysis (PCA), Band Rationing (BR) and Minimum Noise Fraction (MNF) algorithms are applied to map lithological units and extract lineaments in the Amezri-Amassine area, by using multispectral ASTER image and global digital elevation model (GDEM) data for the first time. Following preprocessing of ASTER images, advanced image algorithms such as PCA, BR and MNF analyses are applied to the 9ASTER bands. Validation of the resultant maps has relied on matching lithological boundaries and faults in the study area and on the basis of pre-existing geological maps. In addition to the PCA image, a new band-ratio image, 4/6–5/8–4/5, as adopted in the present work, provides high accuracy in discriminating lithological units. The MNF transformation reveals improvement over previous enhancement techniques, in detailing most rock units in the area. Hence, results derived from the enhancement techniques show a good correlation with the existing litho-structural map of the study area. In addition, the present results have allowed to update this map by identifying new lithological units and structural lineaments. Consequently, the methodology followed here has provided satisfactory results and has demonstrated the high potential of multispectral ASTER data for improving lithological discrimination and lineament extraction. [ABSTRACT FROM AUTHOR]

Over 10,000 published detrital zircon ages have been reprocessed (applying a +10% normal and reverse concordance range) and analysed to understand the evolution of the detrital zircon record of north‐west Africa during the Phanerozoic. Using dissimilarity and clustering analysis, shifts in detrital zircon populations allow interpretation of the evolution of source regions and source to sink systems throughout the Phanerozoic within the West Gondwana superfan. Previous thermochronology and field studies conducted across north‐west Africa indicate significant and sustained shifts in source regions in Meso‐Cenozoic times which are not recorded in the detrital zircon geochronology record. This discrepancy is most notable for Mesozoic to modern source to sink studies focused on the evolution of the Atlasic rift and opening of the Atlantic and Tethyan Oceans to the west and north respectively. Our results indicate a high degree of similarity between samples from Cambrian times onwards due to successive phases of sediment recycling. This highlights the need to integrate detrital zircon analysis with other techniques to provide confident reconstruction of sediment routing systems across Morocco. This systematic review also reveals the ubiquitous occurrence of Mesoproterozoic zircons within Moroccan sediment. No basement of this age is known from north‐west Africa—often described as the 'Mesoproterozoic Gap', which was thought to be a diagnostic feature of sediment derived from the West African Craton. However, zircons of this age form 7% of all analysed zircons and are present in sediments from at least 700 Ma. The presence of this population is interpreted as strongly diagnostic of provenance from either the Amazonian Craton or the Eastern Gondwana Orogen within Central Africa. Their presence in the Moroccan detrital record from the Neoproterozoic onwards raises questions about the position of the West African Craton in the Proterozoic, and for the spatial extent of Mesoproterozoic orogeny within north Africa. [ABSTRACT FROM AUTHOR]

Purpose. The purpose of the present research is to provide a new lithological, structural and magmatic features of the Oumjrane-Boukerzia Mining District. The results obtained are used to guide exploration works for identifying the new Cu, Ni, Pb, Zn depositions and Ba-bearing mineralization within the whole Oumjrane-Boukerzia domain. Methods. This research is based on detailed mapping, structural surveys and geochemical studies performed on the magmatic rocks in the studied area. Findings. Structural and microstructural analyses of the studied area have revealed three complex polyphase tectonic events related to the Variscan orogeny: (i) an extensive phase during the Devonian period; (ii) a NW-SE compressional phase of Namuro-Westphalian age; (iii) a NE-SW compressional phase of Stephanian-Autunian age, and (iv) an extensive late phase probably related to the opening of the Central Atlantic ocean during the Late Trias-Jurassic periods. The sedimentary rocks of the district are locally intruded by small undated gabbroic intrusions. Geochemically, these gabbroic bodies are described as olivine-rich gabbros with a continental tholeiitic affinity and suggested to be related to the Central Atlantic magmatic province (CAMP) during the Pangea break-up. Originality. The present study describes the host-rocks and structural events responsible for Cu, Ni, Zn, Pb deposition and Ba-bearing mineralization in the Oumjrane-Boukerzia Mining District (Eastern Anti-Atlas, Morocco). Practical implications. The geological studies, especially lithostratigraphic, tectonic and magmatism are essential in the mineral exploration. They help exploration geologists identify and define metallotects to discover new minerals. [ABSTRACT FROM AUTHOR]

The Meguma terrane is a unique unit of the Northern Appalachians as it is only identified in Nova Scotia. It was thrust over the Avalon terrane during the Early Devonian Acadian Orogeny. The Avalon and Meguma terranes are exotic to North America and likely originated along the margin of Gondwana. The precise relationship between the terranes is uncertain and very little is known about the basement rocks of each terrane. Hosted within the Late Devonian lamprophyric Popes Harbour dyke of the Meguma terrane are xenoliths of meta-sedimentary and meta-igneous rocks that are from the basement of the Avalon terrane. The xenoliths offer a glimpse into the nature of the lower crust of the Northern Appalachians. In this study, we present in situ zircon U-Pb age dates from a rare dioritic xenolith in order to assess its origin. The results show that the majority of zircons ages are between ~580 Ma and ~616 Ma with smaller groups at 750–630 Ma, ~2100 Ma, and <570 Ma. The zircon 206Pb/238U weighted-mean age of the rock is 603 ± 5.3 Ma and contemporaneous, with granitic intrusions of the Avalon terrane located within the Antigonish and Cobequid highlands of Nova Scotia. The diorite is compositionally similar to granitoids from an active continental margin. The discovery of Early Paleoproterozoic (~2100 Ma) zircons and the absence of Late Paleoproterozoic (1900–1700 Ma) and Mesoproterozoic (1600–1000 Ma) zircons suggests that the parental magma either encounters only Early Paleoproterozoic and Late Neoproterozoic rocks during emplacement or is derived by the melting of Paleoproterozoic rocks and/or the melting and mixing of Paleoproterozoic and Late Neoproterozoic rocks. Therefore, it is possible that Paleoproterozoic rocks may exist within the basement of the Avalon terrane. [ABSTRACT FROM AUTHOR]

The Tagmout Cu-Ag deposit is located at the Saghro mining district (Eastern Anti-Atlas orogenic belt) and about 110 km east to the city of Ouarzazate. Tagmout deposit is hosted by high-K calc-alkaline magmatic rocks (olivine-gabbronorite to granite). These granitoids show a zoned and polyphased hydrothermal alteration (potassic, phyllic, argilic, and propyllitic) that are typically found in neutral epithermal systems. Cu-Ag mineralization is found either disseminated in the granodiorite and/or quartz-monzodiorite or in veins. These vein swarms are cross-cutting the out-croup igneous plutons and are mainly related to the NW–SE, NNE-SSW and rarely to the ENE-WSW oriented faults. Sulfides are the main ore minerals (chalcopyrite, bornite, chalcocite, and covellite) and secondary carbonates (malachite and azurite). Silver is expressed as impurity in copper sulfides or as small inclusions of the stromeyerite (CuAgS) mineral. SEM and microprobe data have revealed that copper sulfides are important silver-bearing minerals (up to 3%wt in chalcocite), as well as other trace elements: Pb, Zn, As, and Cd (ca. 600 ppm Cd). In copper sulfides, the main mechanism is atomic substitution: (i) Cu is substituted by Ag and Fe is substituted by Cd in chalcopyrite and bornite; (ii) Cu is substituted by Ag + Pb in chalcocite. Besides, microthermometric data from the mineralizing fluids of Tagmout deposit reveal that two distinct aqueous fluids have played an important role in the ore formation: (i) an early fluid marked by a high temperature (Th = ⁓300 °C) and intermediate (constant) salinity (⁓12% wt eq. NaCl) was identified in quartz (Lqz). This fluid is likely to be linked to Cu, Pb, and Zn sulfide deposition by cooling; (ii) the second hydrothermal fluid is characterized by low temperature (Th ⁓ 200 °C), and high salinity (⁓ 35% wt eq. NaCl) was associated with the Ag-bearing carbonate stage (LCa). This latter fluid is likely to be coeval to the alteration of primary Cu sulfides, by substituting Ag to Cu with some trace elements (namely, Cd and Pb), as well as neoformation of secondary Cu- and Ag-enriched minerals (chalcopyrite II, bornite II, chalcocite, covellite, and stromeyerite). It could be noticed that the composition of those fluids is quite complex: based on the low eutectic temperatures (Te ⁓ -100 °C), we think that there could be salts like CaCl2, MgCl2, LiCl, AgCl, and LiBr. However, Cu-Ag mineralization in the Tagmout deposit is associated with two distinct mineralizing events: (i) an early hydrothermal event linked to Tagmout granodiorites that probably induced early sulfide stage deposition (chalcopyrite I + bornite I + galena II + sphalerite) and (ii) Ag-rich epithermal stage, which is thought to be linked to late Proterozoic volcanic formations. It is likely to be the cause of Ag-rich paragenesis deposition (stromeyerite + Ag-chalcopyrite II + Ag-chalcocite + Ag-covellite). The first stage is similar to disseminated Cu mineralization in the nearby Cu Bou Skour deposit. The second stage is known at regional scale (Imiter, Zgounder, Jbel Laassal, Tizert, Tazlaght...). [ABSTRACT FROM AUTHOR]