ORCID Profile
0000-0001-7180-3386
Current Organisations
University of Adelaide
,
Université Mohammed VI Polytechnique
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Publisher: Informa UK Limited
Date: 15-05-2018
Publisher: Copernicus GmbH
Date: 04-03-2021
DOI: 10.5194/EGUSPHERE-EGU21-7361
Abstract: & & The Moroccan High Atlas mountain range is an aborted Mesozoic rift basin that was moderately shortened during the Late Cretaceous& #8210 Cenozoic inversion. The range is currently featured in its central part by the presence of conspicuous S-shaped open gentle synclines where Middle Jurassic strata crop out, with sub-horizontal bottom, separated by 15-to-80-km narrow faulted anticline ridges with two distinct directions: ENE and NE. The tight anticline ridges are cored by Triassic continental red-beds intruded by the CAMP basalts and subsequently by Upper Jurrasic& #8210 Lower Cretaceous alkaline magmatism. Regional cleavage with very low-grade anchi- to epi-zonal metamorphism are depicted along several structures of the High Atlas, particularly the NE-trending anticlines. The sedimentary layers thickness, on the other hand, gets thinner towards the faulted anticlines with the development of intraformational truncations. The structural history of the High Atlas syncline-topped anticlinal ridges remains a controversial matter. Any attempt to reconstruct the evolutionary process of such folded structures must take into consideration the following circumstances:& & & ul& & li& After a Triassic rifting episode followed by the establishment of Liassic carbonate platform, the High Atlas basin underwent a wide spread exhumation event at the time interval between the Middle Jurassic and Lower Cretaceous leading to the deposition of continental detrital series and sedimentary hiatus & /li& & li& The upward motion was accompanied with the emplacement of alkaline magmas in the Central High Atlas & /li& & li& A complex halokinetic history characterizes the Central High Atlas salt province during both pre-orogenic and orogenic stages & /li& & li& During the Late Cretaceous& #8210 Cenozoic, the High Atlas experienced a moderate crustal shortening which was focused essentially within the range& #8217 s borders & /li& & /ul& & & In order to bring new insights to the structural history of the High Atlas folded structures, a structural investigation was carried out in Tirrhist and Anemzi ridges. In each station, fractures measurements were taken, and oriented s les were collected for micro-structural analysis. First paleo-stress inversion in some stations reveals the presence of pre-folding bedding-parallel maximal horizontal stress oriented NE to NNE. For a deep analysis of pre syn and post-folding stresses history, we use a calcite stress inversion technique, namely Etchecopar& #8217 s method, to unravel the paleo-stresses orientations and to quantify the differential stresses during the different episodes of deformation. The present work is a preliminary attempt to quantify tectonic stresses in the hinterland of an arguably weakly deformed orogenic belt.& &
Publisher: Copernicus GmbH
Date: 03-03-2021
DOI: 10.5194/EGUSPHERE-EGU21-5091
Abstract: & & Alkaline complexes are an important target for geological exploration, with both scientific and economic interests. They are host to different types of mineral deposits, such as Rare Earths, igneous phosphates, -and K-rich minerals and rocks. In Morocco, the Central High-Atlas (CHA) hosts several transitional to alkaline complexes ranging from Upper Jurassic to Eocene and showing almost all the differentiation terms of transitional to alkaline suites. These alkaline complexes are however poorly explored and their potential in terms of mineral resources is still elusive.& & & & The aim of this research is to use Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) to discriminate different transitional to alkaline rock lithologies and their associated mineralizations. For that purpose, series of band ratios proven to be sensitive to the silica, mafic, felsic and carbonate contents of transitional to alkaline rocks were applied. Our results show that the major Upper Jurassic magmatic intrusions of Moroccan CHA, such as Anemzi, Inouzane, Tassent, and Tasraft, hold distinct igneous facies, mainly composed of Mafic to felsic rocks. Field and petrographic observations have confirmed the ASTER results and highlighted that these rocks are formed of gabbro to syenite. The later are associated with significant feldspar concentrations, but also host apatite, garnet, and magnetite vein-type ores. Thereafter, field- and petrographic-based data were used as training data to perform a supervised classification allowing to refine the geological mapping of the studied alkaline intrusions.& &
Publisher: Copernicus GmbH
Date: 27-03-2022
DOI: 10.5194/EGUSPHERE-EGU22-3272
Abstract: & & Deformation rate analysis (DRA) and Acoustic Emission (AE) are popular methods of in-situ stress measurements from oriented cored rocks which take advantage of the rock stress memory also known as the Kaiser effect. These methods rely on the accurate measurement of a point of inflection in the characteristic DRA and AE curves, however, due to the complex geological stress history in rocks, locating point of inflection can be problematic. In order to better understand the stress memory experiments were performed on a combination of six different types of soft, and hard crystalline rocks including concrete with no stress history. The effect of loading modes, strain rates, and time delay were studied on preloaded rock specimens to investigate their influence on the stress memory. A fading effect was observed when the number of the cycles in the test were increased which led to the development of a new method of quantifying the preloads. Results show that the type of loading and the loading rate has little to no influence on the Kaiser effect, however, under faster loading rates the Kaiser effect is more distinct. Likewise, no time dependency was observed for time delays up to seven months.& &
Publisher: Informa UK Limited
Date: 22-09-2022
Publisher: Elsevier BV
Date: 09-2023
Publisher: American Geophysical Union (AGU)
Date: 03-2017
DOI: 10.1002/2016TC004366
Publisher: Copernicus GmbH
Date: 27-03-2022
DOI: 10.5194/EGUSPHERE-EGU22-3353
Abstract: & & Hydraulic fracturing is increasingly becoming utilized within Underground hard rock mines such as block caves and Sub Level Caves as a way to promote controlled cave propagation, increase resource recovery, and seismic hazard through the manipulation of rock mass properties through fracture surface creation and limiting of stress concentration. & br& While hydraulic fracturing is not a new application, it is still in its infancy in mining projects such as cave mining. It is used on entirely different scales, under different stress regimes and with varying motives. Therefore, more research needs to be carried out in understanding the fundamentals of fracture growths that can help improve hydraulic fracturing applied in mining projects.& & & & & & Predicting breakdown pressure is an important part of the designing of hydraulic fracturing with accurate prediction being the baseline of designing and implementing a successful preconditioning c aign in all industries, but especially so in block cave mining. & br& The most commonly used breakdown pressure theoretical model is the conventional breakdown model and is based on tensile strength and confining stresses acting upon the borehole. This might be imprecise within hard rock mining environments and increasingly so at depth of higher stresses.& & & & & This work compares indirect tensile strength results and their fracture toughness, from both conventional Brazilian Disc Testing and the recently developed Adelaide University Snapback Indirect Tensile Testing (AUSBIT).& br& By using lateral strain control to stabilise the brittle material responses, AUSBIT allows for the capture of true post-peak behaviour, i.e. controlled fracture propagation can be achieved.& & & & The captured post-peak behaviour allows practitioners to measure a more reflective tensile strength and fracture toughness from just one testing method, Alongside this are laboratory hydraulic fracture experiements on the same rock unit, which in turn is used to propose a new Hard Rock Breakdown Pressure prediction based on the conventional method which incorporates fracture toughness when checked against the results of the lab fracture experiments, and other lab studies.& & & & & The results of this work factors in a progressive toughness of a rock at depths, and creates a more accurate predictor of breakdown pressure in underground hard rock mines under varying stress conditions.& & & &
Publisher: Elsevier BV
Date: 08-2014
Publisher: Copernicus GmbH
Date: 26-03-2022
DOI: 10.5194/EGUSPHERE-EGU22-669
Abstract: & & & span& The Moroccan Atlas is an intracontinental chain resulted from an aborted rifting during the Mesozoic time, by an uplifting and moderate shortening during the Late Cretaceous-Cenozoic period. Several studies have highlighted the role of tectonic inversion in the evolution of the High Atlas Range, where strike-slip faults are commonly been considered as a main component of the alpine signature within the High Atlas belt. However, more recent works have focused on the geodynamic model of the evolution of the Atlas Range using different approaches. The structural history and chronology of events are still matter of debates. To contribute to the later, a combined meso and microstructural study was conducted in the western part of the chain. It provided an attempt to quantify paleo-stresses from structural analysis of the Permo-Triassic extensional phase to the tectonic reversal phases, acting from Cenozoic to present days.& br& This work highlighted two major tectonic phases: (1) the first represented by an extensive regime, with a sub-horizontal minimal stress & #963 oriented NE-SW and linked to the Central Atlantic occurrence. This stage is characterized by pull apart basins genesis in horst and graben morphology. (2) the second phase represented by a weakly tilted compression with a maximum stress & #963 oriented in set NNE-SSW to NNW-SSE. This compression began in the Tertiary, contemporary with the Africa and Europe collision. the related inversions are printed at the paleozoic basement/mesozoic cover interface from the Eastern area to the Jurassic-Cretaceous and Cenozoic plateaus in the West, passing through the Triassic detrital formations of the Argana corridor.& br& & /span& & strong& & span& Keywords& /span& & /strong& & span& & strong& :& /strong& Paleo-stress, Structural analysis, Tectonic inversion, Western high Atlas, Morocco, Alpine orogeny.& /span& & &
Publisher: Copernicus GmbH
Date: 27-03-2022
DOI: 10.5194/EGUSPHERE-EGU22-1008
Abstract: & & Located in the western segment of the intracontinental Atlas system, the Moroccan Central High Atlas is a NE-SW to ENE-WSW-trending Fold-and-Thrust Belt that is formed during the Cenozoic Alpine orogeny by a positive inversion of Triassic-Jurassic basin. It is structurally distinguished from the other segments of the Moroccan High Atlas orogenic belt by the occurrence of S-shaped ENE-WSW oriented tight anticlinal ridges bounding wider synclines. The elongated ridges core disordered association of plutonic rocks, Liassic carbonate and Late Triassic arigilites, whilst the wider synclines are filled by thick Jurassic series with minor magmatic manifestations expressed by mafic and felsic dikes. The origin of these structures has been ascribed to pre-inversion wrench tectonics with significant compressive component whereas they have been attached to post-rift rift block tilting and or salt tectonics in an alternative view. Characterizing the paleostress history is thereby a crucial matter to unravel the structural evolution of these structures. In order to bring new insights into the actual understanding of the Central High Atlas post-rift structural history, we reconstruct the paleostress tensors preserved in the folded Jurassic series of Anemzi and Tirrhist regions based on brittle deformation structures together with calcite twins stress inversion. The preliminary results highlight the presence of pre-folding layer parallel maximum horizontal stress during three stages: E-W to ENE-WSW, NNE-SSW and NW-SE compressions. Local extensional stress features are observed essentially near diapiric structures and the exhumed magmatic intrusions. The latest structural stage is featured by a post-folding NW-SR compression likely related to the recent phases of the Alpine orogeny.& &
Publisher: Copernicus GmbH
Date: 15-05-2023
DOI: 10.5194/EGUSPHERE-EGU23-15125
Abstract: Processes such as oblique mid ocean ridge spreading, glacial isostatic adjustment and slope instability provide a highly complex spatial and temporal record of stress in the Fram Strait. The Vestnesa Ridge is a contourite drift bounded by two slow spreading mid ocean ridges located beside a formerly glaciated margin. The total state of stress is difficult to separate into in idual components therefore our focus is to ascertain whether there is a stress transfer from the deep crust into the shallow overlying (~200m) sedimentary cover. We use high-resolution P-cable 3D seismic volumes together with 2D seismic, to map deeper faults connecting with near surface deformation. We perform high resolution mapping of the ridge by examining the dip and strike of each distinct fault system. We use a pre trained 3D model to predict faults within each 3D volume and automatically extract faults at multiple intervals to capture temporal stress changes. To minimize noise, the model identifies faults based on edge preserved smoothing for a selection of peak frequencies. In our results we observe fault linkage between parallel faults that may become favourable locations for transtensional and transpressional stress expected in the strike slip regime predicted in the west of the ridge. Our results show that the east of the ridge has a dominant NW-SE fault strike and a present day tensile stress regime while towards the west, the NW-SE assemblage becomes less prominent and multiple fault systems dominate increasing the complexity of the system. We present a high detail comprehensive structural analysis of 3 study sites across the shallow ridge sediments and use our results to investigate differences in the strike and dip between sites to explore the influence of sedimentary faults and ridge geomorphology on the spatial evolution of seafloor seepage at a deep Arctic oceanic basin.
Publisher: Elsevier BV
Date: 07-2017
Publisher: Copernicus GmbH
Date: 26-03-2022
DOI: 10.5194/EGUSPHERE-EGU22-887
Abstract: & & The Ouled Abdoun sedimentary basin in Morocco contains the largest phosphate reserves in the world. In the southeastern parts of the basin, the phosphorite deposits lay from the Maastrichtian to the Lutetian sediments of the Tadla Plain. This section has a thickness of ~ 30 m and generally protected from erosion by a relatively strong Turritella slab cover. The phosphorite deposits are distributed in horizontal strata interbedded with levels of limestone, marl and clay, that present various silicifications from the Ypresian. This work aims to study and determine their petrographic, granulometric and mineralogical compositions. A multidisciplinary approach was adopted to achieve these objectives. First, the use of sedimentology and the application of sequence stratigraphy allowed the definition of three depositional sequences in this deposit. Second, the granulometric analysis of the phosphate facies reflects a dominance of well classified medium grains. Furthermore, the analysis of the Visher curves revealed up to three major modes of transport: traction, saltation and suspension. Based on their mineral composition, the microfacies are classified into two phosphate families (or types): Coprolite Intraphospharenite type and Granular Pelphosphalrenite type. Finally, the mineral parageneses recognized by the XRD analyses revealed that phosphorits consist mainly of carbonate, silica and apatitic phases in the section of Tadla.& & & & & strong& & em& Keywords& /em& & /strong& : Phosphorite deposit, Tadla plain, Maastrichtian-Lutetian.& &
Publisher: Elsevier BV
Date: 07-2023
No related grants have been discovered for Khalid Amrouch.