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See detailMoroccan clay deposits: Physico-chemical properties in view of provenance studies on ancient ceramics
El Ouahabi, Meriam ULiege; El Boudour El Idrissia,, Hicham; Daoudi, Lahcen et al

in Applied Clay Science (2019), 172(65-74),

Features of clayey raw materials from most important traditional pottery centers in the vicinity of the main medieval sites in Morocco, and their fired products were investigated. Besides clay from the ... [more ▼]

Features of clayey raw materials from most important traditional pottery centers in the vicinity of the main medieval sites in Morocco, and their fired products were investigated. Besides clay from the North of Morocco, the used raw material was illitic clays (10–100%) and smectite-rich clays (0–67%) with variable amount of kaolinite, quartz and feldspars. Chlorite was also present in a small amount. The main major oxides were Si2O, Al2O3 and CaO. The fired tests (800–1100 °C) displayed a decrease in open porosity of the sintered clay by raising the temperature, mainly from 1000 °C due to the inception of melting. This change was coupled with the change in mineralogical composition. New crystalline phases as Ca silicates (diopside and gehlenite), hematite, spinel and mullite occurred during firing process, attesting to the inception of melting and were responsible for porosity reduction. Reference clays for pottery were established based on the clay mineralogy and chemical composition. The present study would help to answer some archeological questions concerning possible sourcing areas for archeological ceramics, to determine techniques for the production of artefacts, and then to interpret cultural influences. Furthermore, the obtained results will support the inception of development of a compositional database for Moroccan pottery. [less ▲]

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See detailAnalytical study of ancient ceramics from the archaeological site of Aghmat, southern Morocco
El Halim, Mouhssin ULiege; Daoudi, Lahcen; El Ouahabi, Meriam ULiege et al

in Materiocedia: Proceedings Series on Materials (2018), 1(1), 47-58

This paper explores Aghmat archaeological materials (VII centuries) using two types of ceramics, come from a recent archaeological excavation in Aghmat (Morocco) in order to enhance documentation ... [more ▼]

This paper explores Aghmat archaeological materials (VII centuries) using two types of ceramics, come from a recent archaeological excavation in Aghmat (Morocco) in order to enhance documentation, conservation and restoration issues, then putting into value the architectural heritage. Fortuitously discovered in 2005, Aghmat village has allowed the reformulation of several hypotheses about Aghmat population skills in construction and handicrafts. Even though the areal extent of this archaeological site exceeds 20 Km2, no traces of furnaces have been found yet, only ruins of buildings and streets. Bricks and pottery samples were the most abundant types of ceramics founded. Mineralogical and chemical analyses of this materials provided information about the origin of raw materials and manufacturing process. The chemical compositions indicated that SiO2, Al2O3 and Fe2O3 are major elements while K2O and MgO are less abundant. The ceramics were produced using at least two raw materials, non calcareous clay of permo-triassic age for bricks, and carbonate quaternary clays for pottery samples, as the calcium oxide content is generally more than 10%. [less ▲]

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See detailWeathering pattern of Messinian lithothamnium limestones: implication about paleoclimatic conditions
Moulana, Meriem Lina ULiege; El Ouahabi, Meriam ULiege; Boulvain, Frédéric ULiege et al

Conference (2018, September 14)

Limestones are prevalent in Algeria. These formations since their deposition have been affected by a range of weathering, dissolution and recrystallization processes dependant of the paleoclimatic ... [more ▼]

Limestones are prevalent in Algeria. These formations since their deposition have been affected by a range of weathering, dissolution and recrystallization processes dependant of the paleoclimatic conditions they sustained. These transformations also affect the potential hazard that these karstic terrains represent. We focus here on the Boukadir Region situated at the foot of the Ouarsenis Mountain (Fig. 1). The region comprises the Ouarsenis northern piedmont composed of ~15o north dipping lithothamnium limestones of the Messinian period that rest unconformably upon blue marls of the upper Miocene, and to the south the E-W striking lower Chlef Basin filled by Plio-Quaternary sediments and flooded by the Chlef River. The lithothamnium carbonates rocks form a major deep aquifer in the Basin. The Basin is crossed along its southern edge by the Relizane strike-slip fault. In June 1988, there was a large collapse sinkhole of 60 m in diameter and 35 m of deep that occurred along the national road RN4 near the southern edge of the basin (LCTP, 1989). Drilling shows that sinkhole can be associated to lithothamnium limestones that were covered by more than 61 m of sediments at that location. No other sinkhole formed since this accident. In this study we investigate the weathering pattern of the lithothamnium limestones to unravel the likelihood of formation of large sinkholes in this formation. Boreholes and quarries show that the Messinian Calcareous limestones of the Boukadir region are deeply weathered and partly recrystallized calcareous rocks; the weathering affects its entire thickness reaching a maximum of 200 m. This weathering pattern is not visible a few kilometres more to the east, in limestones having a similar origin. To unravel the specific paleoclimatic conditions that these limestones sustained, we combine field work and on selected samples, petrographic thin section and mineralogical (XRD) analysis and SEM observations. Field work in quarries and in the wadi shows that the lithothamnium limestones are composed of altering sandstone rich beds with a calcareous cement and bioconstructions rich beds. .. [less ▲]

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See detailHistorical glazes (14th-16th century CE) characterization for the development of adapted restoration materials in Morocco
El Ouahabi, Meriam ULiege; El Halim, Mouhssin ULiege; Daoudi, Lahcen et al

Poster (2018, September)

Historical Islamic monuments are impressive by their artistic and fascinating architecture, and many of them therefore belong to the UNESCO world cultural heritage. Particularly, in Morocco the historical ... [more ▼]

Historical Islamic monuments are impressive by their artistic and fascinating architecture, and many of them therefore belong to the UNESCO world cultural heritage. Particularly, in Morocco the historical monuments are carefully decorated with arranged glazed ceramic pieces, called “zellige”, giving the buildings their typical and colorful appearance. The glaze performs a dual role in the decoration and protection of the surface. Unfortunately these architectural monuments lose their impressive appearance, when the glazed tiles are damaged and the glazes are chipped off (Fig.1). Through time, the influence of climate, water and environmental pollution can cause deterioration of the building materials and contribute to the chipping of the tile glazes (Tite et al., 2016, Gradmann, 2016). Unfortunately this damage affects many historical buildings worldwide, and restoration of glazes becomes urgent to save the brilliant facades from irreversible destruction. In Morocco, eight sites located in the imperial cities Fez and Marrakech, were classified as world heritage by UNESCO in the sixties. Since then, restoration campaigns are being undertaken to preserve the former architecture of these monuments. However, two recent restoration campaigns undertaken in Marrakech have been unsuccessful, because of the weakness of the tiles used. This study aims to characterize the glazes of the main historical buildings (14th-16th century CE) in the Marrakech area with the purpose of developing adapted restoration materials. This study will contribute to selecting the most appropriate glaze composition for restoration purposes. To address this issue, a total of 156 glaze samples were taken. Among these, 27 samples are original to different buildings in the Marrakech and Fez area (Saadian tombs, Bahia Palace, El Badi Palace and Medersa Ben Youssef, 14th to 16th c. CE), 11 samples are assumed to belong to a 1st restoration phase, 18 samples are assumed to belong to a 2nd restoration phase and 97 samples are derived from recent traditional zellige production. The glazes were carefully observed under a binocular to identify any damage affecting the surface of the sherds. The glaze color was determined using a Konica Minolta CM-700d spectrophotometer. Non destructive XRF devices (Thermo Fisher Scientific© Niton XL3t GOLDD) were used to determine the chemical composition of the glaze. Mineralogical phases of different color of glazes were carried out using a BrukerD8-Advance diffractometer with copper anticathode. From 14th to 16th century CE, in Marrakech area, the ceramists use a mixture of clay, sand and flux agents to manufacture glazes. The chemical composition did not highlight obvious correlation between the colors of the glazes and their compositions, except for the green colored glaze. The latter contains copper and sporadic chromium as a colorant. The historical glazes are lead glazes with Pb contents from 37 to 56%, opacified with Sn in the range 4–18%. Our results are in agreement with the composition of Islamic glazes in the Mediterranean area in general, and in Southern Spain in particular (e.g. Molera et al., 2001, Gradmann, 2016). This technology is taken up from the Roman and Byzantine imperia and then continued during the medieval Islamic culture in Morocco. The use of lead as flux, in association with alkalis, promotes the expansion properties during firing and increases the hardness of the tile and makes the color more clear. Furthermore, the glaze appears thicker with a more brilliant color, due to the high diffraction index of lead glass (Tite et al., 1998). In recent glazes, however, a decrease in lead amount is observed for the two restorations phases, reflecting the weakness of the glazed tiles mainly with the lack of any substituent of flux agent (Fig. 2a). This reduction of Pb is not associated with any supply of flux, implying the partial melting at low firing temperature and then the weakness of the glazed tile. [less ▲]

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See detailLacustrine record of last millenia environmental changes in south central Chile
Montes, Isis; Banegas, A; Fagel, Nathalie ULiege et al

Poster (2018, April)

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See detailCharacterization of halloysite from Morocco: evaluation of its suitability for ceramic industry
El Haddar, Abdelilah; Gharibi, Elkhadir; Azdimousa, Ali et al

in Clay Minerals (2018)

Halloysite from Nador (NE Morocco) has been studied to evaluate their suitability in ceramic industry. Cross-section involving all the Messinian facies was performed in the Melilla Neogene basin, at the ... [more ▼]

Halloysite from Nador (NE Morocco) has been studied to evaluate their suitability in ceramic industry. Cross-section involving all the Messinian facies was performed in the Melilla Neogene basin, at the foot of the Gourougou volcano, in order to understand the origin of the halloysite and appreciate its reserves. White layers of halloysite and red clays rich in smectite occurred in contact with basal reef limestone, were characterized by mineralogical (XRD, IR), textural (SEM) and physico-chemical analyzes (grain-size, Atterberg limits, ATD/TG, XRF and specific surface area). Ceramic proprieties were evaluated for fired halloysite from 500 to 1100°C in order to appreciate technical processing for ceramic production. The halloysite consists of fine particles with a high plasticity and a large specific surface area. XRD results revealed the presence of 7Å non-hydrated halloysite with the presence of gibbsite, alunite, K-feldspar plus other minor phases, and traces of smectite and illite. Infrared spectroscopy confirms the occurrence of characteristic bands of halloysite at 3695 and 3618 cm-1. SEM observations confirmed the predominance of tubular facies typical of halloysite. The chemical analysis revealed high aluminum content linked to the presence of some aluminous phases (gibbsite and alunite). ATD/TG and XRD results of fired clay sample evidenced halloysite dehydroxylation and a rearrangement of metakaolinite to form mullite and spinel from 975°C. Moroccan halloysite has good properties for refractory ceramic application. However, quartz sand addition is required to avoid any cracks development at firing as well as to reduce the plastic behaviour of raw halloysite and minimize shrinkage during sintering. [less ▲]

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See detailTechnological behaviour of Cretaceous and Pliocene clays of northern Morocco used in fired brick manufacturing
El Ouahabi, Meriam ULiege; Daoudi, Lahcen; Fagel, Nathalie ULiege

in Journal of Materials and Environmental Science (2018), 9(4), 1140-1151

Northern Morocco has an important local ceramic industry. Twenty-three Craterous and Pliocene clays from Tangier area (Northern Morocco) were studied to test their suitability as raw material for fired ... [more ▼]

Northern Morocco has an important local ceramic industry. Twenty-three Craterous and Pliocene clays from Tangier area (Northern Morocco) were studied to test their suitability as raw material for fired brick production. To assess their behaviour, the chemical composition, specific surface area (SSA), cation exchange capacity (CEC), and apparent density of clays were determined. The chemical composition consisted mainly of SiO2 (32 – 60%), Al2O3 (7 – 30%), and CaO (0.5 – 32%). SSA and CEC values of all the samples were low. The apparent density, pore volume, and micropore values were almost similar. Clay bricks were prepared by forming and shaping, and then fired in the range of 800 – 1100°C. Firing shrinkage, loss on mass and water absorption capacity were done in order to characterize clays after firing. Most of the clay samples have the necessary properties for the manufacturing of brick products. However, some clay samples were above the norm of loss on weight, due mainly to their high amount of carbonates. Furthermore, some kaolinitic samples from Pliocene blue marls and Cretaceous marls are inappropriate for building-related brick fabrication, because of the development of portlandite in brick, when in contact with moisture of the air. However, it will be necessary to mix them with other clays with little or no carbonate to dilute their carbonates content and then enhance their workability. [less ▲]

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See detailLate Holocene changes on erosion pattern on a lacustrine environment: landscape stabilization by volcanic activity versus human activity
Lamair, Laura ULiege; Hubert, Aurelia ULiege; El Ouahabi, Meriam ULiege et al

in Geochemistry, Geophysics, Geosystems (G3) (2018)

Lacustrine sediments are particularly sensitive to modi cations within the lake catch- ment. In a volcanic area, sedimentation rates are directly a ected by the history of the volcano and its eruptions ... [more ▼]

Lacustrine sediments are particularly sensitive to modi cations within the lake catch- ment. In a volcanic area, sedimentation rates are directly a ected by the history of the volcano and its eruptions. Here, we investigate the impact of Mt. Fuji Volcano (Japan) on Lake Motosu and its watershed. The lacustrine in ll is studied by combining seismic re ec- tion pro les and sediment cores. We show evidence of changes in sedimentation patterns during the depositional history of Lake Motosu. The frequency of large mass-transport de- posits recorded within the lake decreases over the Holocene. Before 8000 cal yr BP, large sublacustrine landslides and turbidites were lling the lacustrine depression. After 8000 cal yr BP, only one large sublacustrine landslide was recorded. The change in sedimentation pattern coincides with a change in sediment accumulation rate. Over the last 8000 cal yrs BP, the sediment accumulation rate was not su cient enough to produce large sublacustrine slope failures. Consequently, the frequency of large mass-transport deposits decreased and only turbidites resulting from sur cial slope reworking occurred. These constitute the main sedimentary in ll of the deep basin. We link the change in sediment accumulation rate with (i) climate and vegetation changes; and (ii) the Mt. Fuji eruptions which a ected the Lake Motosu watershed by reducing its size and strongly modi ed its topography. Moreover, this study highlights that the deposition of turbidites in the deep basin of Lake Motosu is mainly controlled by the paleobathymetry of the lake oor. Two large mass-transport deposits, oc- curring around 8000 cal yr BP and 2000 cal yr BP, modi ed the paleobathymetry of the lake oor and therefore, changed the turbidite depositional pattern of Lake Motosu. [less ▲]

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See detailMineralogical and physicochemical characterization of the Jbel Rhassoul clay deposit (Moulouya Plain, Morocco)
Amakrane, Jemaa ULiege; El Hammouti, Kamal; Azdimousa, Ali et al

in Journal of Materials and Environmental Science (2018), 9(2549-2557),

This study aims at the mineralogical and physicochemical characterization of clays of the Missour region (Boulemane Province, Morocco). For this, three samples were collected in the Ghassoul deposit. The ... [more ▼]

This study aims at the mineralogical and physicochemical characterization of clays of the Missour region (Boulemane Province, Morocco). For this, three samples were collected in the Ghassoul deposit. The analyses were carried by X-ray diffraction (XRD), X-ray fluorescence (XRF) and Scanning Electron Microscopy (SEM). The thermal analysis from 500 to1100°C was also performed on studied samples, and the fired samples were characterized by XRD and SEM. The XRD results revealed that raw Ghassoul clay consists mainly of Mg-rich trioctahedral smectite, stevensite-type clay, which represents from 89% to 95% of the clay fraction, with a small amount of illite and kaolinite. The associated minerals are variable amount of quartz, dolomite, hematite, gypsum and K-feldspars. The chemical analysis confirms the presence of Mgrich smectite (stevensite) with largest amount in sample containing the highest MgO. The SEM micrographs revealed the presence of automorphous structures with petalslike shape typical of smectite. The Thermal transformations determined by X-ray diffraction indicated that stevensite was transformed to enstatite from 800ºC. Diopside starts to appear from 700°C, which is confirmed by SEM observations, and the quartz is transformed to cristobalite when the temperature exceeds 1100°C. [less ▲]

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See detailMineralogical and Geochemical Characterization of Archaeological Ceramics from El Badi Palace (XVIth Century), Morocco
El Halim, Mouhssin ULiege; Daoudi, Lahcen; El Ouahabi, Meriam ULiege et al

in Clay Minerals (2018)

Textural, mineralogical and chemical characterization of archaeological ceramics (zellige) of the El Badi Palace (Marrakech, Morocco), the main islamic monument from the Saadian period (XVIth century ... [more ▼]

Textural, mineralogical and chemical characterization of archaeological ceramics (zellige) of the El Badi Palace (Marrakech, Morocco), the main islamic monument from the Saadian period (XVIth century), has been performed, to enhance restoration issues and to determine technology of manufacturing. A multi-analytical approach based on optical and Scanning Electron Microscopy (SEM), cathodoluminescence, X-ray fluorescence (XRF) and X-ray diffraction (XRD) was used. Re-firing tests on ceramic supports were also performed to determine the firing temperatures used by the Saadian artisans. A calcareous clay raw material was used to manufacture these decorative ceramics. The sherds were fired at a maximum temperature of 800°C in oxidizing atmosphere. The low firing temperature for zellige facilitates cutting of the pieces but also causes fragility to these materials due to the absence of vitreous phases. [less ▲]

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See detailMineralogy and firing characteristics of clayey materials used for ceramic purposes from Sale region (Morocco)
El Halim, Mouhssin ULiege; Daoudi, Lachen; El Ouahabi, Meriam ULiege et al

in Journal of Materials and Environmental Science (2018), 9

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See detailInter-techniques comparison of PIXE and XRF for Lake sediments
El Ouahabi, Meriam ULiege; Chene, Grégoire ULiege; Strivay, David ULiege et al

in Journal of Analytical Atomic Spectrometry (2018), 33(883 - 892),

In this paper we describe a validation procedure for chemical analysis of major elements and some minor elements as Sr, Cr, Ni, Zn and Zr in heterogeneous geological sediments. The procedure applies two ... [more ▼]

In this paper we describe a validation procedure for chemical analysis of major elements and some minor elements as Sr, Cr, Ni, Zn and Zr in heterogeneous geological sediments. The procedure applies two distinct techniques (PIXE and XRF) to the analysis of sediments. In this work an inter-technique comparison of the heterogeneous lacustrine sediments from the Amik Lake in the vicinity of the Roman city of Antioch (SE, Turkey) was carried out. Dried raw samples and with the addition of linking powder were analyzed using PIXE performed on the “Arkeo” beam line of the University of Liège AVF-Cyclotron and XRF (University of Liège). The aim of this work was to compare PIXE and XRF analysis with the set-ups routinely in use in the two laboratories. The purpose was also to determine the best combination of techniques and sample preparation protocol to be applied for heterogeneous sediments and the main elements of interest for each specific technique. The results are in agreement among the two techniques, with discrepancies concerning almost lighter and minor elements. These differences are related mainly to the texture of the sediments and the intrinsic features of the XRF and PIXE techniques. Major and selected minor elements are sensitive to the grain-size and the porosity of the samples. However, the accuracy of both XRF and PIXE requires the reduction of the grain-size or addition of linking powder to the sediments to fill the voids in order to increase the intensities of both lighter and minor elements. The results demonstrate the critical importance of sample treatment prior to analysis as well as the necessity of several measurement points and replicates to ensure the accuracy of the PIXE results. [less ▲]

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See detailThe influence of clay composition and lithology on the industrial potential of earthenware
El Boudour El Idrissi, Hicham ULiege; Daoudi, Lahcen; El Ouahabi, Meriam ULiege et al

in Construction and Building Materials (2018)

This paper investigates the influence of clay composition and lithology on the industrial potential of earthenware. The 26 ceramic pastes collected were subjected to particle-size analysis, X-ray ... [more ▼]

This paper investigates the influence of clay composition and lithology on the industrial potential of earthenware. The 26 ceramic pastes collected were subjected to particle-size analysis, X-ray diffraction and X-ray fluorescence to investigate their compositions. The shards properties were determined through porosity tests, shrinkage, flexural and compressive strengths. Based on obtained results, all studied ceramic pastes turn out to offer a great potentiality for the earthenware industry despite their varied lithology. Argillite-based pastes exhibit the highest mechanical strengths while colluvium and schist-based pastes exhibit the lowest mechanical strengths. Further, the results have established a reference database for the perpetual restoration work of Marrakech monuments and can help to tracing back the source areas of the archaeological materials of this city. [less ▲]

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See detailVolcanic influence of Mt. Fuji on the watershed of Lake Motosu and its impact on the lacustrine sedimentary record
Lamair, Laura ULiege; Hubert, Aurelia ULiege; Yamamoto, Shinya et al

in Sedimentary Geology (2018)

Lacustrine sediments are particularly sensitive to modifications within the lake catchment. In a volcanic area, sedimentation rates are directly affected by the history of the volcano and its eruptions ... [more ▼]

Lacustrine sediments are particularly sensitive to modifications within the lake catchment. In a volcanic area, sedimentation rates are directly affected by the history of the volcano and its eruptions. Here, we investigate the impact of Mt. Fuji Volcano (Japan) on Lake Motosu and its watershed. The lacustrine infill is studied by combining seismic reflection profiles and sediment cores. We show evidence of changes in sedimentation patterns during the depositional history of Lake Motosu. The frequency of large mass-transport deposits recorded within the lake decreases over the Holocene. Before ~8000 cal yr BP, large sublacustrine landslides and turbidites were filling the lacustrine depression. After 8000 cal yr BP, only one large sublacustrine landslide was recorded. The change in sedimentation pattern coincides with a change in sediment accumulation rate. Over the last 8000 cal yr BP, the sediment accumulation rate was not sufficient enough to produce large sublacustrine slope failures. Consequently, the frequency of large masstransport deposits decreased and only turbidites resulting from surficial slope reworking occurred. These constitute the main sedimentary infill of the deep basin. We link the change in sediment accumulation rate with (i) climate and vegetation changes; and (ii) theMt. Fuji eruptions which affected the LakeMotosu watershed by reducing its size and strongly modified its topography. Moreover, this study highlights that the deposition of turbidites in the deep basin of Lake Motosu is mainly controlled by the paleobathymetry of the lakefloor. Two large mass-transport deposits, occurring around ~8000 cal yr BP and ~2000 cal yr BP respectively, modified the paleobathymetry of the lakefloor and therefore changed the turbidite depositional pattern of Lake Motosu. [less ▲]

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See detailSaadien Mosaic (Zellige) from historical monuments of Marrakech, Morocco: Degradation state and production technology
El Halim, Mouhssin ULiege; Daoudi, Lahcen; El Ouahabi, Meriam ULiege et al

in Azrour, Mohamed (Ed.) International Symposium on Architectural patrimony and Local building Materials, Abstract Book (2017, October 12)

This study is focused on Saadian ceramics called zellige from the archaeological sites of "El Badi palace" and "Saadian Tombs" (Marrakech, Morocco) dated in late 16th Century and classified as world ... [more ▼]

This study is focused on Saadian ceramics called zellige from the archaeological sites of "El Badi palace" and "Saadian Tombs" (Marrakech, Morocco) dated in late 16th Century and classified as world heritage by UNESCO in 2008. A multi-analytical approach based on optical microscopy, cathodoluminescence, scanning electron microscopy, X-ray fluorescence and X-ray diffraction investigations and re-firing tests on ceramic supports has been used,in order to determineraw materials source, technical manufacturing and firing temperatures used by the Saadian artisans. Production technology, microstructure and the chemical compositionsuggest that the zellige pieces used in the construction of Saadian monuments in Marrakech are either imported from Fez, i.e. the main center of production of the zellige in Morocco, or manufactured locally in Marrakech according to the current standards and procedures in Fez. The calcareous clay raw materialwas used to manufacture these ceramics, but firing temperature was different. Zellige of El Badi palace was fired at a maximum temperature of 700°C in oxidizing atmosphere, while the one of Saadian Tombs was fired in the range 900-950 °C. The low firing temperature for Zellige facilitates the pieces cutting but it is responsible for the poor quality of these materials due to the absence of the vitreous phases. The results provide a scientific support for decision making in future conservation and restoration strategies of historical monumentsacross Morocco. [less ▲]

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See detailLacustrine clay mineral assemblages as a proxy for land-use and climate changes over the last 4 kyr: The Amik Lake
El Ouahabi, Meriam ULiege; Hubert, Aurelia ULiege; Allan, Mohammed ULiege et al

Poster (2017, May 10)

Lake sediments are sensitive to landscape changes and most of these changes seem to be modulated by land-use (anthropogenic factors) coupled to palaeoenvironmental/palaeoclimatic changes. In its detrital ... [more ▼]

Lake sediments are sensitive to landscape changes and most of these changes seem to be modulated by land-use (anthropogenic factors) coupled to palaeoenvironmental/palaeoclimatic changes. In its detrital fraction, the lacustrine sediments record the history of soil erosion within its catchment via the inputs of clays and others detrital products. Within a Mediterranean context, the study investigates the upper sediments infilling the central part of the Amik basin in southern Turkey. This tectonic basin was occupied and exploited by modern human at least since 6000-7000 BC. We focus on the clay mineralogy (x-ray diffraction on oriented aggregates) and magnetic susceptibility measurements (Bartington) of the sedimentary record in the area over the last 4000 years, to assess environmental changes in relation with the different land uses and/or weathering during the successive Bronze, Iron, Roman, Islamic/Ottoman and Modern civilizations. The clay fraction of Amik Lake sediments comprises smectite, kaolinite, illite, chlorite and chlorite/smectite mixed layers that are the inherited clay phases. A relative change in abundance and crystallinity and chemistry of illite attests that environmental conditions evolved in the Amik Plain from the Bronze to Modern Age in relation with climates and/or land-use changes. The history of the Amik Lake reveals different soil erosion episode. The most intense erosion phase occurred during the Bronze/Iron Ages as indicated by the clay and magnetic susceptibility proxies. The Roman period was an exceptional period with soil erosion products arriving from the watershed, probably due the water channelization. A reduction of soil erosion occurred during the post Roman period until nowadays. Significant pedogenesis transformations are evidenced, especially during the Islamic/Ottoman periods suggesting intense chemical weathering conditions related to climate change. [less ▲]

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See detailSedimentation influx and volcanic interactions in the Fuji Five Lakes: implications for paleoseismological records
Lamair, Laura ULiege; Hubert, Aurelia ULiege; Yamamoto, Shinya et al

Conference (2017, April 27)

The Fuji Fives Lakes are located at the foot of Mount Fuji volcano close to the triple junction, where the North American Plate, the Eurasian plate and the Philippine Sea Plate meet. These lakes are ... [more ▼]

The Fuji Fives Lakes are located at the foot of Mount Fuji volcano close to the triple junction, where the North American Plate, the Eurasian plate and the Philippine Sea Plate meet. These lakes are ideally situated to study Mount Fuji volcanism and the interaction between volcanism, changes in lake sedimentation rates and the ability of lakes to record paleoearthquakes. Here, we present newly acquired geological data of Lake Yamanaka and Lake Motosu, including seismic reflection profiles, gravity and piston cores. These two lakes and their respective watersheds were affected by several eruptions of Mount Fuji. Lake Yamanaka, a very shallow lake (max. depth 14 m), was heavily impacted by the scoria fall-out of the A.D. 1707 Hoei eruption of Mount Fuji. A detailed investigation of the effect of the Hoei eruption was conducted on short gravity cores, using high resolution XRD, C/N and 210Pb/137Cs analyses. The preliminary results suggest that the sedimentation rate of Lake Yamanaka drastically reduced after the Hoei eruption, followed by an increase until the present day. Similarly, lacustrine sedimentation in Lake Motosu (max. depth 122 m) was disturbed by Mount Fuji volcanism at a larger scale. The watershed of Lake Motosu was impacted by several lava flows and scoria cones. For example, the Omuro scoria cone reduced the catchment size of Lake Motosu and modified its physiography. The related scoria fall out covered an extensive part of the lake catchment and reduced terrigenous sedimentary influx to Lake Motosu. Within the deep basin of Lake Motosu, seismic reflection data shows two different periods that are distinguished by a major change in the dominant sedimentary processes. During the first period, sublacustrine landslides and turbidity currents were the dominant sedimentation processes. During the second one, the seismic stratigraphy evidences only deposition of numerous turbidites interrupting the hemipelagic sedimentation. Changes in sedimentary processes can be linked to the modification of the lake watershed by Mount Fuji volcanism, leading to a decrease in the sediment volume that can be remobilized, and therefore disappearance of large sublacustrine landslides. Turbidites are deposited due to surficial remobilization of lake slope sediments most probably as a result of earthquake shaking. When studying sedimentological records of lakes to define the paleoearthquake record, eruptions of nearby volcanoes should be taken into account. This study suggests that a large magnitude earthquake occurring few decades after a volcanic eruption (with large scale scoria fall-out), might not be recorded in a lake, or would only be fingerprinted in the sedimentary record by small turbiditic flows. References: Miyaji N., Kan'no A., Kanamaru T., Mannen K. 2011. High-resolution reconstruction of the Hoei eruption (AD 1707) of Fuji volcano, Japan. Journal of Volcanology and Geothermal Research 207, 113–129. [less ▲]

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See detailClay minerals behaviour in thin sandy clay-rich lacustrine turbidites (Lake Hazar, Turkey)
El Ouahabi, Meriam ULiege; Hubert, Aurelia ULiege; Lamair, Laura ULiege et al

Poster (2017, April 23)

Turbidites have been extensively studied in many different areas using cores or outcrop, which represent only an integrated snapshot of a dynamic evolving flow. Laboratory experiments provide the missing ... [more ▼]

Turbidites have been extensively studied in many different areas using cores or outcrop, which represent only an integrated snapshot of a dynamic evolving flow. Laboratory experiments provide the missing relationships between the flow characteristics and their deposits. In particular, flume experiments emphasize that the presence of clay plays a key role in turbidity current dynamics. Clay fraction, in small amount, provides cohesive strength to sediment mixtures and can damp turbulence. However, the degree of flocculation is dependent on factors such as the amount and size of clay particles, the surface of clay particles, chemistry and pH conditions in which the clay particles are dispersed. The present study focuses on thin clayey sand turbidites found in Lake Hazar (Turkey) occurring in stacked thin beds. Depositional processes and sources have been previously studied and three types were deciphered, including laminar flows dominated by cohesion, transitional, and turbulence flow regimes (Hage et al., in revision). For the purpose of determine the clay behavior in the three flow regimes, clay mineralogical, geochemical measurements on the cores allow characterising the turbidites. SEM observations provide further information regarding the morphology of clay minerals and other clasts. The study is particularly relevant given the highly alkaline and saline water of the Hazar Lake. Clay minerals in Hazar Lake sediments include kaolinite (1:1-type), illite and chlorite (2:1-type). Hazar lake water is alkaline having pH around 9.3, in such alkaline environment, a cation-exchange reaction takes place. Furthermore, in saline water (16‰), salts can act as a shield and decrease the repulsive forces between clay particle surfaces. So, pH and salt content jointly impact the behaviour of clays differently. Since the Al-faces of clay structures have a negative charge in basic solutions. At high pH, all kaolinite surfaces become negative-charged, and then kaolinite particles are dispersed, and the suspension is stabilized supported by our SEM observations. In alkaline water, kaolinite reveals a lower degree of consolidation. While, alkaline water has no measurable effect on illite and chlorite surface properties due to the absence of modifications in charge. Illite and chlorite form with other clasts clusters or aggregate structures in suspension when the particle interactions are dominated by attractive energies were formed. The aggregate structure plays a major part in the flow behavior of clay suspensions. Flocs will immobilize the suspending medium, and give rise to increasing viscosity and yield strength of the suspension. [less ▲]

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