Mineralogy

Terracotta is a type of clay that is highly valued for its mineral content. The minerals found in terracotta are commonly used to create pigments that are used to color ceramic bodies and glazes. Terracotta's natural minerals make it unique when compared to commercially available colors. In this study, researchers explored the possibility of using locally sourced terracotta clay in transparent glaze formulations. The team used a variety of experimental methods, including examining the percentage of clay powder, X-ray diffraction, X-ray fluorescence tests, and scanning electron microscope analysis (SEM) to study the clay's morphology and structure. By adding terracotta clay powder in different proportions (ranging from 20 to 50%), the glaze became translucent. The resulting colors were glossy, smooth, and creamy, with no defects, as confirmed by visual inspection after the samples were applied to porcelain and fired at gloss temperatures (1200°C).

Terracotta clay is a natural resource that has the potential as a raw material in the ceramic field. This study investigates the effects of color glaze using terracotta clay powder as an alternative substance for ceramic colorants in glaze formulation. Terracotta clay powder is proportionately added to glaze formulations to determine the potential for color added to the glaze at temperatures ranging from 1140 °C to 1200 °C. The content in terracotta clay is bounded with potash feldspar, silica, zinc oxide, and calcium carbonate. Results show the apparent color of the surface on the ceramic glaze samples with different effects.  

Crystallisation of glasses based on the diopside-anorthite eutectic system, containing increased amount (10- 50 wt.%) of wollastonite based on granite quarries waste, was investigated for the preparation of cheap technical glass-ceramic materials. Granite quarries waste consisted of about 52 wt.% of the batch constituents depending on composition. The granite quarries waste composition was sometimes modified by adding other ingredients such as dolomite, limestone and Al2O3. Batches were melted and then cast into glass, which was then subjected to heat-treatment to induce crystallisation. The resulting glass-ceramic materials (heat-treated at 1000?C for 3 h) were mainly composed of diopside, anorthite, wollastonite and mullite. With increasing temperature (to 1050?C for 3h), diopside and anorthite transformed into akermanite and mullite. It has been found that increasing the content of the diopside-anorthite eutectic in the batch constituents, resulted in increased bulk crystallisati...

A new occurrence of pyrophanite (MnTiO3) in Greece is described from the garnetclinopyroxene-wollastonite exoskarn of western Kimmeria. Hostrock of the pyrophanite-bearing skarn is amphibolite (retrogressed eclogites) of the Nestos suture zone in the Rhodope massif. In addition endo- and exo-skarns occur both in the Xanthi granodiorite and the surrouding marbles and consinst of diopside-vesuvianitequartz and wollastonite-garnet-calcite-quartz respectively. Pyrophanite formed in the prograde stage, together with garnet, pyroxene, wollastonite, titanite, zircon, rutile, thorite and ouranothorianite. Retrograde minerals are quartz, epidote, calcite, hematite, and sulfides. Chlorite-geothermometry revealed temperatures in the range from 300 to 350 oC for the retrograde event. Calcic garnets (andraditegrossular solid solutions) from the prograde amphibolite-hosted skarn are chemically zoned with either isotropic or anisotropic cores surrounded by non-cubic anisotropic rims, thus suggesti...

A lithological and mineral magnetic study of three soil and underlying sedimentary sections located at dierent topographic positions in the Undulating Pampa was performed. On the basis of grain size analyses, clay, silt and sand mineralogy, and total Ti/Zr relationship three dierent sedimentary units were recognised in the pro®les under study suggesting that the area has been in¯uenced by three dierent sources of sediments. Magnetic susceptibility (MS) appears to be related to lithology, allowing the identi®cation of some material and lithologic discontinuities. In the studied cases the maximum values of MS appear in both the B horizons of the present zonal soils as well as in the primary or reworked loess levels. In contrast, minimum values are associated with calcrete, paleosol, and hydromorphic horizons. Although magnetic susceptibility appears to be an eective means for identifying dierent materials and pedological features in this area, due to the superposition of eects on the magnetic signal a thorough interpretation of MS requires that a composite analysis should be made.

D4.15 i Fate of repository gases (FORGE) The multiple barrier concept is the cornerstone of all proposed schemes for underground disposal of radioactive wastes. The concept invokes a series of barriers, both engineered and natural, between the waste and the surface. Achieving this concept is the primary objective of all disposal programmes, from site appraisal and characterisation to repository design and construction. However, the performance of the repository as a whole (waste, buffer, engineering disturbed zone, host rock), and in particular its gas transport properties, are still poorly understood. Issues still to be adequately examined that relate to understanding basic processes include: dilational versus viscocapillary flow mechanisms; long-term integrity of seals, in particular gas flow along contacts; role of the EDZ as a conduit for preferential flow; laboratory to field up-scaling. Understanding gas generation and migration is thus vital in the quantitative assessment of repositories and is the focus of the research in this integrated, multi-disciplinary project. The FORGE project is a pan-European project with links to international radioactive waste management organisations, regulators and academia, specifically designed to tackle the key research issues associated with the generation and movement of repository gasses. Of particular importance are the longterm performance of bentonite buffers, plastic clays, indurated mudrocks and crystalline formations. Further experimental data are required to reduce uncertainty relating to the quantitative treatment of gas in performance assessment. FORGE will address these issues through a series of laboratory and field-scale experiments, including the development of new methods for up-scaling allowing the optimisation of concepts through detailed scenario analysis. The FORGE partners are committed to training and CPD through a broad portfolio of training opportunities and initiatives which form a significant part of the project. Further details on the FORGE project and its outcomes can be accessed at www.FORGEproject.org.

Galleries drilling leads to damage propagation, fracturing and properties modifications in the surrounding medium. The prediction of the damaged zone behaviour is an important matter and needs to be properly assessed. To do so the fractures can be modelled using shear strain localisation. The coupled local second gradient model is used under unsaturated conditions to correctly model the strain localisation behaviour. The permeability evolution and the rock desaturation due to air ventilation in galleries are considered. Finally, a hydro-mechanical modelling of a gallery excavation in Callovo-Oxfordian claystone is performed leading to a fairly good representation of the damaged zone.

D4.15 i Fate of repository gases (FORGE) The multiple barrier concept is the cornerstone of all proposed schemes for underground disposal of radioactive wastes. The concept invokes a series of barriers, both engineered and natural, between the waste and the surface. Achieving this concept is the primary objective of all disposal programmes, from site appraisal and characterisation to repository design and construction. However, the performance of the repository as a whole (waste, buffer, engineering disturbed zone, host rock), and in particular its gas transport properties, are still poorly understood. Issues still to be adequately examined that relate to understanding basic processes include: dilational versus viscocapillary flow mechanisms; long-term integrity of seals, in particular gas flow along contacts; role of the EDZ as a conduit for preferential flow; laboratory to field up-scaling. Understanding gas generation and migration is thus vital in the quantitative assessment of repositories and is the focus of the research in this integrated, multi-disciplinary project. The FORGE project is a pan-European project with links to international radioactive waste management organisations, regulators and academia, specifically designed to tackle the key research issues associated with the generation and movement of repository gasses. Of particular importance are the longterm performance of bentonite buffers, plastic clays, indurated mudrocks and crystalline formations. Further experimental data are required to reduce uncertainty relating to the quantitative treatment of gas in performance assessment. FORGE will address these issues through a series of laboratory and field-scale experiments, including the development of new methods for up-scaling allowing the optimisation of concepts through detailed scenario analysis. The FORGE partners are committed to training and CPD through a broad portfolio of training opportunities and initiatives which form a significant part of the project. Further details on the FORGE project and its outcomes can be accessed at www.FORGEproject.org.

The Joint Transportation Research Program serves as a vehicle for INDOT collaboration with higher education institutions and industry in Indiana to facilitate innovation that results in continuous improvement in the planning, design, construction, operation, management and economic efficiency of the Indiana transportation infrastructure.

Geochemical anomaly separation, using concentration-area method at Zarshuran Au-As deposit, NW Iran, is studied in this work. Lithogeochemical dataset was used in this geochemical survey, which was conducted for exploring Au mineralization in green schist units at Zarshuran Carlinlike gold deposit. Similar surveys were also carried out for Ag and As exploration in these rock units, and obtained results have been interpreted using detailed geological mapping. The correlation between these threshold values and ore grades is clearly interpreted in this investigation. Also, the logarithmic plots show existence of two stages for Au, Ag, and As. According to the SEM studies, it can be concluded that the proposed algorithm is verified technically in order to identify economically valuable Au concentrations in the area under study.

Geochemical anomaly separation, using concentration-area method at Zarshuran Au-As deposit, NW Iran, is studied in this work. Lithogeochemical dataset was used in this geochemical survey, which was conducted for exploring Au mineralization in green schist units at Zarshuran Carlinlike gold deposit. Similar surveys were also carried out for Ag and As exploration in these rock units, and obtained results have been interpreted using detailed geological mapping. The correlation between these threshold values and ore grades is clearly interpreted in this investigation. Also, the logarithmic plots show existence of two stages for Au, Ag, and As. According to the SEM studies, it can be concluded that the proposed algorithm is verified technically in order to identify economically valuable Au concentrations in the area under study.

Water Alternate Gas (WAG) injection methods are the derivative of gas injection methods, wherein water and gas are injected intermittently. WAG injection can lead to improved oil recovery by combining better mobility control and contacting upswept zones and by leading to improved microscopic displacement.

Mesothermal chalcopyrite + pyrite + magnetite-bearing calcite-dominated vein deposits in the Repparfjord Tectonic Window, northern Norway, have been studied to constrain the mechanics of their emplacement and the timing of initial vein formation and reactivation. The veins cut across Paleoproterozoic tholeiitic metabasalts and present textural contrast between their hydrofractured, coarse-grained margins, and the fine-grained mylonitic cores. They formed under overall viscous conditions, although cyclically increased fluid pressures caused transient embrittlement. As mineral precipitation sealed the fractures, deformation was accommodated again viscously leading to mylonitization of the vein's core. Local brecciation of the calc-mylonite demonstrates the cyclicity of this process. Re-Os chalcopyrite-pyrite and K-Ar fault gouge dates define an almost continuous age range from ~2540 Ma to ~460 Ma. Regression of three Re-Os analyses yields a 2069 ± 14 Ma age ( 187 Os/ 188 Os = 0.18 ± 0.04), interpreted as the age of vein emplacement, sulfide precipitation, and initial frictional-viscous deformation. K-Ar ages are mixed ages that constrain a maximum age of faulting in association with the veins at approximately 460 Ma, hence indicating structural reactivation connected with Silurian Caledonian orogenic compression. The spread in Re-Os model ages reflects this reactivation, wherein renewed strain accommodation and circulating oxidizing fluids caused fracturing, dynamic recrystallization, and isotopic disturbance of the sulfides. The study provides evidence for fluid flow during viscous deformation and demonstrates that strain, and flow of oxidizing fluids, can have a significant yet localized control on the integrity of the Re-Os systematic in pyrite and chalcopyrite.

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Microbially induced calcium carbonate precipitation (MICP) by the urease-producing bacteria has wide applications in the field of geology and environmental engineering. Compared to bacteria, fungi usually possess more tolerance to high salts and heavy metals, enabling MICP induced by the urease-producing fungi to be applied to harsh environments. In this study, the carbonate minerals, induced by the urease-producing fungi isolated from marine sediments, were investigated. One of the urease-producing fungi, designated as YPLJS-14, was identified with the high efficiency of precipitating calcium carbonate. The ITS sequence of YPLJS-14 revealed that it belongs to the genus of Cladosporium. The precipitates induced by this strain were characterized by XRD, SEM, TEM, SAED, and FTIR, respectively. The results show that the mineral phase of fungal precipitates is composed of calcite and vaterite. SEM, TEM, and SAED confirm that the minerals in rhombohedral morphology are calcite and the sp...

Pod względem stopnia rozpoznania warunków geotermicznych, jak i samych złóż wód termalnych, region sudecki można zaliczyć do złóż słabo rozpoznanych. Z jednej strony wynika to ze złożoności warunków geologicznych całej jednostki, z drugiej zaś z nielicznych dotychczas wykonanych, głębokich odwiertów rozpoznających takie złoża w obrębie Sudetów. Rozpoznając warunki geotermiczne danego rejonu istotnym jest zlokalizowanie obszarów cechujących się podwyższonymi parametrami przewodności termicznej ośrodka skalnego, powierzchniowego strumienia cieplnego czy gradientu temperatury. Niejednokrotnie rejonom takim towarzyszą wystąpienia wód geotermalnych potwierdzające anomalne, w skali lokalnej, perspektywiczne warunki geotermiczne. Najczęściej wody te przemieszczając się systemem głębokiego krążenia, wykorzystują strefy głębokich dyslokacji o charakterze rozłamów tektonicznych. Z rejonem krzyżowania się rozłamów karkonoskiego i morawsko-śląskiego związane są wypływy wód geotermalnych Lądka-Zdroju.

Crust-form aragonite and needle-shape aragonite crystallized in cavities in magnesites as well as vein magnesite from ultramafic rocks related to the Sleza ophiolite (NE part of Bohemian Massif) have been examined for carbon and oxygen isotope ratios and for some trace elements. 5180SMOW values of magne site, corrected for acid-decomposition fractionation, comprise a narrow range of 23.7 to 27.9%0, which suggests near-surface temperature, high water-to-rock ratio, and meteoric origin of the ore-forming solution . This inference is further supported by 313C values (-18.7 to -6.4%o) which indicate a biogenic origin of carbon. Moreover, chemical analyses of the magnesites showing lack of elements characteristic for intrusion related hydrothermal deposits support the meteoric-biogenic origin of the magnesite deposits of the Gogolow Jordanow massif. The two types of aragonites are uniform in S13C (-15.0 to -16.3%o) and S18Gsmow (23.9 to 25.4%0). The A13Cmg-a, = -3.1 and -3.5%o of two samples of magnesite-aragonite aggregates show the absence of carbon isotope equilibrium in this system. However, the A18Omg-ar = 4.0 and 1.8%.o for the respective samples suggest that the aragonites formed in the magnesites have possibly crystallized in oxygen isotope equilibrium with the host magnesite.

At present, the dealkalization and comprehensive utilization of red mud is a worldwide problem. Studies on the settling performance and phase transformation of red mud by HCl, CaO, and H 2 O leaching are limited. In this study, the characteristics of red mud were systematically analyzed. The average sizes of graded and initial red mud were 4.11 and 9.20 μm, respectively. X-ray diffraction (XRD), X-ray fluorescence spectra (XRF), and thermogravimetry-differential scanning calorimetry (TG-DSC) results indicated the different mineralogical phases, composition, and thermal behavior. The addition of HCl could neutralize the alkalization in the red mud slurry, and CaO could replace the Na and K. Notably, the pH of the red mud slurry had no obvious change with the increase in water washing times in a certain pH. Interestingly, soluble Al and Fe were not detected in the HCl-red mud and CaO-red mud. In addition, the settling ratio was used to express the settling performance of the red mud slurry. Their interaction mechanisms were proposed, which may include phase transformation and the changing of the size and surface area. The research provided a better understanding of the phase transformation and settling performance in the treatment of red mud by HCl, CaO, and H 2 O leaching.

O objetivo desta pesquisa foi caracterizar hidroquimicamente amostras de aguas subterr âneas coletadas em pocos domesticos, inseridos no sistema aquifero de Guaratiba (Serra de Inhoaiba, Guaratiba- Rio de Janeiro/RJ). As medidas in loco obtiveram valores do p H de carater levemente acido a basico. A temperatura variou de 22°C a 29°C. A conduti vidade eletrica apresentou valor medio de 533,8 μS/cm e os solidos totais dissolvidos, v alor medio de 344,06 mg/L. O Digrama de Piper classificou as aguas subterrâneas como bicarbonatadas calcicas ou magnesiana, sulfetadas ou cloretadas sodicas e bicarbonatad a sodica. Os resultados das razoes ionicas indicaram carater continental e doce das agua s subterrâneas, de circulacao em rocha de composicao granitica e com um fluxo normal de rochas cristalinas ou vulcânicas.

The composition of the heavy mineral fraction from the glass sand in Osiecznica (Lower Silesia, SW Poland) was described. Accessory minerals are present in the gravity concentrate mainly as individual grains, whereas lower amounts occur as vein rocks debris, inclusions in quartz grains and heavy minerals. The sample under study contained the following minerals: rutile, anatase, hematitegoethite, ilmenite-leucoxene, zircon, monazite, xenotime, kyanite, pyroxenes, and quartz with inclusions of chalcopyrite, pyrite, pyrrhotite, sphalerite, pentlandite, arsenopyrite, and tetrahedritetennantite. Moreover, the presence of native gold and silver was determined. Major components of the concentrate are rutile, anatase, quartz with inclusions of ore minerals, zircon, and goethitized hematite. The other minerals occur in the amount below 2-3 vol. %. The content of native gold in the concentrate sample (0.11%) may be indicative of a significant concentration (around 1.5 g/Mg) of this metal in the Osiecznica deposit.

The present study proposes a characterization of textural and mineralogical features of branching selenite gypsum lithofacies from the Monferrato area (NW Italy). This facies is considered to have appeared during the sequence of the primary lower gypsum of the Messinian Salinity Crisis starting from the sixth stratigraphical cycle, providing a useful tool for stratigraphic correlation throughout the Mediterranean. It is often associated with thick and continuous beds that are exploited by open-pit and underground quarries. We provide the results of a characterization of the nongypsum minerals that represent approximately 10% in weight of the rock. Mineralogical data were collected with energy-dispersive X-ray spectroscopy (EDS) and X-ray powder diffraction (XRPD) techniques. In addition, a detailed characterization of clay families was performed through dedicated XRPD analyses. Results highlight the presence of detrital minerals (quartz, feldspars and clay minerals), calcite, dolomite and epsomite. Clay analysis registered the existence of five different families (illite, chlorite, smectite and two mixed layers). These mineralogical data suggest that the origin of this lithofacies is connected to both depositional processes and in situ precipitation processes under different conditions of saturation of the brine (respectively undersaturated and supersaturated in sulfates). The mineralogical and textural heterogeneity also represents an important element in controlling the mechanical response of the material and the consequent stability of quarry sites.

Pottery is a complex archaeological material that is found ubiquitously in various spatial–temporal frameworks from all over the world; therefore, it is of great importance to archaeological research. The current paper aims to present and discuss the results obtained on a batch of Neolithic (ca. 6000–5000 BC) and Chalcolithic (ca. 5000–3900 BC) pottery sherds from Southern Romania through X-ray Computed Tomography, a non-destructive methodology that allows for the 3D reconstruction and precise measurement of inclusions and voids present within ceramic artefacts. Images from several potsherds were subsequently exported and analyzed by means of dedicated software (ImageJ 1.44p and GIMP) to extract quantitative information on the observed features. Grain size and morphometric analyses were performed on the particles, while the contour variability of the examined inclusions was characterized through the application of shape descriptors. Voids were analyzed in order to reveal specific or...

The mineral scaling problems in the Kızıldere geothermal field along with hydrogeological and geochemical properties of this field were studied. In this content, chemical analyses for 26 water samples from 12 water points and an additional seven geochemical analyses and six XRD analyses of the scale samples were performed. Measured reservoir temperatures of wells vary from 196 (in the well KD-13) to 242 °C (in the well R-1). Geothermal reservoir waters show the water types of Na-HCO 3 and Na-HCO 3 -SO 4 . Estimated mineral saturations suggest that calcite, aragonite, strontianite, dolomite, amorphous silica, and barite are likely to precipitate as scales. These are confirmed by the results of the geochemical and XRD data of the scale samples. Reservoir chemistry calculations show a fluid richer in steam and acid gases with lower concentrations in the nonvolatile constituents (i.e., Cl, SiO 2 , Na, etc.) at the reservoir. Geochemical modeling shows that CaCO 3 (calcite and aragonite) and strontianite precipitations are inevitable for production and re-injection wells and surface equipment. Amorphous silica scaling is the important risk of re-injection wells. Precipitations of the minerals barite, anhydrite, dolomite, and celestite are also possible. Determinations of the scaling minerals and the safety temperatures to avoid or minimize the scaling problem are the most important parts of this study. It was concluded that cold injection (\50 °C) is favored or inhibitors should be used if any mineral deposition is to be prevented or reduced in injection wells.

The presence of Sr-rich aluminium-phosphate sulphate (APS) minerals in continental sedimentary rocks from the Cañizar and Eslida Formations along the eastern part of the Iberian Range (Spain) is considered as evidence of acidic and oxidising conditions during Early-Middle Triassic times. The formation of APS minerals occurred shortly after sedimentation, in early diagenetic stages, prior to the compaction of the sediments and most probably was related to the circulation of acidic meteoric waters. Such conditions might result from a sustained, damaged environment or from multiple environmental crises, but would have delayed the recovery of life after the end-Palaeozoic mass extinction. APS minerals occur as small disseminated and idiomorphic pseudo-cubic crystals (0.5 to 6 μm long) or as massive and polycrystalline aggregates replacing fragments of fine-grained metamorphic rocks (mainly metapelites). Textural data indicate that the formation of the APS minerals predated the quartz and illite cements, and that they resulted from the destabilisation of pre-existing minerals, as evidenced by the replacement of slate fragments by APS minerals and hematite and by the close association of the disseminated APS crystals and kaolinite with altered detrital mica plates. Electron microprobe analyses and X-ray diffraction study of the APS minerals indicate a rather homogeneous composition in different parts of the basin, corresponding to solid solutions among woodhouseite, svanbergite, crandallite and goyazite. The sources of strontium in the APS minerals remain unclear. Phosphorous was primarily supplied by dissolution of detrital phosphates under acidic conditions, and sulphur derives from the weathering of pyrite.

In antiquity the Osireion was recognized as a well or spring attributed to legendary King Ismandes. But when rediscovered by European explorers in the early 1900s it was labelled as a temple, tomb or cenotaph and assigned to Seti I, ca 1280 BCE. Recently, Westerman (2023) has confirmed a strong aquifer of potable water, independent of local wells and of the Nile. Here, re-examination reveals several structural features that are characteristic of a sophisticated water-supply system.

Recent theories about the sources of silica in bedded and nodular cherts do not fit the origin of cherts from the Krakoẃ-Czestochowa Upland. Since siliceous sponges as a single source of silica is questionable, assumptions about additional sources have to be verified. In order to do so, three samples of nodular cherts and one representative sample of bedded chert were studied by means of 1 H LF-NMR 1D and 2D relaxometry and complementary geochemical methods. The results were compared with the literature and standard silica materials which helped to identify five types of 1 H signal. The very distinct 1D-T 2 spectra of the dried samples indicated the existence of closed pores which, after comprehensive analysis, were identified as inclusions filled with different types of siliceous materials. Saturation revealed the differences between nodular and bedded cherts that were visible mainly in the amount and size of open porosity. The principal component analysis of NMR parameters showed the excellent separation of these two groups of samples and this is well visible on the biplots. Additionally, the estimated pore size distribution revealed that the total porosity of around 2% consisted primarily of mesopores (2-50 nm in diameter) and macropores (diameter >50 nm). In bedded cherts, open porosity is dominated by macropores, while the share of mesopores and macropores is similar in nodular cherts.

El presente trabajo estudió la influencia de la relación suelo/concentración de electrolitos extractantes (CaCl2 0.01 y 0.02 M y KCl 0.1 y 1M), en la medición del pH en suelos ácidos. Se analizaron 180 muestras de suelos, extraídas a 30 cm de profundidad, provenientes del distrito de Iberia en la provincia de Puerto Maldonado región Madre de Dios. Las mediciones se realizaron en la suspensión. El valor de R=0.8880 obtenido del análisis de Pearson y el resultado de la varianza estableciendo el valor de Ficher tabulado (28.8974) mayor que el calculado (4.6005E-10) demostraron, que existe correlación múltiple. Concluyendo que, la dilución del suelo, tiene efecto directo sobre el pH, a mayor dilución mayor incremento del pH, la medición de pH de suelos fuertemente ácidos empleando KCl produce valores más confiables que cuando son medidos en agua y el incremento de la concentración de las sales no tuvo efecto considerable sobre la medición del pH.

In 1829, four Egyptian stelae of Twelfth and Eighteenth Dynasty date were found, surprisingly, on Malta. Based on their far-flung findspot, some have suggested that the stelae were locally made by Egyptian colonists who had settled on the island during the second millennium bc. This contribution argues that the stelae offer no basis for such historical reconstructions. Style, content and petrology demonstrate that all four stelae were made in Egypt and that they originally stood in the necropolis of Abydos in Upper Egypt. Microfossils show that these stelae are made of Egyptian limestones, which are of a different geological age to limestones available on Malta. The examination of polished thin sections of samples from the stelae using scanning electron microscopy suggests that the limestones employed were quarried from four geological formations of different ages in the Nile Valley.

In 1829, four Egyptian stelae of Twelfth and Eighteenth Dynasty date were found, surprisingly, on Malta. Based on their far-flung findspot, some have suggested that the stelae were locally made by Egyptian colonists who had settled on the island during the second millennium bc. This contribution argues that the stelae offer no basis for such historical reconstructions. Style, content and petrology demonstrate that all four stelae were made in Egypt and that they originally stood in the necropolis of Abydos in Upper Egypt. Microfossils show that these stelae are made of Egyptian limestones, which are of a different geological age to limestones available on Malta. The examination of polished thin sections of samples from the stelae using scanning electron microscopy suggests that the limestones employed were quarried from four geological formations of different ages in the Nile Valley.

Los autores desean rendir homenaje a quien por muchos años nos ha brindado su “don de gentes” como un ente de conexión entre colegas, haciendo con ello parte de su actividad profesional y adicionando a su cotidianidad la actividad gremial a través de la Sociedad Venezolana de Geólogos.

Samples of the carbonaceous asteroid Ryugu were brought to Earth by the Hayabusa2 spacecraft. We analyzed 17 Ryugu samples measuring 1 to 8 millimeters. Carbon dioxide–bearing water inclusions are present within a pyrrhotite crystal, indicating that Ryugu’s parent asteroid formed in the outer Solar System. The samples contain low abundances of materials that formed at high temperatures, such as chondrules and calcium- and aluminum-rich inclusions. The samples are rich in phyllosilicates and carbonates, which formed through aqueous alteration reactions at low temperature, high pH, and water/rock ratios of <1 (by mass). Less altered fragments contain olivine, pyroxene, amorphous silicates, calcite, and phosphide. Numerical simulations, based on the mineralogical and physical properties of the samples, indicate that Ryugu’s parent body formed ~2 million years after the beginning of Solar System formation.

This work aims to use a green, economical and efficient adsorbent to remove organic matter from Tunisian industrial wet phosphoric acid (WPA: 52% P2O5). For this purpose, a natural and abundant clay is extracted from the Douiret, Tataouine deposit in southern Tunisia. This clay is being tested for the first time as an adsorbent in WPA medium. The raw clay and purified clay are analysed using standard analytical techniques such as Fourier transform infrared spectroscopy, X-ray diffraction, and BET methods. The results show that the raw clay is a mixture of illite and kaolinite, with other mineral impurities, mainly quartz. Organic matter adsorption tests show that the purified clay exhibits greater effectiveness than raw clay. The parametric study with purified clay indicates that temperature, contact time, and clay dosage strongly influence organic matter adsorption. The highest adsorption occurs at 60 °C after 50 min, reaching 56% with 8 g of purified clay per kg of WPA. Among seve...

Fine ware pottery from the Etruscan town of Tarquinia, whose necropolis in inscribed in the list of UNESCO sites, was studied by means of near-infrared (NIR) diffuse reflection spectroscopy. The aim was to investigate the correlation between the firing conditions of the illitic-calcareous local clay, in terms of temperature and atmosphere, and the physical properties of the ceramic paste, usually exploited by the archaeologists for a classification of pottery sherds. For comparison, analytical data related to the mineralogical composition of the samples were obtained by X-ray diffraction and Fourier-transform infrared (FTIR) spectroscopy. Spectroscopic data were elaborated by methods of multivariate analysis.

Fine ware pottery from the Etruscan town of Tarquinia, whose necropolis in inscribed in the list of UNESCO sites, was studied by means of near-infrared (NIR) diffuse reflection spectroscopy. The aim was to investigate the correlation between the firing conditions of the illitic-calcareous local clay, in terms of temperature and atmosphere, and the physical properties of the ceramic paste, usually exploited by the archaeologists for a classification of pottery sherds. For comparison, analytical data related to the mineralogical composition of the samples were obtained by X-ray diffraction and Fourier-transform infrared (FTIR) spectroscopy. Spectroscopic data were elaborated by methods of multivariate analysis.

Antik dönem doğa bilimcisi Plinius, Hellenistik ve Roma döneminde yaygın olarak kullanılan almandin bileşimli lal taşlarının (Granat) Anadolu'da Karia'da Alabanda (Çine) ve Orthosia'da (Yenipazar) çıkarıldığından bahsetmektedir. Çalışmaya konu edilen granat örnekleri Hacıaliler (Çine-Aydın) bölgesinde Menderes Masifine ait orta-yüksek dereceli, gnays ve mikaşist bileşimli metamorfik kayaçlar içerisinde bulunmaktadır. Boyutları 0.5-2 cm arasında değişen, morumsu-kahverengi renkli ve mat parlaklık gösteren granat porfiroblastları dodekahedron formda kristallenmişlerdir. Mikroskobik incelemelerinde poikloblast doku gösteren granat mineralleri oldukça kırıklı bir yapıda olup, bol miktarda kuvars, muskovit ve opak mineral kapanımları içermektedir. Tahribatsız bir analiz tekniği olan Konfokal Raman spektroskopisi çalışmalarına göre granatların 910-912, 349 ve 553-555 cm -1 güçlü olmak üzere toplam 10 farklı Raman titreşimi gösterdikleri ve tipik olarak almandin bileşiminde oldukları tespit edilmiştir. Mineral kimyası sonuçlarına göre granatlar Alm0.72-0.87 Grs0.

Geothermal systems are essentially associated with hydrothermal alteration mineral assemblages such as iron oxide/hydroxide, clay, sulfate, carbonate and silicate groups. Blind and fossilized geothermal systems are not characterized by obvious surface manifestations like hot springs, geysers and fumaroles, therefore, they could not be easily identifiable using conventional techniques. In this investigation, the applicability of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) were evaluated in discriminating hydrothermal alteration minerals associated with geothermal systems as a proxy in identifying subtle Geothermal systems at Yankari Park in northeastern Nigeria. The area is characterized by a number of thermal springs such as Wikki and Mawulgo. Feature-oriented Principal Component selection (FPCS) was applied to ASTER data based on spectral characteristics of hydrothermal alteration minerals for a systematic and selective extraction of the information of interest. Application of FPCS analysis to bands 5, 6 and 8 and bands 1, 2, 3 and 4 datasets of ASTER was used for mapping clay and iron oxide/hydroxide minerals in the zones of Wikki and Mawulgo thermal springs in Yankari Park area. Field survey using GPS and laboratory analysis, including X-ray Diffractometer (XRD) and Analytical Spectral Devices (ASD) were carried out to verify the image processing results. The results indicate that ASTER dataset reliably and complementarily be used for reconnaissance stage of targeting subtle alteration mineral assemblages associated with geothermal systems.

• The variations of the chemicals were found to be highly dependent on the sampling depth (0-5m). • The age of the two samples was determined as 4752±33 BP years (2.5 m) and 5470±35 BP (5.0 m). • The lowest weathering index values were found in the middle part of the core. • Ca+CaO content was lower and Ti+TiO was higher in the deepest sample indicating rainy periods. • More multidisciplinary paleogeographical research should be carried out in the region.

of magnetic susceptibility (AMS) in samples of Cambrian slate from Penrhynn, Wales, is surprisingly weak (ma~mum/~nimum = 1.1 to 1.2) in view of their large finite strain (X/Z = 3.5 to 4.5), and their hematite-dominated magnetic mineralogy. Several lines of evidence suggest that this is a result of the presence of two or more generations of hematite. SEM observations show a somewhat bimodal size distribution of hematite particles, with modal diameters of approximately 1-3 pm and 10-20 pm. The larger grains tend to have ragged, subequant shapes, and contain titaniferous laminae; they are probably of igneous/detritai origin. The finer grains have c~stallograp~~ally-controlled shapes, are Ti-free, and are probably autbigenic or metamorphic. Initially, chemical leaching of deeply incised solid specimens preferentially removes the more soluble particles, and results in significant changes in AMS. Further leaching attacks the remaining grains on exposed surfaces, and the AMS ellipsoid reverts to its initial shape. Isothermal remanent magnetization (IRM) is si~fic~tly more anisotropic than low-field susceptibility; the variation of IRM anisotropy with applied field indicates relatively strong fabric development in the fine-grained hematite, but weak fabric in the coarser fraction. Grain boundaries were digitized from SEM photos in order to calculate Flinn fabric ratios by the R,+ method. The X/Z ratios thus obtained for quartz and fine hematite grains are 3.14 and 1.70, respectively. It is therefore clear that the hematite fabric does not reflect the totai finite strain. No. 9101 of the Institute for Rock Magnetism,

Inter-laboratory and absolute calibrations of rock magnetic parameters are fundamental for grounding a rock magnetic database and for semi-quantitative estimates about the magnetic mineral assemblage of a natural sample. Even a dimensionless ratio, such as anhysteretic susceptibility normalized by magnetic susceptibility (K a /K) may be biased by improper calibration of one or both of the two instruments used to measure K a and K. In addition, the intensity of the anhysteretic remanent magnetization (ARM) of a given sample depends on the experimental process by which the remanence is imparted. We report an inter-laboratory calibration of these two key parameters, using two sets of artificial reference samples: a paramagnetic rare earth salt, Gd 2 O 3 and a commercial "pozzolanico" cement containing oxidized magnetite with grain size of less than 0.1 m according to hysteresis properties. Using Gd 2 O 3 the 10 Kappabridges magnetic susceptibility meters (AGICO KLY-2 or KLY-3 models) tested prove to be cross-calibrated to within 1%. On the other hand, Kappabridges provide a low-field susceptibility value that is ca. 6% lower than the tabulated value for Gd 2 O 3 , while average high-field susceptibility values measured on a range of instruments are indistinguishable from the tabulated value. Therefore, we suggest that Kappabridge values should be multiplied by 1.06 to achieve absolute calibration. Bartington Instruments magnetic susceptibility meters with MS2B sensors produce values that are 2-13% lower than Kappabridge values, with a strong dependence on sample centering within the sensor. The K a /K ratio of ca. 11, originally obtained on discrete cement samples with a 2G Enterprises superconducting rock magnetometer and a KLY-2, is consistent with reference parameters for magnetites of grain size <0.1 m. On the other hand, K a values from a 2G Enterprises magnetometer and K values from a Bartington Instruments MS2C loop sensor for u-channel and discrete cement samples, will produce average K a /K values that are unrealistically high if not properly corrected for the nominal volume detected by the sensors for these instruments. Inter-laboratory measurements

A strong grouping of the directions of natural remanent magnetization in a collection of Ordovician limestones and dolomites, prior to correction for the in situ orientation of the samples, led us to suspect the presence of a substantial spurious magnetization acquired during sample collection and preparation. A close correspondence between the directions of the remanence vectors and the direction of the ambient magnetic field during sawing and drilling of the samples suggested that the remanence was dominated by a component acquired during cutting of the samples. Ten specimens of the Camp Nelson Limestone and Shakopee Dolomite were demagnetized to 100 mT, given an anhysteretic remanence along their axes, and then sawed again. A substantial magnetization parallel to the ambient field during cutting was acquired by all of the specimens, and the resultant directions deviated by 7-70" from the direction of the anhysteretic magnetization. Stepwise alternating-field and thermal cleaning to 60 mT and 400°C respectively failed to remove preferentially the cutting-induced magnetic contamination. Since the fraction of magnetite grains cut during drilling and sawing must be a linear function of grain size, modified Lowrie-Fuller tests were carried out and the results are interpreted to indicate the presence of a multidomain magnetite fraction in the Shakopee Dolomite, Camp Nelson Limestone and Oregon Dolomite. Ratios of initial to anhysteretic susceptibility (dxARM) correlate well with the angular deviation of magnetic directions produced by sawing. This indicates that acquisition of drilling-induced remanence is a function of magnetite grain size, compatible with the notion that the drillinginduced component resides in large magnetite grains which have been cut.

of anhysteretic susceptibility (AAS) is a recently developed high-resolution method of measuring the magnetic fabric of rocks. In order to test the applicability and limitations of AAS for estimation of strain orientations in weakly-deformed and weakly magnetic rocks, we have used the method to examine the magnetic fabric of samples from a series of sites in limestones of the Helderberg and Onondaga formations along a 500-km E-W transect across New York State. Two distinct shortening directions have been previously identified and interpreted in terms of two separate phases of Alleghenian deformation. Over most of the transect, minimum anhysteretic susceptibility axes within the plane of bedding closely parallel the compression direction of the earlier ("Lackawanna") phase. A few sites show minimum anhysteretic susceptibility parallel to the later ("Main") phase. The threshold for resolution of the tectonic signal by AAS is at anhysteretic susceptibilities of about 2 X lo-' (SI) and strain magnitudes of 0.5 to 1% as recorded by twinning in calcite. The central part of the transect exhibits minimum horizontal anhysteretic susceptibility perpendicular to the inferred tectonic compression, rather than parallel to it. We attribute this to either: (a) anisotropic transmission of stresses from the larger calcite matrix grains to the smaller magnetite grains during twinning; or (b) preferential recording of a late-stage non-coaxial stress direction in this area by late diagenetic magnetite.

This study was conducted to know the effect of the source of sedimentation in the mineralogical composition of sand fraction for some areas of the southern part of the Iraqi alluvial plain. The results of mineralogical composition of sand fraction showed that the dominant minerals, in the light part of sand fraction, were carbonate rock fragments , qurtz , chert , mudstone rock , feldspars , igeous and metamorphic rocks . While , the heavy part showed a similarities in terms of quality and differences in terms of quantity , with dominance of Opaque minerals followed by Staurolite , Kyanite , Rutile , and Tourmaline . In general, the results showed the low rates of the heavy metal group compared to the light metals group of the sand fraction resulting from weathering occurring in their moving places during transportation or after the deposition, this may be attributed to the nature of the mineralogical composition of the deposits material source.

Erionite is a zeolite representing a well-known health hazard. In fact, exposure of humans to its fibers has been unequivocally associated with occurrence of malignant mesothelioma. For this reason, a multi-methodological approach, based upon field investigation, morphological characterization, scanning electron microscopy (SEM)/energy-dispersive spectroscopy (EDS) chemical analysis, and structure refinement through X-ray powder diffraction (XRPD), was applied to different samples of potentially carcinogenic erionite from Northern Italy. The studied crystals have a chemical composition ranging from erionite-Ca to erionite-Na and display variable morphologies, varying from prismatic, through acicular and fibrous, to extremely fibrous asbestiform habits. The fibrous samples were characterized by an unusual preferred partition of aluminum (Al) at tetrahedral site T1 instead of tetrahedral site T2. Further, a mismatch between the a-parameter of erionite-Ca and levyne-Ca that are intergr...

Zn-phyllosilicates are common minerals in nonsulfide Zn deposits and can give crucial information about the genesis of these oxidized mineralizations. They seldom represent the prevailing economic species but might have a significant impact on mineral processing. This study has been carried out on the Mina Grande and Cristal Zn-sulfide/nonsulfide deposits, which occur in the Bongará district (Amazonas region, northern Peru). The Cristal and Mina Grande orebodies are hosted by the sedimentary (prevailingly carbonate) successions of the Pucará Group (Condorsinga formation, Lower Jurassic), in an area affected by Neogene tectonics and characterized by Late Miocene and Pliocene-Early Pleistocene uplift phases (Andean and Quechua tectonic pulses). The Cristal deposit consists of both sulfide (sphalerite with minor pyrite and galena) and nonsulfide concentrations. The nonsulfides consists of smithsonite, hemimorphite, hydrozincite, chalcophanite, goethite, and greenockite, locally associa...