Silicate mineralogy

El eterno dilema que supone la decisión de elegir entre materiales tradicionales y modernos viene ya desde lejos. La búsqueda de un equilibrio entre las dos posiciones puede determinar el éxito de cualquier intervención en conservación y rehabilitación. ¿Existe ese equilibrio?

Горе вляво: Тъмнозелен и жълт яспис с червени петна (хелиотроп) (30х20х17 cm) от Неофит Бозвелиево, Източни Родопи (№9273, Национален природонаучен музей, БАН) Горе вдясно: Мьосбауеров спектър на жълт яспис с гьотит (образец aVu3, Върхари, Източни Родопи) Долу вляво: Червен яспис със зонални хематит-гьотитови коломорфни агрегати (образец Mo1, Източни Родопи; дюншлиф,║N) Долу вдясно: Пъстър ясписов къс (детайл) от Източните Родопи (№21683; Национален музей "Земята и хората")

Die Archäologische Staatssammlung präsentiert  in ihrem Zweigmuseum RÖMERMUSEUM WEISSENBURG eine Auswahl antiker Gemmen, die auf dem Gebiet des heutigen Bayern gefunden wurden. Im Gegensatz zu den meisten Gemmen sind von allen in der Ausstellung gezeigten Gemmen die Fundorte und Fundumstände bekannt. So können sie eingeordnet werden in die antike Kulturgeschichte.
Erste Gemmen kamen schon vor der Eroberung durch die Römer in den Besitz der keltischen Bevölkerung. Dann brachten die römischen Soldaten und Siedler zahlreiche Stücke mit. Sie gelangten mit ihren Besitzern in die Gräber oder gingen verloren in Militärlagern, Siedlungen oder Thermen. Noch im Mittelalter wurden antike Gemmen neu gefasst und weiter verwendet.

Chemical vapor deposition calcium silicate culm minerals a b s t r a c t Multiwalled carbon nanotubes (MWCNTs) were synthesized from bamboo charcoals by chemical vapor deposition in the presence of ethanol vapor. Fresh bamboo culms were first heat treated at 1000e1500 C to form charcoals. The elemental composition and structure of mineral phases in the bamboo charcoal treated at different temperatures were analyzed.

Silica sinters, deposited from alkali chloride waters in the El Tatio geothermal field in northern Chile (22°20'S, 68°01'W), have been characterized by XRD, SEM, TG-DTA, and FTIR. The dominant silica phase is opal-A. Minor contents of opal-A/-CT and opal-CT are also present together with halite (NaCl), sylvite (KCl), and realgar (AsS). Accessory phases include teruggite [Ca4MgAs2B12O22(OH)12·12(H2O)], sassolite (H3BO3), and detrital quartz (SiO2). FWHM values reflect the immature nature of the studied opal-A. DTA heating experiments of opal-A show cristobalite crystallization at ~1000 °C, whereas DTA cooling experiments show the β → α-cristobalite transformation at ~200 °C. The total weight loss is related to changes in the sinter microtextures, mineral phases, and organic matter contents. FTIR spectra show the effects of silica maturation as consequence of the loss of trapped and absorbed water attached to silanols.

Transformation of metakaolinite to basic sodalite
[Na4(AlSiO4)3Cl]2 in the presence of NaCl was investigated.
Experimental synthesis was performed in alumina
crucibles at 850°C and ambient pressure. Reaction progress
was monitored by X-ray powder diffraction from 1h to
400h. During the crystallization of sodalite, the presence
of reacting residual halite was testified throughout the run
synthesis; intermediate-phase carnegieite was detected in
the initial stage of the synthesis run (1h-24h). Both sodalite
and residual halite were evidenced between 24 and 101h,
where sodalite reaches a climax in the crystallization degree.
Progressive replacement of sodalite by nepheline was
testified starting from 171h. Synthesized sodalite was submitted
to chemical-crystallographical and mineralogicaltextural
studies and Infra-Red Spectrometry (IR), providing
values comparable to the ones available in the literature on
this mineral. A continuous loss in weigth of the NaCl plus
metakaolinite starting matrix contained in the alumina
crucible heated in oven was testified and attributed to Cl
vaporization. An analytical mathematical model to solve the
parabolic differential equation related to the chlorine diffusion
processes occurring within the crucible is proposed.
Experimental data and numerical results, when compared,
although satisfactory, suggest the necessity of some modelling
improvements.

The physico-mechanical, chemical and mineralogical characteristics of volcanic glass (perlite) from the Mariovo region (Macedonia) as well as the mineralogical changes that occur during its thermal treatment were investigated to demonstrate its utilization for industrial use. The native perlite was characterized by chemical analysis, X-ray powder diffraction (XRPD), infrared (IR) spectroscopy, thermal analysis (TGA/DTA), scanning electron microscopy (SEM-EDX), transmission electron microscopy (TEM), and solid- state NMR. The chemical examination suggests that the perlite represents an acidic volcanic rock with a high percentage of SiO2 (72.45%), high in alkali metal oxides (4.21 wt.% K2O, 3.56 wt.% Na2O), with a loss of ignition 3.54 wt.%. Results from the XRPD indicated major amorphous behaviour, with low amounts of feldspars, quartz, and cristobalite. SEM examinations revealed glassy structure with presence of certain pores (dimensions ranging from 50–100 μm). The determined expansion coefficient was 20 times its original volume. XRPD of expanded perlite compared to the native perlite depicted new intensive peaks of cristobalite. SEM and TEM revealed irregular morphology with broken or ragged edges. On the basis of the chemical and mineralogical composition, the studied perlite is classified as an appropriate material suitable as ceramic flux to lower the sintering temperature.

The biorelated degradability and clearance of siliceous nanomaterials have been questioned worldwide, since they are crucial prerequisites for the successful translation in clinics. Typically, the degradability and biocompatibility of mesoporous silica nanoparticles (MSNs) have been an ongoing discussion in research circles. The reason for such a concern is that approved pharmaceutical products must not accumulate in the human body, to prevent severe and unpredictable side-effects. Here, the biorelated degradability and clearance of silicon and silica nanoparticles (NPs) are comprehensively summarized. The influence of the size, morphology, surface area, pore size, and surface functional groups, to name a few, on the degradability of silicon and silica NPs is described. The noncovalent organic doping of silica and the covalent incorporation of either hydrolytically stable or redox- and enzymatically cleavable silsesquioxanes is then described for organosilica, bridged silsesquioxane (BS), and periodic mesoporous organosilica (PMO) NPs. Inorganically doped silica particles such as calcium-, iron-, manganese-, and zirconium-doped NPs, also have radically different hydrolytic stabilities. To conclude, the degradability and clearance timelines of various siliceous nanomaterials are compared and it is highlighted that researchers can select a specific nanomaterial in this large family according to the targeted applications and the required clearance kinetics.

The electrical conductivity of San Carlos olivine has been measured at 1100 C under reducing conditions at controlled oxygen fugacity, inside and outside the olivine stability field, in order to study the kinetics of olivine destabilization. Electrical conductivity increases along the direction [010] and decreases along [001]. as oxygen fugacity decreases. To understand these f O 2 dependences, electrical conductivity transitory regimes were studied. In response to decreases in oxygen fugacity, two transient regimes with different time scales have been observed. A fast (»1±2 min) increase of electrical conductivity is first observed, followed by a slower decrease (1± 10 h, depending on the crystal orientation). After a few hours of annealing, precipitation of metallic iron and nickel and formation of amorphous silica can be observed at the crystal surface. The fast conductivity increase in the first transient regime is ascribed to an increase in the population of electrons at the olivine surface. Two effects: (1) equilibration of surface defects with the bulk of the crystal, and (2) iron loss from the olivine due to metal precipitation, could explain the subsequent decrease of electrical conductivity. Anisotropic diffusion of surface defects to the bulk of the crystal, by a process faster than atomic diffusion is the most likely.

Príspevok prináša súhrn informácií zo štúdia nálezového fondu tehál získaných počas archeologického výskumu benediktínskeho kláštora sv. Kozmu a Damiána v Ludaniciach. Štúdium tehál bolo založené na viacerých prístupoch: matematická štatistika (rozmery tehál), archeobotanika (rastlinné odtlačky na tehlách), mineralogicko-petrografická analýza (druh a proveniencia suroviny na výrobu tehál, teplota a podmienky výpalu) a magnetická susceptibilita (určenie tepelne namáhaných častí tehál). Získané výsledky umožňujú pomerne detailne rekonštruovať postup výroby tehál vo vrcholnom stredoveku.

Eudialyte-group minerals (EGM) attract global interest as potential resources for high-field-strength elements (e.g. Zr, Nb, Ta, and rare-earth elements), i.e. critical materials for modern technologies. They are particularly valued for their relative enrichment in the most critical lanthanides, i.e. Nd and heavy rare earth elements (Gd–Lu). However, rare earth element (REE) substitution mechanisms into the EGM structure are still poorly understood. Light and heavy REE may occupy different sites and there may be ordering and/or defect clustering in the structure. This study uses X-ray absorption spectroscopy to determine the structural state of REE in EGM from prospective eudialyte-bearing complexes. Yttrium K-edge and Nd L3-edge spectra were collected as proxies for heavy and light REE, respectively, and compared to natural and synthetic REE-bearing standards. Extended X-ray absorption fine structure data yield best fits for Y in six-fold coordination with Y–O distances of 2.24–2.3...

Article published in the trade journal Solids & Bulk Handling about the dangers associated with respirable crystalline silica dust and suggested control measures based on compliance with the Control of Substances Hazardous to Health Regulations (COSHH).

Cuspidine and götzenite were found as accessories in the pegmatitoid facies of venanzite from the Pleistocene lava flow of Pian di Celle. The modal compositions of venanzite and its pegmatitoid facies have been defined through combined XRF and Rietveld quantitative analyses. Cuspidine and götzenite were unambiguously identified by combining microprobe analyses and structural studies. The structure analyses were carried on with single-crystal XRD data and the refinements converged to R1 = 0.048 and 0.053
for cuspidine and götzenite respectively.
Cuspidine from Pian di Celle, ideally (Ca,Zr) Ca2 (Ca,Na) Si2O7 F2, Z = 4, space group P21/a, a = 10.919(2), b = 10.485(1), c = 7.485(1) Å, β = 109.55(1)°, represents a Zr,Na-rich variety of cuspidine.
Götzenite from Pian di Celle, ideally (Ca,Zr) (Ca,Na) Ca (Na,Ca)0.5 Ti0.5 Si2O7 (F,OH,O)2, Z = 2, space group P – 1, a = 9.636(3),
b =7.341(2), c =5.737(1) Å, α = 89.94(2), β = 100.74(2), γ = 101.06(3)°, represents a Zr-rich variety of götzenite.
Zirconium and sodium enter in the structures substituting part of calcium, according to the main substitution indicated by the
chemical data: 2Ca2+ + F- ↔ Na+ + (Zr+Ti)4+ + O2-.

Diatomite is one of the most intensively examined raw materials in the materials industry with a broad range of various applications. The diatomite sample, collected from Vitačevo plateau in the vicinity of Kavadarci, was fully characterized by means of physical-mechanical, chemical, XRPD, SEM, TEM, DTA/TGA and IR techniques. The physical-mechanical features pointed out to soft, light, white to gray rock with shell-like structure exhibiting compressive strength from 4.65-4.88 MPa in dry form, whereas the total porosity ranges 70-72% and the density is 2.06-2.09 g/cm 3. The chemical analysis of the diatomite revealed that SiO2 content exceeds 91%. The results from the X-ray powder diffraction indicate predominant amorphous SiO2 phase associated with minor presence of crystalline quartz, muscovite, chlorites and plagioclase. The IR spectrum of the diatomite manifested characteristic bands for amorphous silica at 799 cm-1 and 1101 cm-1. DTA/TGA results display great thermal stability of the sample remaining amorphous up to 1050ºC whereas the SEM analysis determined the morphology, surface characteristics and the nanometric pores in the raw material. Thus, the studied diatomite is classified as a natural nanomaterial that is suitable for broad application in various construction materials, refractory ceramics, special oxide ceramics, and also finds potential use in filtering, adsorbent, catalysts, food and pharmaceutical industries.

Two coexisting F-bearing K-richterites from the blueschist-facies metamorphic manganese ore deposit St. Marcel (Val d'Aosta, Italy) have been studied by combined EMPA and IR analytical techniques. Despite their different colors (pink and blue) and cell dimensions, these amphiboles have formulae summing up to near 16 cations pfu on the basis of 220 + 2(OH + F) and are chemically almost identical. The major differences are in the F/OH ratio and the Ca content, and significant minor differences occur in Fe and Ti.

We analyzed the official yearly mortality data due to malignant pleural meso-thelioma (MPM) from 1995 to 2002 in all 107 Italian provinces, and we related them to provincial resident population in the same years. The resulting ratios are displayed as geographically referenced maps, which enhance the visual impact on how that fatal disease distributes over the country. The following results are statistically meaningful: (1) internal migration changed the Italian population distribution, with major increases in regions Lombardy, Trentino–Alto Adige, Veneto, and Emilia–Romagna, and moderate decreases in Piemonte, Liguria, and Friuli–Venezia Giulia. (2) MPM mortality is increasing overall, with five provinces largely exceeding the average Italian rate: Alessandria (Piemonte), Genoa and La Spezia (Liguria), and Gorizia and Trieste (Friuli–Venezia Giulia). (3) There is a substantial mortality rate increase in the same provinces which shows decreasing population. Results are discussed with reference to well-known cases of asbestos-polluted sites such as Balangero and Casale Monferrato (Piemonte), Genoa and La Spezia (Liguria), and Monfalcone and Trieste (Friuli–Venezia Giulia). General unquestionable conclusions are (a) occupational exposure, especially working conditions, increases MPM mortality; (b) non-occupational exposure data are scattered, as are male versus female data, and cannot be dealt with statistically on a nationwide scale; (c) natural environmental exposure may contribute to MPM mortality, but its effect is still statistically minor. The MPM mortality apex is currently reached at Trieste, a province free of asbestos minerals occurring in their natural setting, but where MPM affects workers in the marine industry strongly who operated in contact with insulating outfits. Information on content and type of amphibole present in the asbestos materials used for industrial applications is scattered and generally scarce, thus making the evaluation of the amphibole versus chrysotile relative impact on MPM mortality rates statistically unsound.

The production of pottery represented a significant pyro-technological progress in the ancient world. Two types of characteristics pottery from the transitional period (Neolithic to Chalcolithic) found at the Tappeh Zaghe in northern Iran were analyzed in order to investigate newly formed phases produced during the firing stage of pottery. This might have been a sign of technological evaluation through transitional period. Petrographic analysis, coupled with multi-image analysis, X-ray powder diffraction and environmental scanning electron microscope with energy-dispersive X-rays (ESEM-EDX) provided information on the compassion and microstructure of ceramic samples. Synchrotron micro-XRD beamline allowed the spatial mapping of crystalline phases from near surface (at the surface) into the matrix of potteries and the detection of minute, major and minor phases. The mineralogical interaction between various primary phases and decomposition regard carbonate reaction within the potteries fabrication in the as-received. New phases were followed across the wall thickness which were achieved by sintering (partial or total) and show a clear transition from outer side to the core of the pottery.

the crystal structure of baghdadite,
ideally Ca3Zr(si2o7)o2, was refined using 1986
reflections to R = 0.034. Baghdadite is monoclinic,
space group P21/a, with cell parameters a 10.432(3),
b 10.163(2), c 7.356(2) Å, b 90.96(2)°. the refined
crystal structure is in agreement with the structure of
synthetic Ca3zrsi2o9. the structure is characterized
by the presence of walls of cation polyhedra, four
columns large, linked together by both direct
connection as well as by disilicate groups. Baghdadite
is the first phase in the cuspidine group in which the
Pauling’s fourth rule is violated.

Tiragalloite occurs as small orange grains in veinlets cutting black massive aggregates of braunite and quartz from an abandoned manganese mine at Molinello near Chiavari, Liguria, Italy. The veinlets also contain quartz, manganiferous calcite, parsettensite, albite, and at least one other new mineral related to tiragalloite but containing essential vanadium instead of arsenic. Tiragalloite is optically biaxial, positive, a : 1.745(5), B : 1.751(3), t : 1.760(5), 2V,: 3946", non-pleochroic. The theoretical formula, derived from crystal-structure determination, is Mn [AsSi.O,r(OH)], and the formula derived from 29 microprobe analyses is (MnrrorCaootrFeoo,r)[(AsossVo,6)Si]Or2(OH)1. Density (meas.) 3.84(6); (calc.) 3.829 gcm-3. The crystals are monoclinic, Y),/n, with a : 6.66(l), b : 19.92(2), c : 7.670)4, B:95.7(l)"; the most intense lines in the powder pattern are (as d, I, hkl) 6.299 Q\ ll0; 4.742 (60) l0l,l30; 3.267 (7r) 2tD,032,t22:3.149 (50) 220;3.M2 (66) p6l,l5l; 3.006 (100) 221,042,122:2.496 (64) 062.17I,013. In the crystal structure, the most characteristic feature is the presence of an arsenatotrisilicate ion (AsSirO,rOH)t-, comprising four tetrahedra linked together to form a chain fragment. This new ion is an extension of the trisilicate (SirOto)Eion with an additional As-centered tetrahedron linked to it. This example is the fust of a new series of minerals. The name is for Paolo Tiragallo (b. 1905), a distinguished amateur mineralogist.

Diatomite is one of the most intensively examined raw materials in the materials industry with a broad range of various applications. The diatomite sample, collected from Vitačevo plateau in the vicinity of Kavadarci, was fully characterized by means of physical-mechanical, chemical, XRPD, SEM, TEM, DTA/TGA and IR techniques. The physical-mechanical features pointed out to soft, light, white to gray rock with shell-like structure exhibiting compressive strength from 4.65-4.88 MPa in dry form, whereas the total porosity ranges 70-72% and the density is 2.06-2.09 g/cm 3. The chemical analysis of the diatomite revealed that SiO2 content exceeds 91%. The results from the X-ray powder diffraction indicate predominant amorphous SiO2 phase associated with minor presence of crystalline quartz, muscovite, chlorites and plagioclase. The IR spectrum of the diatomite manifested characteristic bands for amorphous silica at 799 cm-1 and 1101 cm-1. DTA/TGA results display great thermal stability o...

The geomorphic evolution of the upper basin of the Tigris (Dicle) River in southeastern Turkey reflects the interplay of surface processes and the development of topographic relief and lithospheric deformation since the closing of the Southern Neo-Tethyan (formerly Bitlis) Ocean. The study of the Tigris system is a proxy for understanding the deep crustal processes associated with the active Alpine -Himalayan mountain belt. The drainage morphology is linked to the uplift of the eastern Taurus Mountains and deformation of the Arabian foreland system following continent -continent collision. Initial review of landscape features at aerial and field scales confirms that the evolution of the Tigris has been complex, and that valley morphology varies by reach. Within the headwater reach, the Tigris is a transverse river system that flows across metamorphic rocks of the Bitlis -Zagros Suture Zone. Ongoing deformation in the Lake Hazar region bounded by the East Anatolian Fault Zone controls the topographic divide between the watershed draining north to the Euphrates and south to the Tigris. At the junction of the Arabian Plate, the river may be viewed as an antecedent stream system that developed since the Miocene. In the reach near Diyarbakir, valley development (and possibly incision) has been influenced by recent effusive volcanism. East of Diyarbakir, evaporitic karst processes are currently causing sapping, piping, and subsurface collapse as well as valley widening, which is concentrated in folds paralleling the suture zone and orogen to the north. The evolution of the Upper Tigris over the past 13 Myr can be reconstructed as a function of vertical movement (e.g. base-level changes, tectonic uplift, doming, downwarp, and sagging), horizontal deformation Q10 (e.g. folding, faulting, compression, and extension), volcanism, weathering, and erosion (e.g. dissolution processes, karstic erosion, and sapping). It is important to assess the first-order tectonic controls on the evolving fluvial systematics of the Tigris so that its sedimentary and geomorphic records can be used to reconstruct hydroclimatic changes affecting this part of the Near East during antiquity.

Interactions between several silicate and metallic phases are studied by applying a self consistent thermodynamic approach and using recent thermody-namic data. We compute proportions and compositions of oxidized silicates and of reduced metallic phase in equilibrium at various temperatures and oxygen fugaci-ties. The empirically observed activity-composition relationships for ternary metallic alloys are used and their applications to a general thermodynamic expression for a non-regular ternary system is explicitly discussed. We show that the stability limits of olivines and pyroxenes with respect to precipitation of metallic phases under reducing conditions are directly related to the presence of nickel impurities. We precisely evaluate the modi®cations of the stability limits as a function of nickel content. For typical mantle olivines [Fe/(Fe+Mg) = 0.

Sequential washing techniques using single or dual agents [sodium hydroxide (NaOH) and hydrochloric acid (HCl) solutions] were applied to arsenic-contaminated soils in an abandoned iron-ore mine area. We investigated the best remediation strategies to maximize arsenic removal efficiency for both soils and arsenic-containing washing solution through conducting a series of batch experiments. Based on the results of a sequential extraction procedure, most arsenic prevails in Fe-As precipitates or coprecipitates, and iron exists mostly in the crystalline forms of iron oxide. Soil washing by use of a single agent was not effective in remediating arsenic-contaminated soils because arsenic extractions determined by the Korean standard test (KST) methods for washed soils were not lower than 6 mg kg-1 in all experimental conditions. The results of X-ray diffraction (XRD) indicated that iron-ore fines produced mobile colloids through coagulation and flocculation in water contacting the soils, containing dissolved arsenic and fine particles of ferric arsenate-coprecipitated silicate. The first washing step using 0.2 M HCl was mostly effective in increasing the cationic hydrolysis of amorphous ferrihydrite, inducing high removal of arsenic. Thus, the removal step of arsenic-containing flocs can lower arsenic extractions (KST methods) of washed soils. Among several washing trials, alternative sequential washing using 0.2 M HCl followed by 1 M HCl (second step) and 1 M NaOH solution (third step) showed reliable and lower values of arsenic extractions (KST methods) of washed soils. This washing method can satisfy the arsenic regulation of washed soil for reuse or safe disposal application. The kinetic data of washing tests revealed that dissolved arsenic was easily readsorbed into remaining soils at a low pH. This result might have occurred due to dominant species of positively charged crystalline iron oxides characterized through the sequential extraction procedure. However, alkaline extraction using NaOH was effective in removing arsenic readsorbed onto the surface of crystalline minerals. This is because of the ligand displacement reaction of hydroxyl ions with arsenic species and high pH conditions that can prevent readsorption of arsenic. © 2006 Elsevier Ltd. All rights reserved.

http://www.sciencedirect.com/science/article/pii/S0045653506007181

We have inferred the deformation mechanisms of antigorite by high-resolution EBSD mapping of samples from Cerro del Almirez ultramafic massif (Betic Cordillera, SE Spain). Textural relations and phase diagram calculations constrain the foliation development conditions to the subduction prograde path at up to 600–630 °C and 1.6–1.9 GPa. Deformation was followed by static annealing of antigorite at ca. 680 °C. The Crystal Preferred Orientation (CPO) of antigorite is characterised by a strong alignment of (001) poles normal to the foliation plane and a weaker, but clear, parallelism between [100] axes and the macroscopic lineation defined by the elongation of magnetite aggregates. Analysis of misorientations across subgrains shows predominance of [010] rotation axis, consistent with activation of the [100](001) slip system. However, tilt subgrain boundaries subparallel to (100), probably formed by edge dislocations of this system, are subsidiary. Most subgrain boundaries are subparallel to (001) planes. They are interpreted as (001) twins wherein continuing viscoplastic deformation resulted in a slight increase of the misorientation between the twins. Modelling of the evolution of the antigorite CPO using a lower bound approach and considering different deformation regimes and sets of basal and non-basal slip systems has shown that intensities of [100] and [010] maxima reflect the relative strength of the antigorite [100](001) and [010](001) systems. Activation of other basal or non-basal slip systems does not change significantly the CPO patterns, but results in less concentrated CPO. 3D transpression models better reproduce the CPO of natural antigorite serpentinites. We propose that the widespread occurrence of strong CPO in high-pressure antigorite serpentinite is consistent with deformation by dislocation creep with dominant glide on [hk0](001), together with the activation of twinning, implying that a power law rheology would better account for the mechanical behaviour of antigorite serpentinite deep in the subduction channel and mantle wedge.

ABSTRACT The geomorphic evolution of the upper basin of the Tigris (Dicle) River in southeastern Turkey reflects the interplay of surface processes and the development of topographic relief and lithospheric deformation since the closing of the Southern Neo-Tethyan (formerly Bitlis) Ocean. The study of the Tigris system is a proxy for understanding the deep crustal processes associated with the active Alpine – Himalayan mountain belt. The drainage morphology is linked to the uplift of the eastern Taurus Mountains and deformation of the Arabian foreland system following continent – continent collision. Initial review of landscape features at aerial and field scales confirms that the evolution of the Tigris has been complex, and that valley morphology varies by reach. Within the headwater reach, the Tigris is a transverse river system that flows across metamorphic rocks of the Bitlis – Zagros Suture Zone. Ongoing deformation in the Lake Hazar region bounded by the East Anatolian Fault Zone controls the topographic divide between the watershed draining north to the Euphrates and south to the Tigris. At the junction of the Arabian Plate, the river may be viewed as an antecedent stream system that developed since the Miocene. In the reach near Diyarbakir, valley development (and possibly incision) has been influenced by recent effusive volcanism. East of Diyarbakir, evaporitic karst processes are currently causing sapping, piping, and subsurface collapse as well as valley widening, which is concentrated in folds paralleling the suture zone and orogen to the north. The evolution of the Upper Tigris over the past 13 Myr can be reconstructed as a function of vertical movement (e.g. base-level changes, tectonic uplift, doming, downwarp, and sagging), horizontal deformation (e.g. folding, faulting, compression, and extension), volcanism, weathering, and erosion (e.g. dissolution processes, karstic erosion, and sapping). It is important to assess the first-order tectonic controls on the evolving fluvial systematics of the Tigris so that its sedimentary and geomorphic records can be used to reconstruct hydroclimatic changes affecting this part of the Near East during antiquity.

Very low frequency electromagnetic, magnetic, and induced polarization methods. The very low frequency electromagnetic resistivity data show high resistivity zones that correlate with siliceous units known to host the gold. The magnetic data clearly identify the mafic and ultramafic dikes which cut metasediments and also fill faults that offset them. The induced polarization method allows examination of the mineralized metasediments in two dimensions by giving vertical sections of resistivity and percent frequency effect, parameters which correlate with silica and pyrite content, respectively. Lithologic units as well as ore zones can thus be mapped in this terrain which is deeply weathered and partially covered by coastal plain sediments.--Modified journal abstract.

Chemical weathering of Mg, Ca-silicates and alumino-silicates contributes significantly to the drawdown of atmospheric CO 2 over long time scales. The present work focuses on how this mode of weathering may change in the presence of free-living bacteria in oligotrophic waters, which compose most of the surface freshwaters of the Earth. Forsterite (Fo90) was reacted for 1 week with a stable Escherichia coli population in water maintained at 37°C and neutral pH in a batch reactor. Control samples with suspensions of pure olivine powders and E. coli cells in pure water were also used for reference. Olivine controls reproduce the Mg, Si and Fe release in solutions predicted from rates published in the literature with pH shifts of less than 0.5 unit. After 1 week, under abiotic conditions, weathered surfaces are enriched in Fe and Fe 3+ relative to the initial composition of the mineral. Bacterial controls (without minerals) show decreasing Eh with increasing cell concentrations (À50 mV with 7 Â 10 7 cells/mL and À160 mV with 8 Â 10 8 cells/mL). Magnesium concentrations in bacterial control solutions are in the lg/L range and can be accounted for by the release of Mg from dead cells. More than 80% of the cells were still alive after 1 week. The solutions obtained in the experiments in which olivine reacts in the presence of cells show Mg and Si concentrations a few tens of percent lower than in the mineral control samples, with a prominent depletion of Fe(III) content of the mineral surfaces. Magnesium mass balance discounts both significant bacterial uptake and inhibition of the Mg dissolution rates as a consequence of changing pH and Eh. Coating by bacterial cell layers is also negligible. E. coli reduces the chemical weathering of olivine. This study infers that the presence of free-living Proteobacteria, a prevalent group of subsurface bacteria, should decrease the amount of riverine Mg released by chemical weathering of mafic rocks.

Course name: Earth Systems I: Solid Earth

Saint Louis University, Madrid Campus, Faculty: Science and Engineering

Semester:  Spring 2005.

Course description: On the structure of our planet and the forming processes: plate tectonics, crustal evolution, rocks, surface and groundwater hydrology, and so on. Focus on volcanic activity in the Canary Islands, where students will carry out field studies during a long-weekend visit.
Mandatory trip: Lanzarote (Canary Islands); unpaid fees result in automatic removal from class.

Course Objectives: 
By end of the course the student should:
• Know the basic types of rocks and understand the basic principles of the rock cycle.
• Know and understand the basic principles of plate tectonics and volcanism.
• Know and understand the most important processes on the earth´s surface.
• Achieve a foundation on the basic principles underlying the patterns and dynamics of the earth´s surface and interior.

Textbook: Following textbook is absolutely necessary for the course:
PRESS, Frank, & SIEVER, Raymond (2001): Understanding Earth. 3rd edition. – New York (W. H. Freeman and Company).

Supplementary reading: Following books may be interesting or helpful for some aspects of the course, but they are not necessary:
ANDEL, T. H. van, (1994): New views on an old planet. A history of global change. 439 pp.; Cambridge (Cambridge University Press).
ARAÑA, V., & CARRACEDO, J. C. (1979): Los volcanes de las islas Canarias. – Vol. I: Tenerife; Vol. II: Lanzarote y Fuerteventura.
BOLT, Bruce A. (1999): Earthquakes. – 366 p.; New York (W. H. Freeman and Company).
CUNNINGHAM, W.P., & SAIGO, B. Woodworth (1992): Environmental Science – A Global Concern. 2nd edition. – 622 p., Dubuque (Wm. C. Brown Publishers).
CUNNINGHAM, W.P., & CUNNINGHAM, M.A., & SAIGO, B. Woodworth (2002): Environmental Science – A Global Concern. 7th edition. – 646 p., Boston.
DECKER, Robrt & Barbara: Volcanoes. – 321 p.; New York (W. H. Freeman and Company).
MERRITTS, D., & WET, A. DE, & MENKING, K. (1998): Environmental geology. 452 pp.; New York (Freeman a. Co.).
SCARTH, Alwyn & TANGUY, Jean-Claude (2000): Volcanoes of Europe. – Oxford.
YARZA, Esperanza (1988): Volcanes de Iberoamerica. – 128 p.; Madrid (Anaya).

Course Calendar:
Tuesday, Jan. 18th: Introduction – Building a planet (Textbook chapter 1)
Thursday, Jan. 20th: Minerals (Textbook chapter 2)
Tuesday, Jan. 25 & Thursday, Jan. 27: Rocks (Textbook chapter 3)
Thursday, Jan. 27: End of DROP/ADD period
Tuesday, Feb. 1 & Thursday, Feb. 3: Igneous Rocks (Textbook chapter 4)
Tuesday, Feb. 8 & Thursday, Feb. 10: Volcanism (I) (Textbook chapter 5)
Tuesday, Feb. 15: Review & Preparation of first mid-term exam
Tuesday, Feb. 15: Deadline for the submission of the title of the paper
Thursday, Feb. 17: First mid-term exam
Tuesday, Feb. 22 & Thursday, Feb. 24: Volcanism (II) (Textbook chapter 5)
Tuesday, Mar. 1 & Thursday, Mar. 3: Volcanism (III) (Textbook chapter 5)
Saturday, Mar. 5, to Sunday, Mar. 13: SPRING BREAK
Tuesday, Mar. 15: Weathering and Erosion (Textbook chapter 6)
Thursday, Mar. 17, to Sunday, Mar.20: Field trip to the Canary Islands
Tuesday, Mar. 22: Sediments and Sedimentary Rocks (I) (Chapter 7)
Thursday, Mar. 24, to Sunday, Mar.27: Easter
Tuesday, Mar. 29: Review & Preparation of second mid-term exam
Thursday, Mar. 31: Second mid-term exam
Tuesday, Apr. 5: Deadline for the submission of papers and PowerPoint presentations
Tuesday, Apr. 5: Sediments and Sedimentary Rocks (II) (Chapter 7)
Thursday, Apr. 7: Metamorphic Rocks (Textbook chapter 8)
Thursday, Apr. 7: Deadline for the submission of the exercise
Friday, Apr. 8: Last day to drop a class and receive a grade of "W"
Tuesday, Apr. 12: The Rock Record and the Geologic Time Scale (Textbook chapter 9)
Thursday, Apr. 14: Rock Deformation (Textbook chapter 10)
Tuesday, Apr. 19 & Thursday, Apr. 21: The Hydrologic Cycle and Groundwater (Chapter 12)

Heat treatment was performed on selected Fedominant
tourmalines to establish the nature of any change in optical properties. Two tourmaline samples from Dolní Bory, Czech Republic (TDB) and Vlachovo, Slovakia (TVL) were heated at 450, 700 and 900C at 0.1 mPa and ambient oxidation conditions for 8 h. EMPA study shows that tourmaline from Vlachovo has schorlitic composition and tourmaline from Dolní Bory is alkali-depleted schorl to foitite. Although the black colour remained unchanged after heating at 450C, it changed to brown at 700C and reddish brown at 900C. No significant changes of chemical
composition were observed during heating. X-ray diffraction, infrared and Mo¨ssbauer study showed negligible oxidation of tourmaline heated at 450C, but a significant change in iron valency state and deprotonization at 700 °C. The oxidation of Fe is the main cause of tourmaline colour change, and the substitution vector for oxidation of Fe is Fe3+OFe2+-1(OH)-1. The predicted deprotonization of OH was confirmed by infrared spectroscopy, which documented a decrease in OH groups in both samples, mainly at the V site. The oxidation of Fe is mostly significant in the Y site as documented on the compression of the Y-site octahedra and subsequent decrease in the a lattice parameter. This feature is consistent with lattice dimensions in
the transition from schorl and foitite dimensions to those
consistent with fluor-buergerite. The Z-site octahedra did
not compressed and were not affected by heating-induced
Fe oxidation, which indicates only negligible content of
ZFe2? in original samples. After heating at 900C, the
tourmaline structure collapsed likely due to the thermally
induced weakening of bonds in Y and Z octahedra, which
results in amorphization of tourmaline. Subsequently, breakdown products including Fe-oxides and mullite replaced alkali-depleted amorphized tourmaline.

Phosphorus from excess fertilizers and detergents ends up washing into lakes, creeks, and rivers. This overabundance of phosphorus causes excessive aquatic plant and algae growth and depletes the dissolved oxygen supply in the water. In this study, aluminum-impregnated mesoporous adsorbents were tested for their ability to remove phosphate from water. The surface structure of the materials was investigated with X-ray diffraction (XRD), a N2 adsorption-desorption technique, Fourier transform-infrared (FT-IR), and X-ray photoelectron spectroscopy (XPS) to understand the effect of surface properties on the adsorption behavior of phosphate. The mesoporous materials were loaded with Al components by reaction with surface silanol groups. In the adsorption test, the Al-impregnated mesoporous materials showed fast adsorption kinetics as well as high adsorption capacities, compared with activated alumina. The uniform mesopores of the Al-impregnated mesoporous materials caused the diffusion rate in the adsorption process to increase, which in turn caused the fast adsorption kinetics. High phosphate adsorption capacities of the Al-impregnated mesoporous materials were attributed to not only the increase of surface hydroxyl density on Al oxide due to well-dispersed impregnation of Al components but also the decrease in stoichiometry of surface hydroxyl ions to phosphate by the formation of monodentate surface complexes.

http://pubs.acs.org/doi/abs/10.1021/es030488e

A new metal-free catalyst CaSiO3 was developed to grow carbon nanotubes (CNTs) on a pyrolytic graphite paper tape by an ethanol catalytic chemical vapor deposition method at 1200-1400 oC. The prepared CNTs with a droplet tip had a multi-walled structure and were filled with amorphous CaSiO3. Temperature, determining the melting of CaSiO3, was critical for the growth of the CNTs. This new catalyst is suggested to follow the similar roles of transition metals in the growth of CNTs by a molten state to absorb carbon and form CNTs after reaching saturation.