Mineralogy

Snowflakes and silicate mushes are two examples of the terrestrial regimes that may be characterized as partially solidified systems. Change of phase in clouds and magma chambers as well as in the earth's mantle and core introduces a variety of phenomena to challenge both the mathematical modeler and the experimentalist intent upon understanding the nature of such processes. Paralleling the efforts of researchers in the natural sciences, metallurgists and materials scientists have extensively investigated solidification in alloy melts to discover the controlling mechanisms for undesirable behavior such as melt segregation, freckling (Figure 1), and crystal dislocation. Unfortunately, most of the studies, whether in the geosciences or in material sciences, have focused on highly specialized problems with little or no attempt at generalizing the results or methods to other physical systems. During May 12-16, 1986, at the Stanford University Conference Center at Fallen Leaf Lake, ...

The petrography and mineralogy form an integral part of Petrological studies of any area. The petrographical and mineralogical data is very useful in mapping and correlating the flow sequences and in establishing the flow stratigraphy. The petrographic and mineralogical studies also play an important role identification of various petrogenetic processes that may be responsible for producing them. In the present study an attempt has been made to understand the preliminary petrography and mineralogy of lava pile of Muktagiri. The detailed geological mapping of the study area was done, and number of filed traverses were carried out the to identify the various lava flows along with their extensions. The field specimens were collected along all the traverses. The megascopic and microscopic studies were done to identify the petrographic and mineralogical characters. About 15 lava flows were identified in the study area. These lava flows, based on mineralogical and petrographic characters were divided in to four formations namely A, B, C and D formation. Further, the lava flows can be classified into aphyric and phyric lava flows. Mineralogical study revels that the lava flows are composed of plagioclase, clinopyroxene and opaque (mostly Fe-Ti oxide). At few places places primary glass with very small proportion of olivine is also observed.

The roméite-group [1,2] is part of the pyrochlore supergroup and comprises some cubic oxides of A2-mB2X6-wY1-n formula in which Sb 5+ predominates in the B-site. Indices m, w and n indicate vacancies in A, X and Y crystallographic sites, respectively. A-site is typically occupied by cations with ionic radii greater than 1.0Å or H2O, whereas X-site is usually occupied by O 2-, but smaller amounts of OHor Fare also commonly found. Finally, Y-site is typically occupied by anions O 2-, OHor F-; however, large ionic radii monovalent cations (>1.0Å) such as K + , Cs + and Rb + , or even H2O can occupy it. Since the predominance of Sb 5+ for B site is already known, the correct A and Y main occupants determine different minerals in the group and are important for the discovery of new mineral species [3]. As a source of Sb, the roméite-group minerals are economically relevant, since Sb is present in different applications, from cosmetic industry to the metal alloy production. However, only five roméite-group mineral species, namely fluorcalcioroméite, hydroxycalcioroméite, hydroxyferroroméite, oxycalcioroméite, and oxyplumboroméite have been approved by IMA. Many others can probably be discovered from possible chemical substitutions at crystallographic sites. This study analysed three different samples and determined their chemical composition by electron microprobe analysis and Raman spectra and crystal structure obtained from single-crystal X-ray diffraction. The first sample occurs in Kalugeri Hill, Babuna Valley, Jakupica Mountains, Nezilovo,Veles, Macedonia, whereas the other two occur in Prabornaz Mine, Saint Marcel, Valle d'Aosta, Italy. Sample 1 was identified as fluorcalcioroméite, and samples 2 and 3 as hydroxycalcioroméite. These are the first descriptions of these mineral species at the mentioned occurrences.

Rare minerals, chloriane amphiboles and chloriane biotites were discovered in rocks of  Palaeoproterozoic (Jatulian) traps of Karelia: in gabbro-dolerites of layered Kojkarsko-Svjatnavolok sill and in coarse-grained albitic (“karjalitic”) enclave in basaltic flow, which is exposed in village Girvas. Amphiboles detected as chlorinehastingsites (AlVI  < Fe3+, Fe/(Fe2+ + Mg) > 0,6; Cl from 2,03 to 5,50%), chlorinebiotites attributed to phlogopite-annite series with Fe/Mg ≥ 0,7 and Cl content ranging from 1,44 to 3,41%. These minerals were formed at the latest subsolidus stage of crystallization of Karelian traps. The composition of them indicates high chlorine activity in late- postmagmatic fluid, which could be considered as favorable factor when evaluation of PGE metal mineralization, well known in trap layered intrusions, would be conducted.

Copyright 2009, Society of Petroleum Engineers This paper was prepared for presentation at the 2009 SPE/EAGE Reservoir Characterization and Simulation Conference held in Abu Dhabi, UAE, 19–21 October 2009. This paper was selected for presentation by an SPE ...

As questões que envolvem a conservação da diversidade de seres vivos no mundo vem sendo abordados frequentemente em todos os níveis de organização social, entre os temas está a extinção das espécies, como consequência das agressões ao meio ambiente, ás áreas de exploração mineral, são áreas susceptíveis a causarem dados não só ao solo, mas também a toda a diversidade de vida no local, com repercussões no seu entorno, que provoca redução ou destruição de hábitat, afugentamento da fauna, promovendo a morte de espécies da fauna e da flora terrestres e aquáticas. O objetivo deste estudo é apresentar uma lista de espécies da fauna e flora encontradas na Região da Vila Renascer, Petrolina, Estado de Pernambuco, e discutir os impactos na região, que ameaçam essa diversidade. Este estudo foi realizado a partir de entrevistas com a população local residente no entorno de uma mineradora de gnaisse, acerca dos impactos e importância da mineração. A amostragem foi aleatória, sendo selecionados 87 informantes, como critério para inclusão dos participantes na pesquisa foi adotado a idade > 18 anos e escolaridade, optando-se pelos alfabetizados. Os resultados registra que a exploração da rocha, é apontada pelos moradores como redução de espécies da fauna está o Galea spixii, o tatu Euphractus sexcinctus e cascavel Crotalus durissus terrificus pelas mudanças climáticas e pela atividade de caça desses animais e da flora Caesalpinia pyramidalis e o Spondias tuberosa devido ao desmatamento para retirada da rocha, queimadas e abertura de novas vias de acesso para mineração. Diante do exposto, a paisagem como também toda a dinâmica do meio ambiente é alterada, levando extinção de espécies da caatinga, transtornos na saúde da população e também depredação do patrimônio particular, diante disso, não se vislumbra compatibilidade entre a extração de minérios e os objetivos de proteção da fauna e da flora.

The Florida phosphate deposits in Four Corners and Hardee County mines are composed mainly of phosphate minerals and quartz in addition to subordinate proportions of feldspars, dolomite, calcite, gypsum, kaolinite, attapulgite and montmorillonite. These phosphorites contain three structurally different types of mudclasts: massive mudclasts, mudclasts with concentric structure and mudclasts consisting of agglomerates of apatite mi-croparticles. The latter are represented by particles resembling phosphatized fossil bacteria associated with microbial filaments, and hollow apatite particles having surfacial coatings and connected to microbial filaments. The Florida phosphate particles are reworked and vary in mineral composition, color and shape. They are composed of a mixture of well-crystalline species including carbonate fluorapatite (francolite), carbonate apatite and fluorapatite. The color variation of the phosphate particles is related to difference in mineral composition, extent of diagenetic effects and reworking. The light-colored mudclasts are characterized by the presence of carbonate apatite and aluminum hydroxide phosphate minerals, whereas the dark mudclasts are rich in iron aluminum hydroxide phosphate minerals. The Florida phosphorites are suggested to be formed partially by authigenetic precipitation, replacement of the sea floor carbonate and diatomite, and microbial processes. With respect to elemental geochemistry, the analyzed particles contain small percentages of sulfur and iron which are related to the occurrence of pyrite. Traces of silica and alumina are recorded which may be attributed to the diagenetic. Some of the tested particles are relatively rich in phosphorous, fluorine, calcium, and magnesium, while poor in silicon, potassium and sulfur. Whereas, the bioclasts (especially teeth) are relatively rich in calcium, phosphorous and fluorine while poor in silicon, aluminum, magnesium and potassium. Hence, the microchemical analyses revealed that differential dia-genesis affected mudclasts more than bioclasts. There is a complete compositional gradation between clay and phosphate particles which reflects their interaction. This involved kaolinitization of the phosphate particles, phosphatization of the clay mineral particles and production of silica.

We present new data about speleothems of gypsum formerly analyzed by DRX. These speleothems are located in a cave in carbonatic sandstone of the Jaizkibel Formation (of Eocene age). The sample has been analyzed by an energy dispersion microanalyzer (XPS) connected to the equipment of a scanning electron microscopy (SEM). The acicular crystals of gypsum grow on a basis of opal-A. In addition, there are traces of other elements, as C, which we attribute to organic matter from microbial mats adjoining to the speleothems.
Link: http://www.aranzadi.eus/fileadmin/webs/Publicaciones/pdfs/GREEN%20CAVE4.pdf

The origin of chemical and mineralogical heterogeneity in tens-of-microns wide layers and domains in enderbite-hosted couple-of-centimeters wide pseudotachylite vein is examined based on the results of BSE and X-ray element imaging, and electron probe microanalyses of major elements of host-rock minerals, clasts, microphenocrysts, and pseudotachylite matrix. The pseudotachylite layers and domains containing variable proportions of orthopyroxene and magnetite microphenocrysts continue as mantles around quartz, K-feldspar, plagioclase and garnet clasts. The clasts are chemically modified along margins and intra-clast pseudotachylite injections. The chemical modifications are extensive in smaller clasts <5 μm diameter. At least three chemically distinct layers and domains in the pseudotachylite, and their fine-grained matrices, plot in sharply defined, well-segregated and non-overlapping fields in FeO + MgO−Al2O3–SiO2, FeO–CaO–MgO and CaO–Na2O–K2O and FeO vs. FeO/FeO + MgO diagrams. The compositions of the layers and domains—smeared between a feldspar + quartz component and a ferromagnesian component of garnet + Fe–Ti oxides (±orthopyroxene)—possibly correspond to fractionated quenched melts, or admixtures of microphenocrysts that cannot be resolved by the microbeam techniques employed. The compositional variations are incompatible with deformation-driven crystal fractionation in melt. Instead the layers and domains possibly are crystal-melt mushes produced by syn-deformation ultra-high temperature (1,250–1,375°C) melting reactions involving variable proportions of host-rock minerals determined by time-transient local phase aggregates experiencing strain. The similar element variation trends in pseudotachylite examined here and those reported from anorthosite, metapelite and charnockite elsewhere suggests local phase aggregate controlled multi-reaction melting is a phenomenon commoner than hitherto realized in pseudotachylites.

There are a few trade names and expressions that are not exactly accurate if we look at them in a very strict way. However, written or verbal tradition have given them a wide visibility and usage among both professionals and the general public, and many have became part of the trade’s vernacular and nomenclature. Here are a few examples.

Rift-related, late Eocene (≈ 60 Ma) alkaline-carbonatitec intrusions cover ≈ 1200 km2 south of the town of Chhota Udaipur, and form a subprovince within the alkaline magmatism that accompanies the tholeiitic Deccan Traps. They were emplaced temporally between late Deccan Trap flows and late dykes of basalt and picritic basalt. The subprovince comprises five main geographic occurrences (sectors): (1)Amba Dongar: a ring-complex of Ca-Mg-Fe-carbonatites, nephelinites to tephriphonolites, and fluorite deposits; (2)Siriwasan-Dugdha: an intrusive complex of Ca—carbonatites, nephelinites and trachytic rocks; (3)Phenai Mata: a nepheline syenite plug and dykes, plus dykes of tephrites to phonolites and lamprophyres (intimately associated with a layered tholeiitic gabbro—granophyre intrusion); (4)Panwad-Kawant: dykes and plugs of lamprophyres and tephrites to phonolites; (5)Bakhatgarh-Phulmahal: late basic-ultrabasic dykes only. The alkaline rocks range from ultrasodic to ultrapotassic, but are mostly nonperalkaline. Silica-undersaturated examples show higher incompatible and LIL element contents (Rb, K, Nb, Zr, Sr, Ba, LREE, etc.) than the associated tholeiites. However, the late basic-ultrabasic dykes display an continuum of alkaline-tholeiitic compositions. Possible parent magmas are represented among the primitive undersaturated basic dykes (including lamprophyres). The trachytic rocks are subalkaline, and may be genetically related to a tholeiitic rather than alkaline parent magma. Alkalisch-karbonatitische Intrusionen aus dem Obereozän (≈60 Ma) erstrecken sich über 1200 km2 südlich der indischen Stadt Chhota Udaipur und bilden einen Teil des alkalischen Komplexes, der die tholeiitischen Deccan Traps begleitet. Die Gesteine wurden während eines Rifting Prozesses intrudiert und lagern stratigraphisch zwischen Deccan Trap Tholeiiten und basaltischen bzw. pikritischen Ganggesteinen. Das Gebiet läßt sich in fünf geographische Regionen unterteilen: (1) Amba Dongar: ein ringförmiger Komplex aus Ca-Mg-Fe-reichen Karbonatiten, Nepheliniten und Tephriphonoliten mit Fluorit-Lagerstätten; (2) Siriwasan-Dugdha: eine Ca-reiche Karbonatit-Intrusion mit Nepheliniten und Trachyten; (3) Phenai Mata: Eine Nephelin-syenitische Intrusion und begleitende Ganggesteine aus Tephriten, Phonoliten und Lamprophyren, die mit einer magmatisch geschichteten tholeiitischen Gabbro Intrusion vergesellschaftet sind; (4) Panwad-Kawant: Lamprophyrische Ganggesteine neben Tephriten und Phonoliten; (5) Bakhatgarh-Phulmahal: späte basisch bis ultrabasische Ganggesteine. Die alkalischen Gesteine besitzen eine ultrapotassische bis extrem Na-reiche Zusammensetzung, nur vereinzelte Proben weisen jedoch peralkalischen Charakter auf. Silizium-untersättigte (alkalische) Proben besitzen in der Regel höhere Konzentrationen an Mantel-inkompatiblen Elementen (z.B. LREE, Nb und Zr) und LILE (z.B. Rb, Sr und Ba) als die benachbarten Tholeiite. Die späten basisch bis ultrabasischen Ganggesteine stellen ein Kontinuum von alkalischer bis tholeiitischer Geochemie dar. Die “primitiven” Silizium-untersättigten Ganggesteine (und Lamprophyre) repräsentieren vermutlich die Ausgangssehmelzen; die “subalkalischen” Trachyte dürften in genetischem Zusammenhang mit den Tholeiiten stehen.

 The kinetics and mechanism of hydrothermal formation of zeolite A from natural kaolinites have been studied using as starting materials two international kaolinite standards (KGa-1 and KGa-2 from Georgia, USA) exhibiting a different degree of stacking disorder. Precursors utilized for the synthesis were prepared by heating the kaolinites at 800 °C. Metakaolinite was also prepared from KGa-1 by thermal activation at 600 °C. The hydrothermal syntheses were accomplished by heating the samples in NaOH solutions at temperatures between 70 and 110 °C. The kinetic experiments were performed by time-resolved synchrotron powder diffraction in isothermal mode using a transmission geometry and an Image Plate detector. The results of the kinetic analysis are interpreted in the light of the structural state of the starting kaolinite, and of the temperature of activation of the precursor material. For kaolinite activated at high temperature the nucleation and crystallization of zeolite A is essentially independent of the defect density of the original kaolinite, and the thermal history of the precursor seems to be the main controlling parameter. The formation process of zeolite A from metakaolinite materials obtained at lower activation temperatures shows significantly faster reaction rates and lower apparent activation energies. This is again interpreted in the light of the short range inhomogeneities present in metakaolinite. As the reaction proceeds metastable zeolite A transforms into hydroxy-sodalite.

The nature and geodynamic setting of Inner Makran ophiolites (SE Iran) are controversial and are the focus of a growing debate. The Fannuj-Maskutan ophiolite complex (central Inner Makran) is made up of lherzolites, harzburgites, layered and isotropic gabbros and diabase dikes and basaltic lavas. Here we present new textural description, mineral and whole-rock chemistry of peridotites together with bulk geochemistry of magmatic mafic rocks and U-Pb geochronology and Lu-Hf isotopes of inherited zircons in gabbros, with the aim to reconstruct the petrogenesis of the Fannuj-Maskutan ophiolite. The results indicate to a subduction-metasomatized depleted mantle source experienced 10-20% of partial melting. A transition from IAT-gabbros to E-MORB-basalts is also outlined. We interpret the obtained results as evidence for the Fannuj-Maskutan genesis in a supra-subduction zone (SSZ) basin developed in the Iranian cadomian crust as indicated by the presence of inherited Cadomian zircons (ca. 515 Ma, εHf (t) : −13.6-+11.2). Comparing the Fannuj-Maskutan ophiolites to well-known SSZ-systems such as the South Sandwich SSZ, and integrating with the existing literature on Inner Makran ophiolite belt we interpret the Fannuj-Maskutan ophiolite as a part of a major SSZ-basin opened in the Iranian cadomian crust and evolved during the Neotethys subduction under Central Iran.

Vymazalováite, Pd3Bi2S2 is a new platinum-group mineral discovered in the Komsomolsky mine of the Talnakh deposit, Noril’sk district, Russia. It forms small (from a few μm to 20–35 µm) inclusions or euhedral grains in intergrowths of polarite, sobolevskite, acanthite and unnamed (Pd,Ag)5BiS2 in aggregates (up to ~200 µm) in galena and rarely in chalcopyrite. It occurs with telargpalite, cooperite, braggite, vysotskite, sopcheite, stibiopalladinite, sobolevskite, moncheite, kotulskite, malyshevite, insizwaite, Au-bearing silver and the newly described mineral kravtsovite (PdAg2S) in association with pyrite, chalcopyrite and galena in vein-disseminated mineralization in skarn rocks. Synthetic vymazalováite is brittle; it has a metallic lustre and a grey streak. In plane-polarized reflected light, vymazalováite is creamy grey and appears slightly brownish against galena in the assemblage with chalcopyrite. It exhibits no internal reflections. Average reflectance values in air for natural and synthetic vymazalováite are (R natural, R synthetic in %) are: 46.35, 45.7 at 470 nm, 47.65, 47.45 at 546 nm, 48.5, 48.2 at 589 nm and 49.5, 49.0 at 650 nm. Seven electron probe micro-analyses of vymazalováite give an average composition: Pd 40.42, Bi 49.15, Ag 0.55, Pb 1.02, S 7.77 and Se 0.26, total 99.17 wt.%, corresponding to the empirical formula Pd3.05(Bi1.89Ag0.04Pb0.04)Σ1.97(S1.95Se0.03)Σ1.98 based on a total of 7 atoms per formula unit. The simplified formula is Pd3Bi2S2. The mineral is cubic, space group I213, with a = 8.3097(9) Å, V = 573.79(1) Å3 and Z = 4. The density calculated on the basis of the empirical formula and cell dimensions of synthetic vymazalováite is 9.25 g/cm3. The strongest lines in the powder X-ray diffraction pattern of synthetic vymazalováite [d in Å (I) (hkl)] are: 4.15(32)(200), 2.93(78)(220), 2.40(100)(220), 2.08(53)(400), 1.695(34)(422), 1.468(35)(440) and 1.252(31)(622). The structural identity of natural vymazalováite with synthetic Pd3Bi2S2 was confirmed by electron back-scatter diffraction measurements on the natural sample. This new mineral honours Dr Anna Vymazalová of the Czech Geological Survey, Prague.

 The kinetics of the dehydroxylation of chrysotile was followed in situ at high temperature using real-time conventional and synchrotron powder diffraction (XRPD). This is the first time kinetics parameters have been calculated for the dehydroxylation of chrysotile. The value of the order of the reaction mechanism calculated using the Avrami model indicates that the rate-limiting step of the reaction is a one-dimensional diffusion with an instantaneous nucleation or a deceleratory rate of nucleation of the reaction product. Hence, the rate-limiting step is the one-dimensional diffusion of the water molecules formed in the interlayer region by direct condensation of two hydrogen atoms and an oxygen atom. The calculated apparent activation energy of the reaction in the temperature range 620–750 °C is 184 kJ mol−1. The diffusion path is along the axis of the fibrils forming the fibers. The amorphous or short-range ordered dehydroxylate of chrysotile is extremely unstable because forsterite readily nucleates in the Mg-rich regions. Moreover, it is less stable than the dehydroxylate of kaolinite, the so-called metakaolinite, which forms mullite at about 950 °C. This difference is interpreted in terms of the different nature of the two ions Mg2+ and Al3+ and their function as glass modifier and glass-forming ion, respectively.

Crystal morphology and chemical compositions of arsenopyrite and pyrite at the Nam Quang and Bo Va deposits in the Song
Hien basin (Northeast Vietnam) are studied in detail. Arsenopyrite often forms elongated crystals. Their chemical compositions are
relatively poor in As, but rich in S with S/As ratios often >1.1, impurity elements such as Ni, Co, Sb, and sometimes Au (up to 0.02
wt.%). Composition of the pyrite is stoichiometric, but with relatively high arsenic and (sometimes) gold. The correlation between
As and Au concentration in pyrite has been recorded. The morphology and chemical composition of arsenopyrite and pyrite of
Bo Va and Nam Quang deposits can be comparable to those in the Au-sulfide deposits in black shale in Kazakhstan and
Southeastern China.

This paper presents the preliminary findings of on going study intended to develop a cool house by introducing roofing materials with higher Solar Reflectance Index (SRI). SRI is a composed measure that accounts for surface&#x27;s solar reflectance and emittance. It is ...

Thick ferromanganese (Fe-Mn) crusts from four Cretaceous seamounts (The Paps, Tropic, Echo and Drago) at the southern Canary Island Seamount Province (CISP) in the northeastern tropical Atlantic were recovered along the flanks and summits from 1700 to 3000 m water depths. CISP is composed of N 100 seamounts and submarine hills, is likely the oldest hotspot track in the Atlantic Ocean, and is the most long-lived of known hotspots globally. The Fe-Mn crusts grow on basalt-sedimentary rock substrates below the northeastern tropical Atlantic core of the oxygen minimum zone (OMZ) with a maximum thickness of 250 mm at a water depth of 2400 m. The mineral-ogical and chemical composition of these Fe-Mn crusts indicate a hydrogenetic origin. The main Mn minerals are vernadite with minor interlayered todorokite and asbolane-buserite. Fe oxides are essentially ferroxyhyte and goethite. The Fe-Mn crusts show high average contents in Fe (23.5 wt%), Mn (16.1 wt%), and trace elements like Co (4700 μg/g), Ni (2800 μg/g), V (2400 μg/g) and Pb (1600 μg/g). Rare earth elements plus yttrium (REY) averages 2800 μg/g with high proportions of Ce (1600 μg/g). Total platinum group elements (PGEs) average 230 ng/g, with average Pt of 182 ng/g. Two main types of growth layers form the crusts: 1) a dense laminae of oxides with high contents in Mn, Co and Ni associated with vernadite and Cu, Ni, and Zn associated with todorokite; 2) botryoidal layers with high contents in Fe, Ti, V and REY associated with goethite. The Fe-Mn crusts from the CISP region show higher contents in Fe, V, Pb and REY but lower Mn, Co, Ni and PGEs contents than Pacific or Indian ocean seamount crusts. The oldest maximum age of initiation of crust growth was at 76 Ma (Cam-panian, Late Cretaceous). Using a combination of high resolution Co-chronometer and geochemical data along an Electron Probe Micro Analysis (EPMA) transect, four stages in morphology, chemical contents and growth rates can be differentiated in the the Cenozoic crusts since 28 Ma, which we interpret as due to changes in the ventilation of the North Atlantic OMZ and to the increase of Saharian dust inputs. An earliest growth period, characterized by similar contents of Fe and Mn in the interval 27.8–24.45 Ma (late Oligocene-early Miocene) reflects slow precipitation related to a thick OMZ. An intermediate laminated zone with higher contents of Fe, Si and P, high growth rates reaching 4.5 mm/Ma, and precipitation of Fe-Mn oxides during the interval 24.5–16 Ma is related to periods of ventilation of the OMZ by intrusion of deep upwelling currents. Significant increase in Fe contents at ca. 16 Ma correlates with the onset of incursions of Northern Component Waters into the North Atlantic. Finally, since 12 Ma, the very low growth rates (b0.5 mm/Ma) of the crust are related to a thick North Atlantic OMZ, an increase in Sahara dust input and a stable thermohaline circulation.

El presente trabajo tiene como objetivo caracterizar los minerales metálicos presentes en las condritas ordinarias relacionados con el resto de componentes minerales, y evaluar el uso de la microtomografía de rayos X como una herramienta para realizar estudios de distribución tridimensional, necesariamente integrada con una caracterización convencional mediante otras técnicas analíticas básicas. Para ello, se lleva a cabo una completa caracterización petrográfica de la condrita ordinaria KG007 (tipo H6), encontrada en el desierto del Sáhara. Dicha caracterización ha sido realizada a través de análisis petrográficos a diferentes escalas, utilizando las siguientes técnicas: 1) microscopía óptica polarizada de luz trasmitida y reflejada, 2) SEM-EDS, y 3) microtomografía de rayos X.

Los meteoritos son fragmentos rocosos extraterrestres que contienen en su interior un registro exclusivo de la historia del Universo. Dada su procedencia, la disponibilidad de ejemplares de estos materiales, es escasa. Es por ello que, resulta importante abordar sus estudios bajo la premisa de una máxima conservación posible. En este trabajo se exponen algunas ideas sobre las metodologías de análisis mineral aplicadas al estudio de meteoritos y se hace especial énfasis en la técnica de microtomografía de rayos X, ya que representa la base de una nueva generación de equipos que permitirán el estudio cualitativo y cuantitativo de los meteoritos desde un marco tridimensional, sin que ello implique una destrucción total de la muestra.

De los resultados obtenidos en este estudio, se infiere que la microtomografía de rayos X es una técnica idónea para la visualización tridimensional de los componentes minerales de los meteoritos y en especial, de la fase metálica, puesto que permite distinguir y determinar morfologías, distribución, abundancia modal y texturas, en contraste con las otras técnicas que sólo aportan información bidimensional. La información obtenida sobre estos minerales metálicos puede resultar valiosa sobre un amplio abanico de investigaciones enfocado a la reconstrucción de los cuerpos menores del espacio, como los asteroides, así como aspectos de las condiciones de formación del Sistema Solar.