Sumario
 Título / Autor(es)Página(s)
[R]Caracterización de sepiolita sometida a activación ácida / Vicente Rodríguez, M.A. / López González, J / Bañares Muñoz, M.A.
A systematic study of acid treatment influence on sepiolite properties has been started. So that, sepiolite was treated with HCL, at 25ºC, modifyning acid concentration and time of treatment. Afterwards, free silica was removed and measued. Solids obtained after both acid treatment and after free silica removal were systematically characterized by X-ray difraction and thermal analysis, studying the changes observed in their behaviour.
1-5
[R]Estudio del tratamiento ácido de palygorskita / Suárez, M. / Flores, L.V. / Navarrete, J. / Murciego, A. / Marin Pozas, J.M.
The palygorskite of Bercimuel is treated with HCL in growing concentrations (1N, 3N, 5N, 7N). Two samples are treated: the natural palygorskite (With quartz and illite impurities basically) and the minor fraction of two microns. It is studied through XR difraction and chemical analysis, observing how gettin finally the destruction of the structure. The silica that formed the tetrahedral sheet wil remain tied up to the sample for not being soluble in these acid concentrations.
6-10
[R]Precipitación de cristales de fosgenita y cerusita. Historia del crecimiento / Pina, C.M. / Prieto, M. / Fernández-Díaz, L.
Phosgenite (Pb2Cl2Co3) and cerussite (PbCo3) are common products of the weathering of galene deposits. Both pahses crystallization in a diffusing-reacting system has been studied. This sortt of systems shows a continuous changes in its physicochemical conditions. The experimental testing of both mass-transfer and pH allows to understand the crystallization sequence and stablish the relationship between the morphological evolution of the crystals and the system conditions changes.
11-15
[R]Fenómenos de alteración y transformación fosgenita-cerusita / Pina, C.M. / López-Andrés, S. / Rull, F. / Prieto, C. / Fernández-Díaz, M. Prieto, M.
The transformation of phosgenite into cerussite in a diffusing-reacting system has been studied. This transformation occurs in a narrow pH range. Mass-transfer and pH evolution in the system during the process was testified. The transformation development was monitored by Raman spectroscopy.
16-20
[R]Primera aparición en España de cronstedtita. Caracterización estructural / López García, J.A. / Manteca, J.I. / Prieto, A.C. / Calvo, B.
Cronstedtite has been identified in the Fe-Pb-Zn ore of Sierra de Cartagena (S. E. Spain). This mineral has been studied by scanning electron microscopy (SEM), X-ray diffraction and IR spectroscopy. The results confirm the sample as a IT politype of Cronstedtite, trioctraedral 1: 1 layer silicate.
21-25
[R]Análisis térmico y caracterización espectroscópica de Cronstedtita de Sierra de Cartagena / Prieto, A.C. / Rull, F. / Medina, J. / Martín, F. / Manteca, J.I. / López, J.A.
A mineral of Cronstedtite has been identified, by the first time in Spain, in the Fe-Pb-Zn ore deposits of Sierra de Cartagena (Spain). Cationic composition was determined by Electron Microprobe analysis. Thermogravimetric, X Ray Diffraction and Infrared Spectroscopy were used to determine its thermal dexydroxilation process. A kinetic study of this process was also undertaken.
26-27
[R]Estudio y caracterización de la clorita procedente de Hiendelaencina (Guadalajara) / Valle, A. Del / Prieto, C. / González, V. / Medina, J.L. / Álvarez, J.L. / Rull, F.
We have studied a trioctahedric ferro-magnesian chlorite from Hiendelaencina (Guadalajara), Spain. The crystallochemical parameters d001, d0 and polytype were measured from the XRD analysis of the polycrystalline power. Tha chemical composition was obtained by electron microprobe analysis (EMPA). The sample were studied by micro-Raman and IR spectroscopy. Thermogravimetric techniques and XRD and IR spectroscopy were used to determine the thermal dehydroxylation of this sample.
28-29
[R]Estudio mineralógico y cristaloquímico de la casiterita del yacimiento de Lumbrales (Salamanca, España) / Murciego, A. / Martín Pozas, J.M. / García Sánchez, A. / Gonzalo Corral, J.F.
Cassiterite from the Lumbreras deposit (Salamanca, Spain) is inhomogeneous there are light-colored zones, relatively, pure and dark zones, enriched in Ti, Fe, Nb and Ta (the upper concentrations are 3, 22%, 1, 7%, 2, 4% and 1, 4% respectively). Columbite-Tantalite and Ilmenorutile-Struverite microinclusions are located in the light-colored parts. The interpretation of the Fe+Mn/Nb+Ta interelement relationships and the EPR aspectrometric results reveal that coupled substitutions of the type: 1)2Sn4+--F3++(Nb, Ta)5+, 2) Sn4++o2--F3++oH- and 3) 3Sn4+--Fe2++(Nb, Ta) 5+are dominant in this cassiterite.
30-34
[R]Estudio mediante espectrometría infrarroja de la casiterita de yacimientos de Centro-Oeste de España / Murciego, A. / Martín Pozas, J.M. / García Sánchez, A. / Dusausoy, Y. / Suárez Barrios, M.
The study by FTIR of cassiterites samples, of twelve hydrothermal and pegmatitic spanish deposit shows, on the one hand, that besides the four models of normal vibrations still known this mineral, there hare another two new infrared active vibrations, V5= 700-705 y V6=430-440 cm-1 and on the other hand, that the FTIR spectra of cassiterite vary in form and intensity, but not at the positions of absorption peaks, in function of quantity of impurities, in relation to, at time, with ith its genesis.
35-39
 Variaciones en la composición química de allanitas asociadas a rocas metasomáticas / Álvarez, M.A. / Feliu, M.J. / Dominguez Bella, S.40
[R]Secuencias de cristalización de sulfatos de Fe(III), Zn y Mg / Pérez Sirvent, C. / Garrido Medina, M. / Arana, R.
In this paper, the behaviour of concentrated solutions of trivalent and devalent sulphates in a closed system is studied. The experimental conditions are chosen in such manner that they resemble those found in the acidic waters resulting from lixiviation processes in the Mazarrón (Murcia) district area. As this is a sulphide-rich zone submitted to extensive supergenic alteration, the in vitro experiments here reported provide interesting information on the mechanism and final products of such alteration processes.
41-43
[R]Caracterización de alunita asociada a la alteración de pizarras paleozoicas. Almuradiel (Ciudad Real) / Parras, J. / Sánchez Jiménez, C. / Acosta, A.
This paper shows a characterization of alunite associated with alteration products of paleozoic shales in Almuradiel (Ciudad Real, Spain). Alunite is characterized by X-Ray difraction, infrarred spectroscopy and chemical analysis. The possible origin of the alunite is associated with acid solutions circulation produced by oxidation of sulphide contained in shales.
44-48
[R]Caracterización de la arenisca de la Iglesia de San Esteban de Ábalos (La Rioja) por catodoluminiscencia / Pavia, S. / Caro, S. / Valero, B. / Pérez-Lorente, F. / López Aguayo
Cathodoluminescence is an interesting technology in carbonate study. In this paper, the technology is applied to the carbonatic sandstones from the Continental Tertiary of the "Formación Haro". Carbonate is their main component and it appears in different shapes and compositions. The luminiscence of the minerals in these sandstones ha been described. Little introduction about methodology and material is included too.
49-53
[R]Catodoluminiscencia de la arenisca roja utilizada en la construcción de la "Catedral de Santa María" de Calahorra (La Rioja Baja) / Caro, S. / Pavia, S. / Valero, B. / Pérez Llorente, F. / López Aguayo, F.
In the construction of the Calahorra Cathedral, several kinds of sandstone were used, all of them are included in "Formación Alfaro". In this work, cathodoluminescence has been applied to the reed sandstone. Methodology, characteristics of the material and cathodoluminescence of the minerals have been described.
54-58
[R]Microestructura de la arenisca de las Catedrales de Salamanca. Alteración diferenciada / Martín Patino, M.T. / Madruga, F. / Saavedra, J.
The Villamayor sandstone, used as a building material for the cathedrals of Salamanca, presents different degrees of deterioration in areas where the conditions of location and environment are identical. There are no appreciable differences respect to mineral, chemical and physical-mechanical characteristics which justify this fact. The textural anisotropy and the internal microstructure of these stones give the answer to this question.
59-60
[R]Indicadores visuales o formas macroscópicas de alteración de la piedra monumental de la ciudad de Zamora / Añorbe, M. / Sáinz de Cueto, F.J. / Martín Pozas, J.M.
The ornamental stone common in monumental constructions in the city Zamora (Spain) is made up of Paleogene silicified sandstone and conglomerate from the west edge of the Duero basin. This paper describes the macroscopic alterations forms that the stone developes under agents and external agressive factors.
61-65
[R]Estudio de alteración en Travertinos (Iglesia del Salvador, Granada). Propuesta restauradora / Duran, J.A. / García-Casco, A. / Sánchez-Navas, A. / Rodríguez-Gordillo, J.F.
Travertine pillars in the court of the colegiata del Salvador (s. XVI) bear damaged surfaces that were recovered with concrete mortars. This material induced further mechanical and chemical damage in the travertine due to the enhanced capillarity rise resulting from the contrasting thermal behaviour and porosity. Sinthetic mortars (epoxi and PMMA) yielded very low total porosity (2-5%). Thus, in addition to removing the concrete mortars and salts, cleaning, and consolidation (acrylic resins and alchil-aril-polisiloxanes), we propose recovering the eroded surfaces with mixed mortars with the appropiate porosity.
66-70
[R]Formación de sales en materiales pétreos (Monasterio de San Jerónimo, Granada. Origen y procesos de deterioro asociados / Cardell, C. / Rodríguez Gordillo, F.J.
The chemical composition and morphology of salts present in the San Jerónimo Monastery, lead us to establish two different associations and formation processes: a) massive and pulverulent subefflorescence made up of Mg, Na and K sulphates and also by Na carbonate, produced by percolating water through decayed ashlar; b) crystalline subefflorescences of NaCl originated by capillary rise of ground moisture,. Subefflorescences promote pression under wall painting and other decoratives constituents adjoined to the wall leading to their detachement, in some cases irreversible.
71-73
[R]Estudio preliminar de ladrillería en la Alhambra de (Granada). Mineralogía, análisis textural y tecnología de fabricación / Torre, M. De la / Rodríguez Gordillo, J. / Sebastián, E.
In this paper brick samples of different areas of Alhambra are studied. In spite of belonging to different times and constructions, data got to now are fairly homogeneous as to point out that the raw material and manufacture should be very similar. The optical microscopy reveals a very rich matrix in illite, where we can see the begining of formation of high temperature phases. Most of the temper is natural, however there is an addition of "chamotte" and limestone. The mineralogy obtained by XRD show that the bricks were cooked at a temperature between 800 and 850º C.
74-77
[R]Nuevo método para la determinación de los productos de la reacción Alcali-Sílice en hormigones / Fontao, I. / Prendes, N. / Leiro, Angel / Mateo, B.
This technique to identify Alcali-Silica Reaction (ASR) products in concrete is based on the identification od ASR product by staining them with uranyl ions, wich have a characteristic fluorescence under short-wave ultraviolet light. The AAR products are presents as silica gel with adsorted sodium ions. The uranyl ions can replace, by ionic exchange, the sodium ions on silica gel, and under-ultraviolet light by fluorescence of uranyl ions identify the aeras where silica gel is present.
78-82
[R]Potasio asimilable y mineralogía de arcillas en fluvisoles calcáricos del Sector Meridional de la Vega Alta del Segura (Murcia) / Linares, P. / Marin Sanleandro, P. / Alia, L.J.
Available potassium content and clay mineralogical composition of calcaric fluvisols from a part of the Segura flooding plain (SE. Spain) are studied. Soils are low in available potassium and illite is their main clay component. There is a good correlation (p < 0.001) available potassium-illite content for the C horizons, while the long-continued anthropic practices seem to affect seriously soil potassium dynamics, in the Ap horizons.
83-87
[R]Anomalías geoquímicas y efectos textosedimentarios asociados al accidente de Negratin (Depresión de Guadix), Granada / García Aguilar, J.M.
The Guadix bassin (Southern of Spain), shows the activity of an important fault-band of regional scale in Miocene-Pliocene lacustrine sediments. Most important effects of this activity are the appearing of Sr++ and F- geochemistry anomalies, dettached like a Celestine-Fluorine mineraloy association.
88-91
[R]Modificaciones producidas en el sistema poroso de una calcarenita por alteración y tratamiento de conservación / Galan, E. / Fitznr, B. / Carretero, M.I. / Mayoral, E.
Calcarenite from Puerto de Santa María, a stone widely used in historic monuments of Western Andalucía, does not show important porosity variations after five hundred years of weathering in the Cartuja of Seville. However, its macroporosity (ø 10-300µ) falls from 14% to 10% after a treatment with Tegovakon, an ethyl silicate harder, because of amorphus silica is deposited into the big pores, and also to surface area of micropores encreases due to the silica gel presence, but the porosity of the stone treatted with Tegosivin, a water repellent, does not vary. Nevertheless, both treatments lead to an abruptly decreasing of water absorption. In order to improve the technical characteristics of the Puerto stone as building material, a previous protection treatment with a harder followed of a water repellent is suggested.
92-94
[R]Modificaçoes das propiedades físicas y estructurais de caolinetes submetitas a tratamentos com ultrassons / Velho, J.L. / Gomes, C.
In the preparation of kaolin-water suspensions, the use of mechanical treatments is widespread. The action of ultrasounds of variable intensity in association or not to the effect of an intercalation agent is evaluated in kaolin suspensions with different solids concentration through the modification of kaolinite structure a well as of several physical properties of technological interest.
95-98
[R]El proceso de alteración ácida en modelos experimentales de argilización avanzada / Queralt, I. / Plana, F. / Kanazirski, M.
Rock alteration with alunite and pyrophyllite formation have been described in natural systems in epithermal ore deposits where acid solutions are affecting the rocks. This has induced us to carry out experiments in order to establish the effect of reacting agents and the temperature on intermediate rocks alteration. Natural alunite and pyrophyllite formation in advanced argillic alteration, wich commonly takes place by reaction of a solution with a source rock, was simulated in experiments using propilitized granodiorite rocks from Assarel ore deposits (Bulgaria) using hydrochloric and sulfuric acids as reacting solutions. Experiments were performed at two temperatures (250ºC, 350ºC) in autoclave vessels. Reaction products were identified by x-ray diffraction (XRD) procedures using powder to identify the minerals int he whole rock and oriented aggregates to characterize the clay fraction. Alunite appears in the sulfuric acid reaction at both temperatures whilst pyrophyllite only appears at high temperature associated with mixed-layer I/SM clays.
99-103
[R]Los minerales de la arcilla en los ambientes deposicionales de la Fm/ Escucha (Albiense Medio, Sistema Ibérico). / Plana, F. / Queralt, I. / Fernández Turiel, J.L. / Sanfeliu, T.
The Escucha Fm. (middle Albian, Iberian Range, NE Spain) consists of alternating coal bering ans fine siliciclastic depisots up to 550 m thick. Durnig Albian times fluvio-deltaic, swamp and marine environments prevailed in this area. Paleoenvironmental modelization were realized from sedimentology data in an earlier study (Querol, 1990) and allow us to distinguish five depositional zones (a/fluvio-deltaic plain, b/ peat bog flat, c/ brackish water swamp belt, d/ delta front, e/ prodelta) in order to recognize different mineral assemblages. Mineralogical analysis in the whole rock and the clay fraction from 49 sample of sediments interbedded in coal sequences were performed by X-Ray diffraction means. A semiquantitativew estimation of mineral contents in the whole rock and of the clay mineral in fine fraction was obtained follwing the criterion of Chung (1974) and Inglés & Anadón (1991). The mineral assamblages in the rocks studied are formed mainly by quartz and kaolinite. Substantial amounts of illite and mixed layer illete/smectite are present, and it is also possible occasionally to identity feldespars, calcite, gypsum, jarosite, hematite and pyrite. There is no correlation betwenn the mineral features od assembalges and the location of the samples in the vertical profiles. The obtained results show a relationship between mineral distribution and the different depositional zones. In this sense, it can be regarded that the amount of the mixed layer illite/smectite- increases to the prodelta sediments-, the ranges of quartz distribution illite crystallinity spreading to the fluvio-deltaic deposits and the kaolinite/illite ratio lower in prodeltaic environment are reflecting the changes in the physico-chemical conditions of deposition.
104-107
[R]Mineralogía y génesis de los tramos arcillosos en la cuenca de Carrión de Calatrava (Ciudad Real) / Sánchez Jiménez, C. / Parras, J. / Acosta, A.
The palygorskite enriched levels of Carrion Basin (Ciudad Real, Spain) are located in the neighbourhoud of the town of the same name, enclaved in the so called Calatrava Zone. This Palygorskite is associated with neogene sequence. That are the refill of the isolated lacustrine basins. This paper deals with the mineralogical study of this sequences. It proposes that palygorskitic clays are formed by transformation mechanisms from others inherited filosilicates (illite-smectite), in a process of early diagenesis (Suárez et al, 1989).
108-111
[R]Mineralogía y génesis de los filosilicatos del "Trias manchego" bajo la corteza neógena / Córdoba, A. / Acosta, A.
In this paper a mineralogical and genetic study of clay minerals of Triassic sediments covered by Neogen rock at La Mancha (Ciudad Real) is being carried out. Most minerals (illite, kaolinite, smectite and interestratifield are part of the sediment as detritic products, another one mineral (paligorskite) is neoformed, and the rest, of them (interstratifield and clorite are origined by transformation.
112-116
[R]Caracterización de los materiales fibrosos asociados a las pizarras silúricas del sinclinal de Serracín y estudio de su mecanismo de formación / Barrenechea, J.F. / Dominguez, I. / Alonso, J. / Rodas, M.
In the Early Silurian carbonaceous slates of the Serracin sycline there is a series of veins filled by strained fibrous quartz and low-K muscovite. Two types of veins have been distinguished: 1. -veins with antitaxial growth fibers and 2. - veins with sintaxial growth fibers. Fibers in these veins were formed by a "crack-seal" mechanism, produced by sucessive development of microfissures followed by periods of cementation.
117-121
[R]Contribución al estudio mineralógico de la Depresión de Campo Arañuelo (Cáceres-Toledo) / Muñóz, I. / Andrés, A. / Vicente, R.
We can deduce from the spatial distribution of the global mineralogy and the clay mineralogy, that the basin seems to be an homogeneous and uniform one; with a general predominance of quartz feldspars and clays, and a high quantity of carbonate in the southward areas of the basin. The clay fraction is represented by caolinite, illite and smectite. This mineralogical association corresponds with the proximal facies of continental basin.
122-127
[R]Análisis Mineralógico del Permotrías del Complejo Maláguide en los alrededores de Málaga / Ruiz, M. / Puga, E.
The mineralogy of a Permotriassic series from the Maláguide Cover has been studied by optical microscopy X-ray diffraction and electron microscopy. According to petrological and mineralogical data, two spans have been distinguished and detritic members: a) In lower span, lithic wackes dominate, with a scarce content in feldspar and carbonate. Dickite and quartz are the most abundant cements, developed under aicidic pH and high pressure conditions. B) In upper span, feldespathic arenites are dominant, with a variable content in calcareous cement, Illite is the main clay mineral present. Diagenesis is dominated by the development of Fe-dolomite, K-feldspar and Fe-illite. Developed under alkaline pH.
128-133
[R]Mineralogía de las Arcillas de Jimena. Unidades del Campo de Gibraltar, Sur de España / Rodríguez Jiménez, P.
In this paper the mineralgy of four sequences of the Arcillas de Jimena Formation. The mineralogical composition of the fine fraction is characterized by the association: Kaolinite-illite- smectite-palygorskite-chlorite. The smectites predominate in this formation and in the richest levels there is a growth of authigenic Mg-smectite and fibrous palygorskite, while the detritic minerals (kaolinite, illite) decrease or disappear. The chlorite is concentrated in the carbonate levels and it is a authigenic mineral.
134-138
[R]Occurrence of ferriferous in the gabro quarry from Ribamar (Ericeira Portugal) / Gomes, C.S.F.
La sepiolita ferrífera gha sido identificada como el componente principal superficial que aparece rellenando algunas fracturas del gabro, de la cantera de Ribamar (Ericeira-Portugal). La caracterización mineralógica y morfológica se ha llevado a cabo por difracción y fluorescencia de Rayos X y microscopía electrónica de transmisión. Se propone un mecanismo para la génesis de la sepiolita, que consiste en procesos de disolución precipitaicón. El grabo presenta alguna alteración caracterizada por esmectita, illita trioctaédrica y calcita, derivada de la labradorita y pigeonita.
139-142
[R]Estudio de inclusiones fluidas en la mineralización de Bario y Cobre del Alt. Bergueda (Barcelona) / Llorente Casa, J.A.
The mineralitation consists of the filling of metric cavities with karst morphology in Devonian dolomite. The mineralization is situated closely under an erosive surface covered by a sequence of Buntsandstein. Most of the filling in the cavities was precipitated from high brine solutions at low temperature.
143-146
[R]Inclusiones fluidas y distribución de elementos de las Tierras Raras en las Fluoritas del yacimiento de Parzan (Bielsa, Huesca) / Fanlo, I. / Subías, I. / Fernández- Nieto, C.
It can be deduced from fluid inclusion data that the ore forming fluid is polysaline with homogeneization temperatures between 111 and 156ºC and 16.3 %wt eq NaCl average salinity. On the other hand, REE distribution patterns are very similar suggesting the same source as well as fluorite deposition in an open environment. Preferential concentration of LREE implies a primary REE normalization patterns.
147-151
[R]Piemontitas de las litologías ricas en Mn del macizo de Aracena (Macizo Ibérico Meridional, SW de España) / Jiménez Millán, J. / Velilla, N.
Piemontites from the Aracena belt (Iberian Massif, SW Spain) appear in silicate rocks (RS) and carbonate rocks (RC) There are chemical differences among piemontites from, these lithologies, Fe/Ca ratio is ordered as follows: RS3+ content varies in the opposite sense. These differences are due to the effect of fo2, Xco2, bulk composition, fluids composition and mineral assemblage. Temperature conditions has been estimated at 400-485 ºC. Fe3+ content in piemontite composition indicates higher Fo2 in RS than in RC.
152-156
[R]Geoquímica de las mineralizaciones de Baritina de la Unidad de Herrera (Cordillera Ibérica Oriental) / Osacar Soriano, M.C. / Besteiro, J. / González Martínez, J.
Trace elements of barite veins of the hercynian basement of the Unidad de Herrera (Eastern Iberian Chain) have been analysed. The results show the influence of the basement materials on the mineralizing fluids. The barite Sr-content shows the deposit evolution. Barite Sr87/Sr86 ratio ranges from 0.713 to 0.717, far from the seawater or evaporite values; this points to a crustal sources for the barite veins Sr, more likely from sedimentary rocks of the hercynian basement.
157-160
[R]Composición isotópica de polimorfos de sílice hidrotermal en la región volcánica de Cabo de Gata (Almería) / Delgado, A. / Nuñez, R. / Reyes, E.
Oxigen isotope ratios were measured for hydrothermal silica from Cabo de Gata region. The d18O values of the ten analyzed silica (quartz, tridimite-cistobalite) range from 21, 04 to 29, 77 %. Processes caused by low-temperature fluids of meteoric origin could account for the stable isotopic contents. The diferences in d18O values are attributed to variation in hydrothermal temperature, but some variability in oxygen isotopic composition of the water is possible.
161-165
[R]Distribución geoquímica y mineralógica del U en el grantio peralumínico de Alburquerque, Cáceres (España) / Reguillón, R.M. / Arribas, A. / Martín Izard, A.
A study has been carried out on the content and geochemical distrubibution of U in the alkaline and peraluminous granite of Alburquerque. Cáceres, (Spain) and of the primary minerals rich in this element. Of the there petrographic facies distinghed in the study, facies I and facies II are seen to contain the highest mean amounts of uranium. Regarding the mineral phases, uranium is found in uranitita and monacita and also in the intergranular spaces, as demostred by autoradiographic studies.
166-170
[R]Caracterización geoquímica y mineralógica del Tránsito Cretácico-Terciario en la Cuenca Vasco-Cantábrica y en las Cordilleras Béticas / Palomo, I. / Martínez Ruiz, F.
The K/T boundary has for some years been one of the most discussed subjects in the field of Earth Sciences. We have detected in the sediments of this age, an enrichment in the Platinum Group Elements (PGE), as well as in Fe, V, Ni, Cr, Co, Zn or As. Althoug an extraterrestrial event could have happened, several phenomena may have interacted to bring about all the anomalies. Diagenetic processes and microbial activity could have also played an important role in the concentration of these elements.
171-175
[R]Alteración de materiales volcánicos Paleozoicos del Sinclinal de Almadén / Higueras, P. / Acosta, A.
The volcanic rocks of the Almadén synclyne are affected by alteration processes, with carbonate (arkerite, chlorite and cripocrystaline, silica as main paragenetic minerals. In this paper, a study of the mineralogy and the geochemistry of the process is made, concluing that it is of the autometasomathic type, related with a high CO2 and H22O content of the magma.
176-180
[R]Características mineralógicas y geoquímicas de las Metavulcanitas Silúricas de Figueruela-Riomanzanas en el Sinforme de Alcañices (Zamora) / Montero, J.M. / Cembranos, M.L. / Fernández Fernández, A. / Gil Agero, M. / Moro, M.C.
The geological, minetalogical and geochemical characteristics of the Figueruela-Riomanzanas area metavolcanites have been studied. These rocks are of uper Wenlock (Silurian) age. The emplacement conditions of de metavolcanites are analized, and the geotectonic, the relationships between metavolcanites and nearby sulphide mineralizations are described.
181-185
[R]Características mineralógicas y geoquímicas de los basaltos de Latedo (Zamora) / Fernández Fernández, A. / Cembranos, M.L. / Montero, J.M. / Moro, M.C.
A mineralogical and geochemical study of the basalt found in the Southern limb of the Alcañices Symforms (Zamora province) has been done for this work. There basalts outcrop in the Latedo area, associated a the Middle Member of the Lower Ordovivian "Cabeza de las Viñas Formation". The geotectonic stting in which athe basalts formed is discussed.
186-190
[R]Relaciones genéticas entre las turmalinitas estratiformes y los basaltos toleíticos Ordovícicos de Latedo (Zamora) / Fernández Fernández, A.
The spatial and genetic relationships between stratiforms tourmalinites and tholeiitic basalts, found interstrafied in the Middle Member of the Lower Ordovician "Cabeza de las Viñas Formation" are described in the study. The genesis of the stratiform tourmalintes is modelized based in those relationships. It is suggested that in the Alcañices Symform as well as elsewhere in the world, the association of there two rock types can be used as a prospecting guide to located massive sulphide deposits.
191-195
[R]Evidencias texturales de inmiscibilidad entre líquidos magmáticos sulfurados y arseniurados (Amasined, Beni Bousera, Marruecos) / Gervilla, F. / Fenoll Hach-Ali, P. / Leblanc, M. / Torres-Ruiz, J.
The lowermost part of the Amasined sulfide occurrence in the Beni Bousera ultramafic massif consist of clusters of subidiomorphic or corroded chromite crystals and radial fractured, rounded aggregates of nickel arsenides included in a Fe-Ni-Cu sulfide groundmass. This textures is interpreted in terms of gravitational differentiation of an immiscible Ni-As-based magmatic melt in a chromite-bearing sulfide melt.
196-198
[R]Procesos de alteración de las paragénesis primarias de las mineralizaciones de Cr-Ni del macizo ultramáfico de Beni Bousera, Marruecos). / Gervilla, F. / Fenoll Hach-Alí, P / Leblanc, M. / Sánchez-Navas, A. / Torres Ruiz, J.
The chromite-Ni arsenide mineralizations from the Beni Bousea ultramafic massif show secondary arsenide (maucherite, orcelite) and silicate (phlogopite, chlorite, vermiculite, garnierite) associations originates by a progressive hydrothermal alteration of the primary paragenesses. According to field and textural relationshisps this hydrothermal alteration should take place coeval with late brittle fracturing of the peridotites.
199-201
[R]La triplita (Mg) de las pegmatitas graníticas de Sierra Albarrana, Córdoba (España) / González del Tánago, J. / Peinado, M.
The triplite (Mg) is found in two class of the granitic pegmatites of Sierra Albarrana (g4, E2). The composition averages are: the first one, Fe4.53 Mn1.56 Mg9.1 Ca0.08 Ti0.10 F5.37 and the other Fe7.11 Mn2.32 Mg5.42 Ca0.14 Ti<0.24 F4.65. It has been formed by a biotite metasomatism below 600 ºC.
202-206
[R]Variaciones composicionales en las turmalinas de las pegmatitas de Sierra Albarrana (Córdoba) / Abad-Ortega, M.M. / Fenoll Hach-Alí, P / Ortega-Huertas, M.
Compositional variations in tourmalines from Sierra lbarrana granitic pegmatites (Córdoba, Spain) has been studied in order to clarify the petrogenetic process involved in their formation. The composition of the tourmalines supports the metamorphic genesis proposed for the pegmatites and aids to explain the sequence of cristallization of the different pegmatitic zones.
207-210
[R]Características de las turmalinas asociadas a rocas pegmatíticas del área de la Fregeneda, Salamanca (España) / Roda Robles, E. / Pesquera Pérez, A. / Velasco Rodan, F.
In the NW part of the province of Salamanca (Spain) many pegmatites occur. Some of them correspond to Li-bearing pegmatites, but other pegmatitic types are also important. In this paper tourmalines from some of this pegmatitic bodies and their tourmalinized host-rock are examined in terms of their chemistry and conditions of formation. According to their chemistry, they belong to the schorl-dravite series. Substitutions towards alkali-free or proton deficient members are observed. The chemical variations between the studied tourmalines could indicate a different origin for their associate rocks.
211-215
[R]Génesis y medio de formación del yacimiento de minerales de berilio asociados a la pegmatita de Franqueira, Pontevedra (Galicia) / Martín Izard, A. / Moreiras, D. / Acevedo, R. / Paniagua, A. / Marcos-Pascual, C.
The aim of this paper is to describe the geological, mineralogical and geochemical remarks of the Franqueira pegmatitic mineralizations giving raise to a genetic descriptive model. Exometasomatic interaction of Be-rich pegmatitic bodies with dunitic wall-rocks leads to the development of gemstone deposit, several meters thick, formed essentilly of emerald, phenakite and chrysoberyl (alexandrite) in phlogopite gange. Endometasomatic hornblende-pyroxene-garnet facies is also locally developed. The mineralization resambles strongly the emerald-alexandrite type locality from Tokowaja (Oural) although the original dunitic body was this former occurrence not observed.
216-221
[R]Tipología de las pegmatitas del macizo de Tamazeght (Marruecos) / Khadem, B. / Fontan, F. / Kadar, M. / Monchoux, P.
In the pegmatitic dikes inside the alkaline complex from Tamazeght (Morocco), two groups are differenciated taking into account their structural, textural and mineralogical features. Futhermore the paragenesis of these pegmatitic bodies are stablished starting from the mineralogy of the host-roch.
222-226
[R]Aluminofosfatitas Silúricas de la Península Ibérica: Síntesis preliminar / Moro, M. / Gil Agero, M. / Cembranos, M.L. / Pérez del Villar Guillén, L. / Montero, J.M. / Fernández, A. / Hernández, E.
The metallogenic characteristcs of stratiform variscite deposits in the Iberian Península have been reviewed. As a result, the different occurrences have been classified and correlated, and genetic model has been proposed. Some criteria that can serve prospecting guides in similar geological environments are proposed.
227-232
[R]Mineralogía y Geoquímica de Tierras Raras en el Cinturón Pirítico Español / Ruiz, C. / Espí, J.A.
Tree volcanogenic massive suphide deposits of the Iberian Pyrite Belt are considered. Masa Valverde, Aguas Teñidas and Lomero-Poyatos. By means of the mineralogy and the geochemistry distributions of the rare earth elements (REE) three typologies of mineralizations are described in each orebody. The typologies are distingued by their average contents of R.E.E., their anomalies of Eu and their relations between the lightest rare earth terms and the heavy ones.
233-237
[R]Génesis de los yacimientos de hierro de Bilbao (Cretácico Inferior, Cuenca Vasco-Catábrica) / Gil Crespo, P.P. / Velsco Roldán, F.
In the iron deposits of Bilbao ore mineralization types appear: 1)Gallarta-type, hosted in Gargasian limestones, and 2)Dícido-type, assocaited to granitoides of Lower Albian age. The main minerals are carbonates, which show a trend toward iron-rich carbonate from calcite= dolomite=ankerite=siderite, and oxihidroxides (hematite and goethite) as supergene minerals. Chemical data point to a Fe-Mg-Nn association for the mineral assemblages. Oxygen and carbon isotope studies reveal removilization conditions at intemediate temperatures with a possible brines mixture. The genetic model presented is based on the replacement of carbonate sediments during the latesst diagenesis, from hydrothermal fluids, very similar to these proposed for "Mississippi Valley type" deposits.
238-242
[R]Características Geoquímicas de los metasedimentos Ordovícicos de Latedo y mineralizaciones de hierro asociadas (Zamora) / Fernández, A. / Moro, M.C.
In this paper the Ordovician metasediments and iron mineralizations assciataed them from Latedo-Santa Ana zone (NW Zamora) are characterized geochemically, are based on chemical analisys of 55 and 32 samples of whole rock respectively. With the obtained results mayor and minor elements, the correlation matrix, binary (SiO2-Al203 y K20-Al203) and tertiary Al203-(Fe203+MgO)- (CaO+Na2O+K2O) y Al2O3- (Na2O+K2O)x10-(Fe2O3+MgO) diagrams and the main components analisys (M C A) are made.
243-248
[R]La Sierra de Guadarrama: un ejemplo de actividad hidrotermal recurrente en el tiempo y en el espacio / Caballero, J.M. / Casquet, C. / Galindo, C. / González Casado, J.M. / López García, J.A. / Quirez, E. / Sierra, J. / Tornos, F. / Vindel, E.
Geological fluid inclusion and geochronological studies carried in work show that the Sierra del Guadarrama has an important hydrothermal activity that spans, at least, during 200 M.a affter the intrusion of the hercynian granitoids. Only the earliest hydrothermal events are related to these granitoids, while the majority of the hydrothermal alterations are related to regional hydrothermal convective systems. The hydrothermal events are superimposed in time and space due to reactivation of faults.
249-252
[R]Primera aportación al estudio de fases sulfuradas del yacimiento de Lumbrales (Salamanca) / Murciego, A. / Pérez Vázquez, M.J. / Pellitero, E. / Babkine, J. / Dusausoy, Y.
In the Lumbrales deposit (Salamanca Spain) have been recognised different sulphide belonging, partially, or wholly, to the system Sn-Cu-Fe-Zn-Mo-Bi-Ag-As-S. Replacement, exsolution and colloidal textures have been observed. As content of Arsenopyrite range between 34 and 37%, pointing out greatest temperature an crystallization of this assemblages (500-615ºC). Temperatures between 500-300ºC are deduced by Stannite-Stannoidites and Stannoidite-Mawsonite pairs and between 200-70ºC by the presence of Bornite-Chalcopyrite-Tenantite-Diagenite with colloidal textures.
253-257
[R]Estudio mineralógico y químico de la asociación de Sulfuros del yacimiento de la Barquilla (Salamanca, España) / Murciego, A. / Pellitero, E. / Babkine, J. / Dusausoy, Y. / Gonzalo Corral, F.J.
An assemblage of rare sulphides which appears, locally in one of the mines microprobe. Cernyite-Greenockite-Tetrahedrite-Herzembergite and, in smaller quantity, Chalcopyrite, Ag-Bi-Pb bearing-sulfosalts, Galena and native Bi are locates at the Cassiterite-Montebrasite-Apatite-Albite-Q-Mica veins. In the country rock close to the veins, the most abundant sulphide is Chalcopyrite that forms part of different Fe-Zn-Cd-Cu-Sn bearing assemblages. Extensive sustitions are recognized in these minerals.
258-262
[R]Physico-Chemical and Geodynamic constrain in genesis of masive Stibnite veins in the Southwestern European Variscan Belt / Muñoz, M. / Courjault-Rade, P. / Tollon, F.
La recopilación de los datos en los estudios mineralógicos, microtermométricos, de la alteración hidrotermal y de la solubilidad de la Estibina en sus yacimientos de la parte sud- oeste de la Cadena Hercínica, nos muestran, que sus condiciones de cristalización son epitermales (270-150 ºC, #100 bars) y entre 1000 y 450m de profundidad. Estas condiciones se desarrollan durante las etapas tardías de la orogenia Hercícnica.
263-266
[R]Morfología y asociación mineralógica del yacimiento de Sb de Lanzuela (Teruel) / López Ciriano, A. / Subías, I. / Fernández-Nieto, C.
The Sb-Pb ore deposit from Lanzuela are deposed in a shear zone and related fractures. The Sb-Pb sulfosalts have been identified by X-ray diffraction, ore microscopy and electron microprobe. The mineral succession is formed by there stages: an early stages: an early stage (Fe-Sb) characterized by pyrite, stibnite and marcasite, and intermediate stage (Sb-Pb-Zn-Ag-Ba) constituted by fülöppita, zinckenite arsenopyrite, miargirite, galena, sphalerite and barite, and a remobilization stage characterized by semseyite and bournonite.
267-270
[R]Composición mineralógica de los sulfuros y sulfosales de los depósitos hidrotermales del Sector Septentrional del Rif (Norte de Marruecos) / Fkhech, A. / Fenoll Hach-Alí, P.
Hydrothermal sulpide and sulfosalt deposits from North Morocco, located at the Ghomarides/Sebtides contact of Oligocene-Miocene age, are studied by microscopy and electron microprobe. Five types of ore deposits have been identified depending on their mineralogical composition, their different assemblages and the silver content in the tetrahedricte-group sulfosalts. It is suggested a deep origin for the ore bearing fluid, an a forming temperature up to 400ºC for the deeper deposits and around 250ºC for the shallower deposits.
271-275
[R]Geología y control tectónico de la mineralización hidrotermal submarina de Herrerías (Cordilleras Béticas) / López Gutiérrez, J. / Martínez Frías, J. / Lunar Hernández, R. / López García, J.A.
The seafloor, hydrothermal deposits of Herrerías consists of a simple paragenesis of Fe-Mn oxides, base metal sulphides, native silver, baryte, siderite, jasper and gypsum (scarce). Its geotectonic setting corresponds to a positive "flower structure", of Upper Miocene age, within which the N-S the ore fluids. This the main channels for the emplacement of the ore fluids. This mineralized structure ha been formed according to a subvolcanic doming in a shear zone.
276-281
[R]Quimismo de las paragénesis asociadas al Vulcanismo Terciario del Sector Águilas-Sierra Almagrera (SE de España) / Morales Ruano, S. / Fenoll Hach-Alí, P.
BPGC filonian deposits, with Fe-Co-Ni sulfides and sulfoarsenides, and Cu-Ag-Zn-Fe sulfosalts are related with Tertiary vulcanism of SE Spain. Both field and laboratory observations (mineral parageneses, textures and mineral chemistry) indicate that all these deposits were generated by a four-stages hydrothermal process.
282-286
[R]Contenido en plata de las mineralizaciones de plomo-zinc de la región del Valle de Alcudia (Ciudad Real). Implicaciones en la génesis de yacimientos hidrotermales de metales base / Palero Fernández, F.J. / Martín Izard, A.
In the Alcudia Valley region (Central-south of Spain), 5 differents types of Pb-Zn ores can be found. The most important of them is the 4th type, wich is made up by veins hosted in open fractures afecting the Precambrian-Lower Paleozoic metasedimentary sequences. The ore was formed during 3 main and 2 latter suscessives atapes. Ag content in ores of fourth types show a clear regional pattern, showing a preferntial distribution according with corridors where Ag conten increase towards residual thermal focus related with Hercinian granitics rocks.
287-292
 Análisis multivariante en rocas carbonatadas y su relación con las mineralizaciones de Pb-Zn en el Flanco Sur del Sinclinal de Bielba del Oeste de Cantabria (España) / Bravo Fernández, J.I.293-295
 El yacimiento de Zn-Pb de San José (Legorreta, Guipúzcoa) / Boixereu, E. / Locutura, J. / Robador, A.296-300
 La mina de Zn-Pb "Virgen del Carmen" de Santa Cruz de Nogueras: morfología del yacimiento. / López Ciriano, A. / Bauluz Lázaro, B. / Fernández-Nieto, C.301-305
 Medio geotectónico de formación de las mineralizaciones estratiformes de Barita asociadas a los metasedimentos Silúricos del Sinforme de Alcañices (Zamora) / Moro, M.C. / Hernández, E. / Cembranos, M.L. / Pérez del Villar Guillén, L.306-312
 El equilibro en Bi-Bi2S3: algunas precisiones a partir de paragénesis naturales del Skarn de Sarraera, Vall d´Arán (Lleida) / Delgado Martín, J. / Soler i Gil, A.313-318
 El Skarn magnésico de magnetita-ludwigita del Cañuelo (Cordillras Béticas Occidentales) / Curras, J. / Torres Ruiz, J.319-322
 Sedimentología de algunos placeres de oro en terrazas fluviales de la Península Ibérica (León y Cáceres-Beira Baixa) / Pérez-García, L.C.323-327
 Las Médulas de Carucedo (León), contribución a su conocimiento geológico / Pérez García, L.C.328-334
 Las Médulas de Carucedo (León): sistemas de explotación en la antiguedad / Sánchez-Palencia, F.J. / Fernández-Posse, M.D. / Orejas, A. / Pérez García, L.C.335-342