Estudio por microscopía electrónica de transmisión de saponita activada.

This work studies the modifications undergone by the Creen Clays Saponite in the Tagus Basin subjected to activation treatments, and stresses the influence of the development of the electronic microscopy technique for studying these materials. Acid treatment with HU and pillaring treatment with Al13 were performed. Characterization of the samples was carried out by DRX, chemical analysis of majar elements and Transmission Electronic Microscopy. Acid treament causes the delaminarion and fragmentation of the particles, partially dissolving the octahedral layer and generating amorphous silica, coming from the tetrahedral layer. Pillaring treatment gives rise to a stable salid with interlayer spadng at 18A. The high number of crystalline defects present in the saponite conditions the formation of a low number of pillars per cell

Characterization of clay minerals from the hemipelagic succession in the Serra dels Almaens (upper Albian, Prebetic of Alicante)

La determinación de la mineralogía de las arcillas en sistemas deposicionales hemipelágicos tiene un gran potencial para la caracterización de cambios ambientales que, sin embargo, ha sido poco explotado en el análisis de cuencas. En este trabajo se aplica este método a la Formación Represa (Albiense superior, Prebético) en la Serra dels Almaens (Jijona, Alicante). La unidad está caracterizada por una alternancia de margas y calizas depositadas en los ambientes hemipelágicos del antiguo margen continental sudibérico y tiene un notable espesor (> 450 m). Se analiza la composición mineralógica global de las muestras mediante el método de polvo policristalino y la mineralogía específica de filosilicatos mediante agregados orientados en dos fracciones: gruesa (2-20 µm) y fina (< 2 µm). Mineralógicamente la serie está constituida por calcita, filosilicatos, cuarzo y dolomita. Dentro del grupo de los filosilicatos se han identificado esmectita, illita y caolinita. Estos minerales arcillosos presentan variaciones significativas lo largo de la serie estudiada, lo que permite definir cinco intervalos sucesivos e interpretarlos en términos de la evolución de la cuenca sedimentaria.Determination of clay mineralogy in hemipelagic depositional systems has a great potential for the characterization of environmental changes in those systems. However, this potential has been only little exploited in the analysis of sedimentary basins. In this paper this method is applied to the Represa Formation (upper Albian, Prebetic Zone) in the Serra dels Almaens (Jijona, Alicante). There, the unit reaches a remarkable thickness (> 450 m), and is characterized by marl and limestone alternations deposited in the hemipelagic environments of the ancient southiberian continental margin. The bulk mineralogical composition of the samples was analyzed by the method of polycrystalline powder, and the specific mineralogy of clays by means of oriented aggregates in two fractions: coarse (2-20 µm) and fine (<2 µm). Mineralogically, the samples consist of calcite, phyllosilicates, quartz and dolomite. Within the group of phyllosilicates, smectite, illite and kaolinite were identified. These clay minerals reflect significant changes throughout the sedimentary series, allowing the definition of five successive stratigraphic intervals and their interpretation in terms of the evolution of the sedimentary basin.Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEpu

Methods for analyzing the carbonate content in hemipelagic sequences: a comparative study in the Represa Formation (Upper Albian, Prebetic Zone)

En este trabajo se realiza un análisis comparativo de cuatro técnicas de determinación del porcentaje de carbonatos en rocas sedimentarias de composición mixta carbonático-siliciclástica: 1) difracción de rayos-X, 2) determinación de carbono orgánico total, 3) pérdida por calcinación, y 4) calcimetría. Para ello se aplican a la Formación Represa (Albiense superior) en la Serra dels Almaens, en el Prebético de Alicante. Esta serie está formada por 450 m de facies rítmicas hemipelágicas de calizas y margas. Los resultados a lo largo de la serie de estas cuatro técnicas son muy similares, si bien la pérdida por calcinación es la técnica más inexacta e imprecisa, por su dependencia de la mineralogía de la muestra. Por el contrario, la difracción de rayos X aparece como la técnica más adecuada en conjunto, ya que, a su alta precisión y exactitud se le suma la información mineralógica de la muestra. La calcimetría tiene la ventaja de su sencillez y rapidez, a costa de una información más incompleta. El análisis del carbono orgánico total admite muestras de menor tamaño y da resultados más exactos, pero también es la técnica más costosa y la exactitud de los resultados está condicionada a la ausencia de otros carbonatos distintos del carbonato cálcico.In this work a comparative analysis among four different methods for determining the percentage of carbonates in sedimentary rocks of mixed carbonate-siliciclastic composition is carried out: 1) X-ray diffraction, 2) total organic carbon (TOC), 3) loss in ignition (LOI) and 4) calcimetry. With this purpose, these techniques are applied to the Represa Formation (upper Albian) in the Serra dels Almaens in the Prebetic of Alicante. This unit is 450 m thick and consists of rhythmic hemipelagic facies (limestones and marls). The evolution of carbonate content throughout the series, obtained by the four techniques, shows similar patterns, indicating that all of them are adequate for the analyses. However, LOI is most inaccurate and imprecise, as it has a strong dependence on the mineralogy of the sample. By contrast, XRD appears as the most appropriate technique, not only because its good precision and accuracy, but because it yields a complete information about the mineralogy of the sample. The calcimetry technique has the advantage of simplicity and speed, at the expense of a more incomplete and imprecise information. Finally, the TOC technique has the advantage of needing smaller sample sizes and also it gives the most accurate results. But the good results are conditioned to the absence of other carbonates rather than calcium carbonate.Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEpu

Fuentes orales y archivos: Modelos de Syllabus de clases prácticas para Grados de Historia, Historia del Arte y Arqueología

Este documento contiene la memoria final del proyecto de innovación docente nº. 11 de la convocatoria para el curso académico 2022-2023. En ella se contiene modelos de clases prácticas para aquellos profesores de los Grados de Historia, Historia del Arte o Arqueología que pudieran impartir asignaturas de dichos Grados.Depto. de Historia Moderna y ContemporáneaFac. de Geografía e HistoriaFALSEsubmitte

Mg-Rich smectite "precursor" phase in the Tagus basin, Spain

The pink clays from the Tagus basin, Spain, were characterized by X-ray difraction (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Chemical data were obtained by plasma emission spectroscopy and analytical electron microscopy (AEM), and specific surface and cation-exchange capacity were measured also. The data indicate that these pink clays are primarily stevensite. This Mg-rich smectite is characterized by poor crystallinity, a high degree of structural disorder, trioctahedral character (pure magnesian), a very low cation-exchange capacity, a very small crystal size (which generates an abnormally high specific surface area), and a deficiency of octahedral cations. On the basis of the very small crystal size, a large number of edge dislocations, the lack of periodicity (turbostratic) in the structure, and a cellular (spherical) texture observed by TEM, we consider this occurrence to be an early stage of crystallization. Unlike other precursor clay materials described in the literature, this clay is not an alteration of volcanic ash, but it was generated by precipitation from a Si- and Mg-saturated medium

Geothermal resources evaluation: Using O&G exploration data to evaluate low and medium enthalpy resources from deep sedimentary reservoirs

[EN] Geological resources of low enthalpy (and in many cases, also of medium enthalpy) are located mainly in large sedimentary basins with normal geothermal gradients in permeable formations (reservoir); fluid (brine) with high content on dissolved salts circulate through the reservoir; by depth and after a high time of circulation through the reservoir, the fluid reach the temperature level corresponding to that depth.Peer reviewe