Casa Montero is a mining complex located outside Madrid (Spain), dated from the Early Neolithic ( c. 5400–5000 cal bc ). An area of some 4 ha has been investigated and 4000 shafts recorded, which 324 have excavated. The characterization its raw flint materials establishment diagnostic features are indispensable in reconstruction distribution mine's products beyond immediate site. This work reports geological study Miocene layers their petrological characterization. Archaeological samples...

The thermoluminescence (TL) properties of a well-characterised natural α-cristobalite from Lanzarote (Canary Islands, Spain) have been studied. blue emission (at 400 nm) this silica polymorph quartz reveals the appearance three groups components peaked at 150, 230–240 and 370 °C, which could be associated, respectively, with (i) structural defects (similar to quartz), (ii) reversible phase transition β-cristobalite (iii) electron recombination unstable holes trapped oxygen vacancies next Al...

Four regressive sequences are present in the opaline rocks and related deposits of Miocene Intermediate Unit Madrid Basin. The consist silty mudstones argillaceous opals, separated by transitional facies. mudstone consists mainly dioctahedral smectites, whereas opal is principally opal‐CT variable amounts sepiolite. In facies, lamina smectite co‐exist with neoformed Petrological geochemical features (major, trace REE elements) indicate that levels facies a consequence silcrete formation an...

Cauliflower‐shaped nodules are widespread in a single red mudstone bed the Buntsandstein (Triassic) facies of Iberian Range. They consist mostly quartz, dolomite and calcite, but other minerals, such as barite, kaolinite iron oxyhydroxides, also present. The spherical, ovoid or elongate shape range from 1 to 8 cm across. surface is irregular, some show pedogenic coating microspar. sedimentological petrographic data suggest that initial anhydrite formed through progressive increase porewater...

We report on the investigation of contact metamorphism provoked by emplacement a shallow magma chamber during Timanfaya eruption Lanzarote from 1730 to 1736 AD . The study was carried out metamorphic xenoliths basaltic lavas, and shows how primary basanitic contaminated sedimentary rocks. Mineralogical chemical studies allowed definition several xenolith types. Silica (quartz, tridymite, cristobalite or mixture these, constituting more than 50 % xenolith) calc-silicate (wollastonite,...

ABSTRACT In Upper Jurassic carbonate turbidites of the Betic mountains (southern Spain), chert occurs in three morphologies: bedded chert, nodular and mottled chert. The last refers to a weak dispersed selective silification which gives speckled appearance rock. types are formed by replacement limestones associated with different calcareous facies. Turbidite packstones Saccocoma peloids, turbidite lime mudstones pelagic material contain cherts. silicification textures mainly micro‐...

ABSTRACT Varieties of chalcedony (calcedonite, quartzine, and lutecite) other optical micro- cryptocrystalline textures quartz opal from Miocene silcretes the Madrid Basin were studied using a Thermo Fisher DXR Raman microscope. The microscope has point-and-shoot capability 1 µm spatial resolution was coupled with standard Our results show that all varieties can have composite spectrum both moganite. spectra are independent origin by ageing, direct replacement, cementation processes....

Abstract Studying lithic raw material sourcing, processing and distribution is helpful when trying to reconstruct the territory, ecology, cultural practices of Neanderthal groups. The use multiple methods in such analyses allows for more refined characterizations be made, helping distinguish between materials better than any single method. Although 85% making up Mousterian assemblage at Navalmaíllo Rock Shelter (Pinilla del Valle, Madrid Region Spain) correspond available local geological...

This paper reports a detailed study of the calcrete and silcrete profiles in Miocene detrital deposits western area Madrid, at boundary two main sedimentary units.The aims this work were to better understand pedogenic diagenetic environments which these formed determine cause(s) their enrichment uranium.Calcrete duricrusts are characteristic features closed continental basins semiarid climates; discusses significance as indicators important change such basins.This shows that...

El presente trabajo estudia los diferentes tipos de sílex que aparecen en la Formación Calizas Oriñón (Aptiense superior-Albiense inferior), un zona concreta costa oriental Cantabria (Liendo-Castro Urdiales), debido a su gran abundancia y espectacularidad. Las rocas incluyen son principalmente biocalcarenitas (wackestones/packstones pellets, fragmentos equinodermos, ostreidos, foraminíferos espículas calcáreas o silíceas calcificadas), siendo el ambiente depósito marino plataforma abierta,...

Unusual mineralized and silicified carbonate-rich geodes were found hosted in Lower Triassic red mudstones Central Spain. From their borders to centres, the display (a) a millimetric carbonate crust, (b) quartz rim, (c) massive dolomite, (d) gold-bearing iron-rich infills (hematite laths goethite with up 7000 ppm of gold) (e) calcite cements that sometimes seal central hollow. Textural evidence indicates originally anhydrite, which was subsequently replaced by dolomite. The resultant...

Abstract Root-associated stalactites (rootsicles) in Galeria da Queimada lava tube have a mineralogical composition and developmental association with microbes that render them unique. Samples were examined by X-ray diffraction, micro-Raman spectrometry scanning electron microscopy/X-ray energy-dispersive spectroscopy. Three types of rootsicle defined: incipient; hard (white red); black spongy. The incipient rootsicles still contained rotten organic material showed the beginning...

En las facies evaporíticas de la Cuenca Madrid (región Brea del Tajo-Driebes-Almoguera) aparecen diferentes tipos yeso, cuyo contenido en elementos traza ponen manifiesto existencia procesos fraccionamiento durante evolución diagenética. De los analizados el estroncio y magnesio son que mejor reflejan estadio diagenético formación al presentar coeficientes distribución inferiores a unidad (D