Javier Garcia-Guinea - Academia.edu (original) (raw)

Papers by Javier Garcia-Guinea

LA PREHNITA DE LA CABRERA (MADRID). CARACTERISTICAS, GENESIS E INTERES GEMOLOGICO Por J. García G... more LA PREHNITA DE LA CABRERA (MADRID). CARACTERISTICAS, GENESIS E INTERES GEMOLOGICO Por J. García Guinea(1); F. Bellido(2) y..E. Galán(3) 11) Dpto. Geología y Geoquímica. Universidad Aut6noma. Madrid. 12) Instituto de Geología. C.S.LC. Madrid. 13) Dpto. Cristalografia y Mineralogia. Faculta<t"de Ciencias. Universidad. Zaragoza. RESUMEN U prehnit. se .ncuentr •• n el plutón d. LI Cabrerl eomo min .. 11 aeeesorio .n llWoInoa "'Initoa muy dif .... ncilldoa y .n-..19'd0l fibrosorrediedOI o mai_, tapiundo II CUlr~o Y a los feldesplltos,.n llWoIOOS filo"" pegmatitieos. El IIItudio minerllógieo d. la pr .... nita eonduce I int ... pr.~ este mine,.1 eomo formldo I partir de fluidoa hidrot .. mlllll, .nriqu..::idOl .n ulcio probllbl.."enl8 por r .. ¡Ulle de la pla¡ioc:l_ di 1I roc:. anc.ejante. T.niendo en euenta 1111 condiciones d. 'mpllzamiento d,1 plutón d, Le Cebre,. y el Cl mpo d. IStlbilided de II pr .... nita ' n IUlencil d e pomptollitl, M propon' una eondiciones t.rmobÍríe .. perl la formacion y .tabilizac:ión d,l. prllhniu pr6 xim"l l .7Kb y 34gDC. LM ear.eteristicIII tilical de l. prehnitl de 1 .. ",,",.titas y el lImlño d, .Igunos. . epdo., lIí como IU facilidad de t.llado. 1, conti ... ." un cierto inttris gemolótlíeo. ABSTRACT ,",-hnite oecurrs in th, pluton of La Cabrer ... ICCISOfY in lome very diff ... ,"ti.ted .anit • • nd .. ,.diltin, tibraul .1I9 .... t. or m_, coatin¡ qUlrt~ Ind feldspen eryltlll in pegmatite "illl.

Analytical and Bioanalytical Chemistry, Feb 4, 2016

Detection and sizing of natural colloids involved in the release and transport of toxic metals an... more Detection and sizing of natural colloids involved in the release and transport of toxic metals and metaloids is essential to understand and model their environmental effects. Single-particle inductively coupled plasma mass spectrometry (SP-ICP-MS) was applied for the detection of arsenic-bearing particles released from mine wastes. Arsenic-bearing particles were detected in leachates from mine wastes, with a mass-perparticle detection limit of 0.64 ng of arsenic. Conversion of the mass-per-particle information provided by SP-ICP-MS into size information requires knowledge of the nature of the particles; therefore, synchrotron-based X-ray absorption spectroscopy (XAS) was used to identify scorodite (FeAsO 4 .2H 2 O) as the main species in the colloidal particles isolated by ultrafiltration. The size of the scorodite particles detected in the leachates was below 300-350 nm, in good agreement with the values obtained by TEM. The size of the particles detected by SP-ICP-MS was determined as the average edge of scorodite crystals, which show a rhombic dipiramidal form, achieving a size detection limit of 117 nm. The combined use of SP-ICP-MS and XAS allowed detection, identification and size determination of scorodite particles released from mine wastes, suggesting their potential to transport arsenic.

Spectroscopy Letters, Jan 30, 2014

ABSTRACT Results are presented for the cathodoluminescence (CL) probe of an environmental scannin... more ABSTRACT Results are presented for the cathodoluminescence (CL) probe of an environmental scanning electron microscopy (ESEM) with an energy-dispersive spectrometry analyzer (EDS), thermoluminescence (TL), thermo X-ray diffraction in situ (TXRD), and simultaneous differential thermal analysis and thermogravimetric analysis (DTA/TGA) techniques of gem-quality zultanite samples collected from the Muğla region of southwest Turkey. Micro-Raman measurements were also performed on different zultanite orientations and preheated aliquots to study the spectral phase transition diaspore-corundum also detected by the other thermal techniques in the 450°C–500°C thermal range. The thermal phenomena of TL are synchronous with this dehydroxylation process, involving consecutive breaking-linking bonds of Al-O, Cr-O, Fe-O, Al-OH, Cr-OH, and Fe-OH, including the formation of hydrolyzed ions such [Inline formula], and [Inline formula] and redox reactions. Assuming that zultanite oxygen atoms are distributed as a hexagonal close packed layer, the experimental spectrum CL of zultanite is characteristic of the 2E → 4A2 transitions of substitutional Cr3+ luminescent centers in positions of Al3+ in sixfold coordination.

Macla: revista de la Sociedad Española de Mineralogía, Jul 1, 2017

Boletín de la Sociedad Española de Mineralogía, 1990

ABSTRACT Spanish fluorites corresponding to different provenances and colorings have been optical... more ABSTRACT Spanish fluorites corresponding to different provenances and colorings have been optically characterized by means of its optical absorption and photoluminescence spectra (excitation-emission). Our results have permited to detect the presence of Eu2+ and Sm2+ in green coloured fluorites, Cao and complex centres (R,M) in dark blue fluorites. Eu2+, Ce3+, O3- centres in yellow fluorites and molecular centres (Y3+, F-) in pink fluorites.

Férvedes: Revista de investigación, Sep 3, 2008

... Recurso de origen, e-spacio uned. Identificador, http://e-spacio.uned.es/fez/view.php?pid= bi... more ... Recurso de origen, e-spacio uned. Identificador, http://e-spacio.uned.es/fez/view.php?pid= bibliuned:2. Título, Arqueometría en el castro de San Chuis (Allande, Asturias, España). Autor,Carlos Marín Suárez. Autor, Jesús Francisco Jordá Pardo. Autor, Javier García-Guinea. ...

Physica Status Solidi A-applications and Materials Science, Mar 1, 2007

• Silicon Carbide (SiC), also known as carborundum, is a kind of wide bandgap semiconductors. • T... more • Silicon Carbide (SiC), also known as carborundum, is a kind of wide bandgap semiconductors. • TL properties of Silicon Carbide (SiC) used in industry applications were investigated. • The Silicon Carbide sample has a clear TL glow curve with two distinc peaks around 250°C and a shoulder peak around 130°C. • The 250°C peak is useful for dosimetric purposes with good reproducibilty and big linear dose region. • Low temperature peaks were completely faded after 30 min storage in a dark ambient.

Spectroscopy Letters, Oct 1, 2011

Micro-Raman and spatially resolved cathodoluminescence (CL) coupled to environmental electron mic... more Micro-Raman and spatially resolved cathodoluminescence (CL) coupled to environmental electron microscope (ESEM) with energy dispersive spectrometry (EDS) are nondestructive techniques scarcely employed on renal calculi studies. This study used these techniques together with Electron Probe Micro-Analysis (EPMA), X-Ray diffraction (XRD), and Thermogravimetry (TG) to study a rare renal calculus with cystine and a common Ca-oxalate-apatite calculus in order to explore

Arthropod Structure & Development, 2017

Geophysical Research Letters, Sep 1, 2003

The presence of hydrated diaspore (a-AlOOH) on the Martian surface allows us to speculate that th... more The presence of hydrated diaspore (a-AlOOH) on the Martian surface allows us to speculate that this material could act as: a-Al 2 O 3 precursor and water source. In this study, new analytical data on the thermoluminescence (TL) properties of natural diaspore from Goian (Pontevedra, Spain) in the UV-blue spectral region are reported. The results indicate that it could be also used as a dosimeter for dating purposes, since it possesses an acceptable sensitivity to radiation, reproducibility, linear dose response in the studied range (up to 100 Gy), and a high stability of the relative TL emission after six months of storage. Some physical trapping parameters for each irradiated curve (trap depth, pre-exponential factor, intensity and peak position) are estimated assuming first order kinetics for the 180°C TL peak.

Journal of Alloys and Compounds, Dec 1, 2013

In the present study, the structural and optical properties of SrSnO 3 doped with Tb ions are rep... more In the present study, the structural and optical properties of SrSnO 3 doped with Tb ions are reported. Novel SrSnO 3 :Tb 3+ phosphors were conventionally synthesized using a solid state reaction process under a mildly reduced atmosphere (5%H 2 and 95%N 2). The crystal structures, morphologies and optical properties of the resultant materials have been characterised by experimental techniques such as X-ray Diffraction (XRD), Raman spectroscopy (RS), Photoluminescence (PL), Radioluminescence (RL) and Cathodoluminescence coupled to an ESEM (ESEM-CL). The new phosphor material has good crystallization without any impurity phases, which matches with the standard JCPDS files (No. 22-1442) from XRD analysis. The PL, RL and CL measurements taken at room temperature showed that the transitions of 5 D 4 to 7 F J (j = 6, 5, 4, 3) corresponding to the typical 4f ? 4f dipole forbidden intra-configurational transitions of Tb 3+ are largely independent of the host material. The green emissions of the 5 D 4 ? 7 F 5 magnetic dipole transition at $540 nm are predominant for three types of luminescence. PL emission spectra recorded in the temperature range from 10 K to 300 K were influenced by temperature. We report anomalies in the PL spectra of SrSnO 3 :Tb 3+ compatible with a structural phase transition at 260 K while simultaneously exciting and cooling the sample. This work clearly confirms the existence of a phase transition discovered by Singh et al. in SrSnO 3 at 270 K.

Materials Characterization, Apr 1, 2009

... in Table 3. The high Loss On Ignition (LOI) values of M3, AKL8 and E4 samples is attributed t... more ... in Table 3. The high Loss On Ignition (LOI) values of M3, AKL8 and E4 samples is attributed to the higher amounts of calcite and clay minerals in its ... Sample AKL27, though belonging to the same chronological type of pottery (ie archaicclassical) has reduced amounts of calcium ...

The proposed luminescence classification of feldspars is found on the relationships between felds... more The proposed luminescence classification of feldspars is found on the relationships between feldspar lattice defects and their coupled spectra luminescence peaks. The UV emission at 290 nm is linked with the presence of Na and cracks-strainexsolution-twinning; at 340 nm with stress in Si-O bonds; the broad blue band (380-450nm) with [AlO 4 ] o defects; at 560nm with Mn 2+ point defects and at 720nm with iron in the lattice. The feldspar classification here provided can be used as a practical guideline for pegmatite feldspar studies since the luminescence techniques are sensitive tools detecting defects.

LPICo, May 1, 2011

The authors report about the influence of temperature on the thermoluminescence (TL) and cathodol... more The authors report about the influence of temperature on the thermoluminescence (TL) and cathodoluminescence (CL) behavior of a well-characterized topaz from Badajoz, Spain. Cryogenic treatments induce drastic decrease on the CL and TL intensity over 400 nm involving O Al Ã intrinsic defects and iron point defects. It suggests that low-energy emissions should be more associated with point defects and low wavebands to structural or intrinsic defects in the lattice. The tests of thermal stability of the UV-blue TL signal at different temperatures (in the range of 473-673 K) seem to confirm a continuous trap distribution system.

Se describen de forma sucinta los principales yacimientos españoles de diferentes variedades de c... more Se describen de forma sucinta los principales yacimientos españoles de diferentes variedades de cuarzos de interés gemológico, entre los que destacan los cuarzos rosas de Oliva de Plasencia (Cáceres) y Puebla de ÇCaraminhal (Coruña), los cuarzos hialinos de Berbes, Colunga y Cabrales (Asturias), los cuarzos citrinos y ahumados de la zona de Villas buenas (Salamanca); las amatistas de los Pedroches (Cérdoba), Vich (Girona), Montseny (Barcelona), La Unión y Portman (Murcia) y Valladares (Coruña), las maderas agatizadas de Pálmaces de Jadraque (Guadalajara), los jaspes de Zalamea la Real, Valverde del Camino, etc (Huelva). Se aportan algunos datos de caracterización de minerales-gema y algunas consideraciones geográficas-geológicas de mineralizaciones y de rocas encajantes sobre la mineralogía y valoración gemológica de los ejemplares.Peer Reviewe

Boletín de la Sociedad Española de Mineralogía, Jun 28, 1988

Los resúmenes y trabajos que se publican en este número han sido presentados en la VIII Reunión

Analytical and Bioanalytical Chemistry, Feb 4, 2016

Spectroscopy Letters, Jan 30, 2014

Macla: revista de la Sociedad Española de Mineralogía, Jul 1, 2017

Boletín de la Sociedad Española de Mineralogía, 1990

Férvedes: Revista de investigación, Sep 3, 2008

Physica Status Solidi A-applications and Materials Science, Mar 1, 2007

Spectroscopy Letters, Oct 1, 2011

Arthropod Structure & Development, 2017

Geophysical Research Letters, Sep 1, 2003

Journal of Alloys and Compounds, Dec 1, 2013

Materials Characterization, Apr 1, 2009

LPICo, May 1, 2011

Boletín de la Sociedad Española de Mineralogía, Jun 28, 1988

Los resúmenes y trabajos que se publican en este número han sido presentados en la VIII Reunión

La cueva de El Esquilleu (Cillórigo de Liébana, Cantabria, N de España) es un gran abrigo rocoso ... more La cueva de El Esquilleu (Cillórigo de Liébana, Cantabria, N de España) es un gran abrigo rocoso situado
en la región de Picos de Europa (Cordillera Cantábrica) que contiene un importante registro sedimentario, arqueológico
y paleontológico del Pleistoceno superior, con abundantes evidencias de industrias líticas musterienses y restos
óseos de mamíferos y otros vertebrados. La secuencia estratigráfica se compone de 41 niveles agrupados en cuatro unidades
litoestratigráficas con diferente significado sedimentario, que han sido estudiadas con metodología geoarqueológica
y tafonómica. En la unidad inferior hemos detectado una acumulación de hidroxilapatito de origen diagenético,
que hemos estudiado mediante difracción de rayos X (DRX), microscopía electronica de barrido ambiental (MEBA)
y termoluminiscencia (TL). Las dataciones radiocarbónicas existentes y su calibración permiten situar este interesante
registro durante el OIS 3 en una horquilla temporal comprendida aproximadamente entre 60000 y 37000 BP.