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27 results on '"Canaveras, J"'

7. Brucite-aragonite precipitates as weathering products of historic non-MgO-based geomaterials

Author

Martinez-Martinez, J, Benavente, D, Fusi, N, Canaveras, J, Martinez-Martinez J., Benavente D., Fusi N., Canaveras J. C., Martinez-Martinez, J, Benavente, D, Fusi, N, Canaveras, J, Martinez-Martinez J., Benavente D., Fusi N., and Canaveras J. C.

Abstract

This paper analyses the mineralogical composition, texture, and structure of a stalactite sampled from the city-wall storerooms of the Nueva Tabarca fortress (southeast Spain). This speleothem presents an uncommon mineral assemblage: aragonite, brucite, gypsum, silica, and halite. Internally, it shows complex structure: (1) a central soda-straw composed by aragonite; (2) an external puff-pastry cone-crust formed preferentially by aragonite and brucite; and (3) an internal branching of coralloids, showing a subtle layering between brucite and aragonite. Gypsum, halite, and silica locate in the outer coating of the cone-crust. The sequent mineral precipitation sequence has been established: aragonite > brucite > gypsum/silica > halite. Speleothem formation is directly related to the chemical weathering of the rocks and mortars used as building materials of the city-wall. Brucite precipitates has been always linked to the presence of MgO-based geomaterials. However, the lack of these compounds as building materials in Nueva Tabarca fortress makes this investigation a unique example of brucite precipitation. PHREEQC calculations showed that interaction between pore waters and the minerals of mortar aggregates (dolomite, pyroxene, and amphibole) leads to rich-magnesium solutions. Evaporation modelling of lixiviated waters describes the precipitation of the mineral assemblage of the brucite-aragonite speleothems.

Published
2020

9. RpeakChrom: Novel R package for the automated characterization and optimization of column efficiency in high-performance liquid chromatography analysis

Author

Peris-Diaz M, Alcoriza-Balaguer M, Garcia-Canaveras J, Santonja F, Sentandreu E, and Lahoz A

Subjects
Monolithic column, HETP, Column characterization, van Deemter, RpeakChrom
Abstract

Characterization of chromatographic columns using the traditional van Deemter method is limited by the necessity of calculating extra-column variance, issue particularly relevant when modeling asymmetrical peaks eluted from monolithic columns. A novel R package that implements Parabolic Variance Modified Gaussian approach for accurate peak modeling, van Deemter equation and two alternatives approaches, based on van Deemter, has been developed to calculate the height equivalent to a theoretical plate (HETP). To assess package capabilities conventional packed reverse-phase and monolithic HPLC columns were characterized. Peaks eluted from the monolithic column showed a high value of factor asymmetry due, in part, to the contribution of extra-column factors. Such deviation can be circumvented by the two alternatives approaches implemented in the R-package. Furthermore, increased values of eddy diffusion and mass transfer kinetics terms in HETP were observed for the packed column, while accuracy was below 9% in all cases. These results showed the usefulness of the R-package for both modeling chromatographic peaks and assessing column efficiency. The RpeakChrom package could become a helpful tool for testing new stationary phases during column development and to evaluate column during its lifetime. This R tool is freely available from CRAN ().

Published
2017

10. Dating of the hominid (Homo neanderthalensis) remains accumulation from El Sidrón cave (Borines, Asturias, North Spain): an example of multi-methodological approach to the dating of Upper Pleistocene sites

Author

Mercier, Norbert, Torres, T., Ortiz, J. E., Grün, R., Eggins, S., Julia, R., Fortea, J., Rasilla, M., Martinez, E., Sanchez, Sébastien, Canaveras, J. C., Lario, J., Soler, V., Rosas, A., Tisnérat-laborde, N., Valladas, H., Institut de Recherches sur les Archéomatériaux (IRAMAT), Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Montaigne-Université de Technologie de Belfort-Montbeliard (UTBM), IRAMAT-Centre de recherche en physique appliquée à l’archéologie (IRAMAT-CRP2A), Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Montaigne-Université de Technologie de Belfort-Montbeliard (UTBM)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux Montaigne-Université de Technologie de Belfort-Montbeliard (UTBM), Research School of Earth Sciences [Canberra] (RSES), Australian National University (ANU), Institute of Earth Sciences Jaume Almera, Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Géochrononologie Traceurs Archéométrie (GEOTRAC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Université de Technologie de Belfort-Montbeliard (UTBM)-Université d'Orléans (UO)-Université Bordeaux Montaigne (UBM)-Centre National de la Recherche Scientifique (CNRS), Université de Technologie de Belfort-Montbeliard (UTBM)-Université d'Orléans (UO)-Université Bordeaux Montaigne (UBM)-Centre National de la Recherche Scientifique (CNRS)-Université de Technologie de Belfort-Montbeliard (UTBM)-Université d'Orléans (UO)-Université Bordeaux Montaigne (UBM)-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Université, Bordeaux Montaigne

Subjects
[SHS.ARCHEO] Humanities and Social Sciences/Archaeology and Prehistory, [SHS.ARCHEO]Humanities and Social Sciences/Archaeology and Prehistory, datation, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2010

11. A new date for the Neanderthals from el sidron cave (Asturias, Northern Spain)

Author

Wood, Rachel, Higham, Thomas F. G., de Torres, T., Tisernat-Laborde, Nadine, Valladas, Hélène, Ortiz, J E, Lalueza-Fox, C., Sanchez-Moral, S., Canaveras, J C, Rosas, A, Santamaria, D, de la Rasilla, M, Wood, Rachel, Higham, Thomas F. G., de Torres, T., Tisernat-Laborde, Nadine, Valladas, Hélène, Ortiz, J E, Lalueza-Fox, C., Sanchez-Moral, S., Canaveras, J C, Rosas, A, Santamaria, D, and de la Rasilla, M

Abstract

Torres. (2010) published a series of radiocarbon, AAR, ESR and OSL dates from the site of El Sidrón, northern Spain, which is notable for the discovery of the partial remains of 12 Neanderthals. Whilst the non-radiocarbon methods suggested an age beyond

Published
2013

12. Dating of the hominid (homo neanderthalensis) remains accumulation from el sidrón cave (piloña, asturias, north spain): An example of a multi-methodological approach to the dating of upper pleistocene sites

Author

de Torres, T., Ortiz, J. E., Grun, Rainer, Eggins, Stephen, Valladas, Hélène, Mercier, Norbert, Tisnerat-Laborde, N., Julia, R., Soler, V., Martinez, E., Sanchez-Moral, S., Canaveras, J. C., Lario, J., Badal, E., Lalueza-Fox, C., Rosas, A., Santamaria, D., de la Rasilla, M., Fortea, J., de Torres, T., Ortiz, J. E., Grun, Rainer, Eggins, Stephen, Valladas, Hélène, Mercier, Norbert, Tisnerat-Laborde, N., Julia, R., Soler, V., Martinez, E., Sanchez-Moral, S., Canaveras, J. C., Lario, J., Badal, E., Lalueza-Fox, C., Rosas, A., Santamaria, D., de la Rasilla, M., and Fortea, J.

Abstract

The age of Neanderthal remains and associated sediments from El Sidrón cave has been obtained through different dating methods (14CAMS, U/TH, OSL, ESR and AAR) and samples (charcoal debris, bone, tooth dentine, stalagmitic flowstone, carbonate-rich sedim

Published
2010

15. Microbial Communities Associated With Hydromagnesite and Needle-Fiber Aragonite Deposits in a Karstic Cave (Altamira, Northern Spain).

Author

Canaveras, J. C., Hoyos, M., Sanchez-Moral, S., Sanz-Rubio, E., Bedoya, J., Soler, V., Groth, I., Schumann, P., Laiz, L., Gonzalez, I., and Saiz-Jimenez, C.

Subjects
*MICROORGANISMS, ALTAMIRA Cave (Spain)
Abstract

Microbial communities, where Streptomyces species predominate, were found in association with hydromagnesite, Mg5(CO3)4(OH)2.4H2O, and needle-fiber aragonite deposits in an Altamira cave. The ability to precipitate calcium carbonate in laboratory cultures suggests that these and other bacteria present in the cave may play a role in the formation of moonmilk deposits. [ABSTRACT FROM AUTHOR]

Published
1999
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26. Microclimatic characterization of a karstic cave: human impact on microenvironmental parameters of a prehistoric rock art cave (Candamo Cave, northern Spain)

Author

Canaveras, J. C., Soler, V., Sanz-Rubio, E., Sanchez-Moral, S., and Hoyos, M.

Abstract

The Candamo Cave contains an important group of paleolithic paintings which have been seriously deteriorated due to mass tourism. In thiswork, an analysis was carried out of different climatic parameters (CO2, temperature, humidity, 222Rn) during annual cycles with the cave closed to the public and during an experimental period of controlled visits. The effect of visits on the geochemical characteristics of karstic water was also analyzed together with the cave ventilation. The natural variations in the cave air CO2 were above 3000 ppm, the increase produced through visits was only 100-110 ppm and since the humidity is almost permanently at saturation point, the critical parameter which limits the visitor capacity becomes air temperature. The temperature changes during the annual cycle are of the order of 1 deg. C in the external part and less than 0.5 deg. C in the internal part of the cave and a maximum increase of 0.13 deg. C was observed during the period of the visits. The 222Rn and CO2 concentration minimums in the summer period (July-October) show that this is the most propitious time for visits, since the greatest ventilation is produced in the cave at this time and, therefore, the greatest capacity for recovery. The geochemistry of the water, on the other hand, indicated that this is the period of the year in which processes of wall corrosion can be most easilyintroduced, although this would be of limited magnitude. The visitorcapacity calculated was 29 visitors/day. [ABSTRACT FROM AUTHOR]

Published
1998

27. Brucite-Aragonite Precipitates as Weathering Products of Historic Non-MgO-Based Geomaterials

Author

Nicoletta Fusi, J. Martínez-Martínez, David Benavente, Juan Carlos Cañaveras, Universidad de Alicante. Departamento de Ciencias de la Tierra y del Medio Ambiente, Petrología Aplicada, Martinez-Martinez, J, Benavente, D, Fusi, N, and Canaveras, J

Subjects
lcsh:QE351-399.2, Gypsum, Stalactite, stalactite, Dolomite, 0211 other engineering and technologies, Mineralogy, Speleothem, Weathering, 02 engineering and technology, engineering.material, 010502 geochemistry & geophysics, 01 natural sciences, brucite, 021105 building & construction, speleothem, 0105 earth and related environmental sciences, geochemistry, X-ray computed tomography, geography, lcsh:Mineralogy, geography.geographical_feature_category, Brucite, Aragonite, Geology, Geotechnical Engineering and Engineering Geology, Geochemistry, engineering, Halite, Petrología y Geoquímica
Abstract

This paper analyses the mineralogical composition, texture, and structure of a stalactite sampled from the city-wall storerooms of the Nueva Tabarca fortress (southeast Spain). This speleothem presents an uncommon mineral assemblage: aragonite, brucite, gypsum, silica, and halite. Internally, it shows complex structure: (1) a central soda-straw composed by aragonite, (2) an external puff-pastry cone-crust formed preferentially by aragonite and brucite, and (3) an internal branching of coralloids, showing a subtle layering between brucite and aragonite. Gypsum, halite, and silica locate in the outer coating of the cone-crust. The sequent mineral precipitation sequence has been established: aragonite &gt, brucite &gt, gypsum/silica &gt, halite. Speleothem formation is directly related to the chemical weathering of the rocks and mortars used as building materials of the city-wall. Brucite precipitates has been always linked to the presence of MgO-based geomaterials. However, the lack of these compounds as building materials in Nueva Tabarca fortress makes this investigation a unique example of brucite precipitation. PHREEQC calculations showed that interaction between pore waters and the minerals of mortar aggregates (dolomite, pyroxene, and amphibole) leads to rich-magnesium solutions. Evaporation modelling of lixiviated waters describes the precipitation of the mineral assemblage of the brucite-aragonite speleothems.

Published
2020

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