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Abstract  

A solvent extraction technique to separate different chemical species of thorium is presented. The products formed by the chemical effects of the /n,/ reaction on the Th/acac/4 were separated by this method and the retention value was measured.

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Abstract  

Several ornaments named tezcacuitlapilli (coccyx-mirrors) are described and chemical analyses of raw materials (slate and pigments) were carried out by neutron activation, X-ray diffraction, scanning electron microscopy and radiography. Elemental and statistical analyses revealed that three different kinds of slate were used in their manufacture. The white pigment contains gypsum while ochre, yellow and red pigments contain iron oxide. These ornaments were identified as coming from the Cave of the Sun Pyramid of Teotihuacan. An attempt was undertaken to reconstruct the contexts of their manufacture and symbolic interpretation.

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Abstract  

The purpose of this research is the dating of some mammoth bones from the Valley of Mexico, with the uranium-series method, which can determine the activity of the isotopic relationships 234U/238U and 230 Th/234U. Since not all samples could be dated by this method, it was necessary to apply other techniques as well. First of all, the total concentration of uranium was determined in mammoth bones by U. V. spectrometry, then a study of the conservation state of mammoth bone was carried out by scanning electron microscopy and X-ray diffraction. In this way the limiting factors at the application of this method for dating mammoth bones can be determined.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
M. Jimenez-Reyes
,
D. Tenorio
,
E. Martinez-Quiroz
, and
A. Sanchez-Ocampo

Abstract  

Allanites from Telixtlahuaca (Oaxaca, Mexico) were analyzed using the PIXE technique. The concentrations of 12 elements, mainly rare earths, were determined.

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Abstract  

The research was performed with archaeological obsidian scrapers, collected at the Metztitlan area, Hidalgo, Mexico. The provenance of the raw material was determined by NAA. SEM technique was applied to identify use wears on pre-Hispanic tools and experimental replicas. The Metztitlan scrapers made of the obsidian of Zacualtipan, Hidalgo, Mexico, were probably used for Agave juice extraction in the Late Postclassical period.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
R. López-Valenzuela
,
J. López-Palacios
,
M. Jiménez-Reyes
,
G. Cataño
, and
D. Tenorio

Abstract  

Thirteen Teotihuacan-style ornaments of an incense burner were studied. Ceramic pastes, pigments and mica were analyzed by neutron activation, X-ray diffraction and scanning electron microscopy. Elemental (Sc, Cr, Fe, Co, Rb, Cs, La, Ce, Nd, Sm, Eu, Tb, Yb, Lu, Hf, Th and U) and statistical analyses of ceramic-body data showed that these pieces were made from the same raw material, which is chemically different from the fine orange ceramic of Teotihuacan. Montmorillonite and the classical components of sand were the minerals identified in the ceramic pastes. The white pigment contained calcium, titanium and aluminium, the yellow pigment was ocher, and the red pigment was a mixture of red ocher and cinnabar, the binder of the pigments being clay. Exoskeletons of diatoms and locust ootecs were found in the pigments. Mica was identified as biotite, identical with that coming from Monte Alban Oaxaca. We wish to undertake a historical reconstrution of these ornaments based on archaeometric and literature data.

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Summary  

Ceramic samples found in San Miguel Ixtapan, Mexico State, Mexico, were analyzed by means of NAA, PIXE, SEM and XRD. Statistical treatments such as bivariate cluster and principal-components analysis were applied to the data set. The origins of these ceramic samples were classified as local, regional and foreign.

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Abstract  

Obsidian samples from San Miguel Ixtapan Mexico State, Mexico were analyzed by means of neutron activation. Statistical treatments such as bivariate, cluster and principal-components analyses were applied to the data set. Obsidians were identified as coming from three important sources: Sierra of Pachuca in the state of Hidalgo, Zinapécuaro and Zináparo-Varal in the state of Michoacán.

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Abstract  

Obsidian samples from 13 Mexican quarries (Sierra de Pachuca and Zacualtipan, Hidalgo, Zaragoza and Oyameles, Puebla, Altotonga Veracruz and eight sites of the Zinaparo — Varal — Churintzio Hills region) have been analyzed by NAA. The concentration of 19 elements, major and trace, are reported. Excepting Altotonga Veracruz, the chemical composition of other obsidian flows was found homogenous. The region of the Varal obsidian was delimited. An excellent correlation between ytterbium and lutetium contents in obsidians was found.

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Abstract  

Argon ion induced X-ray emission has been used for analysis of Si and Cl present at low concentrations in CdTe crystals. The influence of zone melting on the distribution of these elements along the crystal is examined.

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