Combined PIXE and X‐ray diffraction analysis of accretionary lapilli from the Cretaceous/Paleogene boundary El Guayal Section,Tabasco, Mexico |
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| Authors: | L Bucio J L Ruvalcaba‐Sil C Thions J Urrutia‐Fucugauchi E Orozco |
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| Institution: | 1. Instituto de Física, Universidad Nacional Autónoma de México, Mexico, DF, Mexico;2. Instituto de Geofísica, Universidad Nacional Autónoma de México, Circuito Investigación Científica s/n|, Mexico, DF, Mexico |
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| Abstract: | By employing the techniques, X‐ray powder diffraction (XRPD) and particle‐induced X‐ray emission (PIXE), it could be obtained in a simply way an overall vision of the structure and chemical composition of a spheroid (lapillus) collected in the K/Pg deposit located at the place called El Guayal in Tabasco, Mexico. The XRPD analysis indicates the presence of an amorphous and four crystalline phases (quartz, calcite, ankerite, and montmorillonite) in the spheroid. None sulfur crystalline phases were detected. PIXE results show the presence of different atoms in a weight percentage that follows the sequence: Si > Al > Ca > Fe > Sr > Cu > Ti > Mn > Y > Rb > Zn > Pb. None of platinum group elements were detected. PIXE analysis by of the lapillus shows the presence of the most abundant atoms in the Earth's crust, but in this case, the relative abundance Fe‐Ca is inverted, and the Sr/Rb proportion is considerably higher than that observed in the crust. Additionally, nor sulfur or any of the platinum group elements was detected in the lapillus. Except for the case of trace elements detected, in general, no characteristic pattern is observed in the distribution of the most abundant elements. Copyright © 2015 John Wiley & Sons, Ltd. |
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| Keywords: | lapillus K/Pg deposit Guayal PIXE XRD |
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