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| Format: | Artículo científico |
| Language: | en |
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Universidad Nacional Autónoma de México
2009
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| Online Access: | https://www.redalyc.org/articulo.oa?id=56813222011 |
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Table of Contents:
- Geochemistry and tectonic controls of the effusive activity related with the ancestral Nevado del Ruiz volcano, Colombia C. Borrero L. M. Toro M. Alvarán H. Castillo Ciencias de la Tierra Medium K magmatism Villa María Late Pliocene adakitic signature In this paper, we discuss the geochemical aspects and the tectonic setting of the effusive activity between 2.0 to 1.0 Ma (the Ancestral Ruiz stage) of Nevado del Ruiz Volcano (NRV: 4° 50-55¿N, 75° 14-20¿ W, 5,390 masl), this volcano rises at the northernmost end of the Andean volcanic chain in the Cordillera Central of Colombia. Whole-rock geochemical data of andesitic to rhyodacitic samples from the different vents share specific characteristics: SiO2 = 56 -70.1 wt. %, relatively high MgO (1.1 - 8.1 wt. %) and medium K2O (1.06 - 4.36 wt. %) contents, low FeO/MgO ratios (typically less than 1,9), low fractioned rare earth element patterns with low Y and heavy rare earth elements contents, Sr commonly between 500 and 1,000 ppm and Ba up to 1,600 ppm. K/Rb ratios always show a negative correlation with SiO2 and Rb suggesting assimilation-fractional crystallization(AFC) mechanism. Rb/Sr, Ba/Sr and Rb/Ba ratios display a positive correlation with SiO2, typical of calcalkaline trends. The more acidic suites display the strongest adakitic character such as higher Sr, and lower HREE and Y contents. The N75ºW Villa Maria -Termales fault system was the controller of the magma displacement aside of the main N-S volcanic axis during the Ancestral Ruiz stage. This tectonic control is evidenced by the distribution of the small effusive eruptions in monogenetic vents aligned parallel to the fault system, which were fed by lateral magma flow from the intermediate storage system located 5-10 km below the position of the present Nevado del Ruiz Volcano. 2009 artículo científico 0016-7169 https://www.redalyc.org/articulo.oa?id=56813222011 en http://www.redalyc.org/revista.oa?id=568 Geofísica Internacional application/pdf Universidad Nacional Autónoma de México Geofísica Internacional (México) Num.1 Vol.48