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Chemistry and petrological evolution of the Lastarria volcanic complex in the north Chilean Andes

  • José A. Naranjo (a1)

The Lastarria volcanic complex, along the northern Chile–Argentina border, includes three morphostructural components: Southern Spur, Lastarria (the highest cone, 5697 m) and Negriales (a geographically associated lava field, 5.4 km3). Petrographically, the Lastarria complex consists of pyroxene andesites and pyroxene–amphibole dacites. The whole-rock geochemistry shows a bimodial silica variation between 57 and 68%, with peaks at 59–60% and 61.62% SiO2. Petrographie and chemical data indicate different magmatic sources for Lastarria and Negriales. Whole-rock geochemistry can be explained by crustal contamination and crystal–liquid fractionation, with differences in storage times in magma chambers being a major controlling factor. Strong textural, mineralogical and chemical evidence for magma mixing, shortly before explosive eruptions at Lastarria, suggests that this process may have triggered the violent eruptive volcanic activity which characterizes the latest stages of the main cone. Abundant bombs of banded clear pumice and dark scoria in pyroclastic flow deposits are the texturally heterogeneous products resulting from incomplete mixing homogenization.

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Anderson, A. T. 1976. Magma mixing: petrological process and volcanological tool. Journal of Volcanology and Geothermal Research 1, 133.
Baker, P. E. 1982. Evolution and classification of orogenic volcanic rocks. In Andesites (ed. Thorpe, R. S.), pp. 2595. John Wiley and Sons.
Barazangi, M. & Isacks, B. 1976. Spatial distribution of earthquakes and subduction of the Nazca plate beneath South America. Geology 4, 686–92.
Barazangi, M. & Isacks, B. 1979. Subduction of the Nazca Plate beneath Peru: evidence from spatial distribution of earth quakes. Geophysical Journal of the Royal Astronomical Society 57, 537–55.
Déruelle, B. 1982. Petrology of the Plio-Quaternary Volcanism of the south-central and meridional Andes. Journal of Volcanology and Geothertnal Research 14, 77124.
Dostal, J., Zentilli, M., Caelles, J. C. & Clarck, A. H. 1977. Geochemistry and origin of volcanic rocks of the Andes (26°–28° S). Contributions to Mineralogy and Petrology 63, 113–28.
Eichelberger, J. C. 1975. Origin of andesite and dacite: evidence of mixing at Glass Mountain in California and at other circum Pacific volcanoes. Geological Society of America Bulletin 86, 1381–91.
Eichelberger, J. C. 1978. Andesite volcanism and crustal evolution. Nature 275, 21–7.
Eichelberger, J. C. 1980. Vesiculation of mafic magma during replenishment of silicic magma reservoirs. Nature 288, 446–50.
Ewart, A. 1982. The mineralogy and petrology of Tertiary–Recent orogenic volcanic rocks: with special reference to the and esite–basaltic compositional range. In Andesites (ed. Thorpe, R. S.), pp. 2595, John Wiley and Sons.
Francis, P. W., Moorbath, S. & Thorpe, R. S. 1977. Strontium isotope data for recent andesites in Ecuador and North Chile. Earth and Planetary Science Letters 37, 197202.
Gardeweg, M., Cornejo, P. & Davidson, J. 1984. Geologia del Volcán Llullaillaco, altiplano de Antofagasta, Chile (Andes Centrales). Revista Geológica de Chile 23, 2137.
Harmon, R. S., Barreiro, B. A., Moorbath, S., Hoefs, J., Francis, P. W., Thorpe, R. S., Déruelle, B., McHugh, J. & Viglino, J. A. 1984. Regional O-, Sr-, and Pb-isotope relationships in late Cenozoic calc-alkaline lavas of the Andean Cordillera. Journal of the Geological Society, London 141, 803–22.
Hawkesworth, C. J., Hammil, M., Gledhill, A. R., van Cal Steren, P. & Rogers, G. 1982. Isotope and trace element evidence for late-stage intra-crystal melting in the High Andes. Earth and Planetary Science Letters 58, 240–54.
Hawkesworth, C. J., Norry, M. J., Roddick, J. C., Baker, P. E., Francis, P. W. & Thorpe, R. S. 1979. 143Nd/144Nd, 86Sr/87Sr and incompatible trace element variations in calc-alkaline andesites and plateau lavas from South America. Earth and Planetary Science Letters 42, 4557.
Hildreth, W. & Moorbath, S. 1988. Crustal contributions to arc magmatism in the Andes of Central Chile. Contributions to Mineralogy and Petrology 98, 455–89.
Huppert, H. E., Sparks, R. S. J. & Turner, J. S. 1982. Effects of volatiles on mixing in calc-alkaline magma systems. Nature 297, 554–7.
James, D. E. 1971. Plate tectonic model for the evolution of the Central Andes. Geological Society of America Bulletin 82, 3325–46.
James, D. E., Brooks, C. & Cuyubamba, A. 1976. Andean Cenozoic volcanism a magma genesis in the light of strontium isotopic composition and trace-elements geochemistry. Geological Society of America Bulletin 87, 592600.
Klerkx, J., Deutsch, S., Pichler, H. & Zeil, W. 1977. Strontium isotopic composition and trace-element data bearing on the origin of Cenozoic volcanic rocks of the central and southern Andes. Journal of Volcanology and Geothermal Research 2, 4971.
Kouchi, A. & Sunagawa, I. 1983. Mixing basaltic and dacitic magmas by forced convection. Nature 304, 527–8.
Leake, B. E. 1978. Nomenclature of amphiboles. American Mineralogist 63, 1023–52.
McBirney, A. R. 1980. Mixing and unmixing of magmas. Journal of Volcanology and Geothermal Research 7, 357–71.
McNutt, R. H., Crocket, J. M., Clark, A. H., Caelles, J. C., Farrar, E., Haynes, S. J. & Zentilli, M. 1975. Initial 87Sr/86Sr ratios of plutonic and volcanic rocks of the central Andes between latitudes 26° and 29° South. Earth and Planetary Science Letters 27, 305–13.
Melson, W. G. & Saenz, R. 1973. Volume, energy and cyclicity of eruptions of Arenal Volcano, Costa Rica. Bulletin Volcano logique XXXVII-3, 416–37.
Naranjo, J. A. 1985. Sulphur flows at Lastarria volcano in the North Chilean Andes. Nature 313, 778–80.
Naranjo, J. A. 1987. Nuevos antecedentes acerca de los depdsitos de coladas de azufre en los volcanes Lastarria y Bayo, Andes Centrales (Chile, 25° 20′ S). Actas X Congreso Geoldóico Argenlino 4, 332–3 (expanded abstract).
Naranjo, J. A. 1988. Coladas de azufre de los volcanes Lastarria y Bayo en el forte de Chile: reologia, génesis e importancia en geologia planetaria. Revista Geológica de Chile 15, 312.
Naranjo, J. A. & Francis, P. 1987. High velocity debris avalanche at Lastarria volcano in the north Chilean Andes. Bulletin of Volcanology 49, 509–14.
Naranjo, J. A. & Puig, A. 1984. Geologia de las hojas Taltal y Chañaral. Regiones de Antofagasta y Atacama, Chile. Carta Geoldgica de Chile 62–63, 1140. Servicio Nacional de Geologia y Mineria.
O'Callaghan, L. & Francis, P. W. 1986. Volcanological and petrological evolution of San Pedro volcanco, Provincia El Loa, North Chile. Journal of the Geological Society, London 143, 275–86.
Palacios, C. & Lopez, L. 1979. Geoquimica y petrologia de andesitas cuaternarias de los Andes Centrales, 18° 57′−19° 28′ S. Actas 11 Congreso Geológico Chileno 3, E73E88.
Peccerillo, A. & Taylor, S. R. 1976. Geochemistry of Eocene calc-alkaline volcanic rocks from the Kastamonu area, Northern Turkey. Contributions to Mineralogy and Petrology 58, 6381.
Potts, P. J., Tindle, A. O. & Isaacs, M. C. 1983. On the precision of electron microprobe data: a new test for the homogeneity of mineral standards. American Mineralogist 68, 1237–42.
Potts, P. J., Webb, P. C. & Watson, J. S. 1984. Energy-dispersive X-ray fluorescence analysis of silicate rocks for major and trace elements. X-Ray Spectronietrv 13, 215.
Sakuyama, M. 1979. Evidence of magma mixing: petrological study of Shirouma-Oike calc-alkaline andesite volcano, Japan. Journal of Volcanology and Geothermal Research 5, 179208.
Simkin, T., Siebert, L., McClelland, L., Bridge, D., Newhall, C. & Latter, J. H. 1981. Volcanoes of the World. Hutchinson Ross, Stroudsburg, Pennsylvania.
Sparks, R. S. J., Sigurdsson, H. & Wilson, L. 1977. Magma mixing: a mechanism for triggering acid explosive eruptions. Nature 267, 315–18.
Stern, C. R. 1990. Tephrochronology of southernmost Patagonia. National Geographic Research 6, 110–26.
Taylor, S. R. & McLennan, S. M. 1981. The composition and evolution of the continental crust: rare earth evidence from sedimentary rocks. Philosophical Transactions of the Royal Society of London A 301, 381–99.
Thorpe, R. S. & Francis, P. W. 1979. Variations in Andean andesite compositions and their petrogenetic significance. Tectonophysics 57, 5370.
Thorpe, R. S., Francis, P. W. & O'Callaghan, L. 1984. Relative roles of source compositions, fractional crystallization and crustal contamination in the petrogenesis of Andean volcanic rocks. Philosophical Transactions of the Royal Society of London A 310, 675–92.
Thorpe, R. S., Potts, P. J. & Francis, P. W. 1976. Rare earth data and petrogenesis of andesite from the North Chilean Andes. Contributions to Mineralogy and Petrology 54, 6578.
Wood, D. A. 1979. A variably veined suboceanic upper mantle – genetic significance for mid-ocean ridge basalts from geo chemical evidence. Geology 7, 499503.
Wörner, G., Harmon, R. S., Davidson, J., Moorbath, S., Turner, D. L., McMillan, N., Nye, C., Lopez-Escobar, L. & Moreno, H. 1988. The Nevados de Payachata volcanic group (18° S/69° W, N. Chile). 1. Geological, geochemical and isotopic observations. Bulletin of Volcanology 50, 287303.
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