Hostname: page-component-7c8c6479df-xxrs7 Total loading time: 0 Render date: 2024-03-28T07:44:39.469Z Has data issue: false hasContentIssue false

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

Published online by Cambridge University Press:  01 May 2009

José A. Naranjo
Affiliation:
Servicio Nacional de Geologia y Mineria, Casilla 10465, Santiago, Chile

Abstract

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.

Type
Articles
Copyright
Copyright © Cambridge University Press 1992

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Anderson, A. T. 1976. Magma mixing: petrological process and volcanological tool. Journal of Volcanology and Geothermal Research 1, 133.Google Scholar
Baker, P. E. 1982. Evolution and classification of orogenic volcanic rocks. In Andesites (ed. Thorpe, R. S.), pp. 2595. John Wiley and Sons.Google Scholar
Barazangi, M. & Isacks, B. 1976. Spatial distribution of earthquakes and subduction of the Nazca plate beneath South America. Geology 4, 686–92.Google Scholar
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.CrossRefGoogle Scholar
Déruelle, B. 1982. Petrology of the Plio-Quaternary Volcanism of the south-central and meridional Andes. Journal of Volcanology and Geothertnal Research 14, 77124.Google Scholar
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.CrossRefGoogle Scholar
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.Google Scholar
Eichelberger, J. C. 1978. Andesite volcanism and crustal evolution. Nature 275, 21–7.Google Scholar
Eichelberger, J. C. 1980. Vesiculation of mafic magma during replenishment of silicic magma reservoirs. Nature 288, 446–50.CrossRefGoogle Scholar
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.Google Scholar
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.CrossRefGoogle Scholar
Gardeweg, M., Cornejo, P. & Davidson, J. 1984. Geologia del Volcán Llullaillaco, altiplano de Antofagasta, Chile (Andes Centrales). Revista Geológica de Chile 23, 2137.Google Scholar
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.Google Scholar
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.CrossRefGoogle Scholar
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.Google Scholar
Hildreth, W. & Moorbath, S. 1988. Crustal contributions to arc magmatism in the Andes of Central Chile. Contributions to Mineralogy and Petrology 98, 455–89.Google Scholar
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.CrossRefGoogle Scholar
James, D. E. 1971. Plate tectonic model for the evolution of the Central Andes. Geological Society of America Bulletin 82, 3325–46.Google Scholar
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, 592600.2.0.CO;2>CrossRefGoogle Scholar
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.CrossRefGoogle Scholar
Kouchi, A. & Sunagawa, I. 1983. Mixing basaltic and dacitic magmas by forced convection. Nature 304, 527–8.Google Scholar
Leake, B. E. 1978. Nomenclature of amphiboles. American Mineralogist 63, 1023–52.Google Scholar
McBirney, A. R. 1980. Mixing and unmixing of magmas. Journal of Volcanology and Geothermal Research 7, 357–71.CrossRefGoogle Scholar
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.Google Scholar
Melson, W. G. & Saenz, R. 1973. Volume, energy and cyclicity of eruptions of Arenal Volcano, Costa Rica. Bulletin Volcano logique XXXVII-3, 416–37.Google Scholar
Naranjo, J. A. 1985. Sulphur flows at Lastarria volcano in the North Chilean Andes. Nature 313, 778–80.Google Scholar
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).Google Scholar
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.Google Scholar
Naranjo, J. A. & Francis, P. 1987. High velocity debris avalanche at Lastarria volcano in the north Chilean Andes. Bulletin of Volcanology 49, 509–14.Google Scholar
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.Google Scholar
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.Google Scholar
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.Google Scholar
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.CrossRefGoogle Scholar
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.Google Scholar
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.Google Scholar
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.Google Scholar
Simkin, T., Siebert, L., McClelland, L., Bridge, D., Newhall, C. & Latter, J. H. 1981. Volcanoes of the World. Hutchinson Ross, Stroudsburg, Pennsylvania.Google Scholar
Sparks, R. S. J., Sigurdsson, H. & Wilson, L. 1977. Magma mixing: a mechanism for triggering acid explosive eruptions. Nature 267, 315–18.Google Scholar
Stern, C. R. 1990. Tephrochronology of southernmost Patagonia. National Geographic Research 6, 110–26.Google Scholar
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.Google Scholar
Thorpe, R. S. & Francis, P. W. 1979. Variations in Andean andesite compositions and their petrogenetic significance. Tectonophysics 57, 5370.Google Scholar
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.Google Scholar
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.Google Scholar
Wood, D. A. 1979. A variably veined suboceanic upper mantle – genetic significance for mid-ocean ridge basalts from geo chemical evidence. Geology 7, 499503.2.0.CO;2>CrossRefGoogle Scholar
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.Google Scholar