Abstract
Subduction-related volcanism in the Nevados de Payachata region of the Central Andes at 18°S comprises two temporally and geochemically distinct phases. An older period of magmatism is represented by glaciated stratocones and ignimbrite sheets of late Miocene age. The Pleistocene to Recent phase (≤0.3 Ma) includes the twin stratovolcanoes Volcan Pomerape and Volcan Parinacota (the Nevados de Payachata volcanic group) and two small centers to the west (i. e., Caquena and Vilacollo). Both stratovolcanoes consist of an older dome-and-flow series capped by an andesitic cone. The younger cone, i. e., V. Parinacota, suffered a postglacial cone collapse producing a widespread debris-avalanche deposit. Subsequently, the cone reformed during a brief, second volcanic episode. A number of small, relatively mafic, satellitic cinder cones and associated flows were produced during the most recent activity at V. Parinacota. At the older cone, i. e., V. Pomerape, an early dome sequence with an overlying isolated mafic spatter cone and the cone-forming andesitic-dacitic phase (mostly flows) have been recognized. The two Nevados de Payachata stratovolcanoes display continuous major- and trace-element trends from high-K2O basaltic andesites through rhyolites (53%–76% SiO2) that are well defined and distinct from those of the older volcanic centers. Petrography, chemical composition, and eruptive styles at V. Parinacota differ between pre- and post-debris-avalanche lavas. Precollapse flows have abundant amphibole (at SiO2 > 59 wt%) and lower Mg numbers than postcollapse lavas, which are generally less silicic and more restricted in composition. Compositional variations indicate that the magmas of the Nevados de Payachata volcanic group evolved through a combination of fractional crystallization, crustal assimilation, and intratrend magma mixing. Isotope compositions exhibit only minor variations. Pb-isotope ratios are relatively low (206Pb/204Pb = 17.95–18.20 and208Pb/204Pb = 38.2–38.5);87Sr/86Sr ratios range 0.70612–0.70707,143Nd/144Nd ratios range 0.51238–0.51230, andγ 18OSMOW values range from + 6.8%o to + 7.6%o SMOW. A comparison with other Central Volcanic Zone centers shows that the Nevados de Payachata magmas are unusually rich in Ba (up to 1800 ppm) and Sr (up to 1700 ppm) and thus represent an unusual chemical signature in the Andean arc. These chemical and isotope variations suggest a complex petrogenetic evolution involving at least three distinct components. Primary mantle-derived melts, which are similar to those generated by subduction processes throughout the Andean arc, are modified by deep crustal interactions to produce magmas that are parental to those erupted at the surface. These magmas subsequently evolve at shallower levels through assimilation-crystallization processes involving upper crust and intratrend magma mixing which in both cases were restricted to end members of low isotopic contrast.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Barazangi M, Isacks BL (1976) Spatial distribution of earthquakes and subduction of the Nasca plate below South America. Geology 4:686–692
Barreiro BA (1984) Lead isotopes and Andean magmagenesis. Harmon RS, Barreiro BA (eds) Andean Magmatism, Chemical and Isotopic Constraints, SHIVA Publ. Nantwich, UK, p. 21–30
Barreiro BA, Clark AH (1984) Lead isotopic evidence for evolutionary changes in magma-crust interaction, Central Andes, southern Peru. Earth Planet Sci Lett 69:30–42
Bevis B, Isacks BL (1984) Hypocentral trend surface analysis: Probing the geometry of Benioff zones. J Geophys Res 89:6153–6170
Chase CG (1978) Plate kinematics: The Americas, East Africa, and the rest of the world. Earth Planet Sci Lett 37:355–368
Deruelle B (1982) Petrology of the Plio-Quaternary volcanism of the South-Central and Meridional Andes. J Volcanol Geoth Res 14:77–124
Deruelle B, Harmon RS, Moorbath S (1983) Combined Sr-O relationships and petrogenesis of Andean volcanics of South America. Nature 302:814–816
Dostal J, Dupuy C, Lefevre C (1977) Rare earth element distribution in Plio-Quarternary volcanic rocks from southern Peru. Lithos 10:173–183
Dupuy C, Lefevre C (1974) Fractionnement des elements en trace Li, Rb, Ba, Sr dans les series andesitiques et shoshonitiques du Perou. Comparison aves d'autre zones orogeniques. Contrib Mineral Petrol 46:147–157
Fernandez A, Hörmann PK, Kussmaul S, Meave J, Pichler H, Subieta T (1973) First petrologic data of young volcanic rocks of SW-Bolivia. Tscherm Mineral Petrogr Mitt 19:149–173
Francis PW, Self S (1987) Collapsing volcanoes. Scient Amer 255:90–97
Francis PW, Roobol MJ, Walker GPL, Cobbold RR, Coward M (1974) The San Pedro and San Pablo volcanoes of northern Chile and their hot avalanche deposits. Geol Rundsch 63:357–388
Francis PW, Moorbath S, Thorpe RS (1977) Strontium isotope data for recent andesites in Ecuador and North Chile. Earth Planet Sci Lett 37:197–202
Francis PW, Thorpe RS, Moorbath S, Kretzschmar GA, Hammill M (1980) Strontium isotope evidence for crustal contamination of calc-alkaline volcanic rocks from Cerro Galan, Northwest Argentina. Earth Planet Sci Lett 48:257–267
Francis PW, O'Callaghan L, Kretzschmar GA, Thorpe RS, Sparks RSJ, Page PN, de Barrio RE, Gillou G, Gonzalez OE (1983) The Cerro Galan Ignimbrite. Nature 301:51–53
Francis PW, McDonough WF, Hammill M, O'Callaghan LJ, Thorpe RS (1984) The Cerro Purico shield complex, North Chile. In Harmon RS, Barreiro BA (eds): Andean Magmatism, Chemical and Isotopic Constraints, SHIVA Publ. Nantwich, UK, p. 106–123
Gill JB (1981) Orogenic Andesites and Plate Tectonics. Springer (Berlin-New York), p. 1–390
Grange F, Hatzfeld D, Cunningham P, Molnar P, Roecker SW, Suarez G, Rodrigues A, Ocola L (1984) Tectonic implications of the microearthquake seismicity and fault plane solutions in Southern Peru. J Geophys Res 89:6139–6152
Handschuhmacher DW (1976) Post-Eocene plate tectonics of the eastern Pacific. In Sutton GH, Manghnani MH, Moberly R (eds): The Geophysics of the Pacific Ocean and its Margins. Am Geophys Union, Washington DC, p. 117–202
Harmon RS, Hoefs J (1984) Oxygen isotope ratios in Late Cenozoic Andean volcanics. 9–20
Harmon RS, Thorpe RS, Francis PW (1981) Petrogenesis of Andean andesites from combined O-Sr relationships. Nature 290:396–399
Harmon RS, Barreiro BA, Moorbath S, Hoefs J, Francis PW, Thorpe RS, Deruelle B, McHugh J, Viglino JA (1984) Regional O-, Sr- and Pb-isotope relationships in Late Cenozoic calc-alkaline lavas of the Andean Cordillera. J Geol Soc London 141:803–822
Hawkesworth CJ, Norry MJ, Roddick JC, Baker PE, Francis PW, Thorpe RS (1979) 143 Nd/144 Nd, 87 Sr/86 Sr, and incompatible element variations in calc-alkaline Andesites and Plateau lavas from S-America. Earth Planet Sci Lett 42:45–57
Hawkesworth CJ, Hammill M, Gledhill AR, van Calsteren P, Rogers G (1982) Isotope and trace element evidence for late-stage intracrustal melting in the High Andes. Earth Planet Sci Lett 51:297–308
Hickey RL, Gerlach DC, Frey FA (1984) Geochemical variations in volcanic rocks from central-south Chile (33–42°S). In Harmon RS, Barreiro BA (eds): Andean Magmatism, Chemical and Isotopic Constraints, SHIVA Publ. Nantwich, UK, p 72–95
Hickey RL, Frey FA, Gerlach DC (1986) Multiple sources for basaltic arc rocks from the Southern Volcanic Zone of the Andes (34°–41°S): Trace element and isotopic evidence for contributions from subducted oceanic crust, mantle, and continental crust. J Geophys Res 91:5963–5983
Hörmann PK, Pichler HP, Zeil W (1973) New data on the young volcanism in the Puna of NW-Argentina. Geol Rundsch 62:397–418
James DE (1971a) Plate tectonic model for the evolution of the Central Andes. Geol Soc Am Bull 82:3325–3346
James DE (1971b) Andean crustal and upper mantle structure. J Geophys Res 76:3246–3271
James DE (1982) A combined O, Sr, Nd, and Pb isotopic and trace element study of crustal contamination in central Andean lavas, I. Local geochemical vairiations. Earth Planet Sci Lett 57:47–62
James DE (1984) Quantitative models for Crustal Contamination in the Central Northern Andes. In Harmon RS, Barreiro BA (eds): Andean Magmatism, Chemical and Isotopic Constraints, SHIVA Publ. Nantwich, UK, p. 124–138
James DE, Brooks C, Cuyumbamba A (1976) Andean Cenozoic volcanism: Magma genesis in the light of Sr isotopic composition and trace element geochemistry. Geol Soc Am Bull 7:592–600
Katsui Y, Gonzalez-Ferran O (1968) Geologia del area neovolcanica de los Nevados de Payachata. Publicacion No. 29, Universidad de Chile, Facultad de Ciencas Fisicas y Matematicas, Departmento Geologia, pp 1–61 with plates
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. J Volcanol Geoth Res 2:49–71
Kussmaul S, Hörmann PK, Ploskonka E, Subieta T (1977) Volcanism and structure of SW-Bolivia. J Volcanol Geoth Res 2:3–111
Longstaffe FJ, Clark AH, McNutt RH, Zentilli M (1983) Oxygen isotopic compositions of Central Andean plutonic and volcanic rocks, latitudes 26°–29°S. Earth Planet Sci Lett 64:9–18
McNutt RH, Crocket JH, Clark AH, Caelles JC, Farrar E, Haynes SJ, Zentilli M (1975) Initial87Sr/86Sr ratios of plutonic and volcanic rocks of the Central Andes between latitudes 26° and 29° south. Earth Planet Sci Lett 27:305–313
McNutt RH, Clark AH, Zentilli M (1979) Lead isotope compositions of Andean igneous rocks, latitudes 26°–29°S: petrologic and metallogenic implications. Econ Geol 74:827–837
O'Callaghan LJ, Francis PW (1986) Volcanological and petrological evolution of San Pedro volcano, Provincia El Loa, North Chile. J Geol Soc London 143:275–286
Pardo-Casas F, Molnar P (1987) Relative motion of the Nazca (Farallon) and south American plates since Late Cretaceous time. Tectonics 6:233–248
Pichler H, Zeil W (1972) Paleozoic and Mesozoic ignimbrites of northern Chile. N Jb Mineral Abh 116:196–207
Pilger RH (1981) Plate reconstructions, aseismic ridges, and low angle suduction beneath the Andes. Geol Soc Am Bull 92:448–456
Schwarz G, Martinez E, Bannister J (1986) Untersuchungen zur elektrischen Leitfähigkeit in den zentralen Anden. In: Giese P (ed) Forschungsberichte aus den Zentralen Anden (21°–25°S), Berliner Geowissenschaftliche Abhandlungen 66:49–72
Siegers A, Pichler H, Zeil W (1969) Trace element abundances in the andesite formation of northern Chile. Geochim Cosmochim Acta 33:882–887
Stauder W (1973) Mechanism and spatial distribution of Chilean earthquakes with relation to subduction of the oceanic plate. J Geophys Res 78:5033–5061
Stauder W (1975) Suduction of the Nazca plate under Peru as evidenced by focal mechanisms and by seismicity. J Geophys Res 80:1053–1064
Tagiri M, Onuma N, Lahsen A, Moreno H, Takahashi M, Notsu K. Takaku Y (1985) SB systematics on the central Andes volcanic zone of northern Chile. In: Geochemical Investigation of the Southern Andes Volcanic Belt, 1982-1984. Overseas Scientific Research 59043009, Ibaraki University, Japan, 217–230
Thornburg TM, Kulm LD (1987) Sedimentation in the Chile trench: Depositional morphologies, lithofacies, and stratigraphy. Geol Soc Am Bull 98:33–52
Thorpe RS, Francis PW (1979) Variations in Andean andesite compositions and their petrogenetic significance. Tectonophysics 57:53–70
Thorpe RS, Potts PJ, Francis PW (1976) Rare earth data and petrogenesis of andesite from the north Chilean Andes. Contrib Mineral Petrol 54:65–78
Thorpe RS, Francis PW, Moorbath S (1979) Rare earth and Sr-isotope evidence concerning the petrogenesis of north Chilean ignimbrites. Earth Planet Sci Lett 42:359–367
Thorpe RS, Francis PW, Hammill M, Baker MCW (1982) The Andes. In: Thorpe RS (ed) Andesites: Orogenic Andesites and related Rocks, Wiley and Sons, New York, p 187–205
Tilton GR, Barreiro BA (1980) Origin of lead in Andean calcalkaline lavas, southern Peru. Science 210:1245–1247
Unruh DM, Tasumoto M (1976) Lead isotopic compositions and uranium, thorium and lead concentrations in sediments and basalts from the Nasca plate. Init Rep Deep Sea Drill Project 34:341–347
Wigger P (1986) Krustenseismische Untersuchungen in Nord-Chile und Süd-Bolivien. In: Giese P (ed) Forschungsberichte aus den zentralen Anden (21°–25°S), Berliner Geowissenschaftliche Abhandlungen 66:31–48
Wortel MJR (1984) Spatial and temporal variations in the Andean subduction zone. J Geol Soc London 141:783–791
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Wörner, G., Harmon, R.S., Davidson, J. et al. The Nevados de Payachata volcanic region (18°S/69°W, N. Chile). Bull Volcanol 50, 287–303 (1988). https://doi.org/10.1007/BF01073587
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF01073587