Advertisement

Contributions to Mineralogy and Petrology

, Volume 119, Issue 4, pp 387–408 | Cite as

Late Cenozoic magmatism of the Bolivian Altiplano

  • Jon P. Davidson
  • Shanaka L. de Silva
Article

Abstract

Small basalt to dacite volcanic centers are distributed sparsely over the Bolivian Altiplano, behind the Andean volcanic front. Most are Pliocene to Recent in age, and are characterized by textural and mineralogical disequilibrium with abundant xenoliths and xenocrysts. True phenocrysts are rare in the more mafic samples. Compared with Recent volcanic rocks from Andean stratovolcanoes, the Bolivian centers overlap in major element trends. Incompatible element contents tend to be higher, particularly in the eastern Altiplano. The ranges of isotopic compositions reflect ubiquitous crustal contamination. Pb isotope compositions are dominated by Pb from isotopically heterogeneous basement, resulting in a wide scatter of data lying between inferred crustal compositions and showing little overlap with possible mantle sources in the region. Rocks sampled from the Bolivian Altiplano were probably derived from asthenospheric mantle and subjected to extensive open system differentiation during ascent through the 70 km thick crust of the region. Major element trends are largely controlled by the fractionating phase assemblage (olivine, clinopyroxene and amphibole). Trace element and isotope systematics, however, defy realistic attempts at modeling due to the geographic scatter of samples, the uniformity of compositions at a given center, and the heterogeneity of the contaminant. Nevertheless, there are first order systematic trace element variations that appear to relate to the geometry of the subduction zone. In particular, LIFE/HFSE (exemplified by Ba/Nb), and Zr/Nb ratios decrease from the arc front eastward into the Altiplano. These variations are not easily reconciled with control by crustal contamination alone. A model is proposed in which the asthenospheric source is fluxed by high Ba/Nb slab-derived fluid to induce melting. Beneath the arc, high fluid flux increases the Ba/Nb ratio of the asthenosphre and leads to high degrees of partial melting (high Zr/Nb). To the east, lower or no fluid flux leads to low Ba/Nb and low degrees of partial melting (low Zr/Nb). Melting in the back arc region of the Altiplano may be facilitated by lithospheric delamination that leads to decompression melting of counter-flowing asthenosphere. There is no unequivocal evidence that requires a significant role for the lithospheric mantle.

Keywords

Olivine Crustal Contamination Fluid Flux Volcanic Front Mafic Sample 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Aitcheson S, Wörner G, Harmon RS, Moorbath S, Schneider A, Soler P, Swainbank I, Steele G (1993) Basement domains of the Altiplano in Bolivia and Chile revealed by Pb isotopes. EOS Trans Am Geophys Union 74:662Google Scholar
  2. Avila-Salinas W, Kussmaul S, Hormann PK Carrasco R (1985) Estudio petrólogico de la regón de Sajama (Bolivia). Serv Geol Bolivia Bol Ser A 3:9–32Google Scholar
  3. Barreiro B (1983) Lead isotopic compositions of South Sandwich Island volcanic rocks and their bearing on magmagenesis in intra-oceanic island arcs. Geochim Cosmochim Acta 47:817–822Google Scholar
  4. Bills B, de Silva SL, Currey D, Entemann R, Lillquist K, Donnelan A, Worden B (1994) Hydro-isostatic deflection and tectonic tilting in the central Andes: initial results of a GPS survey of Lake Minchin shorelines. Geophys Res Lett 21:293–296Google Scholar
  5. Carr MJ, Feigenson MD, Bennett EA (1990) Incompatible element and isotopic evidence for tectonic control of source mixing and melt extraction along the central American arc. Contrib Mineral Petrol 105:369–380Google Scholar
  6. Dasch EJ (1981) Lead isotopic compositions of metalliferous sediments from the Nazca Plate Geol Soc Am Mem 154:199–209Google Scholar
  7. Davidson JP, de Silva SL (1992) Volcanic rocks from the Bolivian Altiplano: insights into crustal structure, contamination, and magma genesis in the central Andes. Geology 20:1127–1130Google Scholar
  8. Davidson JP, de Silva SL (1993) Reply to comment on “Volcanic rocks from the Bolivian Altiplano: insights into crustal structure, contamination, and magma genesis” by Hoke et al. Geology 21:1148–1149Google Scholar
  9. Davidson JP, McMillan NJ, Moorbath S, Wörner G, Harmon RS, Lopez-Escobar L (1990) The Nevados de Payachata volcanic region (18° S, 69° W, N. Chile) II. Evidence for widespread crustal involvement in Andean magmatism. Contrib Mineral Petrol 105:412–432Google Scholar
  10. Davidson JP, Harmon RS, Wörner G (1991) The source of central Andean magmas: some considerations. Geol Soc Am Spec Pap 265:233–243Google Scholar
  11. de Silva SL (1989) The Altiplano-Puna volcanic complex of the central Andes. Geology 17:1102–1106Google Scholar
  12. de Silva SL, Francis PW (1991) Volcanoes of the central Andes. Springer, Berlin Heidelberg New YorkGoogle Scholar
  13. de Silva SL, Davidson JP, Croudace IW, Escobar A (1993) Volcanological and petrological evolution of volcán Tata Sabaya, SW Bolivia. J Volcanol Geotherm Res 55:305–335Google Scholar
  14. Dickinson R, Hatherton T (1967) Andesitic volcanism and seismicity around the Pacific. Science 157:801–803Google Scholar
  15. Eggins SM (1993) Origin and differentiation of picritic arc magmas, Ambae (Aoba), Vanuatu. Contrib Mineral Petrol 114:79–100Google Scholar
  16. Feeley TC (1993) Volcán Ollagüe: volcanology, petrology and geochemistry of a major Quaternary volcanic center in the central Andes. PhD thesis, UCLAGoogle Scholar
  17. Feeley TC, Davidson JP (1992) Across-strike geochemical variations in late Cenozoic volcanic rocks from the southern Salar de Uyuni region (20°–22° S), andean central volcanic zone. EOS Trans Am Geophys Union 73:644Google Scholar
  18. Feeley TC, Davidson JP (1994) Petrology of calc-alkaline lavas at volcán Ollagüe and the origin of compositional diversity at central Andean stratovolcanoes. J Petrol 35:1295–1340Google Scholar
  19. Feeley TC, Davidson JP, Armendia A (1993) The volcanic and magmatic evolution of volcán Ollagüe, a high-K, late Quaternary stratovolcano in the Andean Central Volcanic Zone. J Volcanol Geotherm Res 54:221–245Google Scholar
  20. Gerlach DC, Hart SR, Morales VWJ, Palacios C (1986) Mantle heterogeneity beneath the Nazca Plate: San Felix and Juan Fernandez islands. Nature 322:165–168Google Scholar
  21. Hansen C et al. 1994Google Scholar
  22. Hart SR, Davis KE (1978) Nickel partitioning between olivine and silicate melt. Earth Planet Sci Lett 40:203–219Google Scholar
  23. Hawkesworth CJ, Ellam R (1988) Chemical fluxes and wedge replenishment rates along recent destructive plate margins. Geology 17:46–49Google Scholar
  24. Hickey RL, Frey F, Gerlach DC, Lopez Escobar L (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 91:5963–5983Google Scholar
  25. Hickey-Vargas RL, Moreno Roa H, Lopez Escobar L, Frey F (1989) Geochemical variations in Andean basaltic and silicic lavas from the Villarica-Lanin volcanic chain (39.5° S): an evaluation of source heterogeneity, fractional crystallization and crustal assimilation. Contrib Mineral Petrol 103:361–386Google Scholar
  26. Hildreth W, Moorbath S (1988) Crustal contributions to arc magmatism in the Andes of central Chile. Contrib Mineral Petrol 98:455–499Google Scholar
  27. Hilton DR, Hammerschmidt K, Teufel S, Friedrichsen H (1994) Helium isotope characteristics of Andean geothermal fluids and lavas. Earth Planet Sci Lett 120:265–281Google Scholar
  28. Hoke L, Lamb SE, Entenmann J (1993) Comment on “Volcanic rocks from the Bolivian Altiplano: insights into crustal structure, contamination, and magma genesis” Geology 21:1147–1148Google Scholar
  29. Isacks BL (1988) Uplift of the Central Andean Plateau and bending of the Bolivian Orocline. J Geophys Res 93:3211–3231Google Scholar
  30. 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 variations. Earth Planet Sci Lett 57:47–62Google Scholar
  31. Kay RW, Kay SM (1993) Delamination and delamination magmatism. Tectonophysics 219:177–189Google Scholar
  32. Luff IW (1982) Petrogenesis of the island arc tholeiite series of the South Sandwich islands. PhD thesis, Univ of LeedsGoogle Scholar
  33. Morris JD, Hart SR (1983) Isotopic and incompatible element constraints on the genesis of island arc volcanics from Cold Bay and Amak Island, Aleutians, and implications for mantle structure. Geochim Cosmochim Acta 47:2015–2030Google Scholar
  34. Morris JD, Tera F (1989) 0Be and 9Be in mineral separates and whole rocks from volcanic arcs: implications for sediment subduction. Geochim Cosmochim Acta 53:3197–3206Google Scholar
  35. Nye CJ, Reid MR (1986) Geochemistry of primary and least fractionated lavas from Okmok volcano, central Aleutians: implications for arc magmagenesis. J Geophys Res 91:10271–10287Google Scholar
  36. O'Callaghan LJ, Francis PW (1986) Volcanological and petrological evolution of San Pedro volcano, Provincia El Loa, North Chile. J Geol Soc London 143:275–286Google Scholar
  37. Philpotts AR, Asher PM (1993) Wallrock melting and reaction effects along the Higganum diabase dike in Connecticut: contamination of a continental flood basalt feeder. J Petrol 34:1029–1058Google Scholar
  38. Roeder PL, Emslie RF (1970) Olivine-liquid equilibrium. Contrib Mineral Petrol 29:275–289Google Scholar
  39. Rogers GR, Hawkesworth CJ (1989) A geochemical traverse across the north Chilean Andes: evidence for crust generation from the mantle wedge. Earth Planet Sci Lett 91:271–285Google Scholar
  40. Schneider A (1985) Eruptive processes, mineralization and isotopic evolution of the Los Frailes, Kari-Kari region of Bolivia. PhD thesis, Univ of LondonGoogle Scholar
  41. Soler P, Carlier G, Aitcheson SJ, Fornari M (1992) Sr, Nd and Pb isotopic constraints upon the origin of the Quaternary shoshonitic lavas and deep structure of the central Altiplano of Bolivia. Terra Abstracts 5:584–585Google Scholar
  42. Stern CR (1991) Role of subduction erosion in the generation of Andean magmas. Geology 19:78–81Google Scholar
  43. Stern RJ, Ito E (1983) Trace element and isotopic constraints on the source of magmas in the active Volcano and Mariana island arcs, western Pacific. J Volcanol Geotherm Res 18:461–482Google Scholar
  44. Stolper E, Newman S (1994) The role of water in the petrogenesis of Mariana Trough magmas. Earth Planet Sci Lett 121:293–326Google Scholar
  45. Tatsumi Y, Hamilton DL, Nesbitt RW (1986) Chemical characteristics of fluid phase released from a subducted lithosphere and the origin of arc magmas: evidence from high-pressure experiments and natural rocks. J Volcanol Geotherm Res 29:293–309Google Scholar
  46. Taylor SR, McLennan SM (1985) The continental crust: its composition and evolution. Blackwell OxfordGoogle Scholar
  47. Thompson RN, Morrison MA, Hendry GL, Parry SJ (1984) an assessment of the relative roles of crust and mantle in magma genesis: an elemental approach. Phil Trans R Soc London 310:549–590Google Scholar
  48. Thorpe RS, Francis PW, O'Callaghan L (1984) Relative roles of source composition, fractional crystallization and crustal contamination in the petrogenesis of Andean volcanic rocks. Phil Trans R Soc London A 310:675–692Google Scholar
  49. Tilton GR, Barreiro B (1980) Origin of lead in Andean calc-alkaline lavas, southern Peru. Science 210:1245–1247Google Scholar
  50. Unruh DM, Tatsumoto M (1976) Lead isotopic composition and uranium, thorium and lead concentrations in sediments and basalts from the Nazca Plate. Initial Rep Deep Sea Drill Proj 34:341–347Google Scholar
  51. Wörner G, Harmon RS, Davidson J, Moorbath S, Turner DL, McMillian N, Nye C (1988) The Nevados de Payachata volcanic region (18° S/69° W, N. Chile). I. Geological, geochemical, and isotopic observations. Bull Volcanol 50:287–303Google Scholar
  52. Wörner G, Moorbath S, Harmon RS (1992) Andean Cenozoic volcanic centers reflect basement isotopic domains. Geology 20:1103–1106Google Scholar
  53. Yoder HS, Tilley CE (1962) Origin of basalt magmas; an experimental study of natural and synthetic rock systems. J Petrol 3:342:532Google Scholar

Copyright information

© Springer-Verlag 1998

Authors and Affiliations

  • Jon P. Davidson
    • 1
  • Shanaka L. de Silva
    • 2
  1. 1.Department of Earth and Space SciencesUCLALos AngelesUSA
  2. 2.Department of Geography and GeologyIndiana State UniversityTerre HauteUSA

Personalised recommendations