Contributions to Mineralogy and Petrology

, Volume 97, Issue 3, pp 378–388 | Cite as

The Cold Bay Volcanic Center, Aleutian Volcanic Arc

II. Implications for fractionation and mixing mechanism in calc-alkaline andesite genesis
  • James G. Brophy
Article
Received:
Accepted:

Abstract

The Cold Bay Volcanic Center has experienced two major stages of eruptive activity. Early (M-Series) acitivity produced bimodal Hi-Alumina basalt and calc-alkaline andesite lavas while later (FPK-Series) activity produced only calc-alkaline andesite. The spectrum of basalt compositions is believed to be due to high pressure (∼8 kb) fractionation at or near the base of the crust. Abundant mineralogical and geochemical evidence support a lower pressure mixing origin for all andesites. Inspection of the mineralogical data has shown that the earliest (M-Series) andesites were produced by mixing of basalt (<53 wt% SiO2) and silicic andesite (60.5 to 62.5 wt%) while later (FPK-Series) andesites resulted from the mixing of basaltic-andesite (53 to 56 wt%) and less silicic andesite (58.5 to 60.0 wt%). The major element and trace element geochemical data are consistent with a low pressure fractionation origin for the silicic endmember magmas and support the temporal variations in both mafic and silicic endmember compositions. The complete lack of crustal inclusions in all lavas is taken as evidence for a minimal crustal melting and/or assimilation role in the origin of the silicic endmembers. Many of the features of all andesites, including the important long term convergence of endmember magma compositions, are consistent with the process of liquid fractionation, accompanied by large scale magma mixing. A deduced upper limit of 62.5 wt% SiO2 for the silicic endmember magmas suggests that liquid fractionation, in the absence of major crustal melting, cannot produce more silicic magmas. A possible explanation is the presence of a rheological barrier, based on the concept of critical crystallinity (Marsh 1981), which prohibits more silicic liquids from being extracted from a crystal-liquid suspension.

Keywords

Liquid Fractionation Silicic Magma Silicic Liquid Pressure Fractionation Basalt Composition 
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.
This is a preview of subscription content, log in to check access.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Albee AL, Ray R (1970) Correction factors for electron probe micro-analysis of silicates, oxides, carbonates, phosphates and sulphates. Anal Chem 42:1408–1414Google Scholar
  2. Anderson AT (1976) Magma mixing: petrological process and volcanological tool. J Volcanol Geotherm Res 1:3–33Google Scholar
  3. Baker DE, Eggler DH (1983) Fractionation paths of Atka (Aleutian) high-alumina basalts: constraints from phase relations. J Volcanol Geotherm Res 18:387–404Google Scholar
  4. Brophy JG (1986) The Cold Bay Volcanic Center, Aleutian Volcanic Arc. I. Implications for the origin of Hi-Alumina basalt. Contrib Mineral Petrol 93:368–380Google Scholar
  5. Burk CA (1965) Geology of the Alaska Peninsula-Island arc and continental margin. Geol Soc Am Mem 99:250Google Scholar
  6. Burnham CW (1979) The importance of volatile constituents. In: Yoder HS (ed) The evolution of Igneous Rocks, Fiftieth Anniversary Perspectives. Princeton University Press, Princeton, pp 439–482Google Scholar
  7. Byers FM (1961) Petrology of three volcanic suites, Umnak and Bogoslof Islands, Aleutian Islands, Alaska. Geol Soc Am Bull 79:93–128Google Scholar
  8. Carr MJ, Pontier NK (1981) Evolution of a young parasitic cone towards a mature central vent: Izalco and Santa Ana volcanoes in El Salvador, Central America. J Volcanol Geotherm Res 11:277–292Google Scholar
  9. Chen CF, Turner JS (1980) Crystallization in a double-diffusive convective system. J Geophys Res 85:2573–2593Google Scholar
  10. Coats RR (1952) Magmatic differentiation in Tertiary and Quaternary volcanic rocks from Adak and Kanaga Islands, Aleutian Islands. Geol Soc Am Bull 63:485–514Google Scholar
  11. Conrad WK, Kay RW (1984) Ultramafic and mafic inclusions from Adak Island: Crystallization history, and implications of primary magmas and crustal evolution in the Aleutian arc. J Petrol 25:88–125Google Scholar
  12. Conrad WK, Kay SM, Kay RW (1983) Magma mixing in the Aleutian arc: Evidence from cognate inclusions and composite xenoliths. J Volcanol Geotherm Res 18:279–295Google Scholar
  13. Cox KG, Bell JD, Pankhurst RJ (1979) The interpretation of igneous rocks. George Allen and Unwin, London, p 450Google Scholar
  14. Eichelberger JC (1975) Origin of andesite and dacite: evidence of mixing at Glass Mountain in California and the other circum-Pacific volcanoes. Geol Soc Am Bull 86:1381–1391Google Scholar
  15. Eichelberger JC (1980) Vesiculation of mafic magma during replenishment of silicic magma resevoirs. Nature 288:446–450Google Scholar
  16. Ewart A (1982) The mineralogy and petrology of Tertiary-Recent orogenic volcanic rocks: with special reference to the andesitic-basaltic compositional range. In: Thorpe RS (ed) Andesites: orogenic andesites and related rocks. John Wiley and Sons, New York, pp 25–95Google Scholar
  17. Fairbrothers GE, Carr MJ, Mayfield DG (1978) Temporal magmatic variation at Boqueron volcano, El Salvador. Contrib Mineral Petrol 67:1–9Google Scholar
  18. Fenner CN (1926) The Katmai magmatic province. J Geol 34:675–772Google Scholar
  19. Gerlach DC, Grove TL (1982) Petrology of Medicine Lake Highland volcanics: characterization of the end members of magma mixing. Contrib Mineral Petrol 80:147–159Google Scholar
  20. Grove TL, Donnelly-Nolan JM (1986) The evolution of young silicic lavas at Medicine Lake Volcano, California: implications for the origin of compositional gaps in calc-alkaline series lavas. Contrib Mineral Petrol 92:281–302Google Scholar
  21. Grove TL, Gerlach DC, Sando TW (1982) Origin of calc-alkaline series lavas at Medicine Lake Volcano by fractionation, assimilation and mixing. Contrib Mineral Petrol 80:160–182Google Scholar
  22. Huppert HE, Sparks RSJ, Turner JS (1982) Effects of volatiles on mixing in calc-alkaline magma systems. Nature 297:554–557Google Scholar
  23. Kay SM, Kay RW (1985) Aleutian tholeiitic and calc-alkaline magma series I: the mafic phenocrysts. Contrib Mineral Petrol 90:276–290Google Scholar
  24. Kay SM, Kay RW, Citron GP (1982) Tectonic controls on tholeiitic and calc-alkaline magmatism in the Aleutian arc. J Geophys Res 87:4051–4072Google Scholar
  25. Korringa MK, Noble DC (1971) Distribution of Sr and Ba between natural feldspar and igneous melt. Earth Planet Sci Lett 11:147–151Google Scholar
  26. Kouchi A, Sunagawa I (1985) A model for mixing basaltic and dacitic magmas as deduced from experimental data. Contrib Mineral Petrol 89:17–23Google Scholar
  27. Kuno H (1950) Petrology of Hakone volcano and the adjacent areas, Japan. Geol Soc Am Bull 61:957–1020Google Scholar
  28. Luhr JF, Carmichael ISE (1980) The Colima Volcanic Complex, Mexico. I. Post-caldera andesites form Volcan Colima. Contrib Mineral Petrol 71:343–372Google Scholar
  29. Luhr JF, Carmichael ISE (1985) Jorullo Volcano, Michoacan, Mexico (1759–1774): The earliest stages of fractionation in calc-alkaline magmas. Contrib Mineral Petrol 90:142–161Google Scholar
  30. Marsh BD (1976) Some Aleutian andesites: their nature and source. J Geol 84:27–45Google Scholar
  31. Marsch BD (1981) On the crystallinity, probability of occurrence, and rheology of lava and magma. Contrib Mineral Petrol 78:85–98Google Scholar
  32. McBirney AR (1980) Mixing and unmixing of magmas. J Volcanol Geotherm Res 7:357–371Google Scholar
  33. McBirney AR, Baker BH, Nilson RH (1985) Liquid fractionation. Part I: Basic principles and experimental simulations. J Volcanol Geotherm Res 24:1–24Google Scholar
  34. Merzbacher C, Eggler DH (1984) A magmatic geohygrometer: Application to Mt. St. Helens and other dacitic magmas. Geology 12:587–590Google Scholar
  35. 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
  36. Perfit MR, Brueckner H, Lawrence J, Kay RW (1980) Trace element and isotopic variations in a zoned pluton and associated rocks, Unalaska Island, Alaska: a model for fractionation in the Aleutian calc-alkaline suite. Contrib Mineral Petrol 73:69–87Google Scholar
  37. Reyners M, Coles KS (1982) Fine structure of the dipping seismic zone and subduction mechanics in the Shumagin Islands, Alaska. J Geophys Res 87:356–366Google Scholar
  38. Sack RO, Carmichael ISE, Rivers M, Ghiorso MS (1980) Ferric-ferrous equilibria in natural silicate liquids at 1 bar. Contrib Mineral Petrol 79:169–186Google Scholar
  39. Sakuyama M (1979) Evidence of magma mixing: petrological study of Shirouma-Oike calc-alkaline andesite volcano, Japan. J Volcanol Geotherm Res 5:179–208Google Scholar
  40. Sakuyama M (1981) Petrological study of the Myoko and Kurohime volcanoes, Japan: crystallization sequence and evidence for magma mixing. J Petrol 22:553–583Google Scholar
  41. Sparks RSJ, Huppert HE (1984) Density changes during the fractional crystallization of basaltic magmas: implications for the evolution of layered intrusions. Contrib Mineral Petrol 85:300–309Google Scholar
  42. Sparks RSJ, Sigurdsson H, Wilson L (1977) Magma mixing: a mechanism for triggering acid explosive eruptions. Nature 267:315–318Google Scholar
  43. Stormer JC Jr (1983) The effects of recalculation on estimates of temperature and oxygen fugacity from analyses of multi-component Fe-Ti oxides. Am Mineral 68:586–594Google Scholar
  44. Turner JS, Gustavson LB (1978) The flow of hot saline solutions from vents in the sea floor — Some implications for exhalative massive sulfide and other ore deposits. Econ Geol 73:1082–1100Google Scholar
  45. Turner JS, Huppert HE, Sparks RSJ (1983) An experimental investigation of volatile exsolution in evolving magma chambers. J Volcanol Geotherm Res 16:263–277Google Scholar
  46. Von Drach V, Marsh BD, Wasserburg GJ (1986) Nd and Sr isotopes in the Aleutians: multicomponent parenthood of island arc magmas. Contrib Mineral Petrol 92:13–34Google Scholar
  47. Waldron HH (1961) Geologic reconnaissance of Frosty Peak Volcanoe and vicinity, Alaska. US Geol Surv Bull 1028-T, p 31Google Scholar
  48. Walker D, Shibata T, Delong SE (1979) Abyssal tholeiites from the Oceanographer Fracture Zone: II Phase equilibria and mixing. Contrib Mineral Petrol 70:111–125Google Scholar
  49. Wells PRA (1977) Pyroxene thermometry in simple and complex systems. Contrib Mineral Petrol 62:129–139Google Scholar
  50. Wood BJ, Banno S (1973) Garnet-orthopyroxene and orthopyroxene-clinopyroxene relationships in simple and complex systems. Contrib Mineral Petrol 42:109–124Google Scholar

Copyright information

© Springer-Verlag 1987

Authors and Affiliations

  • James G. Brophy
    • 1
  1. 1.Department of GeologyIndiana University BloomingtonUSA

Personalised recommendations