Contributions to Mineralogy and Petrology

, Volume 148, Issue 5, pp 542–565 | Cite as

Magnesian andesite and dacite lavas from Mt. Shasta, northern California: products of fractional crystallization of H2O-rich mantle melts

  • Timothy L. Grove
  • Michael B. Baker
  • Richard C. Price
  • Stephen W. Parman
  • Linda T. Elkins-Tanton
  • Nilanjan Chatterjee
  • Othmar Müntener
Original Paper


Mt. Shasta andesite and dacite lavas contain high MgO (3.5–5 wt.%), very low FeO*/MgO (1–1.5) and 60–66 wt.% SiO2. The range of major and trace element compositions of the Shasta lavas can be explained through fractional crystallization (~50–60 wt.%) with subsequent magma mixing of a parent magma that had the major element composition of an H2O-rich primitive magnesian andesite (PMA). Isotopic and trace element characteristics of the Mt. Shasta stratocone lavas are highly variable and span the same range of compositions that is found in the parental basaltic andesite and PMA lavas. This variability is inherited from compositional variations in the input contributed from melting of mantle wedge peridotite that was fluxed by a slab-derived, fluid-rich component. Evidence preserved in phenocryst assemblages indicates mixing of magmas that experienced variable amounts of fractional crystallization over a range of crustal depths from ~25 to ~4 km beneath Mt. Shasta. Major and trace element evidence is also consistent with magma mixing. Pre-eruptive crystallization extended from shallow crustal levels under degassed conditions (~4 wt.% H2O) to lower crustal depths with magmatic H2O contents of ~10–15 wt.%. Oxygen fugacity varied over 2 log units from one above to one below the Nickel-Nickel Oxide buffer. The input of buoyant H2O-rich magmas containing 10–15 wt.% H2O may have triggered magma mixing and facilitated eruption. Alternatively, vesiculation of oversaturated H2O-rich melts could also play an important role in mixing and eruption.


Olivine Fractional Crystallization Basaltic Andesite Trace Element Abundance Dacite Lava 
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.



The authors thank J. Donnelly-Nolan, T. Sisson and P. Wallace for thoughtful reviews. The authors also thank R.L. Christiansen for sharing unpublished mapping and analyses of Mt. Shasta and for guidance in the collection of lavas discussed in this paper. This research was supported by National Science Foundation Grants EAR-9706214, EAR-0073766 and OCE-00001821.


  1. Albee AL, Ray L (1970) Correction factors for electron probe microanalysis of silicates, oxides, carbonates, phosphates and sulfates. Anal Chem 42:1408–1414Google Scholar
  2. Andersen DJ, Lindsley DH (1988) Internally consistent solution model for Fe-Mg-Mn oxides: Fe-Ti oxides. Am Mineral 73:714–726Google Scholar
  3. Anderson AT (1974a) Evidence for a picritic, volatile-rich magma beneath Mt. Shasta, California. J Petrol 15:243–267Google Scholar
  4. Anderson AT (1974b) Chlorine, sulfur and water in magmas and oceans. Geol Soc Am Bull 85:1585–1492Google Scholar
  5. Anderson AT (1976) Magma mixing: petrological process and volcanological tool. J Volcan Geotherm Res 1:3–33CrossRefGoogle Scholar
  6. Anderson AT (1979) Water in some hypersthenic magmas. Jour Geol 87:509–531Google Scholar
  7. Armstrong JT (1995) CITZAF—A package of correction programs for the quantitative electron microbeam x-ray analysis of thick polished materials, thin-films and particles. Microbeam Anal 4:177–200Google Scholar
  8. Bacon CR, Druitt TH (1988) Compositional evolution of the zoned calcalkaline magma chamber at Mount Mazama, Crater Lake, Oregon. Contrib Mineral Petrol 98:224–256Google Scholar
  9. Bacon CR, Bruggman PE, Christiansen RL, Clynne MA, Donnelly-Nolan JM, Hildreth W (1997) Primitive magmas at five Cascade volcanic fields: Melts from hot, heterogeneous sub-arc mantle. Can Mineral 35:397–423Google Scholar
  10. Baker MB (1988) Evolution of lavas at Mt. Shasta volcano, N. California: an experimental and petrologic study. PhD Thesis, M.I.T.Google Scholar
  11. Baker MB, Grove TL, Kinzler RJ, Donnelly-Nolan JM, Wandless GA (1991) Origin of compositional zonation (high-alumina basalt to basaltic andesite) in the Giant Crater lava field: Medicine Lake Volcano, northern California. J Geophys Res 96:21819–21842Google Scholar
  12. Baker MB, Grove TL, Price R (1994) Primitive basalts and andesites from the Mt. Shasta region, N. California: products of varying melt fraction and water content. Contrib Mineral Petrol 118:111–129Google Scholar
  13. Bence AE, Albee AL (1968) Empirical correction factors for the electron microanalysis of silicates and oxides. J Geol 76:382–403Google Scholar
  14. Benz HM, Zandt G, Oppenheimer DH (1992) Lithospheric structure of northern California from teleseismic images of the upper mantle. J Geophys Res 97:4791–4807Google Scholar
  15. Blakely RJ, Jachens RC, Simpson RW, Couch RW (1985) Tectonic setting of the southern Cascade Range as interpreted from its magnetic and gravity fields. Geol Soc Am Bull 96:43–48Google Scholar
  16. Blakely RJ, Christiansen RL, Guffanti M, Wells RE, Donnelly-Nolan JM, Muffler MJP, Clynne MA, Smith JG (1997) Gravity anomolies, quaternary vents and quaternary faults in the southern Cascade range, Oregon and California: Implications for backarc evolution. J Geophys Res 102:22513–22507Google Scholar
  17. Blatter DL, Carmichael ISE (1998) Plagioclase-free andesites from Zitacuaro (Michoacan), Mexico: petrology and experimental constraints. Contrib Mineral Petrol 132:121–138CrossRefGoogle Scholar
  18. Bottinga Y and Weill D (1970) Densities of liquid silicate systems calculated from partial molar volumes of oxide components. Am J Sci 269:169–182Google Scholar
  19. Cervantes P, Wallace PJ (2003) Magma degassing and basaltic eruption styles: a case study of ~2000 ybp Xitle volcano in central Mexico. J Volcanol Geotherm Res 120:249–270CrossRefGoogle Scholar
  20. Christiansen RL, Kleinhampl FJ, Blakely RJ, Tuchek ET, Johnson FL, Conyac MD (1977) Resource appraisal of the Mt. Shasta wilderness study area, Siskiyou County, California. Open-file Report 77–250, U.S. Geol. Survey, p 53Google Scholar
  21. Condie KC, Swenson DH (1973) Compositional variation in three Cascade stratovolcanoes: Jefferson, Rainer, Shasta. Bull Volcanol 37:205–230Google Scholar
  22. Donnelly-Nolan JM (1988) A magmatic model of Medicine Lake volcano, California. J Geophys Res 93:4412–4420Google Scholar
  23. Eichelberger JC (1980) Vesiculation of mafic magma during replenishment of silicic magma reservoirs. Nature 288:446–450Google Scholar
  24. Ewart A (1979) A review of the mineralogy and chemistry of Tertiary-Recent, dacitic, latitic, rhyolitic and related sialic rocks. In: Barker F (ed) Trondjhemites, dacites and related rocks. Elsevier, Amsterdam, pp 13–121Google Scholar
  25. Ewart A (1982) The mineralogy and petrology of Tertiary-Recent orogenic volcanic rocks: with special reference to the andesite-basaltic compositional range. In: Thorpe RS (ed) Andesites. Wiley, New York, pp 25–95Google Scholar
  26. Fuis GS, Zucca JJ, Mooney WD, Milkereit B (1987) A geologic interpretation of seismic-reflection results in northern California. Geol Soc Am Bull 98:53–65Google Scholar
  27. Gaetani GA, Grove TL (1998) The influence of water on melting of mantle peridotite. Contrib Mineral Petrol 131:323–346CrossRefGoogle Scholar
  28. Gamble JA, Wood P, Price RC, Smith IEM, Waight TE, (1999) A fifty year perspective of magmatic evolution on Ruapehu Volcano, New Zealand: Verification of open system behaviour in an arc volcano. Earth Planet Sci Lett 170:301–314CrossRefGoogle Scholar
  29. Gill JB (1981) Orogenic andesites and plate tectonics. Springer, Berlin Heidelberg New York, p 390Google Scholar
  30. Griscom A (1980) Klamath Mountains province. In: Oliver H (ed) Interpretation of the Gravity Map of California and its Continental Margin, Calif Div Mines Bull 205:34–36Google Scholar
  31. Grove TL, Juster TC (1989) Experimental investigations of low-Ca pyroxene stability and olivine–pyroxene–liquid equilibria at 1-atm in natural basaltic and andesitic liquids. Contrib Mineral Petrol 103:287–305Google Scholar
  32. Grove TL, Kinzler RJ, Baker MB, Donnelly-Nolan JM, Lesher CE (1988) Assimilation of granite by basaltic magma at Burnt lava flow, Medicine Lake volcano, northern California: decoupling of heat and mass transfer. Contrib Mineral Petrol 99:320–343Google Scholar
  33. Grove TL, Donnelly-Nolan, Housh T (1997) Magmatic processes that generated the rhyolite of Glass Mountain, Medicine Lake volcano, N. California. Contrib Mineral Petrol 127:205–223CrossRefGoogle Scholar
  34. Grove TL, Parman SW, Bowring SA, Price RC, Baker MB (2002) The role of an H2O-rich fluid component in the generation of primitive basaltic andesites and andesites from the Mt. Shasta region, N. California. Contrib Mineral Petrol 142:375–396Google Scholar
  35. Grove TL, Elkins-Tanton LT, Parman SW, Müntener O, Gaetani GA (2003) Fractional crystallization and mantle melting controls on calc-alkaline differentiation trends. Contrib Mineral Petrol 145:515–533CrossRefGoogle Scholar
  36. Harris SL (2003) Fire Mountains of the West: The Cascades and Mono Lake volcanoes. Mountain Press, p 372Google Scholar
  37. Huebner JS, Sato M (1970) The oxygen fugacity-temperature relationships of manganese and nickel oxide buffers. Am Mineral 55:934–952Google Scholar
  38. Irvine TN, Baragar WRA (1971) A guide to the chemical classification of the common volcanic rocks. Can J Earth Sci 8:523–548Google Scholar
  39. Jacobsen SB, Quick JE, Wasserburg GJ (1984) A Nd and Sr isotopic study of the Trinity peridotite; implications for mantle evolution. Earth Planet Sci Lett 68:361–378CrossRefGoogle Scholar
  40. Jaupart C and Allegre CJ (1991) Gas content, eruption rate and instabilities of eruption regime in silicic volcanoes. Earth Planet Sci Lett 102:413–429CrossRefGoogle Scholar
  41. Kay RW (1978) Aleutian magnesian andesites: melts from subducted Pacific oceanic crust. J Volcanol Geotherm Res 4:117–132CrossRefGoogle Scholar
  42. MacDonald GA (1966) Geology of the Cascade Range and Modoc Plateau. In: Bailey EH (ed) Geology of Northern California. Calif Div Mines Bull vol 190, pp 65–95Google Scholar
  43. Miller CD (1978) Holocene pyroclastic deposits from Shastina and Balck Butte, west of Mount Shasta, California. J Res US Geol Surv 6:611–624Google Scholar
  44. Miller CD (1980) Potential hazards from future eruptions in the vicinity of Mount Shasta volcano, northern California. Geol Surv Bull 1503:43Google Scholar
  45. Moore G, Carmichael ISE (1998) The hydrous phase equilibria (to 3 kbar) of an andesite and basaltic andesite from western Mexico: Constraints on water content and conditions of phenocryst growth. Contrib Mineral Petrol 130:304–319CrossRefGoogle Scholar
  46. Murphy MD, Sparks RSJ, Barclay J, Carroll MR, Brewer TS (2000) Remobilization of andesite magma by intrusion of mafic magma at Soufriere Hills volcano, Montserrat, West Indies. J Petrol 41:21–42CrossRefGoogle Scholar
  47. Nakagawa M, Wada K, Thordarson T, Wood CP, Gamble JA (1999) Petrological investigations of the 1995 and 1996 eruptions of Ruapehu Volcano, New Zealand: formation of discrete and small magma pockets and their intermittent discharge. Bull Volcanol 61:15–31CrossRefGoogle Scholar
  48. Newman S, MacDougall JD, Finkel RC (1986) Petrogenesis and 230Th–238U disequilibrium at Mt. Shasta, California and in the Cascades. Contrib Mineral Petrol 93:195–206Google Scholar
  49. Norrish K, Chappel BW (1977) X-ray fluorescence spectrography. In: Zussman J (ed) Physical methods in determinative mineralogy. Academic Press, New York, p 514Google Scholar
  50. Norrish K, Hutton JT (1969) An accurate x-ray spectrographic method for the analysis of geologic samples. Geochim Cosmochim Acta 33:431–454Google Scholar
  51. Ochs FA, Lange RA (1999) The density of hydrous magmatic liquids. Science 283:314–317CrossRefPubMedGoogle Scholar
  52. Pichavant M, Martel C, Bourdier J-L, Scaillet B (2002) Physical conditions, structure and dynamics of a zoned magma chamber: Mont Pelee (Martinique, Lesser Antilles Arc). J Geophys Res 107. DOI 10.1029/2001JB000315Google Scholar
  53. Pinel V, Jaupart C (2000) The effect of edifice load on magma ascent beneath a volcano. Phil Trans R Soc London A 358:1515–1532Google Scholar
  54. Pinel V, Jaupart C (2003) Magma chamber behavior beneath a volcanic edifice. J Geopys Res 108(B2):2072. DOI 10.1029/2002JB001751CrossRefGoogle Scholar
  55. Power JA, Jolly AD, Nye CJ, Harbin ML (2002) A conceptual model for the Mount Spur magmatic system from seismic and geochemical observations of the 1992 Crater peak eruption sequence. Bull Volcanol 64:206–218CrossRefGoogle Scholar
  56. Rutherford MJ and Hill PM (1993) Magma ascent rates from amphibole breakdown—an experimental study applied to the 1980–1986 Mount St. Helens eruptions. J Geophys Res 98:19667–19685Google Scholar
  57. Sisson TW, Bacon CR (1999) Gas driven filter pressing in magmas. Geology 27:613–616CrossRefGoogle Scholar
  58. Sisson TW, Grove TL (1993) Temperature and H2O contents of low-MgO high-alumina basalts. Contrib Mineral Petrol 113:167–184Google Scholar
  59. Sisson TW, Layne (1993) H2O in basalt and basaltic andesite glass inclusions from four subduction—related volcanoes. Earth Planet Sci Lett 117:619–635CrossRefGoogle Scholar
  60. Smith AL, Carmichael ISE (1968) Quaternary lavas from the southern Cascades, western USA. Contrib Mineral Petrol 19:212–238Google Scholar
  61. Sun SS, McDonough WD (1989) Chemcial and isotopic systematics of oceanic basalts: implications for mantle composition and p rocesses. In: Saunders AD, Norry MJ (eds) Magmatism in Ocean Basins. Geol Soc Spec Publ 42:313–345Google Scholar
  62. Symonds RB, Rose WI, Bluth GSJ, Gerlach TM (1994) Volcanic gas studies: methods, results and applications. In: Carroll MR, Holloway JR (eds) Reviews in Mineralogy, version 30, Volatiles in magmas, Mineralogical Society of America, p 517Google Scholar
  63. Tatsumi Y, Ishizaka K (1982) Origin of high-magnesian andesites in the Setouchi volcanic belt, southwest Japan, I. Petrographical and chemical characteristics. Earth Planet Sci Lett 60:293–304CrossRefGoogle Scholar
  64. Venezky DY, Rutherford MJ (1997) Preeruption conditions and timing of dacite-andesite magma mixing in the 2.2 ka eruption at Mt. Rainer. J Geophys Res 102:20069–20086CrossRefGoogle Scholar
  65. Volpe AM (1992) 238U−230Th−226Ra disequilibrium in young Mt. Shasta andesites and dacites. J Volcanol Geotherm Res 53:227–238CrossRefGoogle Scholar
  66. Williams H (1932a) Geology of the Lassen Volcanic National Park, California. Calif Univ Dept Geol Sci Bull 21:195–385Google Scholar
  67. Williams H (1932b) Mount Shasta, a Cascade volcano. J Geol 45:417–429Google Scholar
  68. Williams H (1934) Mount Shasta, California. Zeitschr Vulkan 15:225–253Google Scholar
  69. Williams H (1949) Geology of Macdoel quadrangle (California). Calif Div Mines Bull 151:7–60Google Scholar
  70. Yogoszinski GM, Kay RW, Volynets ON, Koloskov AV, Kay SM (1995) Magnesian andesite in the western Aleutian Komandorsky region: implications for slab melting and processes in the mantle wedge. Geol Soc Am Bull 107:505–519CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  • Timothy L. Grove
    • 1
  • Michael B. Baker
    • 2
  • Richard C. Price
    • 3
  • Stephen W. Parman
    • 1
  • Linda T. Elkins-Tanton
    • 4
  • Nilanjan Chatterjee
    • 1
  • Othmar Müntener
    • 5
  1. 1.Department of Earth, Atmospheric and Planetary SciencesMassachusetts Institute of TechnologyCambridgeMAUSA
  2. 2.Division of Geological and Planetary SciencesCalifornia Institute of TechnologyPasadenaUSA
  3. 3.School of Science and TechnologyUniversity of WaikatoHamiltonNew Zealand
  4. 4.Department of Geological SciencesBrown UniversityProvidenceRhode Island
  5. 5.Institut de GéologieUniversité de NeuchâtelNeuchatelSwitzerland

Personalised recommendations