Bulletin of Volcanology

, Volume 49, Issue 6, pp 765–776 | Cite as

Variation in peperite textures associated with differing host-sediment properties

  • Cathy J. Busby-Spera
  • James D. L. White


Peperites formed by mixing of magma and wet sediment are well exposed along Punta China, Baja California, Mexico, where two sills intrude a section of lava flows, limestones, and volcaniclastic rocks. Irregular lobes and dikes extend from the sills several meters into host sediments, including highly comminuted flow top breccias (lithic lapilli tuff breccias) and shelly micrites, whereas intrusive contacts with lava flows are sharp and planar. Where one sill intruded both coarse-grained volcaniclastic rock and fine-grained limestone, textural differences between the hosts produced strikingly different styles of peperite. Blocky masses of the basaltic intrusions up to 1 m in size were dispersed for distances up to 3 m into host lithic lapilli tuff breccias; the blocks consequently underwent in situ fragmentation as they were rapidly quenched. The high degree of dispersion resulted from steam explosions as the magma enveloped pockets of water in the coarse-grained permeable host. Elutriation of fine-grained material from vertical pipes in tuff breccia above the lower sill provides evidence for meter-scale fluidization of the host. The contact zone between the basaltic magma and the shelly micrite host resembles a mixture of two viscous, immiscible fluids (fluidal peperite). Intrusion occurred behind a stable vapor film which entrained lime mud particles and carried them off “grain by grain” as magma advanced into the host. Thin-section-scale elutriation pipes formed. Microglobular peperite represents a “frozen” example of a fuel-coolant interaction (FCI) between basaltic magma and fluidized micrite host. The intimate intermixing of magma and host at the submillimeter level is attributed to fluid instabilities developed along the magma-vapor-host interface. Such intimate intermixing of magma and water-bearing fragmental debris is commonly a precursory step toward explosive hydrovolcanism.


Breccia Lava Flow Micrite Basaltic Magma Steam Explosion 
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  1. Allison EC (1955) Middle Cretaceous Gastropoda from Baja California, Mexico. J Paleontol 29:400–432Google Scholar
  2. Beggs JM (1983) Stratigraphy, petrology, and tectonic setting of the Alisitos Group, Baja California, Mexico [unpub PhD diss]. U Calif Santa Barbara, pp 1–201Google Scholar
  3. Brooks ER, Wood MM, Garbutt PL (1982) Origin and metamorphism of peperite and associated rocks in the Devonian Elwell Formation, northern Sierra Nevada, California. Geol Soc Am Bull 93:1208–1231Google Scholar
  4. Fisher RV, Schmincke H-U (1984) Pyroclastic Rocks. Springer Berlin Heidelberg New York Tokyo pp 1–472Google Scholar
  5. Gastil G, Phillips PR, Allison EC (1975) Reconnaisance geology of the State of Baja California. Geol Soc Am Mem 140, pp 1–170Google Scholar
  6. Hanson RE, Schweickert RA (1983) Chilling and brecciation of a Devonian rhyolite sill intruded into wet sediments, northern Sierra Nevada, California. J Geol 90:717–724Google Scholar
  7. Kokelaar BP (1982) Fluidization of wet sediments during the emplacement and cooling of various igneous bodies. J Geol Soc London 139:21–33Google Scholar
  8. Kokelaar BP (1986) Magma-water interactions in subaqueous and emergent basaltic volcanism. Bull Volcanol 48:275–289Google Scholar
  9. Kunii D, Levenspiel O (1969) Fluidization Engineering. John Wiley and Company New YorkGoogle Scholar
  10. Macdonald GA (1939) An intrusive peperite at San Pedro Hill, California. Univ Calif Pub Geol Sci 24:329–337Google Scholar
  11. Pettijohn FJ, Potter PE, Siever R (1972) Sand and Sandstone. Springer Berlin Heidelberg New York, pp 1–618Google Scholar
  12. Schmincke H-U (1967) Fused tuff and peperites in south-central Washington. Geol Soc Am Bull 78:319–330Google Scholar
  13. Silver LT, Stehli FG, Allen CR (1963) Lower Cretaceous pre-batholithic rocks of northern Baja California, Mexico. Am Assoc Pet Geol Bull 47:2054–2059Google Scholar
  14. Silver LT, Allen CR, Stehli FG (1969) Geological and geochronological observations on a portion of the Peninsular Ranges batholith of northwestern Baja California, Mexico. Geol Soc Am Spec Paper 121:279–280Google Scholar
  15. Smedes HW (1966) Geology and igneous petrology of the northern Elkhorn Mountains, Jefferson and Broadwater Counties, Montana. US Geol Surv Prof Pap 510:1–116Google Scholar
  16. Walton MS, O'Sullivan RB (1950) The intrusive mechanics of a clastic dike. Am J Sci 248:1–21Google Scholar
  17. Williams H, McBirney AR (1979) Volcanology. Freeman San Francisco, pp 1–391Google Scholar
  18. Wilson JL (1975) Carbonate facies in geologic history. Springer Berlin Heidelberg New York 1–471Google Scholar
  19. Wohletz KH (1986) Explosive magma-water interactions: Thermodynamics, explosion mechanisms, and field studies. Bull Volcanol 48:245–264Google Scholar
  20. Wohletz KH, McQueen RG (1984) Experimental studies of hydromagmatic volcanism, in Boyd FR et al, Explosive Volcanism: Inception, Evolution, and Hazards. Nat Acad Press Washington DC, pp 158–169Google Scholar
  21. Woolsey TS, McCallum ME, Schumm SA (1975) Modeling of diatreme emplacement by fluidization. Phys Chem Earth 9:29–42Google Scholar

Copyright information

© Springer-Verlag 1987

Authors and Affiliations

  • Cathy J. Busby-Spera
    • 1
  • James D. L. White
    • 1
  1. 1.University of CaliforniaDepartment of Geological SciencesSanta BarbaraUSA

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