Hostname: page-component-cd9895bd7-7cvxr Total loading time: 0 Render date: 2024-12-23T16:37:53.945Z Has data issue: false hasContentIssue false
  • English
  • Français

Origin of ash deposits in the Santiago area, Central Chile

Published online by Cambridge University Press:  01 May 2009

J. E. Guest  and
G. P. Jones
J. E. Guest
Affiliation:
University of London Observatory, Mill Hill ParkLondon N.W.7
G. P. Jones
Affiliation:
Department of Geology, University College, Gower Street, London W.C.1.
Get access Rights & Permissions [Opens in a new window]

Summary

Non-stratified, poorly-sorted rhyolitic ash deposits previously described as morainic and mudflow deposits are reinterpreted as ignimbrites emplaced in the topographically lower parts of the Santiago basin by pyroclastic flows. These flows probably originated from sources high in the Andes, and swept down the deep Maipo valley to spread out over the sediments filling the basin. An ignimbrite with a zone of dense welding but otherwise of similar character to the non-welded ashes of the basin occurs in one of the Andean valleys; and peculiar ‘pipe’ structures in the ashes of the basin support a pyroclastic flow origin.

Further study of the nature and origin of these rocks may lead to a better understanding of the structural evolution of the area.

Type
Articles
Information
Geological Magazine , Volume 107 , Issue 4 , July 1970 , pp. 369 - 381
Copyright
Copyright © Cambridge University Press 1970

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Borde, J. 1966. Les Andes de Santiago et Leur avant-pays, étude de geomorphologie. These de doctorat, Bordeaux, Union Française d'Impression.Google Scholar
Brüggen, J. 1950. Fundamentos de la geologia de Chile. Santiago de Chile, Instituto Geografico Militar.Google Scholar
Clark, A. H., Mayer, A. E. S. Mortimer, C., Sillitoe, R. H., Cooke, R. U. & Snelling, N. J. 1967. Implications of the isotopic ages of ignimbritic flows, southern Atacama Desert, Chile. Nature, Lond. 215, 723–724.CrossRefGoogle Scholar
Gonzalez, O. & Vergara, M. 1962. Reconocimiento geologico de la Cordillera de los Andes entre los paralelos 35° y 38° latitud sur. An. Fac. Clienc. fis. mat., Univ. Chile, 19 1–121.Google Scholar
Griggs, R. F. 1918. The great hot mud flow of the Valley of Ten Thousand Smokes (Katmai district, Alaska). Ohio J. Sci. 19, 117–142.Google Scholar
Guest, J. E. 1969. Upper Tertiary ignimbrites in the Andean Cordillera of part of the Antofagasta province, northern Chile. Bull. geol. Soc. Am. 80, 337–362.CrossRefGoogle Scholar
Hollingworth, S. E. 1964. Dating the uplift of the Andes. Nature, Lond. 201, 17–20.CrossRefGoogle Scholar
Hollingworth, S. E. & Rutland, R. W. R. 1968. Studies of Andean Uplift, Part I. Post Cretaceous evolution of the San Bartolo area, Northern Chile. Geol. J. 6, 49–62.CrossRefGoogle Scholar
Marsters, V. P. 1912. The physiography of the Peruvian Andes with notes on early mining in Peru. Ann. N.Y. Acad. Sci. 22, 225–258.CrossRefGoogle Scholar
Ross, C. S. & Smith, R. L. 1961. Ash flow tuffs: Their origin geologic relations and identification. Prof. Pap. U.S. geol. Surv., 366, 81pp.Google Scholar
Ruiz, C. 1965. Geologia y yacimientos metaliferos de Chile. Santiago, Inst. Invest. Geol. Chile.Google Scholar
Rutland, R. W. R., Guest, J. E. & Grasty, R. L. 1965. Isotopic ages and Andean uplift. Nature, Lond., 208, 677–8.CrossRefGoogle Scholar
Salas, R., Kast, R. F., Montecinos, F. & Salas, I. 1966. Geologica y recursos minerales del departmento de Arica, Provincia de Tarapaca. Santiago, Inst. Invest. Geol. Chile, Bol. 21.Google Scholar
Segerstrom, K., Castillo, O. & Falcon, E. 1964. Quarternary mudflow deposits near Santiago, Chile. Art 152 in Prof. Pap. U.S. geol. Surv. 475-D, D144–D148.Google Scholar
Tricart, J., Hirsch, A-R, & Griesbach, J-C. 1965. Geomorphologie et eaux souterraines dans le basin de Santiago du Chile. Bull. Fac. Lettres Strasbourg, Année 43, No. 7, 605–673.Google Scholar
Zeil, Von W. & Pichler, H. 1967. Die kanozoish Rhyolith-Formation im mittleren Abschnitt der Anden. Geol. Rdsch, 57, 48–81.CrossRefGoogle Scholar