The electrical conductivity of the Andean crust in northern Chile and southern Bolivia as inferred from magnetotelluric measurements
Article Sidebar
Published:
Aug 30, 1984
Keywords:
Electrical conductivity studies,
Central Andes Magnetotellurics,
Crustal electrical resistivity anomaly,
Partial melting,
Temperature,
Subduction processes,
Plutonites,
Andesitic volcanism,
Separation of E- and B-polarization
Volumes
Vols. 1-18 (1924-1944), ISSN 0044-2801
Main Article Content
Abstract
The subducted Nasca plate produces anomalies of spectacular low electrical resistivity beneath the Andean knee. This is the result of two magnetotelluric field campaigns in 1982. The measurements were carried out on a profile from the Pacific coast to the Eastern Cordillera crossing northern Chile and southern Bolivia. Several anomalies may be distinguished. The strongest anomaly has been detected beneath the Pre- and West-Cordillera, with resistivities around 0.5 Ωm at depths greater than 5-10 km, strike direction roughly parallel to the main crest of the High-Cordillera. But also, the Altiplano is underlain – at a depth of 40-50 km – by very low-resistive material. In agreement with other geophysical and geological observations, we interpret these low resistivities as being due to the partially melted state. Further arguments identify the Pre-Cordillera anomaly, probably, with a plutonite which is still "alive", and the highly-conductive material 40 km beneath the Altiplano with the source of andesitic magma. A crucial point in this study is the distinction between the E- and B-polarization of the apparent resistivities. We distinguished both polarizations by the direction of the induction arrows and by the lateral continuity of the apparent resistivity.
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How to Cite
Schwarz, G., Haak, V., Martinez, E., & Bannister, J. (1984). The electrical conductivity of the Andean crust in northern Chile and southern Bolivia as inferred from magnetotelluric measurements. Journal of Geophysics, 55(1), 169-178. Retrieved from https://journal.geophysicsjournal.com/JofG/article/view/242
Section
References
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Barazangi, M., Isacks, B.L. (1979) Subduction of the Nazca plate beneath Peru: evidence from spatial distribution of earthquakes. Geophys. J. R. Astron. Soc. 57:537-555
Beblo, M., Bjornsson, A. (1978) Magnetotelluric investigation of the lower crust and upper mantle beneath Iceland. J. Geophys. 45:1-16
Beblo, M., Bjornsson, A. (1980) A model of electrical resistivity beneath NE-Iceland, correlation with temperature. J. Geophys. 47:184-190
Breitkreuz, Ch., Berg, K. (1983) Magmatite in der Kustenkordillere sudostlich von Chanaral/Nordchile. Zbl. Geol. Palaont. Teil 1, H. 3/4:387-401
Chelidze, T.L. (1978) Structure-sensitive physical properties of partially melted rocks. Phys. Earth Planet. Inter. 17:41-46
Edwards, R.N., Bailey, R.C., Garland, G.D. (1981) Conductivity anomalies: lower crust or asthenosphere? Phys. Earth Planet. Inter. 25:263-272
Febrer, J.M., Gasco, J.C., Pomposiello, C., Mamami, M., Baldis, B., Fournier, H.C. (1981) Magnetotelluric measurements defining a continental mantle plume in a zone of the Andean belt southeast of the Altiplano in Argentine. Paper presented at 4th IAGA Soc. Ass., Edinburgh
Filloux, J.H. (1973) Techniques and instrumentation for study of natural electromagnetic induction at sea. Phys. Earth Planet. Inter. 7:323-338
Gough, D.I. (1973) The geophysical significance of geomagnetic variation anomalies. Phys. Earth Planet. Inter. 7:379-388
Haak, V. (1972) Bestimmung der Ubertragungsfunktionen in Gebieten mit lateraler Anderung der elektrischen Leitfahigkeit. J. Geophys. 38:85-102
Haak, V. (1978) lnterpretationsverfahren fur die Magnetotellurik unter besonderer Berucksichtigung lateral variierender elektrischer Leitfahigkeit im Erdinnern und eines raumlich inhomogen induzierenden Magnetfeldes. Bayer. Akad. Wiss. Math.-Nat. Klasse Munich 158
Haak, V. (1982) Elektrische Leitfahigkeit von Mineralen und Gesteinen bei hohen Drucken und Temperaturen. In: Landolt-Bornstein, Bd. V /1 b, Physikalische Eigenschaften der Gesteine, G. Angenheister, ed.: pp 291-307. Berlin: Springer
Hempfling, R. (1977) Beobachtung und Auswertung tagesperiodischer Variationen des erdelektronischen Feldes in der Umgebung von Gottingen. Diss. Math.-Nat. Fak. Univ. Gottingen
Hermance, J.F. (1979) The electrical conductivity of materials containing partial melt: a simple model from Archie's law. Geophys. Res. Lett. 6:613-616
Honkura, Y. (1975) Partial melting and the electrical conductivity anomalies beneath the Japan and Philippine Seas. Phys. Earth Planet. Inter. 10:128-134
James, D.E. (1971) Andean crustal structure. Carn. Inst. Wash. Yearb. 69:447-460
Keller, G.V., Furgerson, T.B. (1977) Determining the resistivity of resistant layer in the crust. In: The Earth's crust, J.G. Heacock, ed.: pp 440-469, Geophys. Monogr. 20, AGU, Washington
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Kushiro, J., Goder, H.S. Jr., Mysen, B.O. (1976) Viscosities of basalt and andesite melts at high pressures. J. Geophys. Res. 81:6351-6356
Larsen, J.C. (1975) Low frequency (0.1-6.0 cpd) electromagnetic study of deep mantle conductivity beneath the Hawaiian Islands. Geophys. J. R. Astron. Soc. 43:14-56
Lebedev, E.B., Khitarov, N.I. (1964) Dependence of the beginning of melting of granite and the electrical conductivity of its melt on high water vapour pressure. Geochem. Int. 1:193-197
Luetgert, J.H., Meyer, R.P. (1981) Crustal structure of coastal Peru 12° S to 16.2° S latitude. Paper presented at 21st IUGG General Assembly, London, Canada
Maxwell, J.C. (1892) A treatise on electricity and magnetism. Clarendon, Oxford
Molnar, P., Oliver, J. (1969) Lateral variations of attenuation in the upper mantle and discontinuities in the lithosphere. J. Geophys. Res. 74:2648-2682
Nur, A., Avraham, Z.B. (1982) Oceanic plateaus, the fragmentation of continents, and mountain building. J. Geophys. Res. 87:3644-3661
Ocala, L.C., Meyer, R.P. (1972) Crustal low-velocity zones under the Peru-Bolivia Altiplano. Geophys. J. R. Astron. Soc. 30:199-209
Rikitake, T. (1969) The undulation of an electrically conductive layer beneath the islands of Japan. Tectonophysics 1:257-264
Rikitake, T. (1975) A model of geoelectric structure beneath Japan. J. Geomagn. Geoelectr. 26:233-244
Ringwood, A.E. (1975) Composition and petrology of the Earth's mantle. McGraw Hill, New York
Schmucker, U., Hartmann, O., Giesecke, A.A. Jr., Casaverde, M., Forbush, S.E. (1964) Electrical conductivity anomaly in the Earth's crust in Peru. Carn. Inst. Washington Yearbook 63:354-362
Schmucker, U., Forbush, S.E., Hartmann, O., Giesecke, A.A., Casaverde, M., Castillo, J., Salgueiro, R., del Pozo, S. (1966) Electrical conductivity anomaly under the Andes. Carnegie Inst. Wash. Yearb. 65:11-28
Schmucker, U. (1970) Anomalies of geomagnetic variations in the southwestern United States. Bull. Scripps Inst. Ocean. Univ. Calif. 13
Schmucker, U. (1971) Neue Rechenmethoden zur Tiefensondierung mit langperiodischen Variationen. In: Prot. Koll. Erdmagn. Tiefensond., P. Weidelt, ed.: pp 1-39, Gottingen
Schmucker, U. (1973) Regional induction studies: a review of methods and results. Phys. Earth Planet. Inter. 7:365-378
Schmucker, U. (1974) Erdmagnetische Tiefensondierung mit langperiodischen Variationen. In: Prot. Koll. Erdmagn. Tiefensond., A. Berktold, ed.: pp 313-342, Munich
Schwarz, G. (1984) Die elektrische Leitfahigkeit in der Toskana und ein daraus abgeleitetes geothermisches Modell - insbesondere fur die Anomalie von Travale. Berliner Geowiss. Abh. (B) 8
Shankland, T.J., Waff, H.S. (1977) Partial melting and electrical conductivity anomalies in the upper mantle. J. Geophys. Res. 82:5409-5417
Stauder, W. (1973) Mechanism and spatial distribution of Chilean earthquakes with relation to subduction of the oceanic plate. J. Geophys. Res. 78:5033-5061
Waff, H.S. (1974) Theoretical considerations of electrical conductivity in a partial molten mantle and implications for geothermometry. J. Geophys. Res. 79:4003-4010
Wigger, P., Giese, P., Kausel, E., Ricaldi, E. (1983) Seismologische und refraktionsseismische Untersuchungen in den Zentral-Anden auf einer Traverse von der pazifischen Kuste bis zur Ostkordillere. Contributed paper at 43rd DOG-meeting Aachen
Wyllie, W.J. (1981) Plate tectonics and magma genesis. Geol. Rundsch. 70:128-153
Zeil, W. (1959) Das Fumarolen- und Geysir-Feld westlich der Vulkangruppe des Tatio (Provinz Antofagasta, Chile). Bayer. Akad. Wiss. Math.-Nat. Klasse Munich 96
Barazangi, M., Isacks, B.L. (1979) Subduction of the Nazca plate beneath Peru: evidence from spatial distribution of earthquakes. Geophys. J. R. Astron. Soc. 57:537-555
Beblo, M., Bjornsson, A. (1978) Magnetotelluric investigation of the lower crust and upper mantle beneath Iceland. J. Geophys. 45:1-16
Beblo, M., Bjornsson, A. (1980) A model of electrical resistivity beneath NE-Iceland, correlation with temperature. J. Geophys. 47:184-190
Breitkreuz, Ch., Berg, K. (1983) Magmatite in der Kustenkordillere sudostlich von Chanaral/Nordchile. Zbl. Geol. Palaont. Teil 1, H. 3/4:387-401
Chelidze, T.L. (1978) Structure-sensitive physical properties of partially melted rocks. Phys. Earth Planet. Inter. 17:41-46
Edwards, R.N., Bailey, R.C., Garland, G.D. (1981) Conductivity anomalies: lower crust or asthenosphere? Phys. Earth Planet. Inter. 25:263-272
Febrer, J.M., Gasco, J.C., Pomposiello, C., Mamami, M., Baldis, B., Fournier, H.C. (1981) Magnetotelluric measurements defining a continental mantle plume in a zone of the Andean belt southeast of the Altiplano in Argentine. Paper presented at 4th IAGA Soc. Ass., Edinburgh
Filloux, J.H. (1973) Techniques and instrumentation for study of natural electromagnetic induction at sea. Phys. Earth Planet. Inter. 7:323-338
Gough, D.I. (1973) The geophysical significance of geomagnetic variation anomalies. Phys. Earth Planet. Inter. 7:379-388
Haak, V. (1972) Bestimmung der Ubertragungsfunktionen in Gebieten mit lateraler Anderung der elektrischen Leitfahigkeit. J. Geophys. 38:85-102
Haak, V. (1978) lnterpretationsverfahren fur die Magnetotellurik unter besonderer Berucksichtigung lateral variierender elektrischer Leitfahigkeit im Erdinnern und eines raumlich inhomogen induzierenden Magnetfeldes. Bayer. Akad. Wiss. Math.-Nat. Klasse Munich 158
Haak, V. (1982) Elektrische Leitfahigkeit von Mineralen und Gesteinen bei hohen Drucken und Temperaturen. In: Landolt-Bornstein, Bd. V /1 b, Physikalische Eigenschaften der Gesteine, G. Angenheister, ed.: pp 291-307. Berlin: Springer
Hempfling, R. (1977) Beobachtung und Auswertung tagesperiodischer Variationen des erdelektronischen Feldes in der Umgebung von Gottingen. Diss. Math.-Nat. Fak. Univ. Gottingen
Hermance, J.F. (1979) The electrical conductivity of materials containing partial melt: a simple model from Archie's law. Geophys. Res. Lett. 6:613-616
Honkura, Y. (1975) Partial melting and the electrical conductivity anomalies beneath the Japan and Philippine Seas. Phys. Earth Planet. Inter. 10:128-134
James, D.E. (1971) Andean crustal structure. Carn. Inst. Wash. Yearb. 69:447-460
Keller, G.V., Furgerson, T.B. (1977) Determining the resistivity of resistant layer in the crust. In: The Earth's crust, J.G. Heacock, ed.: pp 440-469, Geophys. Monogr. 20, AGU, Washington
Kleist, H.v. (1807) Jeronimo and Josephe. Eine Szene aus dem Erdbeben zu Chili, vom Jahr 1647. Morgenblatt fur gebildete Stande. 10-17. Sept.
Kushiro, J., Goder, H.S. Jr., Mysen, B.O. (1976) Viscosities of basalt and andesite melts at high pressures. J. Geophys. Res. 81:6351-6356
Larsen, J.C. (1975) Low frequency (0.1-6.0 cpd) electromagnetic study of deep mantle conductivity beneath the Hawaiian Islands. Geophys. J. R. Astron. Soc. 43:14-56
Lebedev, E.B., Khitarov, N.I. (1964) Dependence of the beginning of melting of granite and the electrical conductivity of its melt on high water vapour pressure. Geochem. Int. 1:193-197
Luetgert, J.H., Meyer, R.P. (1981) Crustal structure of coastal Peru 12° S to 16.2° S latitude. Paper presented at 21st IUGG General Assembly, London, Canada
Maxwell, J.C. (1892) A treatise on electricity and magnetism. Clarendon, Oxford
Molnar, P., Oliver, J. (1969) Lateral variations of attenuation in the upper mantle and discontinuities in the lithosphere. J. Geophys. Res. 74:2648-2682
Nur, A., Avraham, Z.B. (1982) Oceanic plateaus, the fragmentation of continents, and mountain building. J. Geophys. Res. 87:3644-3661
Ocala, L.C., Meyer, R.P. (1972) Crustal low-velocity zones under the Peru-Bolivia Altiplano. Geophys. J. R. Astron. Soc. 30:199-209
Rikitake, T. (1969) The undulation of an electrically conductive layer beneath the islands of Japan. Tectonophysics 1:257-264
Rikitake, T. (1975) A model of geoelectric structure beneath Japan. J. Geomagn. Geoelectr. 26:233-244
Ringwood, A.E. (1975) Composition and petrology of the Earth's mantle. McGraw Hill, New York
Schmucker, U., Hartmann, O., Giesecke, A.A. Jr., Casaverde, M., Forbush, S.E. (1964) Electrical conductivity anomaly in the Earth's crust in Peru. Carn. Inst. Washington Yearbook 63:354-362
Schmucker, U., Forbush, S.E., Hartmann, O., Giesecke, A.A., Casaverde, M., Castillo, J., Salgueiro, R., del Pozo, S. (1966) Electrical conductivity anomaly under the Andes. Carnegie Inst. Wash. Yearb. 65:11-28
Schmucker, U. (1970) Anomalies of geomagnetic variations in the southwestern United States. Bull. Scripps Inst. Ocean. Univ. Calif. 13
Schmucker, U. (1971) Neue Rechenmethoden zur Tiefensondierung mit langperiodischen Variationen. In: Prot. Koll. Erdmagn. Tiefensond., P. Weidelt, ed.: pp 1-39, Gottingen
Schmucker, U. (1973) Regional induction studies: a review of methods and results. Phys. Earth Planet. Inter. 7:365-378
Schmucker, U. (1974) Erdmagnetische Tiefensondierung mit langperiodischen Variationen. In: Prot. Koll. Erdmagn. Tiefensond., A. Berktold, ed.: pp 313-342, Munich
Schwarz, G. (1984) Die elektrische Leitfahigkeit in der Toskana und ein daraus abgeleitetes geothermisches Modell - insbesondere fur die Anomalie von Travale. Berliner Geowiss. Abh. (B) 8
Shankland, T.J., Waff, H.S. (1977) Partial melting and electrical conductivity anomalies in the upper mantle. J. Geophys. Res. 82:5409-5417
Stauder, W. (1973) Mechanism and spatial distribution of Chilean earthquakes with relation to subduction of the oceanic plate. J. Geophys. Res. 78:5033-5061
Waff, H.S. (1974) Theoretical considerations of electrical conductivity in a partial molten mantle and implications for geothermometry. J. Geophys. Res. 79:4003-4010
Wigger, P., Giese, P., Kausel, E., Ricaldi, E. (1983) Seismologische und refraktionsseismische Untersuchungen in den Zentral-Anden auf einer Traverse von der pazifischen Kuste bis zur Ostkordillere. Contributed paper at 43rd DOG-meeting Aachen
Wyllie, W.J. (1981) Plate tectonics and magma genesis. Geol. Rundsch. 70:128-153
Zeil, W. (1959) Das Fumarolen- und Geysir-Feld westlich der Vulkangruppe des Tatio (Provinz Antofagasta, Chile). Bayer. Akad. Wiss. Math.-Nat. Klasse Munich 96