Palaeomagnetic and rockmagnetic properties of the Permian volcanics in the western Southern Alps

Main Article Content

C. Heiniger


A palaeomagnetic and rockmagnetic investigation has been carried out in the western Southern Alps. At 31 sites in the Permian volcanics from four regions 349 samples were drilled: 1. the region of Arona (SW of Lago Maggiore), 2. the porphyry district of Lugano and Ganna, 3. the Valle Brembana (N of Bergamo) and 4. the Auccia volcanics (N of Brescia). AF-cleaning as well as continuous and progressive thermal demagnetization reveal, in most of the igneous rocks studied, the presence of a stable characteristic remanent magnetization (ChRM) representing the magnetization acquired at the time of formation of these rocks. Microscopic observations, IRM-acquisition curves and Curie point measurements indicate the ChRM to be carried by Ti-poor magnetite and titanohematite. Stable secondary magnetizations due to oxidation may be present. Their directions, however, are very similar to the primary thermoremanent magnetization (TRM). Therefore it is inferred that the oxidation probably took place shortly after acquisition of the primary TRM. The magnetization directions within individual sites are well grouped (α95 usually < 10°), but the site mean directions are dispersed, due to regional and local tectonic complications. At Arona, Ganna, and Auccia a suitable tilt correction can be made. Since the consistent directions from these sites are very similar to the well defined results from the Bolzano porphyries (Zijderveld et al., 1970), it is suggested that the western and eastern Southern Alps have, on a large scale, behaved as a single tectonic unit. The Southern Alpine block has been rotated anticlockwise by about 50° relative to extra-alpine Europe since the Early Mesozoic. The Permian Southern Alpine palaepoles are situated close to the Permian part of the African polar wander path. Therefore the palaeomagnetic data support geological and sedimentological arguments which consider the Southern Alps as originating on the southern margin of Tethys and forming a parautochthonous extension of the African plate since the Early Mesozoic.

Google Scholar           ARK:



Article Details

How to Cite
Heiniger, C. (1979). Palaeomagnetic and rockmagnetic properties of the Permian volcanics in the western Southern Alps. Journal of Geophysics, 46(1), 397-411. Retrieved from


Birkenmajer, K., Krs, M., Nairn, A.E.M. (1968) A palaeomagnetic study of upper Carboniferous Rocks from the Inner Sudetic Basin and the Bohemian Massif. Geol. Soc. Am. Bull. 78:589-608

Cassinis, G. (1966) Rassegna delle formazioni permiane dell'alta Val Trompia (Brescia). Atti Ist. Geol. Univ. Pavia 17:50-66

Cassinis, G. (1968) La sezione-tipo delle Vulcaniti di Auccia (Permico brcsciano). Atti Ist. Geol. Univ. Pavia 19:40-49

Channell, J.E.T., D'Argenio, B., Horvath. F. (1979) Adria, the African Promontory, in Mesozoic Mediterranean Palaeogeography. Earth Sci. Rev. (In press)

Channell. J. E.T., Horvath, F. (1976) The African/Adriatic Promontory as a palaeogeographical premise for Alpine Orogeny and plate movements in the Carpatho-Balkan Region. Tectonophysics 35:71-101

Dunlop, D.J. (1972) Magnetic mineralogy of unheated and heated red sediments by coercivity spectrum analysis. Geophys. J. R. Astron. Soc. 27:37

Fisher, R.A. (1953) Dispersion on a sphere. Proc. R. Soc. London, Ser. A: 217:295-305

Goree, W.S., Fuller, M. (1976) Magnetometers using RF-driven squids and their applications in rock magnetism and palaeomagnetism. Rev. Geophys. Space Phys. 14(4):591-608

Graeter, P. (1952) Geologie und Petrographie des Malcantone (Suedliches Tessin). Schweiz. Mineral. Petrogr. Mitt. 31:2

Heiniger, C., Heller, F. (1976) A high temperature vector magnetometer. Geophys. J. R. Astron. Soc. 44:281-288

Heller, F., Egloff, R. (1974) Multiple Reversals of Natural Remanent Magnetization in a Granite-Aplite Dyke of the Bergell Massif (Switzerland). J. Geomagn. Geoelectr. 26:499-505

Hilten, D. Van, Zijderveld, J.D.A. (1966) The magnetism of the Permian Porphyries near Lugano (Northern Italy/Switzerland). Tectonophysics 3:429-446

Jaeger, E., Faul, H. (1959) Age measurements on some granites and gneisses from the Alps. Geol. Soc. Am. Bull. 70(12):1553-1558

Kaech, M. (1903) Geologisch-petrographische Untersuchungen des Porphyrgebietes zwischen Lago Maggiore und Val Sesia. Eclogae Geol. Helv. 8(1):47-164

Konrad, H.J., Nairn, A.E.M. (1972) The Palaeomagnetism of the Permian Rocks of the Black Forest, Germany. Geophys. J. R. Astron. Soc. 27:369-382

Kuenen, Ph.D. (1925) The porphyry district of Lugano West of Valganna. Leidse Geol. Meded. 1:129-185

Manzoni, M. (1970) Palaeomagnetic data of Middle and Upper Triassic age from the Dolomites (Eastern Alps, Italy). Tectonophysics 10:411-424

Molyneux, L. (1972) A complete result magnetometer for measuring the remanent magnetization of rocks. Geophys. J. R. Astron. Soc. 24:429-433

Nairn, A.E.M. (1957) Observations palaeomagnetiques en France: roches Permiennes. Bull. Soc. Geol. Fr. 7:721-727

Pavoni, N., El Mikacher, S., Weber, M. (1969) Gesteinsmagnetische Untersuchungen an permischen Porphyriten der Morcote Halbinsel suedlich Lugano. Schweiz. Mineral. Petrogr. Mitt. 49(1):103-107

Pichler, H. (1959) Neue Ergebnisse zur Gliederung der unterpermischen Eruptivfolge der Bozener PorphyrPlatte. Geol. Rundsch. 48:112-131

Porath, H., Stacey, F.D., Aik, S.C. (1966) The choice of specimen shape for magnetic anisotropy measurements on rocks. Earth Planet. Sci. Lett. 1:92

Roquet, J. (1954) Sur Jes remanences des oxides de fer et leur interet en gi:omagnetisme. Ann. Gi:ophys. 10:226-247, 282-325

Sitter De, L.U. (1949) Les porphyres luganois et leurs envelopes. Leidse Geol. Meded. p. II, 1939 Sitter De, L. U., Sitter-Koomans, De, C.M.: The geology of the Bergamasc Alps, Lombardia, Italy. Leidse Geol. Meded. 14B

Yoo, R. Van der, French, R.B. (1974) Apparent polar wandering for the Atlantic bordering continents: Late Carboniferous to Eocene. Earth Sci. Rev. 10:99-119

Zijderveld, J.D.A., Jong, K.A. (1969) Palaeomagnetism of some Late Palaeozoic and Triassic rocks from the eastern Lombardic Alps, Italy. Geol. Mijnbouw 48(6):559-564

Zijderveld, J.D.A., Yoo, R. Van der (1973) Palaeomagnetism in the Mediterranean area. In: Tarling, D.H., Runcorn, S.K. (Eds.) Implications of continental drift to the Earth sciences, pp. 133-161. Academic Press, New York

Zijderveld, J.D.A., Hazeu, G.J.A., Nardin, M., Yoo, R. Van der (1970) Shear in the Tethys and the Permian palaeomagnetism in the Southern Alps, including new results. Tectonophysics 10:639-661