Plio-Pleistocene time-averaged field in southern Patagonia recorded in lava flows

Mejia, V.
Opdyke, N. D.
Vilas, Juan Francisco A.
Singer, B. S.
Stoner, J. S.

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Publication date

March 2004

DOI

10.1029/2003GC000633

Publisher

American Geophysical Union (AGU)

ISSN

1525-2027

Journal

Geochemistry Geophysics Geosystems

Language

English

Citation count (estimate)

Abstract

Paleomagnetic directions were obtained from stepwise alternating-field or thermal demagnetization of 53 lava flows from southern Patagonia (latitudes 49.5°-52.1 °S) that include the Pali-Aike volcanic field and the Meseta Viscachas plateau lavas. In addition to previous Miocene-late Quaternary ages of these flows, 40Ar/39Ar dates spanning from 0.1 to 15.4 Ma were obtained for 17 of the sites. All except one of the magnetic polarities coincide with the expected polarities of the magnetic polarity timescale [Cande and Kent, 1995] for the obtained 40Ar/39Ar ages. The mean direction from 33 sites (eliminating sites <4 Ma) that pass a selection criteria of α95 ≤5° is Dec = 358.7°,Inc = - 68.2°, α95 = 3.5°, a value that coincides within the stati...