Open AccessPalaeomagnetism of alkaline lava flows from El Salto‐Almafuerte, Córdoba Province, Argentina
Author(s) -
Mendía José E.
Publication year - 1978
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1978.tb05493.x
Subject(s) - geology , paleomagnetism , cretaceous , lava , outcrop , geomagnetic pole , paleontology , igneous rock , volcano , magnetic mineralogy , sequence (biology) , lineation , earth's magnetic field , magnetization , remanence , physics , tectonics , quantum mechanics , biology , magnetic field , genetics
Summary. Stable components of magnetization have been isolated in 15 lava flows (mean K‐Ar age 123 ± 4 Myr) from the alkaline sequence outcropping at El Salto‐Almafuerte, Province of Cordoba, Argentina. Magnetic and geologic stratigraphy, as well as K‐Ar ages indicate that this sequence was probably extruded in the Lower Cretaceous during the first volcanic cycle of the Sierra de los Cóndores Group (Vulcanitas Cerro Colorado Formation). The palaeomagnetic pole‐position for El Salto‐Almafuerte lava flows, computed from the mean of 15 virtual geomagnetic poles and denoted SAK 7 , is: 25° E, 72° S ( k = 35, α 95 = 6.5°); it is fairly close to other Lower Cretaceous palaeomagnetic poles for South America. The elongated distribution of Cretaceous palaeomagnetic poles suggest recurrent drift for South America in early Cretaceous time. The palaeomagnetic and radiometric data for the igneous rocks from El Salto‐Almafuerte support the magnetic reversal time‐scale for the early Cretaceous suggested by oceanic magnetic lineations.