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Preliminary paleomagnetic results from the Triassic Prida Formation (Lower Star Peak Group), west‐central Nevada, and implications for latitudinal displacement
Author(s) -
Geissman John Wm.,
Gillett Stephen L.,
Oldow John S.
Publication year - 1990
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl017i006p00697
Subject(s) - paleomagnetism , geology , allochthon , volcanic rock , paleontology , natural remanent magnetization , volcano , remanence , permian , group (periodic table) , nappe , magnetization , tectonics , physics , magnetic field , quantum mechanics , structural basin
Paleomagnetic data were obtained from two oppositely dipping carbonate sections of the Triassic Prida Formation, lower Star Peak Group, in the Humboldt Range of west‐central Nevada. Progressive demagnetization of the rocks indicated that the remanent magnetization consists of three or fewer vector components. A characteristic component, with the highest unblocking temperatures, was most effectively isolated by low temperature (200–300°C) thermal followed by progressive alternating field demagnetization. The sections yield in situ mean directions that differ significantly, but that have similar inclinations (Star Canyon: D=311, I=+34, α95=5, k=22, N=38 samples; Fossil Hill: D=281, I=+33, α95=2°, k=2814, N=3 section means, 154 samples). The directions diverge upon simple structural correction, from which we infer that at least one and probably both of the sections were remagnetized, probably in latest Middle to Late Jurassic time. These data cannot be used to indicate significant southward translation of Golconda allochthon rocks, as inferred from magnetizations in underlying volcanic rocks. The translation interpretation may require revision if magnetizations in the volcanic rocks are also secondary.