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Magnetic fabric determined from Arm and IRM anisotropies in Paleozoic carbonates, Southern Appalachian Basin
Author(s) -
Lu Gang,
McCabe Chad
Publication year - 1993
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 - 10.1029/93gl00986
Subject(s) - geology , lineation , paleozoic , anisotropy , paleomagnetism , deformation (meteorology) , structural basin , tectonics , mineralogy , seismology , geophysics , geomorphology , paleontology , physics , quantum mechanics , oceanography
We have undertaken a comparative study of ARM and IRM anisotropies in Paleozoic carbonate rocks from the Nashville and Jessamine Domes in the Southern Appalachian Basin. The ARMA ellipsoids differ markedly from the IRMA ellipsoids. ARMA appears to reflect a pre‐deformation magnetic fabric due to deposition and/or compaction with minimum axes near vertical and a weak lineation. Conversely, IRMA has minimum axes near horizontal and oriented NE‐SW, which is compatible with a tectonic fabric due to Alleghanian deformation. Percent ARMA is consistently greater than IRMA. ARM was imparted at low alternating fields (30 mT), and thus ARMA may reflect the fabric residing in low and intermediate coercivity (coarse grained) magnetite. However, the IRM was imparted in saturating fields (300 mT) and appears to be dominated by the single domain fraction, which is believed to carry the observed Kiaman Superchron remagnetization.