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Detailed Reference Information |
Tarduno, J.A. (1992). Magnetic susceptibility cyclicity and magnetic dissolution in Cretaceous limestones of the southern Alps (Italy). Geophysical Research Letters 19: doi: 10.1029/92GL01484. issn: 0094-8276. |
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Sampling of a reversed polarity interval previously reported from limestones of the ''Albian'' Valle del Mis section (Southern Alps, Italy) indicates that it represents a recording of chron M3 of Barremian age rather than a brief reversed polarity 'event' in the Cretacous Normal Polarity Superchron (K-N). Hysteresis measurements suggest that magnetic susceptibility in these limestones is dominated by the paramagnetic clay fraction. Bulk magnetic susceptibility values exhibit a cyclicity which is correlated with the 100-kyr Milankovitch eccentricity cycle. The stable record of reversed polarity is interrupted at six stratigraphically narrow intervals (<1 m) by the apparent lack of any mineral having a stable remanent magnetization. I suggest these ''paleomagnetic barren'' intervals mark selective dissolution of magnetite related to increases in organic carbon. Such dissolution may explain some patterns of magnetization and remagnetization observed in world-wide carbonates. ¿ American Geophysical Union 1992 |
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BACKGROUND DATA FILES |
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Abstract |
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Keywords
Geomagnetism and Paleomagnetism, Reversals (process, time scale, magnetostratigraphy), Geomagnetism and Paleomagnetism, Rock and mineral magnetism, Marine Geology and Geophysics, Micropaleontology, Oceanography, General, Paleoceanography |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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