Origin of the smooth zone in early Cretaceous North Atlantic magnetic anomalies
Sager, William W.
MetadataShow full item record
Late Jurassic-Early Cretaceous marine magnetic anomalies observed in the North Atlantic exhibit an abrupt change in character in M5-M15 crust. The anomalies are smoother with low amplitudes, and are difficult to correlate among nearby profiles. The accepted explanation for the origin of this smooth zone is diminished resolution and anomaly interference due to slow spreading rates, which narrows the widths of polarity reversals in the crust and causes interference among sea-surface anomalies. Magnetic modeling of these anomalies indicates that neither slow spreading rates alone nor slow spreading rates in combination with a decrease in geomagnetic field intensity can explain the basic character of the smooth zone. Combined with other geophysical evidence, our study suggests that one consequence of slow spreading rates that is responsible for the magnetic “smooth zone” is a thinned crustal basalt layer or a non-basaltic magnetic source layer resulting from low melt supply during a period of ultra-slow spreading.
Author Posting. © American Geophysical Union, 2010. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 37 (2010): L01304, doi:10.1029/2009GL040984.
Showing items related by title, author, creator and subject.
Oceanic lithosphere magnetization : marine magnetic investigations of crustal accretion and tectonic processes in mid-ocean ridge environments Williams, Clare M. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2007-09)The origin of symmetric alternating magnetic polarity stripes on the seafloor is investigated in two marine environments; along the ridge axis of the fast spreading East Pacific Rise (EPR) (9º 25’-9º 55’N) and at Kane ...
Blackman, Donna K.; Canales, J. Pablo; Harding, Alistair J. (John Wiley & Sons, 2009-05-05)Oceanic core complexes (OCCs) provide access to intrusive and ultramafic sections of young lithosphere and their structure and evolution contain clues about how the balance between magmatism and faulting controls the style ...
3-D focused inversion of near-seafloor magnetic data with application to the Brothers volcano hydrothermal system, Southern Pacific Ocean, New Zealand Tontini, F. Caratori; de Ronde, C. E. J.; Yoerger, Dana R.; Kinsey, James C.; Tivey, Maurice A. (American Geophysical Union, 2012-10-11)We describe and apply a new inversion method for 3-D modeling of magnetic anomalies designed for general application but which is particularly useful for the interpretation of near-seafloor magnetic anomalies. The crust ...