Open AccessEquatorial Pacific magnetic anomalies identified from vector aeromagnetic data
Author(s) -
HornerJohnson Benjamin C.,
Gordon Richard G.
Publication year - 2003
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1046/j.1365-246x.2003.02065.x
Subject(s) - magnetic anomaly , geology , seafloor spreading , lineation , anomaly (physics) , paleomagnetism , clockwise , seismology , geodesy , geophysics , amplitude , pacific plate , subduction , tectonics , physics , quantum mechanics , condensed matter physics
SUMMARY It has long been challenging to identify magnetic anomalies due to seafloor spreading in the equatorial Pacific. Here we show that Project Magnet vector aeromagnetic profiles from the equatorial Pacific record magnetic anomalies due to seafloor spreading much more clearly than do shipboard total intensity profiles. The anomalies are reliably recorded at wavelengths between ≈20 and ≈150 km in the vertical and east components, which have high coherence, differ in phase by ≈90°, and resemble synthetic magnetic anomaly profiles. From an analysis of a single near‐equatorial vector aeromagnetic profile we infer that the magnetic lineations strike ≈8°–10° counter‐clockwise of north and that magnetic anomaly 7 is located ≈400 km further east than previously estimated. The newly estimated location of anomaly 6 is consistent with a tentative estimate by Wilson from a low‐amplitude shipboard magnetic profile. Because the skewness of profiles over the seafloor formed near the paleoequator changes rapidly with paleolatitude and paleostrike, a skewness analysis of these data may provide useful bounds on the location of Pacific Plate paleomagnetic poles, and indicate that this seafloor has had little, if any, northward motion relative to the spin axis since it formed.