J. Dyment et al., SKEWNESS OF MARINE MAGNETIC-ANOMALIES CREATED BETWEEN 85-MA AND 40-MAIN THE INDIAN-OCEAN, J GEO R-SOL, 99(B12), 1994, pp. 24121-24134
We have performed a detailed analysis of the skewness of marine magnet
ic anomalies in Indian Ocean basins created between 85 and 40 Ma as a
result of the northward motion of India. Visual and semiautomated meth
ods of skewness determination were applied to the data. Both provide c
onsistent results, but the visual method is preferred for its ability
to deal with noisy data. Plots of apparent effective remanent inclinat
ion (or skewness corrected for present geomagnetic field inclination)
versus time for conjugate basins display the combination of three effe
cts: a gradual increase with time, related to the northward motion of
the ridges attached to India in the geomagnetic reference frame; a gap
between conjugate curves, which represents anomalous skewness sense s
tricto; and short-period fluctuations, which represent the sequence ef
fect, i.e., the effect of neighboring magnetic sources on the skewness
of a given anomaly. The anomalous skewness decreases with faster spre
ading rate and completely disappears above 50 km/m.y., an observation
which negates geomagnetic field behavior as a possible cause of the ob
served anomalous skewness.