Marine magnetic anomalies, geomagnetic field reversals, and motions of the ocean floor and continents

Abstract

This paper summarizes the results of the three previous papers in this series, which have shown the presence of a pattern of magnetic anomalies, bilaterally symmetric about the crest of the ridge in the Pacific, Atlantic, and Indian oceans. By assuming that the pattern is caused by a sequence of normally and reversely magnetized blocks that have been produced by sea floor spreading at the axes of the ridges, it is shown that the sequences of blocks correspond to the same geomagnetic time scale. An attempt is made to determine the absolute ages of this time scale using palcomagnetic and paleontological data. The pattern of opening of the oceans is discussed and the implications on continental drift are considered. This pattern is in good agreement with continental drift, in particular with the history of the break up of Gondwanaland.

Aeromagnetic survey of South-Western Europe

“…Heirtzler et al [7] have shown that, during the last 80 my, there has been about as much time when the geomagnetic field has a positive polarity as a negative polarity. Thus, an asymmetri~d histogram indicates a predominance of sources of one polarity whereas a symmetrical histogram indicates a probable equality between sources of positive and negative polarity and is compatible with a distribution of anomalies according to the Vine and Matthews model.…”

The Paleomagnetic Field as Inferred from Marine Magnetic Studies

“…There is still disagreement among investigators about the number, Fig. 9 Geomagnetic time scale in column C is that inferred from the magnetization of three sediment cores (D, E, and F) and time scale inferred from magnetic anomalies (column A after Heirtzler et al, 1968, and column B after Pitman and Heirtzler, 1966).…”

“…Heirtzler, et al, (1968) have attempted to find an ocean area where the spreading has apparently been constant in time and in that area extrapolate the time scale to obtain a history of reversals as far as marine data will allow (see If it is assumed that a body width of one-tenth the depth of water could be detected by a sea level magnetic instrument then a body of about 0.3 km wide could conceivably be detected in many ocean areas. If this body is due to material spreading at a rate of 6 cm/yr then the magnetized body would correspond to an event of about 5,000 years duration.…”

“…2 some adjustments have been made in the best history of magnetic reversals from volcanic Fig. 3 Comparison of geomagnetic time scale as inferred from magnetized ocean basement (after Heirtzler et al, 1968) and from magnetization of volcanic rocks (after Cox, 1969). rocks. That more recent history (Cox, 1969) is compared with the record from the ocean basement in Fig 3. For the marine time scale the beginning of the Gauss normal epoch was assumed to have an age of 3.35 m.y.…”

The Tooth of Time: The North American Cordillera from Tanya Atwater to Karin Sigloch

“…The plate circuit Tanya needed stepped from the Pacific to the Antarctic to the Indian (because the Southwest Indian Ridge between the Antarctic and African plates was poorly known) to the African to the North American plate. The basic methodology was laid down by Jason (Atwater and Menard 1970), numbered according to the Heirtzler et al (1968) time scale as calibrated by Berggren (1969). Morgan (1968) and had immediately been taken up by Xavier Le Pichon at Lamont, who alone recognized its significance and single-handedly achieved the first self-consistent global circuit model, involving six plates, before the magnetic polarity time scale was resolved (Le Pichon 1968).…”