Ocean Floor Spreading: Olduvai and Gilsa Events in the Matuyama Epoch

Emilia, David A.; Heinrichs, Donald F.

doi:10.1126/science.166.3910.1267

Cited by 23 publications

(7 citation statements)

References 16 publications

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“…Unfortunately at the type locality on Reunion Island the Olduvai event is not seen. A srnall anomaly is sometimes seen in the sea-floor-spreading record at about this time (Heirtzler et ul.. 1968;Emilia andHeinrichs, 1969, 1972). so the existence of this very short event or events may be real.…”

Section: Eventsmentioning

confidence: 92%

Towards a Quaternary Time Scale

et al. 1980

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Nine first-appearance datums (FADs), twenty-three last-appearance datums (LADs), and three other micropaleontological datums are related to the magnetic-reversal, oxygen-isotope, and calcite-dissolution/coarse-fraction time scales to provide a preliminary basis for subdivision of the Quaternary in deep-sea sediments. The magnetic-reversal, oxygen-isotope, and calcite-dissolution/coarse-fraction scales have been correlated by determination on the same core materials, and absolute dates applied by 40K/40Ar or 14C dating of materials in known positions on one or another of these scales. FADS and LADs have been determined in cores for which either a magnetic-reversal, oxygen-isotope, or calcite-dissolution/coarse-fraction scale has also been available. Altogether 3 FADs and 5 LADs based on diatoms, 4 FADs and 5 LADs based on calcareous nannoplankton, 1 FAD and 8 LADs based on radiolarians, 1 FAD and 5 LADs based on planktonic foraminifers, 2 acme datums, and 1 ratio reversal datum have been determined, and absolute dates inferred by interpolation from known dates on the reference time scales. Some of the FADs and LADs apply or are synchronous only over limited areas of the oceans; others appear to be synchronous throughout the oceans. The base of the Quaternary is set at the top of the Olduvai event at 1.7 my. Four FADs, twelve LADs, two acme datums, and one ratio reversal datum occur above the base of the Quaternary at an average rate of about 1 per 100,000 yr. Five FADs and twelve LADs are recognized in the 0.8-my interval between the top of the Olduvai event and the Gauss/Matuyama Boundary at 2.5 my at an average incidence of about 1 per 50,000 yr.

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Section: Eventsmentioning

confidence: 92%

Towards a Quaternary Time Scale

et al. 1980

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“…For example, the stack profile provides evidence for a short event at 1.96 m.y. as described by Cox [1969] and Emilia and Heinrichs [1969] and for four short events rather than three in the interval 3.32 to 5 m.y. as described by Talwani et al [1971] and Mudie et al [1972].…”

Section: Boundary Between Intervals 332 E Boundary Between Intermentioning

confidence: 99%

Identification of short polarity events by transforming marine magnetic profiles to the pole

Blakely¹,

Cox²

1972

J. Geophys. Res.

107

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A method is presented that permits marine magnetic anomaly profiles from all parts of the world to be stacked for the purpose of enhancing coherent small anomalies due to short geomagnetic polarity events. In general, the shape of a profile depends not only on the sequence of normally and reversely magnetized magnetic prisms that constitute the source, but also on the following five angles: the declination and inclination of the regional field; the declination and inclination of the magnetization; and the azimuth of the magnetic stripes. Our method transforms a measured anomaly to a second anomaly which would have been produced by an identical source with vertical magnetization and vertical regional field. The method uses Fourier transform and linear systems theory and employs filters with a flat spectral response, so that no information is lost at short wavelengths. No assumptions are made about the true depth or shape of the source: this may be any two‐dimensional body or bodies in which the direction of magnetization is constant and the intensity varies arbitrarily. A preliminary application of the method to marine profiles from the East Pacific rise has yielded encouraging results.

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“…These were originally dated at 2.0 ±0.1 m.y. by Chamalaun and McDougall (1966) and thought to be part of the Olduvai event, but there is now some evidence for their being separate and distinct events (e.g., Heirtzler et al, 1968;Emilia and Heinrichs, 1969;Cox, 1969;Opdyke, 1972). Since these events do not always appear in marine magnetic profiles or paleomagnetically studied sediment cores, they probably represent extremely short period reversals, or an effect of the nondipole field, having only local significance.…”

Section: Part Ii: Calibration Of North Atlantic Late Neogene Biostratmentioning

confidence: 99%