Experiment #122 · Scientific experiment

Seafloor Spreading

Continental drift confirmed by ocean-floor magnetism

Alfred Wegener (continental drift, 1912); F. J. Vine and D. H. Matthews (seafloor evidence, 1963) · 1912 / 1963 · Geology, geophysics

First published: A. Wegener, *Die Entstehung der Kontinente und Ozeane* (1915); F. J. Vine & D. H. Matthews, "Magnetic Anomalies Over Oceanic Ridges", *Nature* 199 (1963): 947–949.

Magnetic stripes on the ocean floor, symmetric about mid-ocean ridges, record the Earth's field reversals as new crust forms and spreads.

Wegener's 1912 proposal of continental drift was ridiculed by geologists for decades for lack of a mechanism. Vine and Matthews (1963) provided the decisive empirical confirmation: magnetic surveys of the mid-Atlantic ridge revealed symmetric stripes of normal and reversed magnetisation on either side, matching the known record of geomagnetic field reversals. The pattern is exactly what one expects if new oceanic crust is continuously formed at the ridge and spread outward — recording the magnetic field at each moment of its formation. The combination of seafloor spreading and the theory of plate tectonics (Wilson, Morgan, McKenzie 1965–68) reshaped Earth science and is the foundation of modern geology.

Formulation

Magnetic surveys of mid-ocean ridge crust. Predicted (Vine-Matthews, given seafloor spreading + known field reversals): symmetric striped magnetic anomalies parallel to ridge axis. Observed: exactly this pattern; widths consistent with measured reversal rates and known spreading rates.

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Dimensions Engaged

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Matter

Earth's lithosphere is dynamic: plates form, move, and consume each other on geological timescales.

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Time

The geomagnetic field reversal record provides a calibrated clock for the past 200 million years of seafloor history.

Responses — How Schools Engage

Affirms / takes the bait 5

Naturalism

A canonical empirical decision: a theory long resisted for lack of mechanism is decisively confirmed by an independent line of evidence. Modern geoscience is reshaped.

Realism

Continental drift and plate tectonics describe real Earth processes; the magnetic record on the ocean floor is direct evidence.

Process Philosophy

The Earth is a dynamic process system, not a static configuration; plate tectonics exemplifies process metaphysics in geology.

Structuralism

Plate tectonics provides a structural framework that unifies disparate geological phenomena (earthquakes, mountain building, ocean trenches, magnetic stripes) under a single dynamic geometry.

Logical Positivism

Operationally exemplary: a specific quantitative prediction (symmetric magnetic stripe widths from independent reversal record) is directly confirmed.