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In the 1950s, ocean surveys found a strange pattern on the sea floor: long bands of rock with alternating magnetic properties, lying parallel to the mid-ocean ridges. In 1963 a Cambridge research student, Fred Vine, and his supervisor, Drummond Matthews, explained it in a short paper. Their explanation turned seafloor spreading from a bold idea into a testable one. This post covers what they proposed, why it worked, how to turn the stripes into a spreading speed, and what students can learn from it.
Who were Vine and Matthews?
The Geological Society of London's page on the pair gives Drummond Matthews's dates as 1931 to 1997 and Fred Vine's birth year as 1939, and says they first worked together when Vine was a PhD student under Matthews at the University of Cambridge. The title of the Royal Society's biographical memoir of Matthews gives his dates as 5 February 1931 to 20 July 1997.
Their paper, Magnetic Anomalies Over Oceanic Ridges, appeared in Nature on 7 September 1963, from Cambridge's Department of Geodesy and Geophysics. It is only three pages long.
What did the magnetic stripes look like?
The US Geological Survey's account describes "zebra stripe-like magnetic patterns" in the rocks of the ocean floor, unlike anything seen on the continents. In 1962 the US Naval Oceanographic Office summarised the available maps. Earlier explanations put the bands down to changes in the strength of the Earth's field, or to other causes.
What did they propose?
Vine and Matthews, and independently the Canadian geophysicist Lawrence Morley, suggested something else. The USGS puts it this way: they hypothesised in 1963 that the striping "was produced by repeated reversals of the Earth's magnetic field", not by changes in its intensity. The Geological Society notes that the idea is now called the Vine-Matthews-Morley hypothesis.
Put that together with Harry Hess's idea of seafloor spreading and the stripes make sense:
Molten rock rises at a ridge and cools into new ocean floor.
As it cools, magnetic minerals such as magnetite line up with the Earth's field at that moment and lock that direction in.
The new floor moves away from the ridge on both sides, and fresh rock forms in the gap.
Every so often the Earth's field flips. Rock formed after the flip is magnetised the other way.
The result is a striped record, the same on both sides of the ridge, like a tape coming out of a recorder in two directions. Where a stripe's magnetism adds to today's field, a ship measures a slightly stronger field; where it opposes it, a slightly weaker one.
How was the idea confirmed?
Two things were needed: a dated record of field reversals, and better ocean surveys. The USGS describes how Allan Cox, Richard Doell and Brent Dalrymple used potassium-argon dating on volcanic rocks on land to build a timeline of reversals for the past 4 million years, published in Nature in 1963. Our guide to radioactive decay and half-life explains how such clocks work.
In 1966 Vine compared that timeline with new magnetic profiles in Spreading of the Ocean Floor: New Evidence in Science. His abstract argues that "the entire history of the ocean basins, in terms of ocean-floor spreading, is contained frozen in the oceanic crust". Profiles computed from the reversal timeline showed "remarkably good agreement" with those observed, and he found a spreading rate of approximately 4.5 cm per year in the South Pacific.
Worked example: how fast is the floor spreading?
These are sample numbers for practice. A ship crosses a ridge and finds that a particular reversal boundary lies 20 km from the ridge axis on each side. Land-based dating says that reversal happened 0.8 million years ago.
Half-spreading rate (one side): 20 km ÷ 0.8 million years = 25 km per million years.
Convert units: 1 km = 100,000 cm, and 1 million years = 1,000,000 years, so 1 km per million years = 0.1 cm per year. 25 km per million years = 2.5 cm per year.
Full-spreading rate (the two sides moving apart): 2 × 2.5 = 5 cm per year.
Now try Vine's 1966 figure in reverse. At 4.5 cm per year, which is 45 km per million years, floor formed 4 million years ago would lie 45 × 4 = 180 km from the axis, if that rate is the rate for one side.
Common mistakes:
Mixing half and full rates. Always say which one you mean. A rate quoted for "the ridge" may be either.
Unit slips. Remember that 1 km per million years equals 0.1 cm per year.
Forgetting symmetry. If your two sides give very different rates, re-check which stripe you matched.
The NCERT Class 11 geography chapter (2026-27 reprint) notes that the normal and reverse stripes help scientists determine rates of plate movement, from less than 2.5 cm per year on the Arctic Ridge to more than 15 cm per year on the East Pacific Rise.
What can a student take from their way of working?
Combine two facts nobody had combined. Field reversals were known from rocks on land, and spreading had been proposed. The new step was to put them together.
Make a prediction that could fail. Symmetric stripes, matching a dated reversal timeline, were a test the hypothesis could have failed.
Keep it short. A three-page paper with one clear idea changed a field.
Magnetic fields frozen into moving rock are easier to grasp when you can watch them build up. The Fermi Simulation Lab has interactive simulations for ideas that are easier to see than to read.
Next step: redo the worked example with a boundary 30 km from the axis and the same 0.8 million years, and find both the half and full rates.
