EARTH × TECHNOLOGY

The Sea Floor Is a Conveyor

1963 to 1968 CE

Phanerozoic · Cenozoic · Quaternary · Holocene · Meghalayan

The sea floor records the reversals of the Earth's magnetic field as stripes of alternating polarity, and the stripes on either side of a mid-ocean ridge mirror each other exactly. There is only one way to get that pattern: rock is being made at the ridge and carried away in both directions. Continental drift had been proposed fifty years earlier and rejected for want of a mechanism. Here it was, printed on the ocean floor.

Why it matters

It turned geology from a collection of regional explanations into one theory, and it is why this timeline can speak of supercontinents assembling and breaking at all. Every date on the earth layer of this frieze assumes it.

Dating & uncertainty

Continental drift was proposed in 1912 and rejected for half a century for lack of a mechanism. Magnetic stripes on the sea floor, symmetrical about the ridges, supplied it in 1963; the full theory of plates followed within five years.

Sources

1. Vine & Matthews (1963), Nature · Magnetic anomalies over oceanic ridges
2. Wilson (1965), Nature · A new class of faults and their bearing on continental drift
3. Merdith et al. (2021), Earth-Science Reviews · Extending full-plate tectonic models into deep time

Earth history as one day

23:59:59.99881.2 ms before midnight

if Earth’s 4.54 billion years were compressed into a single day