HypotHESSes - Four Revolutions in the Earth Sciences - page 128

Brazilian rocks, using the Rb-Sr method of age dating. He found it just where the
Bullard fit predicted. Rocks from the two continents, now separated by three thou-
sand miles, even fell on the same Rb-Sr isochron. Just as Alfred Wegener had said
half a century before, the lines of newsprint read across the two sides of the torn
newspaper. Moreover, the ink and the paper are identical!
Toclosethepaleomagneticcaseforseafloorspreading,in1966FredVinerepor-
ted that not only the Juan de Fuca and Gorda ridges in the northeastern Pacific but
the Reykjanes Ridge section of the Mid-Atlantic Ridge southwest of Iceland and
the East Pacific Rise all have symmetrical magnetic anomaly “stripes,” each with
its own distinctive spreading rate. 21 The patterns were so clear that Vine noted that
if he and Wilson “had more faith in the idea . . . of a more constant rate of spread-
ing,” they could have been the first to spot the Jaramillo event. 22 As it was, they
could now use the magnetic anomalies to make slight corrections to the reversal
timescale and extend it out to 11 million years. “The [spreading] rates obtained,”
Vine concluded, “are in exact agreement with those needed to account for contin-
ental drift” (1415). In 1968, James Heirtzler and Lamont colleagues extended the
paleomagnetic timescale back to 80 million years. 23
Seafloor spreading was a fact, but what did it have to do with continental drift
and plate tectonics?