36 Origin and Morphology of Ocean Basins
Fig. 1.17. Age of the sea
tloor in the Atlantic Ocea n.
based chiefly on the magnetic reversa l . calc. The
grad ua l increa e in size of
the Atl antic is evide nt. It
grows at the expense of the
Pacific (whose age di strib uti ons are Ie . swell estabIi hed . IW. H. Berger.
E. L. Winte rer. 1974. lnt
soc edime nt pec Publ
I: III
Challenger set out in 1968 to test this prediction. It was first found to be correct
during Leg 3 (1968/69). Since then, most magnetic and micropa1e-ontological age
determinations have coincided with an astonishing exactness (Fig. 1.18). In the end,
this agreement had to the accepted as "proof' of the new theory.
1.9 Open Tasks and Questions
Plate tectonics brought a wealth of answers to fundamental questions - such as the
origin of mountains! - that had long resisted the most painstaking inquiries. However,
as any good theory should, it raised a host of new problems. Many of them simply
concern refinement of existing concepts, for example the details of processes active
at the plate margins (Fig. 1.20).