The average rate of continental growth since then was perhaps as much
as a one cubic mile a year. The constant rifting and patching of the interior
along with sediments deposited along the continental margins eventually built
the supercontinent outward. By the end of the Archean, it nearly equaled the
total area of today’s continents. Much of the landmass was covered by shallow
seas until around 800 million years ago.
After discussing the simple life-forms of the Archean eon, the next chap-
ter will focus on the more complex organisms and rock formations of the
Proterozoic eon.Figure 29An outcrop of
retrograde blueschist rocks
in the Seward Peninsula
region, Alaska.
(Photo by C. L. Sainsbury,
courtesy USGS)
Historical Geology