Geology Reference
In-Depth Information
Icy cold climates of long ago
Rocks on the Gondwana continents also show evidence of once having been covered by
massive amounts of ice, or
glaciers
(explained in Chapter 13). When glaciers move
across rock, they leave scratches in the surface of the rock. These scratched lines, or
striations,
indicate the direction the glacier ice is moving.
The glacial striations observed on rocks of the same time period in Antarctica, South
America, Africa, India, and Australia allow geologists to recreate how the continents
were connected. Using what they know about glacier ice movement today, scientists can
interpret the striations on the ancient rocks and reconstruct the relative position of the
continents forming Gondwana. The result is illustrated in Figure 8-5.
Figure 8-5:
Recon-
struction of the
continents togeth-
er, based on gla-
cial striations.
