Page 53 - Super Earth Encyclopedia

STATS AND FACTS

TEMPERATURE RIVER EROSION
The exposed layers
of rocks that form On the South Rim, It takes about
ten years for the
the temperature
the high walls of ranges from -4°F river to widen the
the Grand Canyon (-29°C) to 105°F canyon by just
provide Earth (41°C). a millimeter.
scientists with
one of the most ROCK LAYERS CANYON WIDTH
complete records There are about The widest part of
of rock formation 22 major rock the canyon is about
on the planet. layers; in parts, 18 miles (29 km)
there can be as across; the narrowest
many as 40. part is 3.7 miles (6 km).
HIDDEN IN THE LAYERS

The youngest layer of rock Fossils of extinct sea creatures in the rocks
is the pale Kaibab Limestone show that most of the layers were laid down
that forms the canyon rim.
on the seabed. This trilobite was found in
the Bright Angel Shale layer.

The colder North Rim
is more deeply eroded
than the South Rim.

Molten rock erupting FORMIDABLE FORMATIONS
1,700 million years ago
cooled to form the A fracture in the rock—a
Zoroaster Granite. fault—has allowed the rock
layers to move out of line.

The deepest rock layers lie at an
angle because they were tilted by the
collision of two plates of Earth’s crust.
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