1
Fig. C.O., p.428
This cartoon simulates
the impact of a giant
asteroid on the Earth
Fig. 17-1, p.429
Photo compilation shows Asteroid 460 from four different sides.
Fig. 17-2, p.429
A comet consists of a solid nucleus of a rock and ice mixture
surrounded by a “coma” of dust and gas. The tail is a mixture of
water, other volatiles, and dust that the solar wind sprays away
from the direction of the sun.
Fig. 17-4, p.431
This panoramic view of Meteor Crater in Arizona
shows its relatively small size for an impact crater,
1.2 kilometers across.
Fig. 17-5, p.432
The evolution of a moderate-
size impact crater:
(a) A transient crater is
excavated, compressed, and
fractured, and
the base of the cavity melts
with the rim raised. (b) The
ejecta blanket
spreads around the cavity,
and the rim slumps back into
the
cavity. (c) Fallback material
partly fills the cavity, along
with some
melt-rich material.
Fig. 17-6, p.432
FIGURE 17
-
6.
The evolution of a
large impact crater: (a) A transient
crater is excavated and compressed,
and the base of the cavity melts. (b)
The base of the transient cavity
rebounds as excavation continues.
(c) The raised rim of the transient
crater and central uplift both collapse
to form a larger and shallower crater
basin partly filled with inward-facing
scarps, large blocks, smaller
fragments, and melt rocks. (d) The
final crater is much broader and
shallower than the initial transient
crater. Autochthonous refers to
materials more or less in their
original position.
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