Page 84 - DINOSOUR ATLAS

, fallout , climate change
The Chicxulub impact crater is The asteroid impact certainly
buried beneath later sediments, happened, but it may be only
but it shows up clearly in gravity part of the story. The dinosaurs
maps of the area. The vast amount may also have been hit by
of material ejected by the climate change caused by
explosion settled all over the increased carbon dioxide in the
world as a thin layer of clay that atmosphere. Released by huge
divides rocks of Cretaceous and volcanoes, the gas trapped
Tertiary ages. The clay is rich in heat radiated from Earth,
iridium—a rare mineral that is raising temperatures and
usually found only in meteorites. creating a global desert.
Crater gravity map Clay layer

luis alvarez
volcanic winter .
The impact theory
The extinction of the dinosaurs also was suggested in
coincides with massive volcanic 1980 by physicist
eruptions in central India. These Dr. Luis Alvarez
generated enough lava to cover (1911–1988) and
an area the size of Texas and his son Walter
Alaska combined. They could (b. 1940), a geologist.
have thrown so much dust They discovered the
into the atmosphere that thin layer of iridium-
sunlight was blotted
out, making the enriched clay that
planet too cold for is evidence of an
large reptiles. asteroid strike.

87