Transcript Geologic Past - davis.k12.ut.us

Geologic Past
Foundations of Social Studies
History
Geologic Time Scale

System of chronological measurements based on the study
of the/our planets rock layers.

According to the rock layers, Earth was formed about 4.5
billion years ago from dust and gas left over from the
formation of the sun.

Initially earth was just liquid rock, the outer layer cooled
to form a solid crust.

Outgassing produced the atmosphere.

Water vapor accumulated in the atmosphere, it
condensed, and along with ice delivered from comets and
then they produced the oceans.
Geologic Eras
 Earths
life divided into enormously
long time periods.
 Based on changes in the earth’s crust.
 Fossils that appear in rocks help define
the eras too.
Precambrian Era
 Earliest
and longest era.
 Takes the Earth from its molten state
to a solid
 Fossils indicate multi-celled animals
from this era.
Paleozoic Era
Early
in the Era continents are far
apart, then drifted into one
continent Pangea.
Ice covered to Northern Africa.
Large numbers of vertebrates and
invertebrates in the ocean.
Also largest mass extinction.
Mesozoic Era
 Beginning
of land animals and plants.
 Seed producing plants.
 Dinosaurs.
herbivores and carnivores
 First mammals and birds.
 Dinosaurs ended when a meteor hit
Earth.
Cenozoic Era
 Mammals
are the predominant species.
 Diverse mammals, moved and began
eating foods the dinosaurs ate.
 Grasses and grazing animals evolved.
 Human like creatures evolved called
hominids.
Pleistocene Epoch: The Ice Ages

End of the Cenozoic Era.

The most recent episode of global cooling.
Earth warmed and receded four different time

Plant and animal life similar to modern times and many
still survive today.


Large animals, for example the Mammoth, lived in early part
of the era then became extinct.
Expansion of our species homo-sapiens.

These humans did not survive perhaps because of disease.
Fossils in Utah

Cenozoic

Mesozoic

Paleozoic
Dinosaur National Monument-Vernal
Southern Utah Quarries