2. Historical geology or
paleogeology is a discipline
that uses the principles and
techniques of geology to
reconstruct and understand the
geological history of Earth
5. The three primary methods
used to determine the age of
Earth are:
1. Radiation Measurement
2. Stratigraphic Superposition
3. The Fossil Record
6. Radiation Measurement -
The discovery of the natural
radioactive decay of uranium in
1896 by Henry Becquerel, the
French physicist
7. Stratigraphy is a branch of
geology concerned with the
study of rock layers (strata) and
layering (stratification). It is
primarily used in the study of
sedimentary and layered
volcanic rocks.
8. Stratigraphy has two related
subfields: lithostratigraphy
(lithologic stratigraphy) and
biostratigraphy (biologic
stratigraphy)
9. Body fossils and trace fossils
are the principal types of
evidence about ancient life, and
geochemical evidence has helped
to decipher the evolution of life
before there were organisms
large enough to leave body
fossils.
10. The Formation of Fossils
Fossils are the record of life
preserved in monuments of stone.
Almost all living organisms can
leave fossils, but usually only the
hard parts of plants and animals
fossilize.
11. Soft internal organs, muscle, and
skin rapidly decay and are rarely
preserved, but the bones and
shells of animals are good
candidates for fossilization.
Almost no fossil record exists for
soft organisms such as jellyfish
and worms.
12.
13. The Precambrian
• informal unit of geologic time
• subdivided into three eons
(Hadean, Archean,
Proterozoic)
• formation of Earth
• 4.6 billion years ago to about
541 million years ago.
14. The Phanerozoic,
• the eon of visible life
• divided into three major
spans of time the
Paleozoic, Mesozoic,
and Cenozoic eras.
15. The Paleozoic Era
• 542 million years ago to 251
million years ago,
• time of great change on
Earth
• breakup of one
supercontinent and the
formation of another.
16.
17. Paleozoic Era
• Plants became widespread
• first vertebrate animals
colonized land
• life flourished in the seas
• plants most likely did not yet
have leaves
18. Mesozoic Era
• life diversified rapidly
• giant reptiles, dinosaurs and
other monstrous beasts
roamed the Earth
• 252 million years ago to
about 66 million years ago
19. Mesozoic Era
• many modern forms of plants,
invertebrates, and fishes
evolved.
• dinosaurs were the dominant
animals,
• oceans were populated by
large marine reptiles
• Lasted 180 million years
20. Cenozoic Era
• 65 million years ago and
continues into the present
• is derived from the Greek
phrase meaning “recent
life.”
• Paleogene Period,
Neogene, Period and
Quaternary Period
21. Cenozoic Era
• The current locations of the
continents and their
modern-day inhabitants
• the extinction of the non-
avian dinosaurs
• the rise of mankind.
