• Geologic Time- A method of looking back at earth’s history based on the information preserved in the fossils and other rock structures of the rock record.

• Geologic Time Scale- A summary table of the geologic history of the earth.

• Organized into divisions

based on major changes

or events that took place

• 4 Eras

• 15 Periods

D

GEOLOGIC

TIME

SCALE

Tertiary

GEOLOGIC

TIME

SCALE

Tertiary

ERA- largest time division, oldest at bottom, most recent at top

32) Cenozoic

25) Mesozoic

9) Paleozoic

2) Precambrian

3)Hadean : 4.6 BYA-3.8 BYA

-Solar System started to form

-Protoplanet formed

5)Archean 3.8BYA –2.5BYA

-planet cooling-minerals form-oceans form-1st life (bacteria & stromatolites- in oceans)-Cratons form –(original continent- most ancient rocks)

~ 3.5 BY

7)Proterozoic : 2.5 BYA-540 MYA

-Large amount of SIMPLE LIFE-only in ocean; worms, jellyfish, bacteria

10)Cambrian 540- 500 MYA

-Trilobites thrive

-Brachiopods numerous

-1st vertebrates seen (backbone)

12)Ordovician 500- 430 MYA

-Appalachian Mountains form

-Jawless fish seen

14)Silurian : 430 - 400 MYA

-1st plants-1st jawed fish-1st land animals

16)Devonian 400- 345 MYA

                                                                                                      

•Air breathing fish

•1st amphibians

•Insects

•Bony Fish

18)Mississippian- 345-325 MYA

-Ferns thrive-Amphibians common

20)Pennsylvanian- 325-280 MYA

-1st reptiles

-coal forming swamps

-location of coal today

22) Carboniferous

23)Permian: 280-250 MYA

-mammal-like reptile

-mass extinctions

26)Triassic : 250-190 MYA

-1st dinosaurs

-volcanoes on east coast of N.A.

-Conifer trees

-1st mammals

28)Jurassic : 190-135 MYA

-1st birds

-Dinosaurs dominate

30)Cretaceous: 135-65 MYA

-1st flowers

- Bees

-dinosaursbecomeextinct

-Rocky Mtnsform

33)Tertiary : 65-1.5 MYA

•Mammals thrive

•1st human-like creatures seen (hominidshominids)

Quaternary: 1.5 MY- Present

-Modern people-Civilization-Cities