Embed Size (px)
DESCRIPTION
Detailed description on the chronology of the earth. reported are the very good source of information
Citation preview
GEOLOGIC TIME SCALEJason John V. Tabujara BSEdGS IV
START
WHAT IS A GEOLOGIC TIME SCALE?
System of chronologic measurement relating to stratigraphy to time that is used by geologist and other earth scientists
INTRODUCTION TO CONCEPT:
The period is the basic unit of geological time in which a single
type of rock system is formed. Two or more periods comprise a
geological Era. Two or more Eras form an Eon, the largest division of
geologic time. Some periods are divided into epochs.
The major periods in the geologic history of the Earth are
(mya=million years ago):
INTRODUCTION TO CONCEPT:
EonEra
PeriodEpoch
Period
Era Period
PRECAMBRIAN:Hadean, Archean and Proterozoic Eons
PRECAMBRIANHadean Eon4.6 to 3.9
billion years ago
“Rockless Eon" - The solidifying of
the Earth's continental and oceanic crusts.
Archeozoic Eon(Archean)3.9 to 2.5
billion years ago
"Ancient Life" The first life forms evolve
Proterozoic Eon
2.5 billion years ago
to 540 mya*multi-celled, animals appear, including sponges.
*Single supercontinent called Rodinia.
*First multicellular life: colonial algae and soft-bodied invertebrates appear.
PHANEROZOIC EON:Paleozoic Era
PHANEROZOIC EONPaleozoic Era:
The Paleozoic is bracketed by two of the most important events in the
history of animal life. 1. Multicellular animals went
dramatic diversity explosion2. Largest Mass extinction of mostly
90% of marine organisms
PALEOZOIC ERACambrian Period
"The Age of Trilobites"540 to 500 mya
PALEOZOIC ERA
Ordovician Period505 to 438 mya
PALEOZOIC ERA
Silurian Period438 to 408 mya
PALEOZOIC ERA
Devonian Period"The Age of Fishes"
408 to 360 mya
PALEOZOIC ERA
Carboniferous Mississippian Period
360 to 325 mya
PALEOZOIC ERA
Carboniferous Pennyslvanian Period
325 to 280 mya
PALEOZOIC ERA
Permian Period"The Age of Amphibians"
280 to 248 mya
PHANEROZOIC EON:Mesozoic Era
PHANEROZOIC EONMesozoic Era:
Many of the Old life forms had just gone extinct in the Permian
Extinction, the world’s largest mass extinction.
Depleted state was followed by an explosion of new life forms such as
dinosaurs, mammals, birds and flowering plants
MESOZOIC ERA
Triassic Period248 to 208 mya
MESOZOIC ERA
Jurassic Period208 to 146 mya
MESOZOIC ERA
Cretaceous Period146 to 65 mya
PHANEROZOIC EON:Cenozoic Era
PHANEROZOIC EONCenozoic Era:
The most recent Era of the three major subdivisions of animal history.Also called as the Age of Mammals65.5 million years ago to present
REFERENCES:
TARBUCK AND LUTGENS
