Geologic Time Scale

Understanding the different time periods in Earth's history is important for those individuals working to earn a degree in geology, geography, biology, and other fields as well. If you are participating in a distance learning course or pursuing online college degrees, it may be difficult to find the information and resources you need, since you may not have access to a good library. The following resources will aid you in your research into geologic time scales.

Phanerozoic Eon (544 million years ago to present)

The Early Phanerozoic Eon Good description from Volunteer State Community College

Cenozoic Era (65 million years ago to present)

Introduction to the Cenozoic

Quaternary Period (1.8 million years ago to present)

Quaternary Geology Description with illustrations and maps

Holocene Epoch (8,000 years ago to present)

The Holocene Epoch Informative resource containing maps, graphs, and photos

Pleistocene Epoch (1.8 million to 8,000 years ago)

Palaeos Cenozoic: Pleistocene: The Pleistocene Epoch Contains clear descriptions and summary of the time period

 Tertiary Period (65 to 1.8 million years ago)

Tertiary Period: Contains a chart listing the major features of this period

Pliocene Epoch (5.3 to 1.8 million years ago)

Palaeos Cenozoic: Pliocene: The Pliocene Epoch Clear explanations, charts, and pictures

Miocene Epoch (23.8 to 5.3 million years ago)

SDNHM Fossil Mysteries: Geologic Timeline Chart describes the era and compares it with other time periods

Oligocene Epoch (33.7 to 23.8 million years ago)

Palaeos Cenozoic: Oligocene: The Oligocene Epoch Discusses plant life, plate tectonics, animal life, and other aspects of this time period

Eocene Epoch (55.5 to 33.7 million years ago)

Geologic Time: The Eocene Contains great information on the development of primates during this time

Paleocene Epoch (65 to 55.5 million years ago)

Paleocene: Overview Description from the Smithsonian National Museum of Natural History

Mesozoic Era (248 to 65 million years ago) Earth Floor: Geologic Time Summary of this “middle life “era

Cretaceous Period (145 to 65 million years ago)

Cretaceous HSU NHM Collection of fossils from plants and animals of the time period

Jurassic Period (213 to 145 million years ago)

Jurassic Park Plants Large collection of plant photos, illustrations and information

Triassic Period (248 to 213 million years ago) Triassic HSU NHM Contains summary and fossil information

Paleozoic Era (544 to 248 million years ago) The Paleozoic Era Describes the fossils, geodynamics, and climate of this era

Permian Period (286 to 248 million years ago)

Permian Outline of the relevant facts, illustrated with fossil photographs

Carboniferous Period (360 to 286 million years ago)

The Carboniferous Period Scroll down to find information about this period

Pennsylvanian Period (325 to 286 million years ago)

Coal Over Geologic Time - Pennsylvanian Description of this era and how it relates to the formation of coal

Mississippian Period (360 to 325 million years ago)

ISGS Geonote 1 Missippian Rocks Description of the period with an emphasis on rock formation

Devonian Period (410 to 360 million years ago)

Cochise College Devonian Period Information on the Devonian period with lots of interesting pictures and illustrations

Silurian Period (440 to 410 million years ago)

The Virtual Siluiran Reef -- Silurian Period Includes maps and information about the distinctive fossils that date to this time period

Ordovician Period (505 to 440 million years ago)

Ordovician HSU NHM Interesting information from the Humboldt State University Natural History Museum

Cambrian Period (544 to 505 million years ago)

Cambrian Period Discusses climate, tectonics, and the Burgess ShalePrecambrian Time (4500 to 544 million years ago)

Precambrian Era Contains an extensive collection of maps to illustrate pertinent points

Proterozoic Era (2500 to 544 million years ago) Proterozoic: Overview Summary of important points about this period

Vendian Period (544 to 650 million years ago)

Life on Earth | The preCambrian/Vendian extinctions Information about this period and what might have caused the mass extinctions that occurred during this periodArchaean Era (3800 to 2500 million years ago)

Archaean Era Simple explanation of what sets this time period apart from others

Hadean Time (4500 to 3800 million years ago)

Hadean Time Includes information about exciting new discoveries about this time period

Published: 2010-01-20