Geologic Timeline
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 | 715 Ma Snowball Earth Earth at this time is often called “Snowball Earth” by scientists. All of the tectonic plates were located near the equator. Glacial ice deposits have been found in what were tropical areas at that time. This provides evidence that Earth was nearly frozen. The high albedo of the ice lead to planetary cooling. The Northern and Southern continents were beginning to separate. |
 | 540 Ma Cambrian Explosion Rapid evolutionary processes at this time lead to the appearance of many new life forms. Evidence from the fossil record indicates that most major types of organisms appeared at this time. An ancient Atlantic Ocean, the Iaepitus Ocean, was opening and beaches rimmed the North American continent. |
 | 300 Ma Carboniferous Coal Earth at this time included mountains forming all over the world, the super continent of Pangea, and widespread shallow seas. Most plants and animals had colonized land environments. Coal swamps developed in the tropics. Trees evolved bark and much wood was buried that eventually formed into coal. |
 | 100 Ma Cretaceous Warmth Earth at this time included dinosaurs and the evolution of new groups of mammals, birds, and flowering plants. The Earth’s climate was very warm and sea level was very high. Rapid rates of sea floor spreading led to shallower oceans, which overflowed onto the continents. One third of today’s land areas were under water including the center of the United States. Underwater volcanic activity put a lot of carbon dioxide into the atmosphere. This caused temperatures to warm and melted nearly all of the Earth’s glaciers. Tropical plants and reptiles were found close to the Earth’s poles. |
 | 2 Ma Quaternary Ice Age Earth at this time included the formation of glaciers in the northern hemisphere and the expansion of a large Antarctic ice sheet. This frozen water lowered sea level creating vast coastal plains. Humans evolved in Africa and began to migrate northward. During this time, 11 major ice ages, each lasting thousands of years, occurred and were separated by warmer periods. |
 | 50 ka The Last Glaciations The Laurentide ice sheet, centered on Hudson’s Bay in present day Canada, advanced and retreated, carving out the Great Lakes. As the amount of land ice changed, sea level rose and fell creating temporary land bridges across the English Channel and Bering Strait. This allowed Paleolithic (Stone Age) man to migrate to England and North America. Giant mammals flourished in parts of North America and Europe that were not covered in ice. |
 | 10 ka Holocene Development of Civilization The Earth’s climate at this time became warm and has remained relatively stable until the present. Homo sapiens (modern humans) spread to all parts of the world and civilizations developed. Most large land mammals became extinct. Pleistocene ice receded causing sea levels to rise and land to form the shorelines we see today. |
 | 1880 The Anthropocene Earth at this time is marked by humans dominating and rapidly changing the world. Population began to rise sharply, and deforestation and other ecosystem destruction became widespread to make room for more agricultural lands. The industrial revolution saw major changes in technology. Steam power, electricity from coal, and gasoline powered engines became abundant. The heavy use of fossil fuels began and has contributed to the rise in atmospheric greenhouse gases and rapid climate change. Global transport of invasive species changed ecosystems everywhere. Human population reached 1.5 billion by 1880. |
| 2010 Present Day At this time, all parts of the Earth are controlled by human activity. Population has reached 7 billion people. People now use most of the fresh surface water on the planet, have converted a large portion of the worlds plants to agriculture, changed the land cover over broad areas of all continents except Antarctica, and even are beginning to change the chemistry of the world's oceans. The accelerated use of fossil fuels is leading to a sharp rise in atmospheric greenhouse gases and rapid climate change. The most important of these, carbon dioxide, is emitted world-wide from electricity generating plants, from the manufacturing of goods, and the transportation of goods and people in planes, trucks, and cars. |
 | 715 Ma Snowball Earth Earth at this time is often called “Snowball Earth” by scientists. All of the tectonic plates were located near the equator. Glacial ice deposits have been found in what were tropical areas at that time. This provides evidence that Earth was nearly frozen. The high albedo of the ice lead to planetary cooling. The Northern and Southern continents were beginning to separate. |
 | 540 Ma Cambrian Explosion Rapid evolutionary processes at this time lead to the appearance of many new life forms. Evidence from the fossil record indicates that most major types of organisms appeared at this time. An ancient Atlantic Ocean, the Iaepitus Ocean, was opening and beaches rimmed the North American continent. |
 | 300 Ma Carboniferous Coal Earth at this time included mountains forming all over the world, the super continent of Pangea, and widespread shallow seas. Most plants and animals had colonized land environments. Coal swamps developed in the tropics. Trees evolved bark and much wood was buried that eventually formed into coal. |
 | 100 Ma Cretaceous Warmth Earth at this time included dinosaurs and the evolution of new groups of mammals, birds, and flowering plants. The Earth’s climate was very warm and sea level was very high. Rapid rates of sea floor spreading led to shallower oceans, which overflowed onto the continents. One third of today’s land areas were under water including the center of the United States. Underwater volcanic activity put a lot of carbon dioxide into the atmosphere. This caused temperatures to warm and melted nearly all of the Earth’s glaciers. Tropical plants and reptiles were found close to the Earth’s poles. |
 | 2 Ma Quaternary Ice Age Earth at this time included the formation of glaciers in the northern hemisphere and the expansion of a large Antarctic ice sheet. This frozen water lowered sea level creating vast coastal plains. Humans evolved in Africa and began to migrate northward. During this time, 11 major ice ages, each lasting thousands of years, occurred and were separated by warmer periods. |
 | 50 ka The Last Glaciations The Laurentide ice sheet, centered on Hudson’s Bay in present day Canada, advanced and retreated, carving out the Great Lakes. As the amount of land ice changed, sea level rose and fell creating temporary land bridges across the English Channel and Bering Strait. This allowed Paleolithic (Stone Age) man to migrate to England and North America. Giant mammals flourished in parts of North America and Europe that were not covered in ice. |
 | 10 ka Holocene Development of Civilization The Earth’s climate at this time became warm and has remained relatively stable until the present. Homo sapiens (modern humans) spread to all parts of the world and civilizations developed. Most large land mammals became extinct. Pleistocene ice receded causing sea levels to rise and land to form the shorelines we see today. |
 | 1880 The Anthropocene Earth at this time is marked by humans dominating and rapidly changing the world. Population began to rise sharply, and deforestation and other ecosystem destruction became widespread to make room for more agricultural lands. The industrial revolution saw major changes in technology. Steam power, electricity from coal, and gasoline powered engines became abundant. The heavy use of fossil fuels began and has contributed to the rise in atmospheric greenhouse gases and rapid climate change. Global transport of invasive species changed ecosystems everywhere. Human population reached 1.5 billion by 1880. |
| 2010 Present Day At this time, all parts of the Earth are controlled by human activity. Population has reached 7 billion people. People now use most of the fresh surface water on the planet, have converted a large portion of the worlds plants to agriculture, changed the land cover over broad areas of all continents except Antarctica, and even are beginning to change the chemistry of the world's oceans. The accelerated use of fossil fuels is leading to a sharp rise in atmospheric greenhouse gases and rapid climate change. The most important of these, carbon dioxide, is emitted world-wide from electricity generating plants, from the manufacturing of goods, and the transportation of goods and people in planes, trucks, and cars. |