Geological history of Earth

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Geologic Clock with events and periods

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The Mysterious Case of the Disappearing Dust

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Hadean

Archean

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Snowball Huronian

Geological history of Earth refers to the development and changes on the planet Earth from its formation about 4.54 billion years ago to the present day. This history is divided into several key eons, eras, periods, epochs, and ages that represent significant events in the geological, climatological, and biological evolution of Earth.

Precambrian Time

The Precambrian Time spans from the formation of the Earth about 4.54 billion years ago to the start of the Cambrian Period about 541 million years ago. It is divided into the Hadean, Archean, and Proterozoic eons. During the Precambrian, the Earth's crust cooled, the first continents formed, and life began to emerge.

Hadean Eon

The Hadean Eon (4.54 to about 4 billion years ago) is characterized by the formation of the Earth and the creation of the planet's first crust. No known rock record exists from this time, but it is believed that the surface was molten and that the atmosphere and oceans were forming.

Archean Eon

The Archean Eon (4 billion to 2.5 billion years ago) saw the formation of the Earth's first stable continents and the emergence of life, primarily in the form of simple single-celled organisms. The atmosphere was devoid of oxygen.

Proterozoic Eon

The Proterozoic Eon (2.5 billion to 541 million years ago) is marked by the buildup of oxygen in the atmosphere, known as the Great Oxidation Event, and the appearance of more complex life forms, including the first multicellular organisms.

Phanerozoic Eon

The Phanerozoic Eon covers the last 541 million years of Earth's history, from the beginning of the Cambrian Period to the present. It is divided into three eras: the Paleozoic Era, the Mesozoic Era, and the Cenozoic Era.

Paleozoic Era

The Paleozoic Era (541 to 252 million years ago) is known for the Cambrian Explosion, a rapid diversification of life that resulted in the appearance of many of the major groups of animals. This era ended with the largest mass extinction in Earth's history, the Permian-Triassic extinction event.

Mesozoic Era

The Mesozoic Era (252 to 66 million years ago) is often called the Age of Reptiles because of the dominance of dinosaurs. This era ended with the Cretaceous-Paleogene extinction event, which led to the extinction of the dinosaurs and paved the way for mammals to become the dominant land animals.

Cenozoic Era

The Cenozoic Era (66 million years ago to the present) is the current era of geological time. It has seen the rise of mammals and birds, the formation of modern continents and ocean basins, and the development of the current climate.

Current Geological Period

The current geological period is the Quaternary Period, which began about 2.58 million years ago and continues to the present day. It is characterized by a series of ice ages and the evolution of Homo sapiens.