Precambrian - Wikipedia
The Precambrian is an informal unit of geologic time, [3] subdivided into three eons (Hadean, Archean, Proterozoic) of the geologic time scale. It spans from the formation of Earth about 4.6 billion years ago (Ga) to the beginning of the Cambrian Period, about 538.8 million years ago (Ma), when hard-shelled creatures first appeared in abundance.
Precambrian | Life, Climate, & Facts | Britannica
2024年11月8日 · Precambrian, period of time extending from about 4.6 billion years ago (the point at which Earth began to form) to the beginning of the Cambrian Period, approximately 541 million years ago. The Precambrian represents more than 80 percent of the total geologic record.
Precambrian Research | Journal | ScienceDirect.com by Elsevier
Precambrian Research publishes studies on all aspects of the early stages of the composition, structure and evolution of the Earth and its planetary neighbours. With a focus on process-oriented and comparative studies, it covers, but is not restricted to, subjects such as:
Precambrian Time Information and Prehistoric Facts - National …
The Precambrian is the earliest of the geologic ages, which are marked by different layers of sedimentary rock. Laid down over millions of years, these rock layers contain a permanent record...
Precambrian: Facts About the Beginning of Time | Live Science
2016年5月3日 · The Precambrian was the first super eon of Earth’s history. This division of time — about seven-eighths of Earth's history — lasted from the first formation of the planet (about 4.6 billion ...
Precambrian - Natural History Museum
The Precambrian encompasses nearly 90% of the history of the Earth and around a third of the history of the Universe. The Precambrian begins with the formation of the Solar System 4.57 billion years ago (bya) and extends to the beginning …
Precambrian: what it was, characteristics and division
2024年3月21日 · The Precambrian is the earliest and longest time period in Earth's history. It spanned approximately 3.96 billion years, ending about 540 million years ago with the beginning of the Phanerozoic Eon and its first era, the Paleozoic.
The Precambrian - U.S. National Park Service
2023年4月28日 · The Precambrian was the "Age of Early Life." During the Precambrian, continents formed and our modern atmosphere developed, while early life evolved and flourished. Soft-bodied creatures like worms and jellyfish lived in …
Precambrian - Ancient Life, Fossils, Eons | Britannica
2024年11月8日 · It is now known that Precambrian rocks contain evidence of the very beginnings of life on Earth—which, based on the age of the rocks that contain the oldest evidence of life, took place nearly 3.5 billion years ago—the explosion of life-forms without skeletons before the Cambrian, and even the development of sexual reproduction.
Precambrian - The Timeline of Biological History - ThoughtCo
2017年3月8日 · The Precambrian (4500 to 543 million years ago) is a vast period of time, nearly 4,000 million years long, that began with the formation of the Earth and culminated with the Cambrian Explosion. The Precambrian accounts for seven-eighths of our planet's history.