The Precambrian (/ priˈkæmbri.ən, - ˈkeɪm -/ pree-KAM-bree-ən, -⁠KAYM-; [ 2 ] or Pre-Cambrian, sometimes abbreviated pC, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon.

2025年1月3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.

Billion-year-old Precambrian rocks form the walls—and loom on the bottom—of Western Brook Pond, a clear lake in Gros Morne National Park. Learn more about the period that occurred 4.5 billion to...

2016年5月3日 · This division of time — about seven-eighths of Earth's history — lasted from the first formation of the planet (about 4.6 billion years ago) to the geologically sudden diversification of...

2019年1月31日 · The Precambrian Time Span is the earliest time period on the Geologic Time Scale. It stretches from the formation of the earth 4.6 billion years ago to around 600 million years ago and encompasses many Eons and Eras leading up …

The Precambrian is divided into the Archean and Proterozoic eons, with the boundary between them at 2.5 billion years ago. It was originally defined as the era that predated the emergence of life in the Cambrian Period. It is now known, however, that …

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.

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 the world's oceans, but the land remained barren.

2025年1月3日 · Precambrian - Ancient Life, Fossils, Eons: Precambrian rocks were originally defined to predate the Cambrian Period and therefore all life, although the term Proterozoic was later coined from the Greek for “early life.”

The longest span of time is the Precambrian Era, which includes the Proterozoic, Archean, and Pre-Archean (also called the Hadean). The Precambrian began when the Earth formed and ended at the beginning of the Cambrian period, 570 million years ago.