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Precambrian    音标拼音: [prik'æmbriən]

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  • Precambrian - Wikipedia
    The Precambrian is so named because it preceded the Cambrian, the first period of the Phanerozoic Eon, which is named after Cambria, the Latinized name for Wales, where rocks from this age were first studied The Precambrian accounts for 88% of the Earth's geologic time
  • Precambrian | Life, Climate, Facts | Britannica
    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 | 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 of the Cambrian 540 million years ago (Mya, or 0 54 bya)
  • The Precambrian - U. S. National Park Service
    Introduction 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 the world's oceans, but the land remained barren
  • 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
  • The Precambrian - University of California Museum of Paleontology
    Nearly 4 thousand million years passed after the Earth's inception before the first animals left their traces This stretch of time is called the Precambrian To speak of "the Precambrian" as a single unified time period is misleading, for it makes up roughly seven-eighths of the Earth's history
  • Precambrian Era - Michigan State University
    The Precambrian was originally defined as the era that predated the emergence of life in the Cambrian Period It is now known, however, that life on Earth began by the early Archean and that fossilized organisms became more and more abundant throughout Precambrian time
  • Precambrian - New World Encyclopedia
    The Precambrian (or Pre-Cambrian) is an interval of geologic time of roughly 4 billion years, beginning with the formation of Earth around 4500 million years ago (mya) and continuing until the abrupt appearance in the fossil record some 542 mya of abundant macroscopic hard-shelled animals
  • Fossils reveal many complex animals existed before the Cambrian explosion
    Fossils reveal many complex animals existed before the Cambrian explosion New fossils from the Ediacaran Period show that some animal groups are older than we thought
  • Precambrian: what it was, characteristics and division
    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





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