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4.5 to 3.8 billion years ago ... Hadean time is not a geological period as such. No rocks on the Earth are this old - except for meteorites. During Hadean time, the Solar System was forming, probably within a large cloud of gas and dust around the sun, ... The sun formed within such a cloud of gas and dust, shrinking in on...
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www.ucmp.berkeley.edu/precambrian/hadean.html
www.ucmp.berkeley.edu/precambrian/hadean.html
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Precambrian - Wikipedia, the free encyclopedia
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The Precambrian ( Pre-Cambrian ) is an informal name for the span of time before the current Phanerozoic Eon, and is divided into several eons of the geologic timescale. It spans from the format...
en.wikipedia.org/wiki/Precambrian
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An intro to the Precambrian era, includes a review of each of the geological sub-divisions and the various forms of life that lived during this time ... The Precambrian is sometimes referred to as an "eon." However, it actually has no rank. It is simply Precambrian time. The Precambrian is that stretch of geological time...
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www.palaeos.com/Timescale/Precambrian.htm
www.palaeos.com/Timescale/Precambrian.htm
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Precambrian time includes Earth's history from birth up to 590 million years ago. That is, the Precambrian spans 90% of Earth's existence. Fossilized bacteria and blue-green algae show that primitive life existed at least 3,500 million years ago, and possibly earlier.
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fossils.valdosta.edu/era_precambrian.html
fossils.valdosta.edu/era_precambrian.html
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The Precambrian world was almost certainly as diverse and complex a place as today's world. ... The Precambrian is not well known or completely understood. Why? ... Most information is from cratons - large portions of continents which have not been deformed since Precambrian or Early Paleozoic time.
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facstaff.gpc.edu/~pgore/geology/geo102/precamb.htm
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The Precambrian Era is Earth's first era of time. It began with the creation of the Earth around 4.6 billion years ago and lasted until 570 million years ago. The Precambrian saw many drastic changes during this time.
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www.kinderscience.com/precambrian_era.htm
www.kinderscience.com/precambrian_era.htm
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Following its origins, the record of life on earth is limited to stromatilites and bacterial microfossils until development of the metazoans in the late Precambrian. From 3.5 billion years to around 1.8 billion years the fossil record is dominated by prokaryotes.
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www.es-designs.com/geol105/Topics/precambrian.html
www.es-designs.com/geol105/Topics/precambrian.html
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The Precambrian Period ... "What was the climate like during the Precambrian period? What was the average temperature, atmospheric composition, etc.?" ... Below is a table showing the 5 divisions of the Precambrian Period.
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www.seorf.ohiou.edu/~tstork/compass.rose/earth.history....
www.seorf.ohiou.edu/~tstork/compass.rose/earth.history.02/Precambrian%20and%20Siluria/PSpage2.html
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THE PRECAMBRIAN ERA; The Precambrian Era. The name means: "before the Cambrian period." This old, but still common term was originally used to refer to the whole period of earth's history before the formation of the oldest rocks with recognizable fossils in them.
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www.geo.msu.edu/geogmich/Precambrian.html
www.geo.msu.edu/geogmich/Precambrian.html
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