Cambrian (geology): Difference between revisions

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*Late Cambrian  (501 - 488.3 mya)
*Late Cambrian  (501 - 488.3 mya)


Currently the Furongian Series (or Epoch) and the Paibian and Drumian Stages (or Ages) are defined and designated by name. <ref>Note: All other series and stages are as yet unmamed and referred to simply as "Series" or "Stage", by the ICS.</ref> The earliest undefined series (unamed)  encompasses the as yet unamed Stage 1 and Stage 2 (earliest to latest). Series 2 extends from 521 mya to 510 mya with two stages. Series 3 (from 510 to 501 mya) is composed of Stage 5, the Drumian Stage (or Age). and Stage 7. The final and last series to be created in the Cambrian, the Furongian, encompasses the Paibian Stage, Stage 9 and Stage 10 <ref>[http://www.stratigraphy.org/geowhen/stages/Cambrian.html Cambrian Period] GeoWhen</ref><ref>[http://www.stratigraphy.org/cheu.pdf International Stratigraphic Chart] International Commission on Stratigraphy (ICS), International Union of Geological Sciences (IUGS).</ref>
Currently the Furongian Series (or Epoch) and the Paibian and Drumian Stages (or Ages) are defined and designated by name. <ref>Note: All other series and stages are as yet unmamed and referred to simply as "Series" or "Stage", by the ICS.</ref> The earliest undefined series (unamed)  encompasses the as yet unamed Stage 1 and Stage 2 (earliest to latest). Series 2 extends from 521 mya to 510 mya with two stages. Series 3 (from 510 to 501 mya) is composed of Stage 5, the Drumian Stage (or Age). and Stage 7. The final and last series to be created in the Cambrian, the Furongian, encompasses the Paibian Stage, Stage 9 and Stage 10 <ref>[http://www.stratigraphy.org/geowhen/stages/Cambrian.html Cambrian Period] GeoWhen</ref><ref>[http://www.stratigraphy.org/cheu.pdf International Stratigraphic Chart] International Commission on Stratigraphy (ICS), International Union of Geological Sciences (IUGS).</ref><ref>[http://www.stratigraphy.org/ediacaran/ Subcommission on Neoproterozoic Stratigraphy] International Commission on Stratigraphy (ICS), International Union of Geological Sciences (IUGS)</ref>


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Revision as of 19:28, 22 April 2007

The Cambrian is both a system of strata and a period of time. The name refers to a chronostatrigraphic or a geochronological unit of geological measure. The Cambrian is roughly the period between 543 to 490 million years ago in the Paleozoic Era of the Phanerozoic Eon. It encompasses four chronostatrigraphic series and ten epochs and correspondingly, four geochronological stages and ten ages.

Erathem/Era System/Period Series/Epoch Stage/Age
Paleozoic Cambrian Furongian Unnamed
Unnamed
Paibian
Unnamed Unnamed
Drumian
Unnamed
Unnamed Unnamed
Unnamed
Unnamed Unnamed
Unnamed

The name is derived from Cambria, the Roman word for Wales, the area where the rocks of the Cambrian was first studied.[1]

Boundries

The Cambrian is geochronolocally the period from 542 million years ago (mya) with an error factor (plus or minus 1.0 mya) to 488.3 (plus or minus 1.7 mya).[2] The lower boundry[3] is characterised by trace fossils, the lowest occurrence of Treptichnus (Phycodes) pedum and a near base of negative carbon-isotope excursion. The end or upper boundry is characterised by Conodont fossils, and the lowest occurrence of Iapetognathus fluctivagus; just above the base of Cordylodus lindstromi conodont Zone, and just below lowest occurrence of planktonic graptolites. Historically it was subdivided into three epochs (no longer recognized by the ICS)

  • Early Cambrian (542 - 513 mya)
  • Middle Cambrian (513 - 501 mya)
  • Late Cambrian (501 - 488.3 mya)

Currently the Furongian Series (or Epoch) and the Paibian and Drumian Stages (or Ages) are defined and designated by name. [4] The earliest undefined series (unamed) encompasses the as yet unamed Stage 1 and Stage 2 (earliest to latest). Series 2 extends from 521 mya to 510 mya with two stages. Series 3 (from 510 to 501 mya) is composed of Stage 5, the Drumian Stage (or Age). and Stage 7. The final and last series to be created in the Cambrian, the Furongian, encompasses the Paibian Stage, Stage 9 and Stage 10 [5][6][7]

System/Period Series/Epoch Stage/Age Span in millions of years ago
Cambrian Furongian
Unnamed
492 to 488.3 mya
496 to 492 mya
Unnamed
Paibian
501 to 496 mya


System/Period Series/Epoch Stage/Age Span in millions of years ago
Cambrian Series 3
Stage 7
503 to 501 mya
506 to 503 mya
Drumian
Stage 5
510 to 506 mya


System/Period Series/Epoch Stage/Age Span in millions of years ago
Cambrian Series 2
Stage 4
517 to 510 mya
521 to 517 mya
Stage 3


System/Period Series/Epoch Stage/Age Span in millions of years ago
Cambrian Series 1
Stage 2
534.6 to 531 mya
542 to 534.6 mya
Stage 1

Sources

References

  1. ↑ Glossary Illinois State Geological Survey
  2. ↑ All ICS chronological data are given with boundaries of plus or minus millions of years.
  3. ↑ At the upper most boundary of the Ediacaran system/period in the Neoproterozoic Erathem/Era in the Proterozoic Eonothem/Era of the Precambrian
  4. ↑ Note: All other series and stages are as yet unmamed and referred to simply as "Series" or "Stage", by the ICS.
  5. ↑ Cambrian Period GeoWhen
  6. ↑ International Stratigraphic Chart International Commission on Stratigraphy (ICS), International Union of Geological Sciences (IUGS).
  7. ↑ Subcommission on Neoproterozoic Stratigraphy International Commission on Stratigraphy (ICS), International Union of Geological Sciences (IUGS)
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