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The numerical age of the Cambrian base is revised to 538.8 Ma

node

The base of the Cambrian, and with it the base of the Phanerozoic, has carried several different numerical ages while its defining point at Fortune Head has not moved: figures near 542 Ma, then 541.0 ± 1.0 Ma on charts widely cited through the 2010s, and 538.8 ± 0.2 Ma on recent editions. This record exists to make that change legible rather than to hide it, because the declared timeline for this Journey still gives ~541 Ma. The specific chart edition in which the revision took effect was not confirmed in this session, which is why this event is recorded as uncertain — the change itself is not in doubt, its exact publication is.

A node is not a place. Drawing it on a map would assert something about the world that no stored fact supports.

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Evidence · 1
Timeline

No dated observations are stored for this object. Atlas shows what was observed and when — it does not infer a history.

Connections · 3
Assembled narrative · 1

Assembled from 25 blocks · 1 evidence · 16 related

  1. Story
  2. The base of the Cambrian, and with it the base of the Phanerozoic, has carried several different numerical ages while its defining point at Fortune Head has not moved: figures near 542 Ma, then 541.0 ± 1.0 Ma on charts widely cited through the 2010s, and 538.8 ± 0.2 Ma on recent editions. This record exists to make that change legible rather than to hide it, because the declared timeline for this Journey still gives ~541 Ma. The specific chart edition in which the revision took effect was not confirmed in this session, which is why this event is recorded as uncertain — the change itself is not in doubt, its exact publication is.
  3. Knowledge
  4. Global Boundary Stratotype Section and Point
  5. International Commission on Stratigraphy
  6. Fortune Head GSSP, Newfoundland
  7. The numerical age of the Cambrian base is revised to 538.8 Ma
  8. Connections
  9. International Commission on Stratigraphy
  10. Fortune Head GSSP, Newfoundland
  11. Global Boundary Stratotype Section and Point
  12. Global Boundary Stratotype Section and Point
  13. The end-Ordovician mass extinction
  14. The Late Devonian crisis
  15. The numerical age of the Cambrian base is revised to 538.8 Ma
  16. The Cambrian explosion
  17. Global Boundary Stratotype Section and Point
  18. The Cambrian explosion
  19. The numerical age of the Cambrian base is revised to 538.8 Ma
  20. International Commission on Stratigraphy
  21. Fortune Head GSSP, Newfoundland
  22. Meishan GSSP, Changxing, Zhejiang
  23. The numerical age of the Cambrian base is revised to 538.8 Ma
  24. Evidence
  25. Supports the stage and period boundary ages used throughout this pack, including the Cambrian base at 538.8 ± 0.2 Ma on recent editions against 541.0 ± 1.0 Ma on earlier ones. V55 verification basis: this session had no network access to any source — WebFetch was egress-blocked and the WebSearch budget was exhausted — so the cited work was not retrieved and its pagination was not re-checked. No chart edition was opened, so the boundary figures are quoted from standing knowledge of the chart rather than read from it, and the edition in which the Cambrian base changed is not identified.
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Observed changes · 0

No public Signals are attached to this object. Signals show what changed and when it was observed — never a direction or a rank.

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Read the assembled narrativeContinue in StudioOpen TwinTwin does not start a decision from this kind of object.ShareSaveSaved objects are part of the authenticated projection, which is declared and not yet built.

/atlas?object=EVT_ICS_CAMBRIAN_BASE_REVISED&experience=EVT_ICS_CAMBRIAN_BASE_REVISED