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Ypresian

First age of the Eocene Epoch

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General referenceInterpretive dossier study · Crown Archives visual atlas
Record originEnglish Wikipedia
Text licenseCC BY-SA 4.0
Source revisionSep 22, 2026
Entity authoritySource title only
Source-derived summary

In the geologic timescale the Ypresian is the oldest age or lowest stratigraphic stage of the Eocene. It spans the time between 56 and 48.07 Ma, is preceded by the Thanetian Age and is followed by the Eocene Lutetian Age. The Ypresian is consistent with the Lower Eocene. The beginning of the age is defined by a strong negative anomaly in δ13C values at the PETM.

Editorial summary

The public source identifies “Ypresian” as first age of the Eocene Epoch. This brief keeps that definition visible, then builds a research path around Ypresian, First and Eocene.

Editorial reviewA concise reference frame for defining the subject, testing terminology and identifying the institution closest to the evidence. The current 66-word lead offers orientation but no explicit four-digit date, so chronology should not be assumed. The selected authority fields contribute no independent date. Its value is orientation rather than verdict, with Ypresian, First and Eocene providing the first useful test.
Editorial analysis

Why this record matters

A short description can identify a subject without explaining its stakes. For “Ypresian”, the useful work is to connect “first age of the Eocene Epoch” to the records capable of establishing context and consequence.

Evidence profile

Vocabulary and entity names are the principal evidence signals here, because they determine the precision of every later search. The source revision retrieved here is dated Sep 22, 2026.

Critical limits

A concise general-reference account can conceal disagreements about scope, terminology or the weight assigned to individual sources. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.

How to read it

Use the entry as an orientation point, then follow its citations and revision history. Names, dates and institutional relationships should be checked against the original record.

Best used for
  • Subject orientation
  • Search vocabulary
  • Locating named sources
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The closest primary source, responsible institution and strongest cited specialist reference.

Three-step research path

  1. Establish the record: confirm the title “Ypresian”, its source revision and the description used here.
  2. Expand the search: follow Ypresian primary sources, Ypresian archive and Ypresian research across catalogues and specialist indexes.
  3. Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.

Questions for further research

  1. Which source most directly establishes the central claim about “Ypresian”?
  2. Which cited source is closest to the event, object or claim?
  3. Which institution is responsible for the underlying evidence?
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Source & attribution

This entry incorporates text from “Ypresian” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.