175 – 171 MA

Age · Middle Jurassic

Aalenian

175–171 Ma

The Aalenian is an age within the Middle Jurassic, spanning roughly 175 to 171 million years ago.

Rankage· Macrostrat
Base175 Ma· Macrostrat
Top171 Ma· Macrostrat
Duration3.8 Myr· Macrostrat
ChartICS International Chronostratigraphic Chart v2023/09 (ages from Macrostrat/PBDB interval tables)

Elsewhere

Cite this article

Stratum Study. "Aalenian" (Time interval). Stratum Study pack 2026.09, as of 2026-09-19. https://stratum.black/study/time/aalenian. Accessed 2026-09-20.

@misc{stratum-aalenian,
  title        = {Aalenian},
  author       = {{Stratum Study}},
  howpublished = {\url{https://stratum.black/study/time/aalenian}},
  year         = {2026},
  note         = {Time interval article, Stratum Study pack 2026.09, as of 2026-09-19; sources: stratum, macrostrat, pbdb. Accessed 2026-09-20.}
}

Citations carry the pack version and the article's as-of date so they resolve to the same text later. The facts themselves belong to the sources listed below; cite those for the science.

Sources for this article: Stratum editorial (Stratum editorial);Macrostrat (CC-BY-4.0);Paleobiology Database (CC-BY-4.0). As of 2026-09-19; Study pack 2026.09. Data reproduced under the licences shown; text in Stratum's own words unless a section names its source.

Found an error? Write to drew@tyr.ac with the article id interval:aalenian.