The Calcium Isotope (δ44/40Ca) Record Through Environmental Changes: Insights From the Late Triassic

Zsófia Kovács*, Isaline Demangel, Andre Baldermann, Dorothee Hippler, Anne Désirée Schmitt, Sophie Gangloff, Leopold Krystyn, Sylvain Richoz

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Calcium isotopes (δ44/40Ca) are particularly useful in palaeo-environmental studies due to the key role of carbonate minerals in continental weathering and their formation in seawater. The calcium isotope ratio can provide hints on past changes in the calcium fluxes, environmental shifts, ecological factors and alternatively diagenesis of carbonate rocks. The investigation of the Late Triassic calcium isotope record offers a great opportunity to evaluate such factors in a time interval that witnessed important environmental and ecological turnovers, such as the first appearance of calcareous nannoplankton, ocean acidification and periods of elevated extinction rates. In this study, we present a δ44/40Ca data set from the upper Norian (Upper Triassic) through the lower Hettangian (Lower Jurassic) interval. The isotope records reveal two globally significant signals: a ∼ 0.20‰ decrease through the early Rhaetian (Upper Triassic) and a small, negative (∼0.14‰) excursion corresponding to the emplacement of the Central Atlantic Magmatic Province, at the end of the Triassic. The possible explanations for these signals are changes in the isotopic ratio of the continental calcium influx to the ocean due to the high chemical weathering rate of carbonates and possibly ocean acidification, respectively. The considerable (∼0.15–0.30‰) offset in δ44/40Ca between study areas is likely the combined result of local differences in lithology and early marine diagenesis. The major evolutionary step represented by the first occurrence of calcareous nannoplankton did not have at this time a determining role on the calcium isotopic signature of the marine carbonates.

Original languageEnglish
Article numbere2022GC010405
JournalGeochemistry, Geophysics, Geosystems
Issue number12
Publication statusPublished - Dec 2022


  • carbonates
  • end-Triassic mas extinction
  • isotope proxy
  • nannofossils
  • Rhaetian
  • Triassic/Jurassic boundary

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology


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