Definition of index fossil in English:

index fossil

noun

Geology
  • A fossil that is useful for dating and correlating the strata in which it is found.

    • ‘These rocks are interbedded in Emsian marine sedimentary successions that are well documented by index fossils.’
    • ‘Possibly the species will prove to be an index fossil for the lower Frasnian and uppermost Givetian of the Sauerland and the Maider in Morocco, ‘Ait Ou Amar’.’
    • ‘Stratigraphic occurrences of Carcineretes in the Caribbean Province suggest that this crab should be regarded as an index fossil for the early Maastrichtian.’
    • ‘Carboniferous and Permian strata often contain useful index fossils belonging to this group.’
    • ‘This ‘dating’ is based on the presence of the ammonite index fossil Dactylioceras tenuicostatum.’
    • ‘They are very abundant in some Paleozoic formations and include useful index fossils.’