Concreções calcárias da formação Santana, bacia do Araripe: uma proposta de classificação.

18 pages; The calcareous concretions of the Santana Formation have been known since 1800 thanks to the work of João da Silva Feijó (1800). Their study was promoted internationally by the report of von Spix and von Martius (1823-1831), and their richness in fossil fishes led Silva Santos to name them “ichthyoliths” in 1950. Here we propose a classification for the various types of calcareous concretions that occurred in the Santana Formation (Late Cretaceous, Araripe Basin). We consider their geographic distribution and we propose a terminological uniformization for the descriptions of that material. This will serve future statistical, geographical, geochemical and taphonomical studies that,…