Original paper

The Trombetas Group chitinozoans of the Amazon Basin, Northern Brazil

de Azevedo-Soares, Hilda; Leonor Cuevas,


Using palynological and biostratigraphical methods an attempt was made to elate the age of the Nhamundá, Pitinga and Manacapuru formations of the Trombetas Group (Amazon Basin) by studying chitinozoans from fifteen boreholes and thirteen outcrops. Up to ninety-one different species were found in the outcrops comprising for example Margachitina margaritana, Sphaerochitina densibaculata and Pogonochitina djalmai. The boreholes yielded assemblages of twenty-five species. Therefore, a Late Llandoverian to Early Wenlockian age is indicated for the Lower Pitinga Formation and the Nhamundá Formation, Ludlovian to Pridolían age for the Upper Pitinga Formation, and a Pridolían to Early Lochkovian age for the Manacapuru Formation.


siluriandevonianchitinozoaamazon basinnhamunda formationpitinga formationmanacapuru formation