The Trombetas Group chitinozoans of the Amazon Basin, Northern Brazil

Using palynological and biostratigraphical methods an attempt was made to elate the age of the Nhamunda, 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 Nharmunda Formation, Ludlovian to Pridolian age for the Upper Pitinga Formation, and a Pridolian to Early Lochkovian age for the Manacapuru Formation.