La Formación Macuma en la cordillera de Cutucú al sureste de Ecuador: paleontología y estratigrafía

Abstract

The Macuma Formation preserve the only fossiliferous assemblage of the Carboniferous Period known in Ecuador, their outcrops appear in the Southeastern, in the northern part of the Cutucú Mountains. Previous studies of the Oriente Basin are focused on the Mesozoic rocks due to its potential as crude oil parent rocks. The present study is a general review of the Paleontology and the Stratigraphy of Macuma Formation, with the objective to understand the processes that conditioned their sedimentation. The Macuma formation is a sedimentary sequence wich is mainly composed of limestones and the fossil content includes brachiopods, bryozoans, crinoids, trilobites, corals and fusulinids in a very diverse microfauna. The location of one sienitic sill rear to the Macuma Formation is described within the studied sequence. The Macuma Formation is deformed and with NW dip. As results of the analysis of the spatial-temporal distribution of fauna found in this Formation, a shallow carbonate platform environment is established and its age is restricted to the Upper Carboniferous (Pennsylvanian). For the first time in the country was made the taxonomic description of a trilobite, rugose coral, a variety of brachiopods, bryozoans, crinoids and benthic foraminifera in the suborder Fusulinina, Miliolina and Textulariina