Ocorrência de rochas sedimentares carbonáticas do Cretáceo superior no substrato da cidade de Fortaleza e suas possíveis implicações estratigráficas e estruturais

Abstract

The northern equatorial margin basins are research targets involving hydrocarbons and their production. We highlight studies carried out in the Potiguar Basin and most recently in the Mundaú Sub-Basin. This last, focus of this research could be sampled for the first time in the onshore part, where limestones were discovered due to the Metrofor and water well drilling. There are two drill holes SR-103+020 and SM-13, and the Condominio Essenza’s water well, all in the urban area. The unpublished data they seek to correlate the carbonate sedimentation of the Upper Cretaceous where the samples would be correlated to the Jandaíra Formation (Potiguar Basin). Petrography, micropaleontology and nanofossils were evaluated and data from ANP and Siagas / CPRM wells were investigated in the section between Graben Cascavel. No calcareous layers were found in the graben section, in the samples studied in the holes were described as calcarenites and wackestones. Microfossils were identified as bivalves, ostracoids, foraminifera, algae, bryozoans; besides 49 taxons of nanofossils. The data allowed to construct a sedimentation arrangement of the Upper Cretaceous from Cenomanian to the Mastrichtian where two models could occur: carbonaceous sedimentation of single platform (continuous or discontinuous) in the Potiguar and Ceará basins or carbonaceous sedimentation separated by the Graben Cascavel where the Potiguar Basin and Ceará had no connection but synchrony in the sedimentation.