Geochemical stratigraphy of the Paraná Continental Flood Basalts: borehole evidence

TL;DRAbstract

Stratigraphic studies can provide an insight into the poorly understood geodynamic processes for the generation and emplacement of large continental flood basalt provinces by revealing the structure and sequential evolution of the lava field. Such studies are still in their infancy in the Paraná, where lack of sufficient topographic relief has confined work mainly to the well-exposed coastal escarpment in south-east Brazil. In this paper, a new approach is taken by analysing drillcore chippings from four oil-company boreholes in the central Paraná basin. Major and trace element analyses distinguish three geochemical units by their low, intermediate, and high Ti0 2 contents respectively, and demonstrate the validity of geochemical data from such material. Each borehole retains a coherent stratigraphy with the transition from low-Ti to high-Ti then intermediate-Ti lavas with time, and together they show an overlapping sequence of geochemical units dipping northwards, which could suggest

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