Three-dimensional geological modeling of the Itataia Phosphate-Uranium Deposit (Ceará, Brazil)

Abstract

The Itataia phosphate-uranium deposit is located in the northwest segment of the Borborema Province in the Ceará Central Domain. The ore mineral is uranium-enriched microcrystalline collophanite apatite that occurs in massive bodies and lenses, stockworks, as well as hydrothermal and karst breccias associated with marble, calc-silicate rocks and gneisses of the Itataia Group. The deformational history of the deposit includes ductile structures developed in the final stages of thrust tectonics linked to the Brasilian orogeny and later brittle phases related to extensional tectonics, which influenced phosphorus and uranium remobilization and the formation of ore bodies. The main uranium anomaly coincides with the upper part of the Serrote da Igreja hill, bordered to the north by an E-W trending subvertical fault scarp that controls a wide valley. Geometric modeling of the geological data of the deposit provides a three-dimensional view of the geometry of ore bodies, distribution of host rock and faults that propagate beneath the surface and control mineralization, as well as the upper and lower limits of surface weathering. The three-dimensional geometric model using the GoCAD software served as a powerful tool for the analysis of the geology of the Itataia deposit, highlighting the geometry of rocks and ore bodies and the processes involved in the genesis of phosphate-uranium mineralization.

KEYWORDS:
geological modeling; phosphate-uranium ores; Itataia deposit