Lithogeochemistry and 3D geological modeling of the apatite-bearing Mesquita Sampaio beforsite, Jacupiranga alkaline complex, Brazil

Abstract

The Mesquita Sampaio beforsite is a mineral exploration area with apatite mineralization occurring near the northern portion of the Morro da Mina apatite deposit (Cajati Mine), in the Jacupiranga Alkaline Complex. This study presents the mineralogical, geochemical and 3D geological modeling data of this target. Four lithotypes are presented for Mesquita Sampaio: the fine-grained beforsite (FGB), the coarse-grained beforsite (CGB), the xenolith zone (XEN), and the jacupirangite ( JAC). The 3D geological model shows the Mesquita Sampaio beforsite as a vertical body with an NNW direction and approximately 350 meters in length, 150 meters in width, and 400 meters of depth, with open extensions. The main mineral assemblage of the beforsite is dolomite, apatite, phlogopite, serpentine, calcite, and magnetite, in order of abundance. The distribution of major elements for both types of beforsites (FGB and CGB) indicates the same composition with only a small variation in the mineral proportions. Although no direct contact relation between Mesquita Sampaio and Morro da Mina is known, both may be the same carbonatite body with a gradual compositional variation, or the Mesquita Sampaio beforsite could be a distinct late or even earlier carbonatite pipe.

Mining Induced Ground Motions in a Tailings Dam

“…The main structural elements of carbonatites, such as joints, faults, dikes and fluid structures, are arranged in a radial and concentric manner, suggesting an intrusive body in the southern part of the occurrence, cut in turn by a posterior intrusion with a center in the north, resulted from 5 successive intrusions that led to five different types of carbonatites, according to structural, mineralogical and petrographic features (Barros 2001;Alves 2008). Faria Junior et al (2010 and Oliveira and Sant'Agostino (2020) cited the work developed by Saito et al (2004) in identifying a total of twelve geological units from the open pit, that considered not only geological characteristics but also relevant characteristics of the rock as ore in the beneficiation plant (Figure 3).…”

Mining Blast-Induced Ground Motions in Tailings Dam

“…The main structural elements of carbonatites, such as joints, faults, dikes and fluid structures, are disposed in a radial and concentric aspect, suggesting an intrusive body from 5 successive intrusions that led to five different types of carbonatites, according to structural, mineralogical and petrographic features (Barros, 2001;Alves, 2008). Faria Junior et al (2010 and Oliveira & Sant'Agostino (2020) cited the work developed by Saito et al (2004) in the identification of a total of twelve geological units from the open pit, that considered not only geological characteristics but also relevant characteristics of the rock as ore in the beneficiation plant (Fig. 5).…”

“…Drilling has demonstrated that the carbonatites extend in depth to at least 400 m below the sea level, with a general dip angle of 80 o , and the structures are mainly represented by a shear zone (fault), a set of joints and fractures (Alves, 2008). According to Oliveira & Sant'Agostino (2020), the fault zone corresponds to the main fault of a brittle shear regime that produced the main fault system and subsidiary faults, with N75W/subvertical direction.…”

“…1), following the road BR-116 in the direction of the city of Curitiba (Paraná State). The open pit is inserted in the Jacupiranga Alkaline Complex, a classic Brazilian occurrence of alkaline and ultrabasic rocks with associated carbonates in a phosphate deposit of magmatic affiliation (Barros, 2001;Oliveira & Sant'agostino, 2020), reaching in 2020 the production of 400,000 t of phosphate concentrate with 33.8% P2O5.…”

“…Figure 5 -Simplified geological map of carbonatitic bodies in the open pit(Saito et al, 2004;Faria Junior et al, 2010;Oliveira & Sant'agostino, 2020;Oliveira, 2021). (A) View from the North sector and (B) view from the South sector of the open pit.…”