The Tertiary volcano of the Macau Formation, related to the last magmatic pulses of the Borborema Province in the states of Paraíba and Rio Grande do Norte, manifested itself in the forms of plugs, dikes, veins, piroclasts and fissural flows. In the municipalities of Boa Vista, Sossego, Barra de Santa Rosa and Olivedos, the volcanic protoliths are arranged in the form of fissural flows of amoeboidal architecture, subjected to intense chemical weathering, evolving into calcium bentonite clays of the Campos Novos type, mined in the open pit. Boa Vista is the municipality that has the main bentonite deposits, with the occurrence of fossilized tree trunks; In Sossego, pockets of chalcedony are carved together with the bentonites; In Barra de Santa Rosa, the quantification of the deposits is in the conclusive phase of research. In Olivedos, the main bentonite mining takes place on the Campos de Baixo farm by Mineradora Meira de Melo. The open pit is constantly evolving, currently with a depth of more than 6 meters, where it was possible to establish on the main slope of the mine, a lithostratigraphic column consisting from the top to the base of soil, high Ti basalt, high Ti tuff, red bentonite, cream bentonite and white bentonite. The alteration products were submitted to expandability tests when submerged in water, petrographic analysis and geochemical analysis by X-ray Fluorescence (XRF), with the objective of contributing to the genetic knowledge through the geochemical composition and ionic mobility in the weathering profile. The results indicated that the mobility of the iron and manganese oxides-hydroxides, with impoverishment from the top to the bottom of the profile, were the main responsible for the change in the shade of the bentonites. White bentonite is essentially carbonate, with extremely high Ca values, around 83.76%, of zero expansion, with the presence of calcite. This factor, associated with the very low levels of SiO2, Al2O3 and Fe2O3, make the white bentonites distinguishable from the others, with special characteristics for the manufacturing industry. Trace elements and incompatible elements occur variably along the weathering profile, and are sometimes completely leached into the more evolved bentonites. The results obtained are considered preliminary, since they are part of the set of data related to the Doctoral Thesis being prepared by the first author at the Federal University of Campina Grande.
The Núcleo de Estudos de Pegmatitos (N-PEG) is a multidisciplinary study center addressing granitic pegmatites in the most diverse aspects: mineralogy, petrology, geochemistry, internal structure, gemology, geochronology, experimental studies, fluid inclusions, associated mineralizations, small-scale and artesanal mining and mine waste recycling. It was created in 2013, at IFPB, Campina Grande campus, subordinate to the Coordination of Technical Courses in Mining. N-PEG arose from the need to disseminate publications addressing granitic pegmatites (many of them not available on the Internet) and share experiences and research with researchers from different regions, in addition to providing scientific support for students and professionals in the area. It has a digital database (in pdf), currently with 6402 publications (scientific articles, theses, dissertations, event summaries, technical reports, among others), with emphasis on pegmatites from the Borborema Pegmatite Province (BPP), located between the states of Rio Grande do Norte and Paraíba. The digital database was assembled from the acquisition of publications available on the Internet and in university libraries and private collections, placed in digital media. The samples from the PPB's educational collection of pegmatite minerals were collected in the field or acquired from local miners. A photographic database was created from field trips, aiming to generate a digital photographic atlas. N-PEG has collaborated with the preparation of theses and dissertations from several institutions. The partnership between researchers from IFPB and other national and international institutions has enabled the publication of scientific articles that have generated several citations on the Web of Science, Scopus and Google Scholar platforms. A research group was recently created with CNPq (https://dgp.cnpq.br/dgp/espelhogrupo/8331635171367817)and a group on the Whatsapp application (https://chat.whatsapp.com/BdANcqYlHclDLugL5uETpC) aiming at greater interaction between researchers. N-PEG makes national and international publications available to researchers and students, in addition to contributing to the advancement of research related to granitic pegmatites.
Stratigraphy examines the origin, sequence, structure, fossils and lithology, age of rocks, age of formations and layers of the earth's crust. Stratigraphic studies are not only based on knowing the sequence of sedimentary layers in different geological times in order to understand the history of earth events and the evolution of organisms, but also examines the lateral changes of facies in different places. In other words, stratigraphy examines the determination of changes in the earth's layers and their relative age, which is based on the following three principles: 1- The principle of stacking of layers: In this case, the layers may have changed due to tectonic factors, in this condition, the science of stratigraphy is related to the science of structural geology. 2- The principle of continuity in a certain sedimentary layer in terms of petrological properties: in this case, stratigraphy is related to petrology. 3- The principle of similitude in the paleontology of strata: in this case, palaeontology is considered the basis of the science of stratigraphy.
Bentonite is an industrial clay widely used in various sectors, such as well drilling, ceramics, foundry, and environmental barriers, due to its unique physicochemical properties. This study aims to characterize the bentonites from the Campo Novo Mine, located in the municipality of Sossego-PB, by analyzing their formation processes, mineralogical properties, and industrial applications. The bentonites in this region originate from the weathering and hydrothermal alteration of basalts, leading to the formation of clay minerals from the smectite group, such as montmorillonite. To analyze these clays, technical visits were carried out for sample collection, followedby laboratory tests, including drying in an oven, comminution, dry and wet sieving, magnetic separation, and swelling tests. The results indicated that the cream-colored bentonite 2 had the highest swelling capacity, while the white bentonite showed lower expansion, possibly due to its high calcium content. Mineralogical analysis revealed variations in the composition of the samples, confirming the influence of geological processes on their formation. Magnetic separation demonstrated differences in the mineralogical composition among the samples, suggesting variations in bentonite quality. From an economic perspective, the exploitation of bentonites in Sossego represents a promising opportunity for the local industry, provided it is carried out sustainably. Thus, this study contributes to the geological and technological knowledge of Paraíba's bentonites, providing informationfor optimizing their industrial use and for future research on the mineralogical variability of the region.