Use of hydrogeophysical data to determine the role of faults in the geometry of the Barreiras Aquifer, Brazil

Abstract

Characterizing the geometry of an aquifer is fundamental for determining the locations of more productive wells. Commonly, flow and hydraulic parameters, such as transmissivity, are related to the thickness of the aquifer, which emphasizes the importance of regional hydrogeophysical characterization. Shuttle radar imagery, well profiles and geoelectric models (thickness x resistivity) from sixteen soundings were used to identify Neogene faults in the Barreiras Aquifer in the Catu River basin, northeastern Brazil. The joint analysis of the geomorphological data enabled the development of a synthesis map characterizing morphotectonic alignments that are mainly N50º-60ºE and N40º-60ºW trending. A number of these alignments were interpreted as faults based on 10 to 44 throws that were identified in the hydrogeophysical cross-sections.The highest values were located in the northeastern portion of the area, suggesting the direct association between saturated thickness and Neogene faults. Additionally, the geoelectric and hydraulic head data of the aquifer allowed the identification of the most promising sites for future water exploitation in the northeastern portion of the study area with transverse resistances equal to or greater than 40,000 Ohm.m. The geometry and transmissivity of the Barreiras Aquifer indicate that porous aquifers in structural highs could be controlled by faults.

Reserve evaluation of a fault-conditioned aquifer: the Barreiras Aquifer in the coastal region of NE Brazil

“…10) was produced from the results of geomorphological analysis involving morphotectonic alignments, the hydrogeophysical cross-sections in Figure 9, and the geological base map of Angelim et al (2006). The main structures display NE-SW and NW-SE trends, consistent with other studies performed in the northeastern area of Brazil and reflecting the regional Neogene-Quaternary stress field (Bezerra 1998, Lucena 2005, Bezerra et al 2014, Souza et al 2019.…”

“…Therefore, anomalies in drainage networks and land reliefs different from the patterns of surface features of a given region were associated with structures in the subsurface, reflecting the structural framework of the area (Bezerra 1998, Lucena et al 2006. In this respect, structural trends can be characterized by features such as valley alignment and elevations in preferred directions, springs, abrupt deflections of fluvial channels, and linear water bodies (Souza et al 2019).…”

Contribution of Hydrogeophysical Data for the Assessment of Unconfined Aquifer Protection Levels - An Example from the Northeast of Brazil

“…Barreiras formation is an outcropping sequence of siliciclastic Cenozoic lithologies ranging from argillite to conglomerates, with clay sandstones predominating, which are found discordantly overlapping Precambrian rocks of the crystalline basement of the Mesozoic sediments (Lucena, 2005;Souza et al, 2019;Nunes et al, 2019). We have all Quaternary sedimentation heaving the Barreiras formation, distinguishing between subrecent sedimentation (beachrocks and fixed dunes) and recent sedimentation (sandy coverage, silts, moving dunes, besides the sediments of current beaches, and mangroves).…”

“…The nonoutcropping sequence consists of a Precambrian crystalline basement and sedimentary rocks of a Mesozoic basin (considering the profile information of regional wells), whereas the outcropping sequence comprises sedimentary Cenozoic rocks of the Barreiras Formation (Tertiary-Quaternary in age) and a Quaternary coverage (Bezerra, 1998;Lucena, 2005;Rossetti et al, 2011;Lucena et al, 2013b;Bezerra et al 2014;Souza et al, 2019;and Dantas et al, 2021). The crystalline basement is represented by granite, granodiorite, migmatite, and gneisses correlated with the Caicó Complex (Bezerra, 1998;Lucena, 2005).…”

Uso de dados hidrogeofísicos e modelos numéricos como alternativa na otimização de locações de poços em um aquífero não confinado

“…(MELO et al, 2014). O seu caráter hidráulico predominantemente livre, com semi-confinamentos localizados, deve-se à variabilidade faciológica da Formação homônima, sendo esses semi-confinamentos decorrentes da presença de lentes de argilitos ou siltitos da própria Formação Barreiras (LUCENA, 2005;SOUZA et al, 2019;NU-NES et al, 2020).…”