Abstract
The Paraná-Etendeka Magmatic Province is associated with the distensive tectonics that caused the rupture of the Gondwana continent during the Lower Cretaceous and generated an intense volcanism that covers South America and the NW portion of Namibia in Africa. In Brazil, this volcanic sequence is named Serra Geral Group and predominantly consists of basalts and subordinated silicic rocks. The goal of this study is to characterize the geomorphological features observed in the Aparados da Serra region, southern Brazil, and to evaluate the relationship between these structures and the primary silicic volcanic structures. The geomorphological features were first identified using remote sensing and then correlated with flow structures observed in the field, as well as petrographic and geochemical data. AMS data were used to determine magnetic patterns and the direction of magmatic flow of the rocks. Despite the low degree of anisotropy, clear patterns of lineation and foliation were identified in the studied rocks. Our data shows that Units I and II correspond to silicic lava flows linked to effusive fissure eruptions, presenting a dome morphology caused by differential erosion. Unit III rocks may correspond to true volcanic domes, whereas the Unit IV corresponds to the effusive feeder structures.
Highlights
The Serra Geral Group (SGG) represents the Brazilian portion of the Paraná-Etendeka Magmatic Province (PEMP), which is the second largest Large Igneous Province (LIP) in the world (White & Mckenzie 1995 apud Frank 2008)
This study aims to investigate the landforms related to the silicic magmatism of the Serra Geral Group in the Aparados da Serra region (Fig. 1), with the intend to draw considerations about its genesis and to analyze if the landforms identified through remote sensing are primary structures or resulting from secondary erosive processes
The region known as “Aparados da Serra” in southern Brazil consists of the silicic volcanic rocks of the Serra Geral Group, which is linked to the PEMP
Summary
The Serra Geral Group (SGG) represents the Brazilian portion of the Paraná-Etendeka Magmatic Province (PEMP), which is the second largest Large Igneous Province (LIP) in the world (White & Mckenzie 1995 apud Frank 2008). The region known as Aparados da Serra is located in the extreme south of Brazil and hosts several geomorphological structures identified by remote sensing (Benites 2015). These structures may correspond to domes and volcanic conduits, or they may result from differential erosion processes (Benites 2015). The morphology of lava domes is variable. According to Polo et al (2017a), the wide variety of structures such as lava-domes, simple
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