Paleomagnetic analysis of rocks of the Lavras de Mangabeira (CE)

• Grant number: 19/15818-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): September 01, 2019
• Effective date (End): October 31, 2020
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal Investigator: Giancarlo Scardia
• Grantee: João Carlos Cerqueira
• Host Institution: Instituto de Geociências e Ciências Exatas (IGCE). Universidade Estadual Paulista (UNESP). Campus de Rio Claro. Rio Claro , SP, Brazil

Abstract

The Lavras da Mangabeira Basin is a basin traditionally included in the set of the of the Brazilian Northeast's interior basins, linked to the Cretaceous rift of the South Atlantic. It is originated upon pre-Cambrian rocks, it's filling is composed of two sedimentary units, the formations Iborepi and Serrote do Limoeiro, and a basaltic flow between them. From the radiometric dating methods, the flow was referred to the Triassic-Jurassic boundary, with significant implications on the tectonic evolution of the Lavras basin and the age of it's sedimentary units. Assuming a Triassic-Jurassic age for basaltic flow it's evident that the lower sedimentary unit should have a Triassic or Paleozoic age, while the upper unit should be Jurassic or Cretaceous, but no fossil was found in this basin to help in the chronostratigraphic positioning. The sedimentary units' age has a great impact on our understanding of the Lavras da Mangabeira Basin's generating and deforming tectonics. In order to contribute to the solution of this problem, it is proposed here to apply the paleomagnetism method to date the two sedimentary units and independently confirm the chronological assignment of the basaltic flow.