Using Self-Organizing Maps (SOM) technique to compare chemical characteristics between Mesozoic LIPs (Large Igneous Provinces) in the South America

Abstract

Mafic dike swarms and sills intruding the Precambrian Borborema Province and the Paleozoic Parnaíba Basin (NE Brazil) have been recently proposed as part of a hitherto known large igneous province (LIP) in South America, named Equatorial Atlantic Magmatic Province (EQUAMP; Hollanda et al., 2018). This proposal is based on geochemical and geochronological data of two regional magmatic events - the Rio Ceará Mirim dyke swarm and the Sardinha sills, until now individually understood as events related to the opening of the Atlantic Ocean during the Cretaceous. Genetic and temporal correlations between mafic dykes and sills are currently being discussed within the EQUAMP Project funded by FAPESP 2017/08423-9, being the focus of my PhD project (2017/13130-0). One relevant question that raises from the recognition of a new Mesozoic LIP in South America is to understand its geodynamic relationship with the other LIPs - Central Atlantic Magmatic Province (CAMP) and Paraná-Etendeka. From the geochemical point of view, the relationship should be explored after comparisons between their geochemical (and isotopic) signature in order to well constrain the (1) magmatic diversity within EQUAMP LIP (sills and dikes) and between LIPs (EQUAMP and others), to discuss which were the mantle source(s) activated during the LIP formation and, furthermore, if they were a common source or not. For achieving these objectives, we intend to apply a computacional modeling based on the Self-Organizing Maps (SOM) technique as a way to strength the robustness of the data analysis and, therefore, further correlations between the LIPs that were related with the Atlantic Ocean opening.