In situ U-Pb rutile dating and provenance analysis by LA-ICP-MS of Jaibaras and Serra Grande sequences

• Grant number: 19/26257-4
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: March 28, 2020
• End date: June 27, 2020
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal Investigator: Lucas Verissimo Warren
• Grantee: Rodrigo Irineu Cerri
• Supervisor: David Chew
• Host Institution: Instituto de Geociências e Ciências Exatas (IGCE). Universidade Estadual Paulista (UNESP). Campus de Rio Claro. Rio Claro , SP, Brazil
• Institution abroad: Trinity College Dublin, Ireland
• Associated to the scholarship: 17/19550-1 - Jaibaras tectonossequence genesis (Ediacarano - Ordoviciano) and its inheritance in the sedimentation of Serra Grande sequence (Ordoviciano - Siluriano), Northeast edge of Parnaíba Basin, BP.DR

Abstract

The origin of intracratonic basins is currently one of the most prolific topics in the geologic sciences, constituting a challenge in itself. The complexity of this theme, added to the necessity of an integrated approach based in a multi-proxy analysis, places this study on the frontier of modern science. The almost complete lack of integrative studies focused in sedimentological, stratigraphic, geochemical and geochronological data from the basal successions of intracratonic basins hampering the elaboration of a predictive model for the origin of these geotectonic units. It is recognized that several sag-type basins apparently developed from rift systems, but there is no consensus about how and if these grabens influenced the sedimentation of the sag phase. Considering this, recent studies have been conducted in the Jaibaras and Parnaíba basins, northeastern Brazil, seeking to identify patterns and differences between successions deposited in rift and sag stages of these basins. Several geochronological ages obtained from detrital zircons of these units, as well as paleocurrents and provenance data based in macroscopic analysis and detrital rutile geochemistry, are revealing interesting patterns between the distinct sequences. However, in the last decade a large number of new dating techniques are being used for provenance studies, including Lu-Hf and U-Pb ages of detrital rutile. Since rutile is one of the most stable minerals during weathering and a common accessory mineral, he is being used in a wide range of techniques for sedimentary provenance studies, including trace elements analysis and U-Pb dating. The main objective of this internship is to perform LA-ICP-MS U-Pb analyses in detrital rutile from the Jaibaras and Parnaíba basins, in order to refine the age spectrum of the rocks related with the rift-to-sag evolution. In the literature, a wide range of studies compare detrital rutile to zircon U-Pb ages, demonstrating that rutile analyses can reveal sources that zircon sometimes do not show. This internship will be developed at the Trinity College Dublin, supervised by Prof. Dr. David Chew, specialist in geochronology and isotope geochemistry. (AU)