Provenance of Quaternary fluvial deposits from the Western Amazon and effects of grain size biases on provenance

• Grant number: 23/09643-3
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2023
• End date: December 31, 2024
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal Investigator: André Marconato
• Grantee: Rafaela Maciel Lopes de Paula
• Host Institution: Instituto de Geociências (IGC). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 18/23899-2 - Trans-Amazon Drilling Project: origin and evolution of the forests, climate, and hydrology of the South American tropics, AP.PFPMCG.TEM
• Associated scholarship(s): 23/16881-8 - Fine-grained sedimentary provenance analysis: a new approach for deposits in the Western Amazon, BE.EP.IC

Abstract

Heavy mineral analysis for provenance determination in sediments is commonly performed on fine to very fine grain size fractions, excluding fractions smaller than 64µm. However, recent contributions in the literature have explored the analysis of heavy minerals in these fractions smaller than 64µm, using techniques such as Raman spectroscopy, which allows the identification of mineralogical composition in silt particle size ranges. This approach overcomes the limitations of conventional optical microscope analysis, enabling the identification of opaque minerals and offering a more accurate characterization of heavy mineral assemblages. In this context, the present study aims to analyze the heavy mineral assemblages in the Içá Formation and the surrounding modern terraces, in the western Amazon, using both the conventional sandy fraction and the fine silt fraction. The results obtained will be integrated with geochronological and palynological data, providing a more complete understanding of the sedimentary provenance in the region. In addition, this work will have relevance for future studies related to the application of heavy minerals in drill cores - associated with the FAPESP Thematic Project TADP (Trans Amazon Drilling Project) -, allowing provenance analysis in finer granulations and in situations with restricted sample volume.