Climate and sedimentary dynamics of Amazonian floodplains during the Quaternary: assessing provenance changes via luminescence of quartz and feldspar

• Grant number: 23/15448-9
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: May 01, 2024
• End date: September 30, 2024
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal Investigator: Cristiano Mazur Chiessi
• Grantee: Fernanda Costa Gonçalves Rodrigues
• Supervisor: Mayank Jain
• Host Institution: Escola de Artes, Ciências e Humanidades (EACH). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Technical University of Denmark (DTU), Denmark
• Associated to the scholarship: 22/05520-1 - Climate and sedimentary dynamics of Amazonian floodplains during the Quaternary and its role on biotic diversification, BP.PD

Abstract

The Amazonian drainage system is responsible for creating highly dynamic landscapes as sediments from several sources are transported to distant sinks, playing a crucial role in shaping the biodiversity of this region. Precipitation changes in the headwaters of Amazonian rivers influence the flow of water and sediments in the drainage basin, that in turn can change the distribution and connectivity of different habitats in the lowlands. The expansion and contraction of floodplains in the lowlands impact the dispersal and colonization of floodplain species, leadingto hybridization and speciation events, respectively. Hence, comprehending the development of floodplains in response to varying precipitation patterns across diverse temporal scales holds crucial importance in elucidating the contemporary biodiversity of the Amazon region. Within this scientific framework, the Quaternary epoch assumes particular significance since it is a critical period for biotic diversification of the Amazonian biome. In this study, we aim to (i)investigate alterations in the sources of siliciclastic sediments and the discharge of the Amazon River over the past 1.93 million years and (ii) examine the repercussions of these changes on the availability of floodplains. Through this research, we seek to enhance our understanding of how shifts in the distribution and connectivity of Quaternary Amazonian floodplains and upland fluvial terraces occurred and how these shifts influenced the current biodiversity and dispersion of species adapted to seasonally flooded or upland habitats. Tracking of different sediments sourceswill be performed through pulsed optically stimulated luminescence analysis to betterdiscriminate the signals of quartz and feldspar on the < 63¼m fraction from marine sediment coreCDH-79. This marine core is already under investigation within the post-doctoral project of the candidate. Besides the CDH-79 marine sedimentary record, modern suspended sediment samples from the rivers and the topmost layer of different oceanic areas under the influence of the Amazon basin will also be analyzed. The internship will be developed at the Department of Physics- Technical University of Denmark (DTU Physics, Denmark), under supervision of Dr. Mayank Jain. The research group led by Dr. Jain at DTU is recognized as the world´s top group for development of luminescence methods applied to Geosciences and related fields. This proposal will enable the proponent to learn cutting-edge analytical procedures to develop and test different luminescence signals for provenance analysis, as well as to interpret the obtained data necessary to improve the understanding on the landscape history of the Amazon.