The erosion and sediment flux response to late Quaternary hydroclimate change quantified using in situ cosmogenic nuclides and optically stimulated luminescence.

• Grant number: 23/16001-8
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: February 01, 2024
• End date: January 31, 2027
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal Investigator: Fabiano do Nascimento Pupim
• Grantee: Anarda Luísa Sousa Simões
• Host Institution: Instituto de Geociências (IGC). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 22/03007-5 - From sand grains to mountain chains: linking recent Andean orogenesis and climate changes to the assembly of lowland Amazonia (PAALE), AP.PNGP.PI

Abstract

Transcontinental fluvial systems are very dynamic and largely influence the distribution of animal and plant species. In Amazonia, the Quaternary hydroclimatic changes (e.g., precipitation and river flow) were essential for the spatial structuring of the complex mosaic of non-flooding (terra firme) and seasonally flooding (várzea and igapó) terrains, thus being a key factor in the spatial distribution and evolutionary processes of the most diverse biota on the planet. However, the time and response mechanisms. Here, we will (i) investigate the effects of the late Quaternary hydroclimate changes on paleoerosion rates and sediment provenance from the eastern Andes to its foreland basins in Amazonia, and (ii) access how these erosion and provenance signals propagate along with the Amazon fluvial system, since the Andes until the river mouth. Therefore, we will use in situ cosmogenic nuclides (10Be and 26Al; TCN) in sediment deposits dated by optically stimulated luminescence (OSL). The project seeks to reconstruct erosion rates and propagation of the TCN signal both spatially and temporally (for orbital to abrupt millennial variations). The expected outcomes will provide new deals about: (1) how erosion rates in the Andes-foreland system responded to hydroclimate change during the late Quaternary; (2) the behavior of erosion/sedimentation rates of large tropical plains over time (Mid-Late Pleistocene to Modern); (3) use an integrated approach combining OSL and TCN methods to understand how the propagation, storage, and recycling of sediments occur in the largest watershed in the world. Applying cosmogenic nuclides in well-dated sediments is a pioneering approach in the Amazon basin. This doctoral project is related to the FAPESP Research Grants (# 2022/03007-5).