From sand grains to mountain chains: linking recent Andean orogenesis and climate changes to the assembly of lowland Amazonia (PAALE)

Abstract

The uplift of the Andes has been recognized as a key driver of South America climatic regimes and lowland Amazonian landscapes, whose changes through time were directly or indirectly crucial to Amazonia becoming the most diverse continental ecosystem on Earth. However, the timing, rates, and mechanisms that link the recent growth of the Andes (ca. 10Ma) to regional climate and physical landscape in the Amazonian lowlands remain poorly understood. Here, we will reconstruct the spatiotemporal trends of erosion rates and sediment flux from the Andes to the Amazonian lowlands using cosmogenic nuclides, luminescence signals, and magnetic parameters. Therefore, we will investigate a unique and comprehensive set of spatially distributed surface sedimentary deposits, as well as deep and continuous sediment cores that will be drilled in strategic sites at western (Acre Basin), central (Solimões Basin), and eastern (Marajó Basin) Amazonia, under the "Trans-Amazon Drilling Project (TADP)" and Ocean Drilling Program (ODP). Our records will provide original insights into (1) how the history of uplift and erosion of the world's longest mountain chain is stored in the world's largest river basin; (2) how orbital and millennial-scale hydroclimate variability affects erosion rates and sediment flux from Andean and cratonic terrains within the Amazon; (3) how the mountain erosion signal is transformed from its source to the ocean, the ultimate sink in the system; and (4) a potentially transformative history of uplift and climate change in Amazonia's lowland physical landscapes and its influence on biotic diversification over the last 10 Ma, a period when most extant species originated. In addition, this project will allow the outstanding training of students and scientific development through exchange among national and international research institutions from Brazil, Germany, and Peru. (AU)