Topographic Construction Across the Northern Peruvian Andes

• Grant number: 23/07113-7
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate (Direct)
• Start date: August 25, 2023
• End date: August 24, 2024
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal Investigator: Mauricio Parra Amézquita
• Grantee: Sebastián Gómez Marulanda
• Supervisor: Edward Sobel
• Host Institution: Instituto de Energia e Ambiente (IEE). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: University of Potsdam, Germany
• Associated to the scholarship: 20/06420-5 - Exhumation and uplift of the Northern Peruvian Andes, BP.DD

Abstract

Since its onset in late Cretaceous-Paleogene times, mountain building in the Andes has shaped the landscape, biota, and climate of Western South America. During the Neogene, uplift episodes in the central and northern Andes have been linked to major landscape-transforming events in the Amazon basin, including the development of a megawetland in western Amazonia at ~23 Ma million years ago and its later transition to a modern-like eastern flowing transcontinental river at ~ 10 Ma. However, the magnitude, timing, and extent of these uplift pulses, and in general of topographic construction along the Andes, as well as their driving tectonic and geodynamic processes remain poorly constrained, in part due to the incompleteness and spatial bias of the record on exhumation and surface uplift along the Amazonian Andes, which is particularly poor in northernmost Peru. To address this issue, my PhD project aims at determining the temporal and spatial trends of topographic construction across the Northern Peruvian Andes as well as its underlying controlling mechanisms. Doing so requires independently constraining both the surface uplift and exhumation histories of this region. For this, during this BEPE project I plan to (1) study the elevation-dependent stable isotope signature of paleowater stored in volcanic glass fragments from Eocene to Late Miocene ash tuffs and ignimbrites to determine the paleoelevation at which they were deposited and (2) date the exhumational cooling of rocks across this region using zircon and apatite (U-Th)/He. Given that this region sits above the northernmost termination of the Peruvian Flat slab, and that the onset and development of flat slab subduction has been proposed as an important factor in uplift and subsidence generation in the Andes and the Amazon basin, the results of this project can help elucidate the surface response to flat slab subduction and its potential effect on the evolution of the Amazon basin. (AU)