Isotopic analysis of fluid inclusion and TEX86 applied in speleothems

• Grant number: 23/04580-3
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: August 15, 2023
• End date: August 07, 2024
• Field of knowledge: Physical Sciences and Mathematics - Geosciences
• Principal Investigator: Francisco William da Cruz Junior
• Grantee: Angela Ampuero Grández
• Supervisor: Hubert Vonhof
• Host Institution: Instituto de Geociências (IGC). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Max Planck Society, Mainz, Germany
• Associated to the scholarship: 20/09258-4 - Evapotranspiration and moisture recycling effects on the climate of the Amazon Forest during the Last Glacial Maximum and the Holocene, BP.DR

Abstract

Paleoclimate reconstructions in South America strongly rely on the interpretation of ´18O and ´13C from carbonate (´18OC, ´13CC) of speleothems. However, these registers are often affected by complex processes along atmospheric transport pathways and inside the cave system, which makes their interpretation challenging. Particularly, variations of temperature in the cave environment and in the exchange time between dripping and cave atmosphere may affect the ´18OC composition of the precipitating carbonate. Large temperature variations, as occurred from the Last Glacial Maximum (LGM) to the Holocene, may be critical for the speleothem ´18OC. Notwithstanding, continental surface temperature reconstructions are highly scarce in South America, which also prevents a more comprehensive understanding of the environmental changes that took place during the glacial phases on the ecological systems of the Neotropic. Therefore, the main goal of this research is to evaluate paleoclimate reconstructions from the LGM to the Holocene, based on the traditional ´18OC and ´13CC from stalagmites in the light of the new registers produced, and obtain paleotemperature reconstructions based on TEX86 and fluid inclusion analyses. The study will prioritize speleothems from central eastern Brazil, as it is a region largely affected by rising temperatures under current climate change; and the eastern subtropical Andes, in the transition region between the South American Monsoon System and the westerlies, studied for the first time in the context of this project. (AU)