PALEOCLIMATIC INSIGHTS FROM NOBLE GASES: GROUNDWATER DYNAMICS IN A SEMIARID AQUIFER, POTIGUAR BASIN (BRAZIL)

• Grant number: 25/05374-3
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: July 01, 2025
• End date: February 28, 2026
• Field of knowledge: Physical Sciences and Mathematics - Geosciences
• Principal Investigator: Didier Gastmans
• Grantee: Natália de Souza Arruda
• Supervisor: Werner Aeschbach
• Host Institution: Centro de Estudos Ambientais (CEA). Universidade Estadual Paulista (UNESP). Campus de Rio Claro. Rio Claro , SP, Brazil
• Institution abroad: Heidelberg University, Germany
• Associated to the scholarship: 24/10099-9 - MULTI ISOTOPIC AND NOBLE GASES APPROACH TO UNDERSTAND THE GROUNDWATER FLOW CONDITIONS AND RECHARGE IN AÇU AQUIFER IN THE POTIGUAR BASIN, BP.DR

Abstract

Located in the Brazilian semi-arid region, the Potiguar Sedimentary Basin (PSB) preserves records of the Last Glacial Maximum (LGM) in its carbonates, reflecting changes in rainfall patterns due to the migration of the Intertropical Convergence Zone (ITCZ). Within this basin, the Açu Aquifer is a deep, porous, and semi-confined water source for subsistence and irrigation. Its characteristics make it a valuable site for paleoclimate studies, as its waters may contain preserved information on long-term climate trends. Noble gases, due to their conservative properties and solubility dependence on pressure, temperature, and salinity, serve as key tracers in hydrogeochemical studies. They enable the interpretation of recharge conditions and groundwater residence time, providing essential data for both paleoclimatic reconstructions and sustainable water resource management. While Unesp Rio Claro currently conducts helium analyses in apatite crystals using a high-sensitivity magnetic sector mass spectrometer (GVI-Helix-SFT), expanding these analyses to other sample types requires specialized training and collaboration with experienced research groups. The Environmental Physics Institute at Heidelberg University, specifically the HydroTrap research group led by Prof. Werner Aeschbach, is internationally recognized for its expertise in environmental tracers and paleoclimate studies. With a strong record of seminal publications and a collaborative approach, the group has developed innovative methodologies for noble gas analysis. Thus, the request for the research internship aims to develop the following activities: training in mass spectrometry for noble gas analysis, data modeling and interpretation (including excess air and recharge temperature calculations), participation in conferences, and the preparation of a scientific paper. These activities will advance expertise in noble gas applications, strengthening national research on aquifers and paleoclimatology and expand the international collaboration between research groups from São Paulo State University (UNESP) and University of Heidelberg.