Paleoclimate inferences from stable isotopes (O and C) and microstratigraphy on Holocene stalagmites from Brazil

• Grant number: 06/02834-2
• Support Opportunities: Regular Research Grants
• Start date: November 01, 2006
• End date: November 30, 2009
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal Investigator: Ivo Karmann
• Grantee: Ivo Karmann
• Host Institution: Instituto de Geociências (IGC). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

We aim to investigate paleoclimatic variations during the Holocene in regions primarily influenced by South American Summer Monsoon (SASM) and Intertropical Convergence Zone (ITCZ) systems in Brazil. This scientific proposal refers to a multi-proxy study of laminae thickness and isotope ratios of oxygen and carbon on annual banding stalagmites dated by U-Th method. We intend to discuss paleorainfall variations in the different climate systems on interannual and interdecadal time scales and possibly relate them to the El Ninõ-Southern Oscilation (ENSO) phenomena. In addition the influence of northern hemisphere climate events such as Bond events, Medieval Warm and Little Ice Age on centennial to millenial activity SASM and ITCZ will be checked out.In order to calibrate the paleoclimatic signal embedded in the stalagmites we plan to study the relationship between isotopic composition of modern speleothems/cave drip waters and climatology. This approach will be performed at a two years monitoring program by: i) Investigating the rainfall isotopic composition (D and O) on seasonal, monthly and daily resolution; ii) Comparing the isotope ratios of rainfall, speleothems and cave drip waters with climatic and hydrologic parameters from the same cave site where the old stalagmite samples were collected. (AU)