USING GEOLOGICAL ARCHIVES

to reconstruct climate and environmental changes in the past

while calibrating proxy via field monitoring and/or laboratory experiments

 

Welcome to my personal website!

 

My name is Ny Riavo Voarintsoa (known by many as Voary). I am a geologist with specific interests in paleoclimate and paleoenvironmental reconstruction in tropical regions, presently in Southern Africa, the Mascaregne Islands and Madagascar. I use a variety of geological archives, such as stalagmites and lake sediments, and I investigate their geochemical properties (the conventional stable isotopes of O and C and the newly developed clumped and triple oxygen isotopes) and other  physical aspects to understand how climate and environment have changed in the past.

 

After completing my PhD in 2017 at the Department of Geology of the University of Georgia, USA, I went to the Hebrew University of Jerusalem in Israel where I was involved in developping two relatively new proxies in paleoclimate studies (clumped isotopes Δ47  and triple oxygen isotopes Δ17O in carbonates and their parent water). For the clumped isotopes, my job was mainly to calibrate the new  mass spectrometer using a variety of carbonate certified and in-house standands and other in-house CO2 standards. The goal is to define  the absolute reference frame for ‘clumped’ isotope of CO2 of  the new Isotope Ratio Mass Spectrometer (IRMS) - Perspective from Nu Instruments, according to Dennis et al., 2011. In addition to this, I performed and designed a range of experiments aiming at understanding isotopic equilibrium under constrained lab environments. For the triple oxygen isotopes, I have been involved intensively in preparing and measuring δ17O and 17Oexcess values of three international standards: IAEA‐603, NBS19 and NBS18 (Barkan et al., 2019). I was also involved in developping and desgining a range of short term and long term experiments, and I performed a range of analyses starting from extracting CO2 from carbonates on an offline vacuum line, following the acid digestion method of McCrea (1950) and equilibrating CO2-H2O, then extracting  the equilibrated CO2 on an offline vacuum line, following Epstein and Mayeda (1953) and O’Neil and Truesdell (1991). Using complex and laborious geochemical separation procedures, I was also involved in performing CO2–O2 exchange experiment over hot platinum  following the procedures of Barkan et al. (2015). The goal of the set of precipitation experiments was to determine the triple oxygen isotope fractionation between CaCO3 and H2O under well-constrained laboratory conditions. I additionally performed laboratory experiments to precipitate CaCO3 polymorphs, either calcite or aragonite, at temperatures varying between 10 and 35°C to evaluated the effect of polymorphism, temperature, and solution concentration on the 17Oexcess of CO2 extracted from these carbonates and the 17O isotopic fractionation (17α) between H2O and CaCO(see Voarintsoa et al., 2020).

 

Currently, I am a Marie Curie Fellow at the Department of Earth and Environmental Sciences, at KU Leuven in Belgium. I lead a project entitled "PALEOMADA", which stands for Paleoenvironmental Reconstruction in Madagascar using two geological archives (speleothems and lake sediments). One of the main objectives of this project is proxy calibration. This approach uses knowledge of modern (bio)geochemical processes, via field monitoring, as a tool to calibrate paloclimate and paleoenvironmental changes in Madagascar. More specifically, the research aims at understanding how environmental signals around/inside the cave are transferred into speleothems or lake sediments.

 

GREAT NEWS!! I will be at the University of Houston, Texas, USA starting January 2021 for more exciting and amazing research.

 

I will join the Department of Earth and Atmospheric Sciences of  the College of Natural Sciences and Mathematics of the University of Houston, in Texas, USA as a new Faculty starting in January  2021I am currently looking for graduate student and postdoc to work with me starting in Fall '21, so if you are interested in joining my team, visit the departmental website and check the University of Houston Graduate Programs Overview. Note the deadline for Fall '21 application is 05 January 2021. I dedicated a page for prospective graduate students and postdoctoral researchers here. For questions about research and collaboration, contact me directly either by filling up the form  below or by using both e-mail address (use cc:) nyriavo.voarintsoa[at]gmail[dot]com and ngvoarin[at]cougarnet[dot]uh[dot]edu.

 

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© Ny Riavo Voarintsoa 2015-2020