USING RAMAN SPECTROSCOPY TO ANALYZE OXYGEN ISOTOPE RATIOS IN CALCITE SPELEOTHEMS

Paleoclimate reconstruction is a valuable resource for determining the past climate conditions. The use of Raman spectroscopy on calcite speleothems can be used to determine the oxygen isotope ratios, which can be used as a climate proxy for paleoclimate reconstruction. Oxygen isotope ratios can be used to accurately project past climate conditions including seasonal precipitation amount, temperature influences, and many others. Tropical speleothems grow quickly due to abundant rainfall and ideal conditions for calcite precipitation in a cave environment. Use of Raman spectroscopy for isotope ratio analysis is a relatively new method that has only been used on lab grown calcite and not on calcite speleothems. A speleothem collected from Barbados will be micromilled at selected high-resolution intervals for analysis using mass spectrometry to test for oxygen isotope ratios and trace elements, which also serve as proxies for precipitation and Uranium-series dating will be conducted for multiple layers. The speleothem will then be tested using the Raman method for oxygen isotope ratios to determine if it can produce comparable results. Preliminary results indicate that it may be possible to generate oxygen isotope ratio data using Raman spectroscopy and thus provide a nondestructive method for testing the ratios in speleothems.