This project is enabling the University of Arizona, University of Washington, and private sector partner Aerodyne Research to develop a next-generation laser spectroscopy system to measure combinations of carbon and oxygen isotopes that are known as "clumped isotopes." The new technology will enable researchers to study the earth's past climate at lower cost, with smaller sample sizes, and in greater numbers than is currently possible by mass spectrometry. The new instrument will make possible a large increase in the number of proxy measurements of past earth temperatures because it eliminates the need for separate estimates of oxygen isotopes. Such a system is expected to be adopted quickly by laboratories around the world for application to geologic, oceanographic, biologic, and atmospheric samples. This project links the University of Arizona and the University of Washington with Aerodyne Research in improving the precision of Aerodyne's Tunable Infrared Laser Direct Absorption Spectroscopy (TILDAS) system to make clumped isotope measurements of carbon dioxide that are competitive with current techniques using mass spectrometry. The key measurement is of the different isotopic combinations of carbon dioxide, such as carbon 13, oxygen 18, and oxygen 16. The ability to analyze samples that are 30 to 80 times smaller means that higher spatial resolution can be obtained to allow research into better time resolution such as that afforded by seasonally-banded shells. Other research opportunities include the ability to study soil processes and Holocene paleoclimate using layered soil carbonates from the Andes and northwestern US; seasonality and carbon cycle during the Early Eocene Climatic Optimum and Cretaceous greenhouse from lake and soil carbonates; and the detailed history of fluid-fault interactions, cross cutting relationships and multiple fluids preserved in calcite veins from paleo and active fault zones and hydrothermal systems.