ORGANIC MOLECULAR PROXIES FOR PALEOCLIMATE AND PALEOELEVATION: APPLICATIONS, ADVANCES AND LIMITATIONS OF ORGANIC BIOMARKERS AS A RECORD OF PALEOENVIRONMENTAL CHANGE

Reconstructing the paleoelevation of the world’s major mountain belts provides critical information for linking models of past global climate with terrestrial temperature data. However, paleoelevation histories of the major mountain-belts are uncertain due to difficulties in distinguishing between climatic and topographic effects in the geochemical and fossil record. Organic molecular fossils provide a relatively new and novel means of reconstructing ancient climate, hydrology and elevation. In particular, organic biomarkers preserved in ancient soils and lake sediments can record both the hydrogen isotopic composition of past precipitation and temperature, two key pieces of geochemical data that are critical to understanding past climatic, hydrologic or topographic change. This talk will focus on the applications, limitations and new advances in the use of organic molecular proxies for the reconstruction of paleoelevation and paleoclimate. Specifically, it will address the application of compound-specific stable isotopes of plant and microbial biomarkers for hydrogen isotope reconstruction of ancient precipitation and the recently established soil tetraether paleotemperature proxy and show how these data can be coupled to place new constraints on the Eocene to Miocene paleoenvironment of the Sierra Nevada and Basin and Range.