HR: 12:05h
AN: PP42A-08    [Abstracts]
TI: A Climate Driven Speleothem Stable Isotope Model
AU: * Shorey, C V
EM: christian-shorey@uiowa.edu
AF: Department of Geoscience University of Iowa, 120E Trowbridge Hall, Iowa City, IA 52242 United States
AU: Gonzalez, L A
EM: lgonzlez@ku.edu
AF: Department of Geology University of Kansas, 1475 Jayhawk Boulevard, Lawrence, KS 66045-7613 United States
AB: We have constructed a climate driven stalagmite growth model that faithfully reproduces the major annual growth trends of temperate climate stalagmites. Model results indicate that speleothem growth rate in temperate regions, although depending primarily on precipitation amount, is a complex function of the timing of precipitation relative to seasonal temperature changes as well as other non-climatic parameters. We have incorporated into this climate driven growth model the capability to simulate climate driven carbon and oxygen stable isotope changes and their incorporation in speleothem calcite. The model allows us to investigate the relationship between isotopic changes in soil CO2 and seepage fluids, and the isotopic composition of the growing stalagmite. We also explore the impact of sampling resolution on the extracted speleothem isotope record. We calibrated the model to replicate the growth and isotopic record of a stalagmite collected in 1982 from Mystery Cave State Park, in Southeastern Minnesota and using temperature and precipitation records spanning 1935-1982 from a nearby weather station. The model generally replicates the \delta13C and \delta18O record for this case. Model ouput indicates that that large deviations of temperature or precipitation from average conditions in a single year can be recorded in speleothems. Increases in temperature have a clear postive correlation with \delta13C values, and a less direct negative correlation with \delta18O values. Increases in precipitation have an inconsistent positive correlation with \delta13C values and a clear positive correlation with \delta18O values.
DE: 3344 Paleoclimatology
DE: 1040 Isotopic composition/chemistry
DE: 1045 Low-temperature geochemistry
DE: 1055 Organic geochemistry
DE: 0315 Biosphere/atmosphere interactions
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2004 AGU Fall Meeting