HR: 0830h
AN: B51C-0982    [PDF]
TI: Distinct D/H Signatures From Miocene Sediment Water in Clarkia Fossil Bed, Northern Idaho: Implications for Preservation of Ancient Biomolecules
AU: * Yang, H
EM: hyang@bryant.edu
AF: Bryant College, Department of Science and Technology, Smithfield, RI 02917 United States
AU: * Yang, H
EM: hyang@bryant.edu
AF: Brown University, Department of Geological Sciences, Providence, RI 02912 United States
AU: Huang, Y
EM: Yongsong_Huang@brown.edu
AF: Brown University, Department of Geological Sciences, Providence, RI 02912 United States
AU: Gruenenfelder, G R
EM: grg1@bryant.edu
AF: Bryant College, Department of Science and Technology, Smithfield, RI 02917 United States
AU: Chamberlain, V E
EM: vec@uidaho.edu
AF: University of Idaho, Department of Geological Sciences, Moscow, ID 83844 United States
AB: Water saturated in the Clarkia Miocene lacustrine sediments (15-20 Million years old) at the St. Maries River Valley in northern Idaho holds critical information regarding preservation of exceptional leaf compressions, unaltered ancient biomolecules, and their isotopic signals. To further understand the nature of sediment water, we developed a method to extract these waters from sediments and to characterize their D/H compositions. During an one-year duration, sediment water was periodically obtained from the Horizon 2B and along a vertical profile at the P-33 site, and water samples from nearby pond, creek, precipitation, a underground aquifer were also collected monthly for comparison. The hydrogen isotope compositions from sediment waters in Horizon 2B are distinct from other environmental waters in the following two ways: (1) They differ from pond, creek, and ground water by up to 36 per mil and from meteorological water by up to 72 per mil. (2) The hydrogen isotope ratios remain stable throughout the year with little fluctuation (within error range). The D/H ratios along the vertical section vary slightly by about 20 per mil. The hydrogen isotope values of sediment water offset D/H ratios determined from different lipid compounds derived from Clarkia sediments by 122-196 per mil. Although the precise age of the sediment water can not be determined, a source other than modern environmental water is highly likely. Further information regarding its mobility and resident time is critical to elucidate the role that these water molecules have played in degradation of abundant labile ancient biomolecules and their isotope signatures preserved in Clarkia fossils and sediments.
DE: 0330 Geochemical cycles
DE: 0400 Biogeosciences
DE: 1055 Organic geochemistry
DE: 1899 General or miscellaneous
SC: Biogeosciences [B]
MN: 2003 Fall Meeting