HR: 0800h
AN: B31B-0998    [Abstracts]
TI: Fluorescent signatures of 2 Ma old travertine deposits in Death Valley, CA
AU: * Adachi, T
B31B-0998 AF: Catholic University of America, Department of Physics, 200 hannan hall, Washington, DC 20064 United States
AU: * Adachi, T
B31B-0998 AF: NASA-GSFC, Solar System Exploration - Astrochemitry, Code 691, Greenbelt, MD 20771 United States
AU: Kletetschka, G
EM: gunther.kletetschka@gsfc.nasa.gov
AF: Catholic University of America, Department of Physics, 200 hannan hall, Washington, DC 20064 United States
AU: Kletetschka, G
EM: gunther.kletetschka@gsfc.nasa.gov
AF: NASA-GSFC, Solar System Exploration - Astrochemitry, Code 691, Greenbelt, MD 20771 United States
AU: Kletetschka, G
EM: gunther.kletetschka@gsfc.nasa.gov
AF: Acad. Sci., Institute of Geology, Rozvojova 6, Prague, 20063 Czech Republic
AB: Epifluorescence petrography clearly images information that cannot be seen in a standard petrographic microscope with regular transmitted polarized light. Epifluorescence examination reveals hidden structures located in less transparent areas of the thin section from Pliocene-Pleistocene spring travertine deposits in Funeral Formation in Death Valley, CA. Thin section material absorbs and reradiates light (autofluorescence). This can be caused by an extremely small number of fluorescent molecules (50 molecules per cubic micron). Fluorescent material in our thin section can be both of organic and inorganic nature. We cannot rule out micropore space filled with organic matters (aminoacids with ring structures autofluoresce). Fabric-specific isotope and textural analysis on the spring travertine deposits indicate that these deposits closely resemble modern hot-spring travertine in Yellowstone National Park. Modern deposits are known to contain abundant microbial life forms. These microbial communities live in the hot-spring and entrapped by rapidly precipitating calcite or aragonite. Epifluorescence examination of thin sections of the spring travertine calcite revealed presence of autofluorescence material in less transparent areas of thin section where the hidden distinctive structure was not otherwise seen by regular transmitting polarized light. These structures may be organic signatures trapped in between the inorganic precipitates and may be the hall mark for future approach of biosignature detection in ancient hydrothermal deposits on terrestrial and extraterrestrial environment.
DE: 0419 Biomineralization
DE: 0420 Biomolecular and chemical tracers
DE: 0424 Biosignatures and proxies
DE: 0444 Evolutionary geobiology
DE: 0463 Microbe/mineral interactions
SC: Biogeosciences [B]
MN: Fall Meeting 2005