HR: 0800h
AN: P11C-0699    [Abstracts]
TI: Hydrogen Peroxide Production at the Rock-Water Interface
AU: * Bose, M
EM: milton.bose@gmail.com
AF: Carl Sagan Center SETI Institute, 515 N Whisman Rd., Mountain View, CA 94043, United States
AU: * Bose, M
EM: milton.bose@gmail.com
AF: UC Riverside, Department of Physics, Riverside, CA 92521, United States
AU: Balk, M
EM: Melike.Balk@wur.nl
AF: Wageningen University, Laboratory of Microbiology Dreijenplein 10, Wageningen, HB 6703, Netherlands
AU: Ertem, G
EM: gertem@mail.arc.nasa.gov
AF: NASA Ames Research Center, Code SSX, MOffett Field, CA 94035-1000, United States
AU: Rogoff, D A
EM: drogoff@mail.arc.nasa.gov
AF: Carl Sagan Center SETI Institute, 515 N Whisman Rd., Mountain View, CA 94043, United States
AU: Rogoff, D A
EM: drogoff@mail.arc.nasa.gov
AF: NASA Ames Research Center, Code SGE, Moffett Field, CA 94035-1000, United States
AU: Rothschild, L J
EM: lrothschild@mail.arc.nasa.gov
AF: NASA Ames Research Center, Code SGE, Moffett Field, CA 94035-1000, United States
AU: Freund, F T
EM: ffreund@mail.arc.nasa.gov
AF: Carl Sagan Center SETI Institute, 515 N Whisman Rd., Mountain View, CA 94043, United States
AU: Freund, F T
EM: ffreund@mail.arc.nasa.gov
AF: NASA Ames Research Center, Code SGE, Moffett Field, CA 94035-1000, United States
AU: Freund, F T
EM: ffreund@mail.arc.nasa.gov
AF: San Jose State University, Department of Physics, San Jose, CA 95192-0106, United States
AB: The theme "Follow the Oxidants" draws attention to the role of oxidants in planetary evolution. Earth, which acquired a progressively more oxidizing surface environment of the first 2+ Gyrs, provides a good example. The cause of Earth's slow oxidation is still not fully understood. Here we show that an electric current unlike any current previously described flows through igneous rocks (1, 2). The current arises when rocks are stressed. The charge carriers derive from oxygen anions in the minerals that have changed their valence from 2– to 1–. An O– in a matrix of O2– represents a defect electron or hole, also known as positive hole (3) or "phole" for short. Normally the O– occur in the structure of their host minerals in the form of pairs, O–-O–, equivalent to peroxy links. As such they are dormant and electrically inactive. When stresses are applied, dislocations move through the mineral grains, causing the peroxy links to break up, creating electrons and pholes. These charge carriers are capable of generating currents that flow for hours and days. In the laboratory the pholes propagate readily through 3 meter of dry granite. In the field they are expected to flow through kilometers of rocks. When the pholes reach a rock-water interface, they oxidize H2O quantitatively to H2O2. On the early Earth, which was certainly tectonically active, this mechanism represents a global source of H2O2, which must have been available over Gyrs. It has far-reaching implications for the oxidation of the early Earth and the evolution of early Life. 1. F. T. Freund, D. Sornette, Tectonophys. 431, 33 (2007). 2. F. T. Freund, A. Takeuchi, B. W. Lau, Phys. Chem. Earth 31, 389 (2006). 3. D. L. Griscom, Glass Sci. Technol. 4B, 151 (1990).
DE: 2732 Magnetosphere interactions with satellites and rings
DE: 5421 Interactions with particles and fields
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting