HR: 1340h
AN: U43C-1392    [Abstracts]
TI: Carbon sequestration and eruption hazards
AU: * Zhang, Y
EM: youxue@umich.edu
AF: The University of Michigan, Department of Geological Sciences, Ann Arbor, MI 48109-1005, United States
AU: * Zhang, Y
EM: youxue@umich.edu
AF: Peking University, School of Earth and Space Sciences, Beijing, 100871, China
AB: In order to reduce the buildup of carbon dioxide in the atmosphere, proposals have been made to sequestrate carbon in ocean, or in coal mines and other underground formations. High gas concentration in ocean or underground formations has to potential to power gas-driven eruptions. In this presentation, possible eruption hazards are explored. Whenever carbon dioxide is sequestrated in the form of carbon dioxide gas, or dissolved and/or absorbed carbon dioxide, it is necessary to exercise caution to avoid gas-driven eruption hazard. It is long known that explosive volcanic eruptions are driven by H2O gas in magma. Lake eruptions powered by dissolved CO2 in lake bottom water were discovered in the 1980's (Kling et al., 1987; Zhang, 1996). Gas-driven ocean eruptions with mechanism similar to lake eruptions have been hypothesized (Zhang, 2003; Zhang and Kling, 2006) although not confirmed. Mud volcanos are commonly thought to be driven by methane-rich fluids in sediment (Milkov, 2000). Recently, Zhang et al. (2007) have proposed that coal outbursts in underground coal mines are driven by dissolved high CO2 concentration in coal, causing coal fragmentation and outburst. That is, coal outbursts may be regarded as a new type of gas-driven eruptions. Therefore, high concentrations of free gas or dissolved/absorbed gas may power eruptions of magma, lake water, ocean water, sediment, and coal. Gas- driven volcanic, lake and ocean eruptions are due to volume expansion from bubble growth, whereas gas-driven coal and sediment eruptions are due to high gas-pressure, leading to fragmentation of coal and sediment. (In explosive volcanism, magma fragmentation is also a critical point.) The threshold conditions for many of these eruptions are not known yet. In planning large (industrial) scale injection of CO2 into a natural reservoir, it is important to know the eruption threshold and design the injection scheme accordingly. More safe sequestration in terms of eruption hazards would utilize chemical reactions to immobilize gaseous CO2 into carbonates. References Kling G.W. et al. (1987) Science 236, 169-175. Zhang Y. (1996) Nature 379, 57-59. Zhang Y. (2003) Geophys. Res. Lett. 30(7), (51-1)-(51-4), doi 10.1029/2002GL016658. Zhang Y., Kling G.W. (2006) Annu. Rev. Earth Planet. Sci. 34, 293-324. Zhang Y., Guan P., Wang H. (2007) 6th IPACES meeting abstract, 26-29 June 2007, Wuhan, China.
DE: 3004 Gas and hydrate systems
DE: 4806 Carbon cycling (0428)
DE: 8426 Mud volcanism
DE: 8428 Explosive volcanism
DE: 8430 Volcanic gases
SC: Union [U]
MN: 2007 Fall Meeting