HR: 16:00h
AN: GC14A-01 INVITED    [Abstracts]
TI: Roles of Clathrate Hydrates in Crustal Heating and Volatile Storage/Release on Earth, Mars, and Beyond
AU: * Kargel, J S
EM: jkargel1054@earthlink.net
AF: Jeffrey S Kargel, Department of Hydrology & Water Resources, University of Arizona, Tucson, AZ 85742, United States
AU: Beget, J
EM: ffjeb1@uaf.edu
AF: Jim Beget, University of Alaska at Fairbanks, Fairbanks, AK 99775, United States
AU: Furfaro, R
EM: robertof@email.arizona.edu
AF: Roberto Furfaro, Department of Aerospace & Mechanical Engineering, University of Arizona, Tucson, AZ 85742, United States
AU: Prieto-Ballesteros, O
EM: prietobo@inta.es
AF: Olga Prieto-Ballesteros, Center for Astrobiology/INTA, Torrejon de Ardoz, 28850, Spain
AU: Palmero-Rodriguez, J A
EM: alexis1709@yahoo.com
AF: J. Alexis Palmero-Rodriguez, Planetary Science Institute, Tucson, AZ 85721, United States
AB: Clathrate hydrates are stable through much of the Solar System. These materials and hydrate-like amorphous associations of water with N2, CO, CH4, CO2, O2 and other molecules could, in fact, constitute the bulk of the non-rock components of some icy satellites, comets, and Kuiper Belt Objects. CO2 clathrate is thermodynamically stable at the Martian South Pole surface and could form a significant fraction of both Martian polar caps and icy permafrost distributed across one-third of the Martian surface. CH4 clathrate is the largest clathrate material in Earth's permafrost and cold seafloor regions, and it may be a major volatile reservoir on Mars, too. CO2 clathrate is less abundant on Earth but it might store most of Mars' CO2 inventory and thus may be one of the critical components in the climate system of that planet, just as CH4 clathrate is for Earth. These ice-like phases not only store biologically, geologically, and climatologically important gases, but they also are natural thermal insulators. Thus, they retard the conductive flow of geothermal heat, and thick accumulations of them can modify geotherms, cause brines to exist where otherwise they would not, and induce low-grade metamorphism of upper crustal rocks underlying the insulating bodies. This mechanism of crustal heating may be especially important in assisting hydrogeologic activity on Mars, gas-rich carbonaceous asteroids, icy satellites, and Kuiper Belt Objects. These worlds, compared to Earth, are comparatively energy starved and frozen but may partly make up for their deficit of joules by having large accumulations of joule-conserving hydrates. Thick, continuous layers of clathrate may seal in gases and produce high gas fugacities in aquifers underlying the clathrates, thus producing gas-rich reservoirs capable of erupting violently. This may have happened repeatedly in Earth history, with global climatic consequences for abrupt climate change. We have hypothesized that such eruptions may have occurred during interglacial epochs and formed super-size maar craters in Bering Land Bridge National Preserve (Alaska). On Mars, clathrates and gas-saturated aquifers apparently played some role in the largest flood- and debris-flow-forming events in that planet's history, with vast consequences for landform development and resurfacing. This heating phenomenon also has possible implications for carbon sequestration as a means of climate change mediation on Earth; besides other concerns about their long-term stability, artificial hydrates produced by carbon dioxide pumping onto the seafloor might heat up and become unstable over time due to normal background radiogenic heat flux.
DE: 0714 Clathrate
DE: 0768 Thermal regime
DE: 1605 Abrupt/rapid climate change (4901, 8408)
DE: 5422 Ices
DE: 5460 Physical properties of materials
SC: Global Environmental Change [GC]
MN: 2007 Fall Meeting