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Dynamics of Mantle Plumes

Dynamics of Mantle Plumes. Methods for modeling basic thermal plumes (with and without tracers) Plumes interacting with plates (and ridges) Plumes in thermo-chemical convection More elaborate proposals for plumes. Dynamics of the mantle…. Fine-scale variations in the Galapagos.

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Dynamics of Mantle Plumes

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  1. Dynamics of Mantle Plumes • Methods for modeling basic thermal plumes (with and without tracers) • Plumes interacting with plates (and ridges) • Plumes in thermo-chemical convection • More elaborate proposals for plumes

  2. Dynamics of the mantle…

  3. Fine-scale variations in the Galapagos Global scale: mantle contains both well-mixed regions and heterogeneity Fine scale heterogeneity Harpp and White, G-cubed 2001 Galapagos Islands (from Harpp and White, 2001, G-cubed)

  4. Hawaiian emperor track (Steinberger et al. Nature 04)

  5. From Garnero, Annual Reviews of Earth & Planetary Sciences, 2000

  6. Figure courtesy of E. Garnero, ASU

  7. Farnetani et al. 2002: Model 1: uniform mantle, low viscosity plume

  8. Farnetani et al. 2002: Model 3: viscosity jump in transition zoneThin dense layer at baseLow viscosity in plume

  9. Farnetani et al: EPSL, 2002Detail of mixing in plume:black tracers are from basal b.l.grey are from transition zone

  10. Courtesy of Shijie Zhong,U. Colorado (see:Entrainment of a dense layer by thermal plumesZhong and Hager, Geophysical Journal InternationalSeptember 2003)

  11. Courtesy of Shijie Zhong, U. Colorado

  12. Double Diffusive Convection Model of D” B=1 Ra = 107 N. Montague and L. Kellogg, JGR, 2000 Earth’s surface Core-mantle boundary Color indicates Temperature

  13. time horizontal distance N. Montague and L. Kellogg, JGR, 2000 time

  14. N. Montague and L. Kellogg, JGR, 2000 A dense layer stabilizes the flow With a dense layer in D” No dense layer time

  15. B= 1 More temperature-dependent viscosity Kellogg and Montague, in preparation

  16. Hansen & YuenVarying properties with depth allows layering

  17. Layered convectionexperiments by Anne Davaille, (Nature 402, 756,Dec. 1999)

  18. Davaille experiments + several numerical models (redrawn from Davaille, 1999; color points are numerical models from various sources)

  19. Courtillot, V., Davaille, A., Besse, J., Stock, J., Earth and Planetary Science Letters, 2003.

  20. Courtillot, V., Davaille, A., Besse, J., Stock, J., Earth and Planetary Science Letters, 2003.

  21. Olympus Mons (Mars)-Hawaii Comparison

  22. Hunt and Kellogg, 2000 0 km 670 km Depth 2900 km 10 100 1 Normalized viscosity • Mixing in 2-D with particles • Added at subduction zones • Removed at mid-ocean ridges

  23. Hunt & Kellogg, 2000 - effect of viscosity on mixing 1 10 100 Constant viscosity viscosity 10 1 100 Pressure-dependent viscosity: smooth increase 1 10 100 Transition zone viscosity: Jump at 670 km

  24. D. L. Hunt & L. H. Kellogg, 2000 Distribution of heterogeneities

  25. Heat budget of the Earth (all values given in terawatts)various sources Total global heat flow: 44 TW Total BSE Heat production: 20 TW + (from cosmochemistry) Continental crust produces: 4.6 to 10 TW A uniform, depleted mantle could produce: 5 – 7 TW Requires (AT LEAST) 3to 10.4 TW produced elsewhere (mantle or core)

  26. Comparisons of mantle cooling regimes Lithospheric Conduction Mercury Moon Mars? Venus? Earth Io Hotspot Volcanism Plate recycling

  27. Kellogg et al., 1999

  28. After a figure in E. M. Moores, L. H. Kellogg, and Y. Dilek, Ophiolites, Tectonics, and Mantle Convection: a contribution to the "Ophiolite Conundrum", in Optiolites and the Oceanic Crust, GSA Special Paper 349, 3-12, 2000.

  29. After a figure in E. M. Moores, L. H. Kellogg, and Y. Dilek, Ophiolites, Tectonics, and Mantle Convection: a contribution to the "Ophiolite Conundrum", in Optiolites and the Oceanic Crust, GSA Special Paper 349, 3-12, 2000.

  30. http://www.nsf.gov/pubs/2004/nsf04593/nsf04593.htm or link to this from: http://www.csedi.org National Science Foundation Cooperative Studies Of The Earth's Deep Interior (CSEDI) NSF 04-593 Full Proposal Deadline(s) (due by 5 p.m. proposer's local time): September 20, 2004 August 25, 2005 and annually thereafter Synopsis of Program: The Division of Earth Sciences (EAR) invites the submission of proposals for collaborative, interdisciplinary studies of the Earth's interior within the framework of the community-based initiative known as Cooperative Studies of the Earth's Deep Interior (CSEDI). Funding will support basic research on the character and dynamics of the Earth's mantle and core, their influence on the evolution of the Earth as a whole, and on processes operating within the deep interior that affect or are expressed on the Earth's surface. Projects may employ any combination of field, laboratory, and computational studies with observational, theoretical, or experimental approaches. Support is available for research and research infrastructure through grants and cooperative agreements awarded in response to investigator-initiated proposals from U.S. universities and other eligible institutions. Multidisciplinary work is required. EAR will consider co-funding of projects with other agencies and supports international work and collaborations.

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