Mathematics – Logic
Scientific paper
Dec 2001
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2001agufmip12b..02d&link_type=abstract
American Geophysical Union, Fall Meeting 2001, abstract #IP12B-02
Mathematics
Logic
1863 Snow And Ice (1827), 3924 High-Pressure Behavior, 5104 Fracture And Flow, 5120 Plasticity, Diffusion, And Creep, 5460 Physical Properties Of Materials
Scientific paper
Barclay Kamb is well known for his seminal work on the motions and internal flow of glaciers, but he was also a pioneer in research on the crystal structures, chemical bonding, and rheologies of the high-pressure phases of ice. In the flow and fracture of terrestrial materials, no rock is more studied than ice. Water ice also has an important presence on other solar system bodies, in particular the moons of the outer solar system, where its flow may extend to deep interiors. Most of these low-density (< 2 Mg/m3) moons have volume fractions of ice well above 0.5, and the largest moons, for example Ganymede, Callisto, and Titan, have sufficient internal pressures to stabilize the high-pressure phases II, III, V, VI, VII, and, possibly in early satellite history, ice VIII. The rheology of ice I has important influence on the surface morphologies of the moons, and the rheologies of all these phases (including ice I) can affect the thermal evolution of the moons by governing the rates of advection of internal radiogenic heat. Polycrystalline ice I under terrestrial conditions is far warmer than ice I in most planetary settings. The phenomenon of "premelting" in ice at T > 255 K leads to high grain-boundary mobility and much higher activation energy in warm ice than in cold ice under the same stress, so the flow of terrestrial ice may not be a good analog for that in the outer solar system. Phenomena from the rheological law itself to the development of lattice preferred orientation may be affected. Of the high-pressure phases through ice VI (all whose rheologies have been explored to date), ices III and VI are the weakest, an effect that, as Kamb has pointed out, parallels and draws explanation from the high rate of dielectric relaxation in those phases. Ice III is exceptionally weak and is stable over a very small part of the (P, T) phase diagram that is situated very close to possible planetary temperature profiles. This could lead to either self-regulation or instability in convective flow depending on the assumptions of the model. Experimental investigation of the transformation of metastable ice I to ice II under non-hydrostatic stress has led to the discovery of transformational faulting (a mechanically unstable transformation under shear with possible applications to deep earthquake faulting in Earth's mantle) and a stable stress-induced ice I to ice II transformation mechanism involving anisotropic growth of ice II inclusions, producing a simple form of metamorphic foliation.
Durham William B.
Kirby Stephen H.
Stern Laura A.
No associations
LandOfFree
Ice Rheology Beyond Planet Earth does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Ice Rheology Beyond Planet Earth, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ice Rheology Beyond Planet Earth will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1240613