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The Sheahan Diamond Literature Reference Compilation - Scientific and Media Articles based on Major Keyword - Rheology
The Sheahan Diamond Literature Reference Compilation is compiled by Patricia Sheahan who publishes on a monthly basis a list of new scientific articles related to diamonds as well as media coverage and corporate announcements called the Sheahan Diamond Literature Service that is distributed as a free pdf to a list of followers. Pat has kindly agreed to allow her work to be made available as an online digital resource at Kaiser Research Online so that a broader community interested in diamonds and related geology can benefit. The references are for personal use information purposes only; when available a link is provided to an online location where the full article can be accessed or purchased directly. Reproduction of this compilation in part or in whole without permission from the Sheahan Diamond Literature Service is strictly prohibited. Return to Diamond Keyword Index
Sheahan Diamond Literature Reference Compilation - Scientific Articles by Author for all years
Each article reference in the SDLRC is tagged with one or more key words assigned by Pat Sheahan to highlight the main topics of the article. In an effort to make it easier for users to track down articles related to a specific topic, KRO has extracted these key words and developed a list of major key words presented in this Key Word Index to which individual key words used in the article reference have been assigned. In most of the individual Key Word Reports the references are in crhonological order, though in some such as Deposits the order is first by key word and then chronological. Only articles classified as "technical" (mainly scientific journal articles) and "media" (independent media articles) are included in the Key Word Index. References that were added in the most recent monthly update are highlighted in yellow.
Rheology is a scientific term for the study of how matter flows in both a liquid and solid state. Terms like "plastic" and "viscosity" are part of rheology. It is relevant to diamonds because the mantle between the liquid outer core and the solid crust is a plastic, semi-solid material. These are exclusively scientific articles which are relevant to diamonds because somehow this hardest of naturally occurring substances forms within a semi-solid environment. Any media reference tagged with "rheology" will be worth reading because it would not dare touch the topic without attempting to make the subject intelligible to lay people.
A new method to simulate convection with strongly temperature and pressure dependent viscosity in a spherical shell: applications to the Earth's mantle.
Physics of the Earth and Planetary Interiors, in press available
Strain heating as a mechanism for partial melting and ultrahigh temperature metamorphism in convergent orogens: implications of temperature dependent thermal
Journal of Geophysical Research, Vol. 115, B 12 B12417
Abstract: Rheological properties of the lower mantle have strong influence on the dynamics and evolution of Earth. By using the improved methods of quantitative deformation experiments at high pressures and temperatures, we deformed a mixture of bridgmanite and magnesiowüstite under the shallow lower mantle conditions. We conducted experiments up to about 100% strain at a strain rate of about 3 × 10(-5) second(-1). We found that bridgmanite is substantially stronger than magnesiowüstite and that magnesiowüstite largely accommodates the strain. Our results suggest that strain weakening and resultant shear localization likely occur in the lower mantle. This would explain the preservation of long-lived geochemical reservoirs and the lack of seismic anisotropy in the majority of the lower mantle except the boundary layers.
Earth and Planetary Science Letters, Vol. 496, pp. 29-36.
Mantle
rheology, tectonics
Abstract: Recent seismic observations, focused on mantle flow below the Pacific plate, indicate the presence of two shear layers in the Earth's asthenosphere. This is difficult to explain under the classic assumption of asthenosphere flow driven by plate shear from above. We present numerical mantle convection experiments that show how a power law rheology, together with dynamic pressure gradients, can generate an asthenosphere flow profile with a near constant velocity central region bounded above and below by concentrated shear layers (a configuration referred to as plug flow). The experiments show that as the power law dependence of asthenosphere viscosity is increased from 1 to 3, maximum asthenosphere velocities can surpass lithosphere velocity. The wavelength of mantle convection increases and asthenosphere flow transitions from a linear profile (Couette flow) to a plug flow configuration. Experiments in a 3D spherical domain also show a rotation of velocity vectors from the lithosphere to the asthenosphere, consistent with seismic observations. Global mantle flow remains of whole mantle convection type with plate and asthenosphere flow away from a mid-ocean ridge balanced by broader return flow in the lower mantle. Our results are in line with theoretical scalings that mapped the conditions under which asthenosphere flow can provide an added plate driving force as opposed to the more classic assumption that asthenosphere flow is associated with a plate resisting force.
