Download or read book Structure, Properties, and Dynamic Behavior of Earth's Inner Core written by Daniel Marcus Reaman and published by . This book was released on 2011 with total page 57 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Long-standing debate has persisted regarding the nature of the Earth's inner core, from its age and composition to its structure and dynamic high-pressure, high-temperature behavior. The equation of state of the alloy which comprises the inner core, the material transport properties of inner-core materials and the mechanism responsible for its structure are all required to gain further insight into the current and past state of the Earth's deep interior. Experimental work in the diamond-anvil cell (DAC) coupled with theoretical calculations are reported here to constrain these aspects of the Earth's inner core. Use of the DAC has allowed us to determine an equation of state of a planetary-core representative Fe64Ni36 alloy to 95 GP and ~ 3000 K. Increasing the Ni content in these experiments relative to the estimated abundance in the inner core (~5-10%) provides a critical investigation on the effects of increasing Ni content on the equation of state of FeNi alloys, thereby providing insight in to the behavior of these alloys at high pressures and temperatures with applications to other planetary cores. The use of micro-fabricated samples in the DAC is a novel new way of measuring material transport properties under high-pressure and temperature conditions. Using micro-fabricated samples in these experiments, with a controlled geometry of Fe and Ni, has allowed the measurement of interdiffusion coefficients in FeNi alloys and extended the previous pressure range of these experiments by a factor of three. The resulting data has been extrapolated to inner-core conditions to place constraints on material transport properties at those conditions while providing insight into some of the other physical properties of inner-core material, such as the solid-state viscosity. The seismically-anisotropic structure of the inner core remains a point of contention amongst geophysicists. Though many viable hypotheses have been put forth regarding the nature of this structure, debate still persists regarding the mechanism responsible. Theoretical calculations assuming high-temperature creep are presented which show that the structure of the inner core can be explained by a dislocation-based creep mechanism coupled with grain-boundary migration recrystallization and a grain growth model. These calculations provide a viable set of mechanisms which satisfactorily account for all of the structural features of the inner core. The results of this research provide an overall thermal and structural history of the inner core, in addition to placing constraints on its current state and mechanical behavior.