Dr. Wen-Pin Hsieh of the IES high-pressure mineral physics laboratory has combined ultrafast optics with diamond cell techniques to measure the thermal conductivity of ferropericlase at high pressures. His team found that the thermal conductivity of iron-rich ferropericlase drops significantly across spin transition of iron, resulting in an enhanced iron substitution effect in the low-spin iron-rich ferropericlase. Combined with prior results and data modeling, they demonstrated that iron plays critical roles in affecting the thermal conductivity, thermo-chemical structures, cooling rate, and geodynamics in the lower mantle. These results further help better understand the thermal history of ultra-low velocity zones at the bottom of the mantle: if these regions are hot and enriched in iron, their exceptionally low thermal conductivity may delay their cooling and keep them substantially hotter than their surroundings. The international research team includes Drs. Wen-Pin Hsieh and Frédéric Deschamps of IES, Prof. Jung-Fu Lin of University of Texas at Austin, and Dr. Takuo Okuchi of Okayama University. [Article website]
