Title of article :
Determination of post-perovskite phase transition boundary up to 4400 K and implications for thermal structure in D″ layer
Author/Authors :
Tateno، نويسنده , , Shigehiko and Hirose، نويسنده , , Kei and Sata، نويسنده , , Nagayoshi and Ohishi، نويسنده , , Yasuo، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2009
Abstract :
We have determined the post-perovskite phase transition boundary in MgSiO3 in a wide temperature range from 1640 to 4380 K at 119–171 GPa on the basis of synchrotron X-ray diffraction measurements in-situ at high-pressure and -temperature in a laser-heated diamond-anvil cell (LHDAC). The results show a considerably high positive Clapeyron slope of + 13.3 ± 1.0 MPa/K and a transition temperature of about 3520 ± 70 K at the core–mantle boundary (CMB) pressure. The thermal structure in D″ layer can be tightly constrained from precisely determined post-perovskite phase transition boundary and the depths of paired seismic discontinuities. These suggest that temperature at the CMB may be around 3700 K, somewhat lower than previously thought. A minimum bound on the global heat flow from the core is estimated to be 6.6 ± 0.5 TW.
Keywords :
Post-perovskite , Core–mantle boundary , In-situ X-ray diffraction , Lower mantle , phase transition
Journal title :
Earth and Planetary Science Letters
Journal title :
Earth and Planetary Science Letters