Monnereau Marc, Yuen David A
Unité Mixte de Recherche 5562, Centre National de la Recherche Scientifique-Université Paul Sabatier Toulouse III, 14 Avenue Edouard Belin, 31400 Toulouse, France.
Proc Natl Acad Sci U S A. 2007 May 29;104(22):9156-61. doi: 10.1073/pnas.0608480104. Epub 2007 May 3.
The postperovskite (ppv) phase transition occurs in the deep mantle close to the core-mantle boundary (CMB). For this reason, we must include in the dynamical considerations both the Clapeyron slope and the temperature intercept, T(int), which is the temperature of the phase transition at the CMB pressure. For a CMB temperature greater than T(int), there is a double crossing of the phase boundary by the geotherms associated with the descending flow. We have found a great sensitivity of the shape of the ppv surface due to the CMB from variations of various parameters such as the amount of internal heating, the Clapeyron slope, and the temperature intercept. Three-dimensional spherical models of mantle convection that can satisfy the seismological constraints depend on the Clapeyron slope. At moderate value, 8 MPa/K, the best fit is found with a core heat flow amounting for 40% of the total heat budget (approximately equal to 15 TW), whereas for 10 MPa/K the agreement is for a lower core heat flow (20%, approximately equal to 7.5 TW). In all cases, these solutions correspond to a temperature intercept 200 K lower than the CMB temperature. These models have holes of perovskite adjacent to ppv in regions of hot upwellings.
后钙钛矿（ppv）相变发生在靠近核幔边界（CMB）的下地幔中。因此，我们必须在动力学考虑中纳入克拉佩龙斜率和温度截距T(int)，T(int)是CMB压力下的相变温度。当CMB温度高于T(int)时，与下沉流相关的地温线会两次穿过相边界。我们发现，由于CMB处各种参数（如内部加热量、克拉佩龙斜率和温度截距）的变化，ppv表面形状具有很高的敏感性。能够满足地震学约束的地幔对流三维球模型取决于克拉佩龙斜率。在中等值8MPa/K时，发现最佳拟合情况是，地核热流占总热收支的40%（约等于15TW），而在10MPa/K时，拟合结果对应的地核热流较低（20%，约等于7.5TW）。在所有情况下，这些解对应的温度截距比CMB温度低200K。这些模型在热上升流区域中，与ppv相邻处存在钙钛矿孔洞。
