A revised estimate for the temperature structure of the oceanic lithosphere
A revised estimate for the temperature structure of the oceanic lithosphere
复制标题
海洋岩石圈温度结构的修正估计
DOI：
10.1029/91jb02998
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发表时间：
1992
影响因子：
--
通讯作者：
R. Denlinger
中科院分区：
文献类型：
--
作者：
R. Denlinger
岩石圈的传导冷却模型为解释海洋测深和热流提供了基础，从而为目前公认的海洋岩石圈的温度结构提供了基础。这些模型是基于橄榄石和辉石的热性质的平均值，没有考虑这些性质随温度的任何变化。本文给出了橄榄石和辉石的热流方程的解，其中包含了观测到的橄榄石和辉石的热扩散率随温度的变化。地表热流和水深测量可以随岩石圈年龄的平方根而变化，但扩散系数不变，就像固定扩散系数溶液一样，但温度结构有很大不同。具体地说，变扩散系数模型得到的浅层(800℃等温线以上)的温度梯度和温度小于平均扩散系数模型得到的温度梯度，而800℃等温线以下的温度梯度较大。使用可变扩散系数模型，岩石圈机械强度较强的部分(<；800°C)内给定深度的温度降低约100°C，这使得岩石圈的这一部分更厚，与软流圈的边界在力学和热学上都得到了更清晰的界定。这些变化降低了从岩石圈挠曲解释的有效弹性模数。
Models for conductive cooling of the lithosphere provide the foundation for interpretation of oceanic bathymetry and heat flow and consequently provide the basis for the currently accepted temperature structure of the oceanic lithosphere. These models are based upon average values for the thermal properties of olivine and pyroxene and do not account for any variation in these properties with temperature. In this paper a solution of the heat flow equation is presented that incorporates the observed variation of thermal diffusivity with temperature for olivine and pyroxene. The surface heat flow and bathymetry can vary with the square root of lithosphere age with variable diffusivity just as they do for a constant diffusivity solution, but the temperature structure is significantly different. Specifically, the temperature gradients and temperatures at shallow depths (above the 800°C isotherm) obtained with the variable diffusivity model are less than those obtained with the averaged diffusivity model, whereas the temperature gradients at depths below the 800°C isotherm are greater. Temperatures at a given depth within the mechanically strong portion of the lithosphere (<800°C) are about 100°C less using a variable diffusivity model, making this portion of the lithosphere thicker and the boundary with the asthenosphere more sharply defined mechanically as well as thermally. These changes reduce the effective elastic moduli interpreted from flexure of the lithosphere.