Comment on: “Crustal strength in central Tibet determined from Holocene shoreline deflection around Siling Co” by Xuhua Shi, Eric Kirby, Kevin P. Furlong, Kai Meng, Ruth Robinson and Erchie Wang

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• 作者：Philip C. England ; ^{Philip.England@earth.ox.ac.uk" class="auth_mail" title="E-mail the corresponding author} ; Richard T. Walker
• 关键词：rheology ; Tibet ; palaeoshorelines ; elastic thickness
• 刊名：Earth and Planetary Science Letters
• 出版年：2016
• 出版时间：1 January 2016
• 年：2016
• 卷：433
• 期：Complete
• 页码：393-395
• 全文大小：281 K

文摘

Shi et al. (2015) analysed the distributions of elevation of palaeoshorelines around Siling Tso, central Tibet assuming a model in which surface loads are entirely supported by an elastic lid overlying an inviscid fluid. They concluded that the thickness of the elastic lid is 20–30 km and that, for the assumption of an inviscid substrate in this model to be valid, the viscosity of the crust below the elastic lid must be less than $1\text{–}2\times {10}^{19}\text{Pa}\text{s}$. Here we relax the assumption of an inviscid lower crust and show that the distribution of shoreline elevations may be explained either by a thick elastic lid or by high viscosity in the lower crust. In the limit of an inviscid lower crust, the thickness of the elastic lid must be greater than 25 to 39 km. If the elastic lid is thinner than this, then the viscosity of the crust beneath must be at least 5×10¹⁹$5\times {10}^{19}$ to $2\times {10}^{20}\text{Pa}\text{s}$, depending on the time interval over which the lake was loaded.