Impact basin relaxation as a probe for the thermal history of Pluto
Impact basin relaxation as a probe for the thermal history of Pluto
复制标题
撞击盆地弛豫作为冥王星热历史的探测器
DOI：
10.1002/2014je004679
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
S. and F. Nimmo
中科院分区：
文献类型：
--
作者：
Kamata;S. and F. Nimmo
我们研究了冥王星上的粘弹性冲击盆地松弛，包括对流和导电冰壳的各种热演化情景。直径小于200 km的盆地没有明显的松弛，而大型撞击盆地的松弛分数可高达60%。控制盆地松弛的主要因素是岩心放射成因热的量；我们的结果对盆地的形成时间、采用的参考冰粘度以及地下海洋的存在与否不敏感。其他挥发物，如co2或NH3，如果在冰壳中有足够数量的存在，可以增加预测的盆地弛豫分数。松弛引起盆地内部的张拉应力；盆地下有效弹性厚度控制了构造特征的走向。因此，未来对撞击盆地的松弛状态和构造的观察可能会为冥王星的热历史提供关键的约束。
We investigate viscoelastic impact basin relaxation on Pluto for a variety of thermal evolution scenarios encompassing both convective and conductive ice shells. Basins smaller than 200 km in diameter do not relax appreciably, while relaxation fractions can be up to ∼60% for large impact basins. The main control on basin relaxation is the amount of radiogenic heat produced in the rocky core; our results are insensitive to the formation time of the basin, the ice reference viscosity adopted, and the presence/absence of a subsurface ocean. Other volatiles, such as CO2or NH3, if present in the ice shell in sufficient quantities could increase the predicted relaxation fraction of basins. Relaxation causes extensional stresses interior to the basin; the orientation of the resulting tectonic features is controlled by the effective elastic thickness beneath the basin. Future observations of the relaxation states and tectonics of impact basins are therefore likely to provide a key constraint on Pluto's thermal history.