The role of episodic overturn in generating the surface geology and heat flow on Enceladus
Craig O’|Neill & Francis Nimmo 2010, Nature Geoscience 3, 88–91
http://www.nature.com/ngeo/journal/v3/n2/full/ngeo731.html
Enceladus, Saturn’s second closest satellite, is well known for its icy and even snowy aspect and structure. It has a diameter of 500km and, even though it is all composed out of ice, it has shown signs of tectonic and volcanic activity, which, interestingly, is concentrated in the south pole of the moon, emanating geyserlike jets, watery plumes that spew outward from a region carved up by unusually warm gashes known as "tiger stripes"
O’Neill & Nimmo 2010 observed abnormally high heat flux at the south pole which can be explained by the existence of a convecting mantle plume under the moon’s tectonic plates. They propose a model through which this dispersion can very probably be due to tidal heating. This effect could be possible in the south pole due to the ice shell being thinner over a region with a warmer interior.
During Enceladus orbit around Saturn, the strong gravity from the massive planet causes the icy moon to “stretch”, thus generating tidal heat waves (similar to the tidal waves on Earth cause by the moon). O'Neill & Nimmo 2010 assume that what is being observed on Enceladus currently is quite an unusual behavior which can be described as a brief period of tectonic activity that resurfaces a limited area of the moon. In the model that they create, they describe how the heat is being stored up inside over billions of years, thus, building up to a maximum point at which it starts “erupting, escaping in a brief volcanic-like activity.
No comments:
Post a Comment