Mars -- subsurface temperature

[gunsandrockets]

Does anyone have any good estimates on how quickly the temperature should rise underneath the surface of Mars? Are the southern highlands different than the northern lowlands? Are the subsurface temperature conditions below deep impact craters such as Hellas different?

 

[JonClarke]

There's been no direct measurments to my knowledge, just some modelling. One estimate is 12-20 dgrees K per km. Other estimates 10-14 degres per km.<br /><br />Hope this helps.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[gunsandrockets]

Thanx!

 

[JonClarke]

No worries! <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[silylene old]

Hello Jon,<br /><br />On a distantly related note, but something that I have been curious about for a while, do you know what would the subsurface temperature profile for Venus might look like?<br /><br />As a result, is Venusian lava thought to be a lower viscosity than is commonly observed on Earth? (I think the lava flows, shield volcanoes and pancake volcanoes do imply a lower viscosity lava....as does the relative lack of tall cinder volcanoes).<br /><br />For other forum members, here are websites with several nice pictures of Venusian volcanoes: Venus volcanoes, Venus volcano map, volcanoes <br /><br />thanks! <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>

 

[mithridates]

I've been wondering the same thing for a while now too, thanks for asking the question. I wonder what sort of dark caves they have on Venus and how much cooler they might be than the surface. <div class="Discussion_UserSignature"> <p>----- </p><p>http://mithridates.blogspot.com</p> </div>

 

[JonClarke]

Hi silylene<br /><br />This abstract says the surface heat flow of Venus is about the same as Earth's, ~90Wm2.<br /><br />Most of the surface rocks on Venus are thought to be basaltic and are probably erupted at much the same temperature as on Earth. the long flow distances is due to the slower cooling rates, compared to here.<br /><br />Cinder ones are formed from volatile-rich eruptions, the volatiles can be from groundwater interaction with magma (hydro-magmatic or phreato-magmatic eruptions) or from co-magmatic volatiles (fire fountaining). On Venus there is no groundwater and the surface pressure is so great (~90 atmospheres, equiavelent to 900 m down in the ocean) that the volatiles don't readily exolve from the magma. For this reason we don't see many deep water submarine pyroclastics either.<br /><br />Jon <br /><i>Edited to fix link</i> <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[JonClarke]

Caves on earth seem generally cooler than the outside because their temperatures represent the climatic average. If you go down a cave in winter it will seem warmer, for the same reason. On Venus, where there is little diurnal and seasonal temperature variation, a cave would be just as hot as outside. Unfortunately.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>