An Alternative Model to Explain the Origin of Recent Volcanism on Mars An Alternative Model to Explain the Origin of the Recent Volcanism on Mars <p> HR: <span class="hr"> 11:45h<br></span> AN: <span class="an"> P32A-06 <a href="../absbook/sm05_P32A.html">[Abstracts]</a><br></span> TI: <span class="ti"> An Alternative Model to Explain the Origin of Recent Volcanism on Mars An Alternative Model to Explain the Origin of the Recent Volcanism on Mars <br></span> AU: <span class="au"> * Breuer, D <br></span> EM: <span class="em"> doris.breuer@dlr.de<br></span> AF: <span class="af"> Institute of Planetary Research, DLR, Berlin, Rutherfordstr. 2, Berlin, 12489 Germany <br></span> AU: <span class="au"> Schumacher, S <br></span> EM: <span class="em"> Sandra.Schumacher@uni-muenster.de<br></span> AF: <span class="af"> Institute of Planetology, Uni. M］ster, Wilhelm-Klemm Str. 7, M］ster, 48149 Germany <br></span> AU: <span class="au"> Spohn, T <br></span> EM: <span class="em"> Tilman.Spohn@dlr.de<br></span> AF: <span class="af"> Institute of Planetary Research, DLR, Berlin, Rutherfordstr. 2, Berlin, 12489 Germany <br></span> AB: <span class="ab"> The detection of recent volcanism (2 - 100 Ma) in the areas of Tharsis and Elysium raises questions about its origin. In the past, it was widely believed that the interior of a small planet like Mars, which is only about half the size of the Earth, cooled very fast associated with a rapid decrease and disappearance of the volcanic activity. This picture has been modified with more recent parameterized evolution models based on temperature-dependent viscosity laws, which show that the interior of a small planet cools more slowly as previously thought due to the development of a thick stagnant lid on top of the convecting mantle. However, even these models predict that volcanism has ceased at least one billion years ago unless long-lived, stable plumes exists in the Martian mantle whose existence is strongly debated. An alternative explanation for the recent volcanic activity might be the inefficient heat transport through the basaltic crust. Previous thermal evolution models have assumed the same thermal conductivity in the mantle and the crust. Due to its composition and structure, the basaltic crust, however, has a thermal conductivity which is at least a factor of about 2 lower than that of the mantle. In the present study, we examine the influence of such a low crustal thermal conductivity on the thermal evolution. A value of 2 W/mK typical for basaltic material and 4 W/mK for the mantle has been used. As a consequence of the thermal blanketing due to the low conductivity, a partial melt zone is located below the stagnant lid during most if not the entire evolution. Underneath regions with increased crustal thicknesses, e.g. underneath Tharsis, this melt zone has locally even an increased melt content and might be the source region for the observed recent volcanism. <br></span> DE: <span class="de"> 5430 Interiors (8147)<br></span> DE: <span class="de"> 5455 Origin and evolution<br></span> DE: <span class="de"> 5480 Volcanism (8450)<br></span> DE: <span class="de"> 6225 Mars<br></span> SC: <span class="sc"> Planetary Sciences [P]<br></span> MN: <span class="mn"> 2005 Joint Assembly<br></span></p></body></html>