Effects of the Borealis impact on the thermal evolution of Mars

The near hemispheric dichotomy of Mars is attributed to a giant impact called Borealis impact [Andrews-Hanna et al., 2008]. In this work, we investigate the effect of Borealis impact, happened 4.5 Gyr ago, on the thermal evolution of the Martian planet. We show that the impact increases the rate of crustal production for a period of about 50 m.y. after the impact, reduces core mantle boundary heat flux significantly for a period of less than 5 m.y. after the impact but does not change significantly the total volume of melt production of the Mars. We discuss implications of our results on the postulated equivocal theories on the demise of Martian dynamo and conclude that none of them is capable to explain the demise of the Mars magnetic filed happened about 4 Gyr ago.