Nuclear Winter On Mars

The Martian surface is covered with a thin layer of radioactive substances including uranium, thorium and radioactive potassium But why is there radioactive substaces on mars is it a proof of Nuclear Winter happened on Mars ? Earlier Dr. John Brandenburg, a senior propulsion scientist at Orbital Technologies Corp said that there was a natural nuclear blast on Mars. According to Brandenburg, the natural explosion, the equivalent of 1 million one-megaton hydrogen bombs, occurred in the northern Mare Acidalium region of Mars where there is a heavy concentration of radioactivity. But I the writer of this blog thinks that it is not natural it may have happened during a war between the Martians and the same once happened on Earth during the World War II Mare Acidalium as seen from Google Earth There are many craters in the Mare Acidalium region on Mars which is a proof that may be it was a city which w