Time Odyssey

The lastest news out of NASA is the revelation of a massive impact crater on Mars which possibly accounts for the differences in geological appearance between the northern and southern hemispheres. One suggestion is that such a collision occurred roughly 3.9 Billion years ago. However even a cursory glace at our own world shows all kinds of cratering far more extensive that in the northern Martian hemisphere. Considering our planet is subject to erosion and movement through plate tectonics, it would seem that the lack of cratering on Mars may suggest a more recent phenomena.

So for example, wouldn’t it be neat if the impact was more on the order of say 65 million years ago rather than 3.9 Billion. Narrowing down the age and comparing it to impacts on Earth and other locations could potentially lead to a map which may establish whether there are certain danger zones around the galaxy where asteroid activity is generally more intense than at other times. We tend to think of our region of space as being fairly benign but since we are constantly moving at 600km/s there really is no guarantee that the near earth objects in our path today will be the same ones that will be there tomorrow.

Beyond this though is another aspect of geological behaviour that may be worth exploring. The Chicxulub meteor impact which was originally considered to have wiped out the dinosaurs may have led to another interesting phenomena such as the swelling of magma deep in the earth’s core. Its sort of like popping a water balloon. You push on one side and water comes gushing out at a 90 degree angle to the direction of the force.

We sort of see this with the revelation that the Deccan Traps lava beds in India were formed within 300,000 years after the Chicxulub meteor and are roughly at a 90 degree rotation to the meteor’s impact. These eruptions are now widely attributed to have been the final straw the doomed the dinosaurs. However, when we compare this to the Mars’ impact – a similar pattern seems to emerge. Leveling approximately 40% of the Martian surface, massive volcanoes seem to have sprung up from just around the impact area – something that would be consistent with the application of force to an area surrounded by weak spots.

The question now is – which came first – the meteoroid or the volcano? The suggestion in the article is that the volcano came first but I have a sneaking suspicion that when push comes to shove (okay – bad joke I admit) that both the Martian volcanoes and the impact crater itself are going to far less old than what is currently assumed.  – K