I am always a sucker for research that uses very simple observations to come to profound conclusions, and that is definitely the case with “The dual nature of the martian crust: Young lavas and old clastic materials” by Josh Bandfield, Chris Edwards, David Montgomery, and Brittany Brand. This paper suggests that the martian crust has a dual nature, where the oldest rocks are actually softer and easier to erode, while more recently lava flows have led to much more durable terrain.