Flying_ScotchMan

When crossing the border, did you meet immediate resistance by Iraqi troops?

That's... wow. Awesome.

On Earth (and presumably on Mars as well), mountains are indeed formed by tectonic collisions, or by magma pushing upward. However, because this is a really slow process, the crust which is pushed upward is eroded at the same time. Mountains only really form when the upward pushing rate is higher than the erosion. So yes, mountains are formed by tectonics, but shaped by erosion. So when a bit of crust is pushed upwards, the first bits that are going to be exposed by erosion are the top bits which are (most often) the youngest parts. If the upwards pushing lasts longer, more older rocks, below the youngest rocks, are exposed. This is very simplified, but this is why you would find older rocks at the base of a mountain, and younger rocks near the top. I would show you a diagram to explain it, but I can't find one right now. If you insist I might draw one myself.

Edit: I haven't been paying full attention. Apparently Curiosity is driving towards Mount Sharp, which is the central peak of Gale Crater, which it is currently in. So Mt Sharp isn't your ordinary mountain, but was formed when a meteoroid crashed into Mars' surface. It will very probably show older layers when were hidden beneath the surface before the impact happend.