Question

because of the isostasy a mountain will ultimately

Answer 1

Because of isostasy, a mountain will ultimately erode to near sea level. When isostasy is reached, the mountain is no longer being pushed upwards because the force of gravity pulling the lithosphere down equals the buoyancy of the lithosphere pushing it up. As erosion occurs, the mass of the mountain decreases, and the lithosphere will push upwards in response to the lowered mass, but it does not push up so far as to make the mountain actually grow beyond where it was eroded. Over a very long time, the mountain will continue to be eroded slightly more than the lithosphere is pushing upwards, and eventually, the mountain will wear away to near sea level