What makes bedrock resistant?

Question

i'm finishing a science lab "landscapes of new york state" and one of the questions is: what physical characteristics of the bedrock are responsible for the oldest rock remaining at the highest elevation?

i'm no science wiz so...any idea of what to put?

*** and: what factors result in the formation of landscapes?

Answer 1

And, the biggest factor affecting the landscape is precipation or rainfall. Mountains are erroded down with valleys and rivers forming the landscape. Northern climates have glaciers that carve their way to the valleys and seas. Tropical rain forest have faster errosion cycles than areas with less rainfall.

Answer 2

The other answers had something to do with the rock type and its resistance to weathering. That's probably part of it, but...
But I'm thinking maybe it's simply the shape of the rock that was responsible for the oldest rock to remain at the highest elevation.
Maybe the bedrock is an eroded dome or anticline. The older layers are always at the middle (or top) of these kinds of structures. To find out why, you have to have good imagination. I myself didn't understand why until I studied a diagram for awhile. Just look for a picture of an eroded dome or anticline on the internet, and pay attention to where the younger layers used to be. Notice the middle of the dome, and try to figure out how old each visible layer is using the law of superposition. This is the law that says a bed of rock is always older than the one above it. You're also going to have to imagine where all the rock that got eroded away used to be, and how it curved over the remaining rock before it was eroded away. You will then realize that the remaining rock in the center is the oldest, and that the rock gets progressively younger as you move away from the center (or top) of the dome. Since the structure is shaped like a dome, in which the middle or center is higher in elevation than the surrounding rock, then that means the older rock is indeed remaining at the highest elevation. Thus answering your question.

Answer 3

Exposed rock that persists does so because of imperviousness to the elements: water, freeze-thaw cycles, wind-borne dust, and other causes of erosion. The physical characteristics of such rock might include hardness, insolubility in water, and lack of porosity. Such rock is hard to wear down by wear against other (softer) rock, would not be slowly dissolved by water, and would not allow water in to freeze, expand, and break it up.