Rocks with mysterious deep scratches????

Question

I hiked Mt. Magalloway in NH and all the way up the rocks had strange ruts or scratches on the edges and tops of the rocks .It wasnt possible for a truck, atv or dirtbike to climb this grade, and the scratches/ruts appeared on random rocks all over the trail. So i guess i was wondering if humans put those there for grip if the rocks are wet, or if its from moose hooves or how it got there......please help if you can.

Answer 1

You might have seen glacial straitions. I don't know if NH was covered with ice during the last glacial maximum, but maybe the mountain was, even if the rest of the state was not.

Glaciers contain lots of rocks and when the glacier flows downhill, these rocks are pushed down and dragged across the landscape, eroding and scarring the underlying surface.

Here's a picture:

http://www.sciencelearn.org.nz/var/scien...

Answer 2

Glacial striations, scratches in the rocks caused by the passage of glaciers carrying other rocks, are very common on the surfaces of bedrock in the mountains of northern New England.  Normally the scratches will be oriented in about the same direction, and this is the direction that the ice was moving.

Gives you an idea of how thick the ice actually was, that it was able to bury these hills and mountains completely.  Only the very highest mountains were actual sources of the glaciers, the lower mountains and high hills were ridden right over by the ice.

Answer 3

The scratches you're seeing are a natural phenomenon... they are almost certainly a geological feature called glacial striations. During the last ice age, all of New Hampshire was covered by glaciers. When these glaciers first crossed into New Hampshire, their undersides (which are full of debris) scraped against the underlying rock and carved out these grooves.  When the ice melted away, the rocks were left behind but were still scarred by their experience with the glaciers.