A glacier is a mass of compacted snow which deforms and flows due to gravity. Glaciers contain ice and sediments that becomes part of the glaciers load. Once sediment becomes part of the glacier, it moves with it. This sediment is then able to act as an abrasive force on the bedrock.
Glacial striations are grooves or scratches in bedrock that were made by glaciers as they moved across the bedrock. The glaciers would pick pieces of hard rock and grind them into the softer bedrock, causing the striations. Striations will be parallel to each other. Most striations are rather shallow but can be deeper. Below is a photo of the glacial striations on Kellys Island in Lake Erie north of Sandusky, Ohio which are some of the best in the world.
The glacier that caused these striations covered this area over 10,000 to 12,000 years ago which is when the ice sheet started to retreat. The ice sheet was over a mile high and was present for thousands of years.
At this site the glacial striations are not anywhere as pronounced as those on Kellys Island. You will have to look for them as they are not that numerous. This tells us that the rocks that scratched the bedrock were also small in size. The direction of movement can be determined by looking for the overall pattern of the striations. All the scratches will be aligned in the direction that the glacier was moving. You will also be able to see how the glacier polished the bedrock into a smooth surface.
The requirements to log this cache are to email me the answers to questions 1, 2 & 3 at my profile:
1.)Use a compass or your GPS to tell me the two headings that the grooves follow. Such as 45 degrees and 225 degrees.
2.)What is the average depth of the striations here.
3.)What is the average width of the striations here.
4.)Optionally it would be nice for you to post with your log a photo of the striations. It would be nice to see you holding your GPS and your smiling face. This item again is absolutely optional.