South March Highlands: An Earthcache EarthCache

This will not be available in winter. 

Note that this is an earthcache. There is no container at any of the stages. 

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The posted cooridnates are a great place to start your little hike. The hike is short: Only just over a kilometer round trip, and shouldn't take you more than an hour or so.  In this tour you will find glacial striations, chatter marks, potholes, and even more! It is wise to bring this page with you, so you can refer to it.

I placed this with a large group of amateur geologists, and others who were interested. We made all the observations in the field, with proffesional geologist Allan Donaldson. So everything on this cache page is form a reliable source, and has been confirmed with what i find online as well.

Step #1: N45 20.802 W075 56.811: Park on the side of Old Second Line Road, or Klondike Road. Walk to the posted coordinates.

Step #2: N45 20.763 W075 56.799: Start your hike here. The terrain shouldn't be too bad. You will cross two boardwalks on your journey, so any swampy areas will be no problem.

Step #3: N45 20.614 W075 57.006: Walk about 300 meters down the trail, and stop here, and the end of your first boardwalk. Take a look at the rock underfoot. Sweep it off if it's covered in sand, dirt and leaves. If it's covered in snow... Well, come back in summer! This area is really the most important stop of this stop stop tour. It holds the most of the features we will be looking at. 

So what's here that's of geological interest?

The rock here is Nepean Sandstone. It is an estimated 480 million years old. Here there are glacial straitions. Why? Because this area, 12,000 years ago was covered in three kilometer high glaciers, that swept across the St-Laurent Lowlands. They left chatter marks, and glacial striations, or glacial etchings here to see. 

Small holes in the rock:

All over this stretch of rock, you will find small circular features. What are they? How did they get there? Most geologists, and geology websites describe them as: ertical, U-shaped burrow with spreite; has arms that are parallel or divergent. Top of burrow forms a relatively wide semi-spherical bulb or dumbbell shape; tube can be indicative of protrusive (downward movement) or retrusive (upward movement) burrowing relative to position of spreite. These are called trace fossils. These are fossils of diplocraterion. When this rock was here, and the first organisms and creatures came out. These diplocraterion were worm-like creatures who burrowed themselves down into the sediment. However at this location, geologists don't know what shape or for how long these fossils continue beneath the surface of this rock, since we only have a top view. Look at the picture below taken here. See all those little holes?

Glacial etchings/strations:

Look at the rock towards the swampy area. The rock should be very smooth, except for the parallel ligns you should find in the stone. These were created when a glacier passed over this rock. it smoothed out the rock, but the ice ripped off sediments, which left this pattern of ligns. Geologists use these ligns here to identify which way the glacier went. But sometimes it's hard to tell.

Chatter Marks:

When a geologist can't tell what direction a glacier is moving based on the etchings and striations, he/she looks for chatter Marks. A chatter mark is one or, more commonly, a series of wedge shaped marks left by chipping of a bedrock surface by rock fragments carried in the base of a glacier. Basically what happened here, is when the glacier passed over this rock, it grabbed everything it could: Sediments, dirt, mud, and boulders. When the heavier or bigger rock was caugth under our glacier, it was dragged across the rock's surface, leaving these increasingly growing wegde shaped marks. On this rock, the glacier moved in the direction the chatter marks grow in. Look a bit further away from the swamp to find the chatter marks. I'll attatch a picture so you know what to look for.

Cross-bedding:

Cross-bedding is hard to identify when you do not have a 3-dimensional view of it. Unfortunatley this area, you only have a 2D view. Cross-bedding is horizontal units that are internally composed of inclined layers. This is a case in geology in which the original depositional layering is tilted, and the tilting is not a result of post-depositional deformation. Cross-beds or "sets" are the groups of inclined layers, and the inclined layers are known as cross strata. I will not make you find the cross bedding, because identifying it from above can take a looooooong time.  I just wanted to point it out as one of the many incredible features in this one expanse of rock.

Step #4: N45 20.577 W075 57.034: Once done observing the first rock surface, walk onto the boardwalk which should be right in front of you. Follow it for a hundred meters or so, and when you get off it, you should be at an other rock surface, similar to the other one.

So what's here that's of geological interest?

The rock here is a similar estimated age as the last one. (About 480 Million years old). It is also Nepean San You can see more glacial etchings, and striations here, but as far as I can see, no more chatter marks. 

Potholes:

Not the kind your car goes *bump* over... These potholes were created a while back! Back when the lowlands here were covered in a vast body of water, these potholes were formed. How? Take a look at the image below, and then the explanation.

As you can see in the picture above, a pothole is formed when the current of a river/sea/body of water drags down rocks to the bottom and swirls them around, drilling a hole into the rock. Some potholes are deeper than others. This pothole is not on the big rock surface. When you step off of the boardwalk, walk to the right instead. Cooridnates for the pothole are 20.572 and 57.048. These have an estimated accuracy of 5 meters, so search around for a bit. Here's a picture of the one that's here. You cannot see the bottom for the mud and water.

More glacial etchings:

on the bigger body of rock, there are more glacial etchings similar to the ones we saw before. These are just merely a point of interest, as the other ones serve as a better example. 

Ripples in the stone:

As I metioned before, this area was covered in a body of water. This water was here because when the glaciers passed over, parts of them melted, and covered the St-Laurent Lowlands in water. This body of water was called the Champlain sea. The sea's current left ripples, like waves, in the stones below. So how did an ordinary sea leave rippples in the stone? Well, at the time, the stone here wasn't stone. It was sediments. Long ago, the rock here was not solid rocks, but was in fact sediments; Bits of sand and minerals that had been scraped off of the bedrock by the glaciers. Have you ever been to a beach (I sure hope so...). Whe  you walk into the shallows of the water, you can see the water that gently laps the shore of the beach creates awave like pattern in the sand below, because of it's movements. This is what happened, just after a period of time, the sediments that were in a wave-like formation, underwent the process of sedimentation: When a bunch of sediments become a sedimentary rock, and solidifies. The rock solidified into the form it was in, in this case, with ripples.

Step #5: Re-visit both stages now, and answer the questions below;

Questions at Stage #1

1. Examine the glacial etchings, striations, and chatter marks. Whay direction was the glacier moving?
2. Remember those cicular features, and how they were old diplocraterion fossils? If you see any square-like features, those are not diplocraterion, those are where different types of salt used to be, before disolving. Do you see many or any square shapes in the rock?
3. Bonus Question: can you find/identify where there is cross-bedding beneath the surface of this rock? (This question is not mandatory. If you cannot find an answer don't worry about it).
4. Look at the striations again: What is the average distance between them? (Pick a few striations and get the average distance).

Questions at Stage #2

1. How deep is that pothole?
2. How far across is it (the pothole)?
3. Why do you think this is a likely spot for a pothole? Or is it an unlikely spot? Explain why/why not. (This question could probably be done just by reading the description)

Step #6: Email me the answers to the six (or seven) questions above. Photo proof is not mandatory, but is strongly recommended. 

Please remeber to email me the answers to the questions!

Any logs with spoilers/answers will be deleted without notice!

Some other cache details:

The hike was about 600-700 meters both ways, which totals up to being just over one kilometer.

At Stage #1-

Any swamps are covered by boardwalks, so don't worry about those. However at the first stage the swamp come right up on top of some of the rock. During some seasons, I'm sure the water is higher up than others. When I placed it this (April 27^th 2014) the rocks I looked at were not covered in water. During the big thaw after spring I would imagine the water is higher, but not high enough to make a big difference. You don't need to go really close to the water, so don't worry too much about wet feet. (Note that the little bits of grass between the different rock surfaces can get muddy, but those can easily be avoided). 

At Stage #2-

It can be a bit muddy off of the rock surface here, but can easily be avoided. Please keep in mind, that as mentioned in the desciprition above, the pothole you need to find it not located on the bigger rock surface, but is located to one of the smaller ones to the right. 

Happy caching! Keep walking along the trail to find some other great caches in the South March Highlands!

And most importantly, have fun.

If you don't understand soemthing, email me; I'll help you out!

Greg-