Hafren Parc Slate bed Earth Cache EarthCache

Hafren Park Earth cache

A drive-by EC, which you could almost do without getting out of the car.

This is a quiet road but be careful because some cars pass quickly.

Please visit the location, gather the information required and message me the answers, at the same time as you claim the find.

Park at the roadside near the road sign.

Slate

Slate was part of the bedrock (sorry for the pun) of the Welsh economy in the 20^th century and though this area wasn’t especially part of that industry, you will find a large outcrop of a slate bed at the side of the road.

 Slate is a fine-grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade regional metamorphism. It is the finest grained foliated metamorphic rock.  A very strong foliation is called "slaty cleavage". It is caused by strong compression causing fine grained clay flakes to regrow in planes perpendicular to the compression. Many slates will form smooth flat sheets of stone which have long been used for roofing and floor tiles and other purposes. Slate is frequently grey in colour, especially when seen, en-masse, covering roofs. However, slate occurs in a variety of colours even from a single locality; for example, slate from North Wales can be found in many shades of grey, from pale to dark, and may also be purple, green or cyan. Slate is not to be confused with shale, from which it may be formed, or schist.

The slate bed at this location is visible all the way down this road and is a bed of very thin layers of grey rock.  Its angle of exposure is not horizontal but sticks up like a box of knives, this is what you are looking for. 

Slate can be exposed by a range of different methods.

Method 1; Weathering.

Weathering is when rock or earth is moved by water, wind or other erosive methods.

Method 2; Natural Earth movement

Earthquakes, landslips and rivers can all expose rock which would otherwise be deep underground.  Earthquakes are often caused when two pieces of land move in respect to each other either horizontally or vertically causing ‘faults’.  If this is an earthquake you will see significantly different rocks right next to each other. Landslips and river erosions expose rock by moving the top surface, which is washed away and tends to leave V shaped valleys with water-flow still occurring in the bottom of the valley.

Method 3; Man made rock exposure

This type of exposure of rock is cause when humans have moved rock to make an artificial pathway for their convenience.  This type tends to be severe and often you can find evidence of mechanical movement of rock. If this is the method used here you will see scars created by machinery as the rock was dug away and you can often see drill holes where explosives might have been inserted.

So hopefully from reading in the information above and looking around you, you have gathered enough information for the questions below; so here are the questions.

1. Please look for the slate outcrop and describe the face of the rock.
2. Which of the methods above do you think was responsible for exposing this slate bed?
3. What angle from the horizontal does the slate bed stick up at?
4. Look up and down the roadside and tell me for how many metres this rock face exposed.

If you feel willing and able please include a photo in your log but please be careful that it doesn’t give away the answers to any of the questions above.

Thanks for visiting the cache and good luck with the answers.