I parked here to do come caches and spotted this memorial (which is part of the adventure lab in town). It was unveiled in October of 2019 and is tucked away at the entrance to Stepps’ train station’s Park and Ride car park. A homage to all who worked and lost their lives in the colliery through several tragedies that befell the place.
You'll need to look at the stones that make up the memorial to answer the questions.
1) Look at the stones that make up the memorial
- what size are the grains?
- are they the same size, or are they a mix of lots of different sizes?
- are the grains that make up each stone well sorted, or poorly sorted?
2) Now look at the rings - there are several on the right side of the monument. Are the concentric rings squashed tight together, or are they spread out?
3) Use your observations from Q1 to explain your answer to Q2.
4) Take a photo of yourself at GZ, or an identifying item, being careful not to reveal any of the answers to the questions.
Please submit your answers via message though the Geocaching website or by sending me an email - there is no need to wait for a response before logging your find.
Grain Size and Sandstone Sorting
The term "grain size" refers to the diameter of individual particles within a sedimentary rock like sandstone. If these grains are all roughly the same size, the sandstone is described as "well sorted." Conversely, if there's a wide variety of grain sizes present, from very fine to coarse, the sandstone is considered "poorly sorted." Well-sorted sandstones typically form in environments where sediment is transported and reworked by consistent energy, such as beaches or sand dunes, which effectively separate grains by size.
Well-sorted sandstone is often preferred for building as its uniform grain size can lead to strength - poorly sorted sandstone is more susceptible to weathering..
Liesegang Rings
Liesegang rings are patterns of concentric or parallel bands found in some rocks, often sandstone. They form when two chemical solutions react and precipitate in a porous medium, creating layers of minerals that can appear as circles or squares - think a bit like the rings in a tree trunk. These patterns are a result of diffusion and precipitation processes occurring within the rock's pore spaces.
Although there are no complete rings here, there are several sections of rings where observations may be made.
Influence of Sorting on Ring Spacing
When sandstone is well sorted, meaning its grains are of a uniform size, the spaces between these grains are also very consistent. This uniformity in pore space allows the chemical solutions responsible for Liesegang rings to diffuse through the rock at a very even rate. Consequently, the conditions required for mineral precipitation are met more predictably, leading to the formation of Liesegang rings that are positioned closer together. The consistent pathways for fluid movement prevent the precipitating minerals from spreading out widely, resulting in a more compact and tightly banded pattern.
In contrast, in poorly sorted sandstone, the varied pore sizes and irregular pathways lead to less predictable diffusion, often resulting in Liesegang rings with uneven and wider spacing between the bands.
Think about filling a bucket with sand - if you pour in water, it moves through the sand slowly as there is not so much space between the grains. Then fill the bucket with pebbles - pour in the water and it moves through quickly, in a more haphazard way.