An Urban Earthcache in Leeds, letting you learn about the geological world around us while enjoying a walk around the city centre. This cache will highlight the Corn Exchange and the materials used to construct this building.
The Corn Exchange
The corn exchange was built in 1863. The dome design was based on that of the Bourse de Commerce in Paris.
Its ingenious roof gave an even northernly light for the careful inspection of grain by merchants from all over the country who occupied its 59 offices and 170 stands on the trading floor.
Trade continued strongly until the 1950s, and the building fell into disrepair. In the 1990s it was converted into a speciality shopping centre.
Types of Rock
Sedimentary rocks are formed from particles of sand, shells, pebbles, and other fragments of material. Together, all these particles are called sediment. Gradually, the sediment accumulates in layers and over a long period of time hardens into rock. Generally, sedimentary rock is fairly soft and may break apart or crumble easily. You can often see sand, pebbles, or stones in the rock, and it is usually the only type that contains fossils. Examples of this rock type include conglomerate and limestone.
Metamorphic rocks are formed under the surface of the earth from the metamorphosis (change) that occurs due to intense heat and pressure (squeezing). The rocks that result from these processes often have ribbonlike layers and may have shiny crystals, formed by minerals growing slowly over time, on their surface. Examples of this rock type include gneiss and marble.
Igneous rocks are formed when magma (molten rock deep within the earth) cools and hardens. Sometimes the magma cools inside the earth, and other times it erupts onto the surface from volcanoes (in this case, it is called lava). When lava cools very quickly, no crystals form and the rock looks shiny and glasslike. Sometimes gas bubbles are trapped in the rock during the cooling process, leaving tiny holes and spaces in the rock. Examples of this rock type include basalt and obsidian.
Logging your Find
In order to log your find, please send a message to my profile answering the below questions. There is no information about the stone around the Corn Exchange, so you may need to do some research to answer these questions, the answers to which are freely available on the internet. You will need to look at the blocks of stone used to construct the exterior walls of the building.
- Describe how the stone looks and feels.
- What makes up the grains in the rock? Describe their size and shape.
- What does this tell you about how the rock was formed?
- Based on the above, what type of rock (Igneous, Sedimetary or Metamorphic) is used?
In addition to the above questions, optionally upload a picture of yourself at the corn exchange. You can log your find immediately, but please send the answers within 24 hours. I will respond to your message as soon as I can. Logs where incomplete answers have been given, or where an email has not been received, may be deleted.