When visiting Liverpool I spotted these handsome columns along one edge of Derby Square on what appears to have until recently been a bank.
They're worth a look - they get their name from the similarity to Serpent Skin, though I think there is a strong similarity to shattered glass.
GZ takes you to a column on the corner of the building, but there are plenty to choose from.
1) Describe the column in front of you - what colours can you see, what shapes and sizes can you see?
2) Where abouts does the metamorphism take place for these types of stone?
3) Based on your answer to (1), would you say serpentine is a Breccia or Conglomorate? Why do you say this?
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 via email - there is no need to wait for a response before logging your find.
Serpentine is a rock composed of minerals from the serpentine subgroup. This subgroup consists of Antigorite, Chrysotile and Lizardite, what they all have in common, is that they are silicate rocks, that are rich in iron and magnesium.
These rocks are metamorphic rocks. Metamorphic rocks form through the transformation of an existing rock type, known as the protolith, via a process called metamorphism, which means "change in form." During metamorphism, the protolith is subjected to heat and pressure, resulting in significant physical and/or chemical changes. This is a low-grade metamorphic process involving heat and water. Technically known as a hydration and metamorphic transformation, it simply means that water enters the rock, causing the iron and magnesium within it to react and transform into serpentine materials. This process occurs on the sea floor, near tectonic plates.
In these types of rocks, this is called serpentinization.
Breccia vs Conglomorate
Breccia
Breccia is a type of rock composed of broken fragments of minerals or other rocks. These fragments are angular and sharp-edged. They are cemented together by a fine-grained matrix.
Conglomorate
Conglomerate rocks are sedimentary rocks composed of rounded pebbles, cobbles, and boulders cemented together by a fine-grained matrix. These rocks form in high-energy environments, such as riverbeds or shorelines, where water smooths the edges of the fragments.