Lickey Quartzite boulders
Boulders of Lickey Quartzite. If you look really closely, you may be able to see grains of quartz in some parts of the rock.
Much of the rock of these boulders is broken up into angular fragments from a few mm to 10cm in size, but the fragments have been cemented together. This would have happened at the time when the rocks of the Lickey Hills were folded at depth by tectonic forces. In some places this hard rock did not ‘give’ and bend, but shattered. Hot, mineral-rich fluids circulate in such tectonically dynamic settings, re-cementing the shattered rock as it cools.
Breccia or Conglomerate?
Geologists would describe the Lickey Quartzite in these boulders as being ‘brecciated’.
Breccia is a mix of ANGULAR shaped pieces of rock cemented together. As shown in the picture above on the right.
Conglomerate is a mix of ROUNDED pieces of rock (round pebbles) cemented together. As shown in the two pictures on the left.
Move onto Task Site 6
After answering the questions for Task Site 5 move onto Task Site 6 which is just a few paces from the boulders. Task Site 7 lies at the end of a rougher section of path with a slight slope. If you prefer to stay on the level you can look at the information and answer the task questions for Site 7 from this location.
Task Site 5 Questions
What is different about the texture of the rock here compared with the pieces you picked on the floor of the quarry earlier?
a) It is very muddy and smooth
b) It is made up of many rounded pebbles
c) Cemented patches of angular fragments
What do we call a rock made up of angular fragments?
c) Pebbly sandstone