The Brecon Beacons National Park is a special place in Wales where there are lots of rocks, mountains, and pretty landscapes. Geology is the study of rocks and how they formed, and geologists have been studying the rocks in the Brecon Beacons for a long time.
The rocks in the Brecon Beacons are really old, millions and millions of years old! They formed a long time ago when the land was really different from what it is now. The rocks are made of lots of different minerals and look different too. Some are hard and shiny, like quartz, while others are softer and crumbly, like clay.
The mountains in the Brecon Beacons were created by big movements in the Earth's crust a long, long time ago. The Earth has lots of big plates, and sometimes these plates move and bump into each other. This is what caused the mountains to form in the Brecon Beacons. The mountains were pushed up and some parts of the Earth's surface were pushed down, creating valleys and streams.
The Brecon Beacons has lots of different kinds of rocks, but some of the most interesting are the ones that were formed by volcanoes! A long time ago there were lots of active volcanoes in the area, and they spewed out lava and ash over the land. The lava hardened into a type of rock called basalt, which is very strong and durable. You can still see these rocks today in some parts of the Brecon Beacons!
Overall, the geology of the Brecon Beacons National Park is really cool because it tells us so much about how the Earth has changed over millions of years. With the help of geologists, we can learn so much about the rocks, the mountains, and even the history of the area!