Rocks… why are they interesting? Year 8 Science Seaview High School

Giant’s Causeway, Ireland This is an image of Giant’s Causeway (UNESCO World Heritage Site). Named the 4th greatest natural wonder in the UK. How did it form? 50-60 million years ago Intense volcanic activity Rock cooled and contracted. Fractured like drying mud. Size of columns determined by the rate at which it cools. What type of rock is this? Why are the hexagonal tiles so large?

Margaret Rose Caves, Victoria Recognised for an extensive fossil record and in 1994 was added to the World Heritage List. Includes 26 caves. Formed from coral and marine creatures 200 million years ago and again 20 million years ago. At these times, the land was below sea level. Ground water has dissolved and eroded the rock. As water seeps through the rock, it collects minerals from the rock. This water then slowly drips down inside the cave, leaving mineral deposits at the top and bottom (stalactites and stalagmites). What sort of rock is this?

The discus thrower, or Discobolus Image is of a marble rock at Marble Caves in Chile. This type of rock is used to make sculptures, such as the Discobolus. The original was made of bronze (metal alloy). This is one of many rock sculpture copies made around 470 BC by the Greeks. The rock used is chosen because it is very hard and can be sculpted to maintain a shape. It is decorative because the minerals form large crystals (slow cooling) which are evenly distributed (not lined up). It is made from limestone (sedimentary rock) that has been heated and placed under pressure. What type of rock is this?

Slate in the North Pindus Mountains Image shows a rock wall consisting of slate in the North Pindus Mountains, near Pindus, Greece. This rock formed from shale, under pressure, during a volcanic event. It is very fine-grained and is highly foliated as shown by the distinctive layers in the image. As a result, it can be cut to form smooth, flat sheets for use in roofing, tiling etc. What type of rock is this?

Uluru, Northern Territory Uluru formed at the base of a mountain range, which today, barely exists (Petermann Ranges). The mountain range was made mostly of granite. As the mountain range eroded due to weathering processes, the rocks and sand were trapped at the base. These rocks and sand have been welded together so tightly, very little erosion occurs.

Granite Island, South Australia The granite that makes up this island was formed around 10 km under the ground around 480 million years ago. It was once attached to the mainland, but the surrounding land was washed away by the weathering and erosion forces of the ocean. It formed under extreme pressure and great heat. The molten rock was forced to the surface where it cooled. What type of rock is this?

Vocabulary Words Intrusive Extrusive Weathering Erosion Magma Compaction Clastic Foliated Lithification Sediment Crystallization Metamorphism Task: Listen for a definition for these words. If you miss one, or I move to quickly you can research them yourself, ask a friend, or ask me to explain them again. Include these words and definitions in your own concept map, try to link the terms.