Transcript Day 2
Day 2 When someone says a rock has fine grains or coarse grains, what are they talking about? Grains are the particles that make up a rock. The words fine and coarse refer to the size of the grains. Fine grains are small, and coarse grains are larger. What is molten rock? Molten rock is melted rock. Daily Warm-Up Exercises 1 Trilobite Hunter, Part 2 Introduction to the Grand Canyon Earth History, Investigation 8 2 Return to Trilobite Hunter Are igneous rocks good for finding trilobite fossils? granite pumice No, because they are made of molten rock, which is much too hot to preserve organisms. 3 Return to Trilobite Hunter We are now going to look at a second type of rock, called metamorphic. We’ll find out if metamorphic rocks are good for finding fossils. These rocks are found in some of the deepest layers of the Grand Canyon. 4 Compare Rock Types Contrasting Case Activity 1, Part 2 Earth History, Investigation 8 Compare Rock Types 5 List Observable Features Metamorphic #1 Metamorphic #18 List the features you can observe about the two metamorphic rock samples. Compare Rock Types 6 Which is Which? 1 18 Can you figure out which rock is schist and which is quartzite? Compare Rock Types 7 What’s the Same? What’s Different? 1 18 Identify similarities and differences and write them in the Venn diagram. Compare Rock Types 8 Metamorphic Schist Only Both Schist & Quartzite Quartzite Only Fairly shiny Rough Dull and hard Medium to coarse grain size Made of minerals Fine grain size Crystals are flat and arranged in layers Formed when a rock changes due to heat and/or pressure Grains appear to be fused together Formed from slate, a metamorphic rock Formed deep beneath Earth’s surface Compare Rock Types Formed from sandstone, a sedimentary rock 9 Return to Trilobite Hunter Are metamorphic rocks good for finding trilobite fossils? schist quartzite Not very good because the heat and/or pressure will usually destroy any fossils contained in the original rock. 10 Return to Trilobite Hunter Let’s look at one more type of rock, sedimentary. We’ll find out if sedimentary rocks are good for finding trilobite fossils. 11 List Observable Features Sedimentary #7 List the features you can observe about the two sedimentary rock samples. Sedimentary #8 Compare Rock Types 12 Which is Which? 7 8 Can you figure out which rock is shale and which is sandstone? Compare Rock Types 13 What’s the Same? What’s Different? 7 8 Identify similarities and differences and write them in the Venn diagram. Compare Rock Types 14 Sedimentary Shale Only Both Shale & Sandstone Sandstone Only Smooth Dull and hard Very fine grain size Grains are arranged in layers Formed from particles of silt or clay Rough May contain fossils Made of minerals Formed when something gets compacted and cemented together Medium to coarse grain size Formed from grains of sand May form on or below Earth’s surface Compare Rock Types 15