Lab-6

Geology Name: ___________________________ Igneous Rocks Identification (with at home lab kits) Lab Report Complete your responses in a color other than black or red . Part 1: Classification (Texture) 1. Which “rocks” (dish 1 or 2) represent plutonic (intrusive) rocks, and volcanic (extrusive) rocks? Dish 1 represents extrusive, and Dish 2 represents intrusive. 2. What is the relationship between cooling rate and crystal size? Dish 1 cools rapidly at the Earth’s surface, while Dish 2 is slowly cooled under the Earth’s surface. Dish 1 also has hard to see crystals while Dish 2 has all the minerals visible. 3. Which of these rocks is more likely to be found in a home, and for what purpose? Dish 2 is used for countertops and kitchen/bathroom décor. 4. Find three rocks from your kit that you think are the igneous rocks. Insert a photo of the rocks you chose here : 1

Igneous Rocks Identification Lab Report Part 2: Classification (Composition) 1. Which “rock” (dish 3 or 4) represents low silica content rocks, and which represents high silica content rocks? Dish 3 has a releatively high silica content and Dish 4 has a low silica content. 2. What is the relationship between silica content and volcano type/eruptive style? The higher the silica, the more explosive the eruption, the lower the silica, the gentler and steadier the eruptions are. 3. In what plate tectonic setting(s) are high silica content volcanic eruptions found? (Options: convergent plate boundaries, divergent plate boundaries, transform plate boundaries, hot spot in oceanic crust, hot spot in continental crust) High silica rocks are usually found in convergent plates. Part 3: Andesite and Diorite Andesite (A) Diorite (B) 1. Textural term Porphyritic Phaneritic 2. Cooling rate Moderate Slow 3. Environment of formation Subduction zones Deep in crust 4. Minerals Plagioclase Feldspar, Amphibole, and Biotite. Plagioclase feldspar, and Hornblende 5. Plate tectonic setting Convergent Continental Part 4: Basalt and Gabbro Gabbro (C) Basalt (D) 1. Textural term Phaneritic Aphanitic 2

Igneous Rocks Identification Lab Report White, Brown 2. Shade of overall sample White White Black 3. Textural Term Brecciated Phaneritic Phaneritic 4. Environment of formation Volcanic Eruptions Mountains Deep in crust 5. Name of rock Volcanic Breccia Granite Diorite 6. Minerals volcanic rock, Pumice, volcanic ash Quartz, Feldspar, and Mica Plagioclase feldspar, and Hornblende 7. Plate tectonic setting Divergent Continental Continental (K) (L) (M) 1. Shade of all colors present Dark Brown Gray, Black, Green, White Green and Maroon 2. Shade of overall sample Dark Brown Green Green 3. Textural Term Vesicular Phaneritic Glassy 4. Environment of formation Volcanic Eruptions Upper Mantle High silica volcanic eruptions 5. Name of rock Scoria Xenolith Perodite Mahogany obsidian 6. Minerals plagioclase feldspar and pyroxene Olivine and pyroxene Volcanic glass 4

Igneous Rocks Identification Lab Report 7. Plate tectonic setting Divergent Oceanic Convergent/Diverge nt (N) (O) (P) 1. Shade of all colors present Gray/dark Gray Gray, dark gray Black, brown, gray 2. Shade of overall sample Gray Dark Gray Black 3. Textural Term Vesicular Phaneritic Aphanitic 4. Environment of formation Volcanic Eruptions Deep in crust Ocean ridges 5. Name of rock Pumice Gabbro Basalt 6. Minerals plagioclase feldspar and pyroxene Plagioclase Feldspar, Pyroxene, and Olivine Plagioclase Feldspar, Pyroxene, and Olivine 7. Plate tectonic setting Divergent Continental Divergent (Q) 1. Shade of all colors present Black, white, Grey 2. Shade of overall sample Gray 3. Textural Term Porphyritic 4. Environment of formation Subduction zones 5