Geology Rocks Quartz crystal Galena Barite Bauxite Sulphur
Geology Rocks!
Quartz crystal Galena Barite Bauxite Sulphur Granite Chert
What do we call a person who studies rocks? Geologist What are rocks made of? Minerals How many minerals have scientists discovered in the Earth? 3700
Minerals • • Salt (Na. Cl) Sand Clay Gemstones – Diamonds – Rubies – emeralds • Metal – Iron – Silver – Gold
How are rocks formed? 1. Igneous (65%) 2. Sedimentary (8%) 3. Metamorphic (27%)
IGNEOUS ROCKS are “born of fire”. In other words, they were once molten and upon cooling, the magma (molten rock) crystallized into solid rock. Igneous rocks may form deep inside the Earth or at the Earth’s surface when a volcano erupts.
Granite Gabbro Igneous Rocks Basalt Obsidian
Sedimentary Rocks • SEDIMENTARY ROCKS are composed of particles derived from pre-existing rocks or by the crystallization of minerals that were held in solutions. A general characteristic of this group is the layering or stratification, as seen in the outcrop.
Badlands
Taconite Conglomerate Sedimentary Rocks Sandstone Iron Ore
Fossils • The remains of dead animals and plants from about 10, 000 years ago.
Pelecypods (clams) Cephalopods Gastropods (Snails) Horn coral Brachiopods
Sharks Tooth Crinoids (Sea Lilies) Petrified Wood
Metamorphic Rocks • Metamorphic rocks form deep within the Earth, when heat and pressure applied to either igneous rocks, or sedimentary rocks. This heat, and pressure in essence cooks the rocks, changing their structure substantially. • The rocks are partially melted, and the chemicals within them are rearranged, so that the final rock is very different than the original rock. • If you squeeze your hands together very hard, you will feel heat and pressure. When the earth's crust moves, it causes rocks to get squeezed so hard that the heat causes the rock to change. Marble is an example of a sedimentary rock that has been changed into a metamorphic rock.
Limestone Marble Sandstone Gneiss Feldspar Metamorphic Rocks Quartzite Slate Shale
Tests Geologists use to tell rocks apart • Color • Luster Metallic • Feel • Streak • Smell Nonmetallic • Magnetic • Chemical • Hardness
Hardness: Based on Moh’s scale of hardness
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