Table
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The Geology Book The Geology Book
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Type | Category | Composition | Formation | Found |
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Granite | Igneous | Quartz and feldspar with mica and hornblende | Formed when molten rock is cooled | Mountains
Upper mantle |
- Write a paragraph for each category of rock, describing how it forms, and where it is found.
Activity:
Start collecting stones/small rocks from around your area (or other areas to which you travel). Try to classify the type of rock you have found. Can you find samples of each rock you described in the above table?
Note: If you go to a National/State/local park, please ask permission to remove the stones/rocks you are collecting.
Additional resources:
Answers:
Type | Category | Composition | Formation | Found |
---|---|---|---|---|
Granite | Igneous | Quartz and feldspar with mica and hornblende | Formed when molten rock is cooled | Mountains Upper mantle |
Rhyolite | Igneous | Quartz and feldspar with mica and hornblende | Formed when molten rock erupts on land and solidifies | Land |
Obsidian | Igneous | Quartz and feldspar with mica and hornblende | Formed by the rapid cooling of lava as it flows in the surface of the ground | Land |
Pumice | Igneous | Quartz and feldspar with mica and hornblende | Formed by eruptions on land—the cooling process forms air pockets in the rock | Land |
Basalt | Igneous | Pyroxene, plagioclase feldspar | Solidified molten lava under water and on land | Oceanic crust, land |
Shale | Clastic Sedimentary | Cemented particles of clay (and minor silt) | Formed from previously existing rocks that were eroded, transported and redeposited elsewhere | Mountains, land |
Sandstone | Clastic Sedimentary | Quartz sand, particles big enough to be seen | Formed from previously existing rocks that were eroded, transported and redeposited elsewhere | Mountains, land |
Conglomerate | Clastic Sedimentary | Pebble-size to boulder-size grains mixed with smaller sand or clay particles | Formed from previously existing rocks that were eroded, transported and redeposited elsewhere | Mountains, land |
Limestone | Organic chemical sedimentary | Calcium carbonate from shells of sea creatures, reef fragments or limey secretions of sea creatures | Formed when water can no longer keep various chemicals dissolved within it | Sea floors, land |
Diatomaceous earth | Organic chemical sedimentary | Collection of shells from diatoms or radiolarians and certain algae | Formed when water can no longer keep various chemicals dissolved within it | Land |
Coal | Organic chemical sedimentary | Buried plant material | Formed when water can no longer keep various chemicals dissolved in it | Land |
Limestone | Inorganic chemical sedimentary | Calcium carbonate derived from inorganic sources | Formed when water can no longer keep various chemicals dissolved in it | Caves, mineral springs, stalactites, stalagmites |
Dolomite | Inorganic chemical sedimentary | Calcium carbonate with magnesium atoms | Formed when water can no longer keep various chemicals dissolved in it | Land |
Evaporites | Inorganic chemical sedimentary | The remains of evaporated seawater | Some were formed when a huge volume of mineral-laden water came up through the ocean floor basalts and released its dissolved content when it hit the cold ocean waters | Land |
Slate | Metamorphic | Shale | Shale subjected to heat and pressure | Land |
Schist | Metamorphic | Shale | Slate that continues to undergo heat and pressure | Land |
Gneiss | Metamorphic | Alternating bands of different minerals from other sedimentary or igneous rocks | Formed from other sedimentary or igneous rocks that have been subjected to heat and pressure | Land |
Quartzite | Metamorphic | Quartz sandstone | Quartz sandstone that has been subjected to change | Land |
Marble | Metamorphic | Limestone | Heat and pressure applied to limestone | Land |
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