Rocks Igneous Sedimentary Metamorphic

Objectives: Explain how rocks form. Distinguish between the three main types of rocks. Identify rock samples based on physical characteristics.

Igneous Rocks

Terms: Types of Igneous Rocks Intrusive igneous rocks form from magma beneath the Earth’s surface. Extrusive igneous rocks form from lava on the Earth’s surface. magma - beneath the surface

Igneous Rock lava magma magma pool

Igneous – From Fire Extrusive lava volcano or fissure glassy holes from gas basaltic – dark color high % -iron -magnesium -calcium Intrusive magma beneath surface large crystals no holes granitic - light color high % -silica

Intrusive igneous rocks have large crystals that are easy to see. Extrusive igneous rocks do not have large crystals that you can see easily. intrusive igneous rock extrusive igneous rock

Granite intrusive igneous rock light gray, pink or white feels a little rough more than one mineral can be seen hard to scratch with a nail

Pumice extrusive igneous rock light tan or white full of tiny bubbles light weight often floats on water

Obsidian extrusive igneous rock looks like black glass red or white spots or streaks feels very smooth

Gabbro intrusive igneous rock dark gray to black feels a little rough more than one mineral can be seen hard to scratch with a nail

Rhyolite extrusive very fine grained pinkish-grey color sometimes has dark streaks

Basalt extrusive rock dark grey or black feels little rough different minerals can be seen hard to scratch with a nail

Which are intrusive and which are extrusive rocks? Basalt Rhyolite Gabbro GranitePumice Obsidian Extrusive intrusive Extrusive

Can you identify this igneous rock? Physical properties: light colored floats in water has air bubbles Pumice Intrusive or extrusive extrusive

Can you identify this igneous rock? Physical properties: dark colored not glassy more than one mineral is visible Gabbro Intrusive or extrusive extrusive

Can you identify this igneous rock? Physical properties: light gray, pink or white feels a little rough more than one mineral can be seen graite Intrusive or extrusive intrusive

Can you identify this igneous rock? Physical properties: dark grey or black feels a little rough air holes basalt Intrusive or extrusive extrusive

Can you identify this igneous rock? Physical properties: looks like black glass red or white spots or streaks feels very smooth obsidian Intrusive or extrusive extrusive

Can you identify this igneous rock? Physical properties: fine grained pinkish-grey color sometimes has dark streaks rhyolite Intrusive or extrusive extrusive

Sedimentary Rocks

Sedimentary Rocks sedimentum means “to settle” rocks form from sediments that have been pressed together sediments come from: plant or animal remains minerals dissolved in water large rocks that have broken up

Sediment is normally deposited in horizontal layers parallel to the Earth’s surface

Three Types of Sedimentary Rocks Detrital sediment deposited by: wind ice water gravity Chemical minerals left behind: geysers hot springs salt water Organic fossils plants / animals coal limestone

Detrital Sedimentary Rocks - Identified by Grain Size clay sized – shale silt sized – siltstone sand sized – sandstone pebble sized- conglomerate Shale Sandstone Siltstone Conglomerate

siltstoneconglomerate sandstone shale

Conglomerate may be tan, red, or white full of pebbles of sand hard to scratch – breaks first

sandstone layers of slightly different colors may be red, brown, or gray granular appearance can scratch off grains of sand

Siltstone

shale may be red, brown, or gray feels smooth splits into almost flat layers smells like mud when wet easy to scratch

Chemical Sedimentary Rock

Mineral Rich Water Evaporates salt water geysers hot springs Examples: halite – rock salt gypsum - chalk

limestone may be black, gray or white may feel rough or smooth easy to scratch powder from scratch bubbles with vinegar

Organic Sedimentary Rock

Fossilerous Limestone and Coal  fossil – remains or trace of a once living plant or animal  coal – fossilized plant  limestone – fossilized ocean organisms  chalk = limestone  fossil – remains or trace of a once living plant or animal  coal – fossilized plant  limestone – fossilized ocean organisms  chalk = limestone

Fill in the name of a rock (s) that fits each of the properties. sandstone no pebbles conglomerate pebbles shale does not bubble limestone bubbles with acid conglomeratesandstone hard to scratch limestoneshale easy to scratch

Metamorphic Rock

heat limestone pressure marble

Metamorphic – change of form Great pressures and heat look different recrystallized chemically changed Any existing type of rock can morph igneous sedimentary metamorphic

granite detrital sedimentary chemical sedimentary gniess igneous sandstone quartzite limestone marble

Slate Metamorphic marble schist gniess

white, yellow or tan color mineral grains can be seen powder from scratch bubbles with acid easy to scratch with a nail nonfoliated Marble

gniess colors are usually black and white, black and red or black and brown minerals in ribbon like layers hard to scratch with a nail foliated

Schist black to silvery minerals in leaf- like layers soft and easy to scratch with a nail foliated

slate black, grey, red or green easy to scratch with a nail splits into thin, flat, smooth plates foliated

Classifying Metamorphic Rocks Texture differences Two main groups –Foliated visible layers or leaves bands of different colored minerals - Nonfoliated no distinctive bands or layers no pattern to any visible mineral grains

Foliated and Nonfoliated Rocks Marble (nonfoliated) Slate (foliated)

Identify the properties of the following metamorphic rocks Gneiss – Schist – Slate - Marble hard to scratcheasy to scratch minerals seenminerals not seen bubbles with vinegardoes not bubble foliated,nonfoliated gneissschist, slate, marble gneiss, schist, marble slate marble gneiss, schist, slate gneiss, slate, schistmarble

metamorphicsedimentary foliatednonfoliateddetrital chemical organic intrusiveextrusive Rocks igneous Three classes two kindsthree kindstwo kinds

The Rock Cycle “ a model in diagram form ” compaction cementation weathering erosion melting heat and pressure cooling

The word “igneous” means... A. from fire B. from water C. to be ignited

What is magma? A. molten rock on the earth’s surface B. molten rock below the earth’s surface C. volcanic ash

What is lava? A. an abrasive in soap B. molten rock above the earth’s surface C. molten rock below the earth’s surface

Igneous rock forms from …. A. lava B. magma C. either lava or magma

Obsidian, granite, pumice, and basalt are examples of ….. A. igneous rocks. B. sedimentary rocks. C. metamorphic rocks.

The nickname for this rock is “volcanic glass” A. pumice B. shale C. obsidian

This rock is has colored dots. A. pumice B. granite C. marble

This rock can float in water. A. pumice B. limestone C. sandstone

The Hawaiian Islands are made of this rock. A. obsidian B. basalt C. sandstone

Sedimentum means…. A. to settle B. solid rock C. move slowly

Sedimentary rocks form from... A. sediments pressed together. B. rocks cemented together. C. both A and B

Conglomerate, sandstone, and limestone are examples of …. A. sedimentary rocks. B. igneous rocks. C. metamorphic rocks.

A rock made from pebble sized rocks cemented together with mud. A. sandstone B. limestone C. conglomerate

This rock is made from mud and forms in layers. A. shale B. slate C. gneiss

This rock is made from granite. A. marble B. schist C. sandstone

These rocks are formed from existing rocks. A. igneous rocks B. sedimentary rocks C. metamorphic rocks

Metamorphic rocks form when rocks are placed under …. A. mud in a river bed. B. frozen ice. C. heat and pressure.

Metamorphic rocks form from... A. igneous rocks. B. sedimentary rocks. C. both A and B

This rock is formed from quartz, feldspar and mica. A. schist B. marble C. gneiss

This rock makes “chalk” marks A. sandstone B. limestone C. slate

Name this rock….. A. gniess B. granite C. marble

Name this rock….. A. obsidian B. basalt C. marble

Name this rock…… A. sandstone B. pumice C. conglomerate

A. shale B. basalt C. schist Name this rock …

A. sandstone B. pumice C. limestone

Name this rock….. A. obsidian B. granite C. marble

Name this rock….. A. obsidian B. granite C. slate

A. shale B. schist C. sandstone Name this rock …

A. sandstone B. slate C. obsidian

Name this rock….. A. schist B. granite C. gniess

End of Presentation

Resources and Citations Resources: Text : Clip art: Sound: Rock Pictures: Rocks and Minerals: The Hard Facts. Rainbow Educational Media unitedstreaming. 28 January 2006