You are going to have to answer a few questions at the end of this presentation!

Geology is the study of the earth which includes rocks and minerals.

THERE ARE 3 MAIN GROUPS OR CATEGORIES OF ROCKS IGNEOUS SEDIMENTARY METAMORPHIC

“The Rock Cycle” The Rock Cycle is the way rocks become rocks! The Rock Cycle is a natural process where rocks form in 3 different ways.

The Rock Cycle (easy version)

Igneous Rocks

Rocks formed by “FIRE” (magma & lava) are called IGNEOUS ROCKS.

Igneous Rocks -Description * Normally contain no fossils * Rarely react with acid * Usually have no layering * Usually made of two or more minerals * May be light or dark colored * Usually made of mineral crystals of different sizes * May have openings (pores) or glass fibers * May be fine grained (intrusive) formed from magma * May be glassy (extrusive) formed from lava

Some Common Igneous Rocks NameColorTexture Granite Pink/GrayIntrusive Gabbro Dark Gray to BlackIntrusive Rhyolite Light Pink or GrayExtrusive Basalt Dark Gray to BlackExtrusive Obsidian Usually Dark ColoredExtrusive Scoria Dark ColoredExtrusive

Here is a lump of IGNEOUS ROCK you might be familiar with. Mount Rushmore National Memorial, near Keystone, South Dakota, is a monumental granite sculpture by Gutzon Borglum

Sedimentary Rocks

SEDIMENTARY ROCKS are formed from SEDIMENTS which are bits and pieces of other rocks moved, pushed and carried by Erosion, Weathering & then naturally Cemented together in a process called LITHIFICATION.

Sedimentary Rocks -Description * Classified by texture and composition * Often contains fossils * May react with acid * Often have flat or curved layers * Often composed of pieces - cemented or pressed together * Have great color variety * Particle size may be the same or vary * May have pores between pieces * May have cross-bedding, mud cracks, worm burrows, or even raindrop impressions

Some Common Sedimentary Rocks NameColorComposition Sandstone Red or GraySand grains cemented together Limestone White to GrayCalcite and sometimes fossils Shale Dark GrayCompacted mud Conglomerate Different Colors Rounded cobbles and pebbles cemented together

An example of SEDIMENTARY ROCK. Can you see the bits and pieces of smaller rocks in the layers?

METAMORPHIC ROCKS are formed when existing rocks “CHANGE” by the earth’s heat and pressure

Metamorphic Rocks

Metamorphic Rocks -Description * Classified by texture and composition * Rarely have fossils * May react with acid * May have alternate bands of light & dark minerals * May be composed of only one mineral * May have layers of visible crystals * Usually made of mineral crystals of different sizes * Rarely has pores or openings * May have bent or curved foliation (folds)

Some Common Metamorphic Rocks NameImageColorTexture Gneiss Pink/GrayFoliated Marble Light ColoredUnfoliated Quartzite Light ColoredUnfoliated Slate Dark Gray to BlackFoliated

Hope you paid attention, now lets answer some questions! Huh? Was I supposed to be listening? Whoops!

Summary “Ticket out the Door” List the 3 main categories of rocks. List ONE specific type of rock mentioned in today’s lesson and the category it belongs to. (Name of rock + Category) List one “good” fact from any of the 3 videos that were part of this presentation.