ROCK- a mixture of 2 or more minerals (They are classified by how they form) A) IGNEOUS ROCK- formed when molten rock cools 1) INTRUSIVE –formed when magma cools below ground a) large crystals because they cool slowly allowing the atoms time to line up b) granite- most common rock on earth..75% of the crust

2) EXTRUSIVE-- formed when lava cools outside the earth (cools quick) (can have air or water cool it)

a) small crystals (rhyolite) or if formed in cool water NO crystals (obsidian aka volcanic glass) b) Basalt makes up the ocean floor. It is formed at mid ocean ridges when magma hits sea water

Hawaii has black sand beaches from broken up basalt.

c) May contain air pockets – trapped gasses due to a quick cool (pumice - used to scrape callouses off feet) and (scoria- used in gas grills and for landscaping)

3) How magma forms a) pressure- as hot rocks rise, pressure releases and minerals melt b) temperature- a rise in temperature causes minerals to melt c) composition- when fluids mix with rock (like water) melting points get lowered and minerals melt

B) SEDIMENTARY rock – deposited sediments (tiny chunks of rock) are stuck together to form solid rock in layers (strata) ABOVE ground, but UNDER water If it all forms underwater, why is 70% of the rock we see sedimentary? What does this tell us about Earth’s past?

1) CLASTIC - broken fragments of rocks are “glued” together to make a new rock b) sandstone = sand (medium grains) c) conglomerate = pebbles and gravel (large grains) a) shale = clay (very fine grains)

2) CHEMICAL –water evaporates leaving dissolved minerals behind (limestone, rocksalt, travertine- which makes stalactites and stalagmites “cave icicles”)

3) ORGANIC – formed from dead plants and animals a) fossiliferous limestone- small fossilized shells of marine creatures b) coquina – large shells glued together c) coal – buried plants and animals

C) METAMORPHIC Rock – formed by heat or pressure or both (underground) 1) PRESSURE-(Regional metamorphism)- from plate movement squeezing rocks from the sides Forms here tectonic plate

A) FOLIATED- has parallel bands that formfrom uneven pressure that squeeze the mineral grains flat (squished, layered) Granite (igneous)Gneiss (metamorphic)

2) HEAT (Contact Metamorphism)- forms deep underground near the edge of the magma

A) NON-FOLIATED no parallel bands, minerals NOT aligned Limestone - sedimentary Marble- metamorphic it gets “melty” like a plastic figurine in an oven due to the HEAT HEAT CAUSES 1 caused by HEAT 2 caused by EVEN pressure

EVEN PRESSURE CAUSES Granite (igneous) Gneiss (metamorphic)

METAMORPHIC IGNEOUS SEDIMENTARY WEATHER, ERODE, DEPOSIT, COMPACT, CEMENT WEATHER, ERODE, DEPOSIT, COMPACT, CEMENT HEAT AND PRESSURE MELTING AND COOLING THE ROCK CYCLE METAMORPHIC

PROCESSES OF THE ROCK CYCLE WEATHERING- break off the sediment EROSION- moving the sediment DEPOSITION- dropping off the sediment COMPACTION- pressing together sediments CEMENTATION- gluing together sediments HEAT and PRESSURE MELTING and COOLING