TYPES OF ROCKS And how they form on Earth

ROCKS How are rocks formed? Minerals + Fire or Heat = Rock (c) 2013 S. Coates

IGNEOUS Intrusive RockExtrusive Rock (c) 2013 S. Coates Large Black Crystals TINY White Crystals

IGNEOUS (c) 2013 S. Coates Intrusive or Extrusive? Pumice

WEATHERING AND EROSION (c) 2013 S. Coates Weathering usually happens when something slowly SQUEEZES AND PUSHES its way into a rock. This type of weathering can be caused by water, ice, or plant roots.

EROSION Erosion can be caused by moving water, like the Nile River. (The river formed this delta. A delta is a formation caused when sediments from a fast river are deposited into a still ocean or lake.) (c) 2013 S. Coates

SEDIMENTARY All of those small pieces of rock can be glued together to form sedimentary rock. The cement that holds sediments together are actually MINERAL CRYSTALS, usually from groundwater. (c) 2013 S. Coates

SEDIMENTARY—WELL SORTED (c) 2013 S. Coates Sand, like in a desert, can become sandstone after millions of years of cementation

SEDIMENTARY—POORLY SORTED Landslide debris can be cemented together to form conglomerate rocks (c) 2013 S. Coates

SEDIMENTARY (c) 2013 S. Coates Well sorted or poorly sorted? Breccia

METAMORPHIC Metamorphic rocks DO NOT COMPLETELY MELT ! They are solid rocks that are changed when they are heated…like heating clay until it turns into a pot (c) 2013 S. Coates

METAMORPHIC (c) 2013 S. Coates Heat and Pressure

METAMORPHIC-- FOLIATED Foliated metamorphic rocks form wavy “bands” of crystals. (c) 2013 S. Coates Gneiss

METAMORPHIC VS. SEDIMENTARY What is the difference between sedimentary layers and metamorphic foliations? (c) 2013 S. Coates

METAMORPHIC (c) 2013 S. Coates Foliated or Non- foliated? Gneiss