Rock Unit Test Study Guide - KEY

Three Origins Of Rocks / How Do They Form? / Types of Rocks in this Origin / If looking at this origin of rock, what would you look for? / Three Examples of This Origin Of Rock / Other
Igneous / Igneous rocks are formed from the cooling (solidification) of magma and lava. / Intrusive and extrusive / Visible mineral crystals that would suggest an intrusive igneous rock.
Air bubbles that would suggest an extrusive igneous rock. / Answers may vary –
Intrusive:
  • Granite
  • Diorite
  • Gabbro
Extrusive:
  • Basalt
  • Obsidian
  • Pumice
  • Scoria
/ How does cooling rate affect the texture of this rock origin?
Faster cooling rate = fine-grain (smaller crystals)
Slower cooling rate = coarse-grain (larger crystals)
Sedimentary / Sedimentary rocks are formed by sediments compacted and cemented together – weathering, erosion, deposition, compaction, and cementation (WEDCC) / Clastic, Chemical, and Organic / Rock fragments, fossils, shells / Answers may vary –
Clastic
  • Conglomerate
  • Shale
  • Sandstone
Chemical
  • Chert
  • Limestone
  • Rock salt
Organic
  • Coal
  • limestone
/ List the 5 steps for a sedimentary rock to form?
Know what each step does.
WEDCC
Weathering – breaks a rock into sediments
Erosion – transports sediments
Deposition – drops sediments into layers
Compaction – presses sediments together
Cementation – cements sediments together
Metamorphic / Metamorphic rocks are formed from intense heat and pressure. / Foliated and non-foliated / Mineral bands or layers / Answers may vary –
Foliated
  • Gneiss
  • Schist
  • Slate
Non-Foliated
  • Marble
  • quartzite
/ Where are metamorphic rocks likely to form?
Below Earth’s surface
What types of rocks can become metamorphic?
All types
  • Lava is found on or above the Earth and magma is found below the surface ofthe Earth.
  • Intrusive igneous rock forms from magma found inside the Earth with acoarse-grained texture.
  • Extrusive igneous rock forms from lava found outsidetheEarth with afine-grainedtexture.
  • Foliated rocks have mineral bandswhile non-foliated rocksdo not.
  • Clastic rocks are made fromrock fragmentswhile organic rocks are made of plant and animal remainsand chemical rocks are made from dissolved minerals in a solution.

Rock Cycle

Directions: Fill in the diagram below with the following words. Some words may be used more than once.

Weathering and Erosion (WE) / Heat and Pressure (HP) / Melting (ME)
Cooling (C) / Compaction and Cementation (CC) / Magma (M)
Sedimentary Rock (SR) / Metamorphic Rock (MR) / Igneous Rock (IR)
Sediments (S)