| A | B |
|---|
| Rock | a solid mixture of crystals of one or more minerals (usually) |
| Mineral composition of rock | proportions of minerals found in rock, expressed in % by volume |
| Bulk composition of rock | sum of different elements, expressed in % by weight |
| Rock Cycle | process by which one type of rock changes into another |
| 3 categories of rock | igneous, sedimentary, metamorphic |
| Igneous rock | rock that forms from the cooling of magma or lava |
| Sedimentary rock | rock that forms when sediments are compacted and cemented together |
| Metamorphic rock | rock that forms when texture and composition of pre-existing rock is changed by heat or pressure deep underground |
| 2 criteria for classifying rock | composition & texture |
| composition of rock | description of the minerals or elements contained within rock |
| texture of rock | sizes, shapes and positions of grains found within rock (fine, medium or coarse grained) |
| 3 ways in which magma forms | increase in temperature, release of pressure, change in composition |
| felsic rock | igneous rock that is lightweight, lighter in color, less dense |
| mafic rock | igneous rock that is darker, denser, rich in iron |
| 2 types of igneous rock formations | intrusive (cools below surface) & extrusive (cools on surface) |
| 3 types of sedimentary rock | clastic, chemical, organic |
| clastic sedimentary rock | rock or mineral fragments (clasts) stick together (sandstone, shale) |
| chemical sedimentary rock | minerals crystallize out of solution (chemical limestone) |
| organic sedimentary rock | formed from the remains of organisms, such as shells or skeletons (fossiliferous limestone) |
| fossils | remains or traces of plants and amimals preserved within layers of sedimentary rock |
| stratification | layering of sediments within rock (strata=layers) |
| ripples or crossbeds | record of wind or wave action within strata of sedimentary rock |
| 2 types of metamorphism of rock | contact and regional metamorphism |
| contact metamorphism | magam flows nearby and "cooks" surrounding rock rather than melting it |
| regional metamorphism | occurs with great pressure deep underground or where tectonic plates collide |
| 2 textures of metamorphic rock | foliated and non-foliated metamorphic rock |
| foliated metamorphic rock | metamorphic rock which contains mineral grains that are aligned by pressure (slate, schist, gneiss) |
| non-foliated metamorphic rock | rocks that lack aligned mineral grains (marble, quartzite |
| lava flow | extrusive igneous rock formation that results when lava flows from a volcano |
| lava plateau | extrusive igneous rock formation that occurs when lava erupts from cracks (fissures) on Earth's surface and covers a vast area |
| plutons | large, balloon shaped intrusive igneous rock formation that occurs when magma cools at great depths |
| examples of intrusive igneous rock formations | plutons, sills, batholiths, laccoliths, dikes, volcanic necks |
