Geography 3B: Discussion Section Meeting #1 Rock Identification Exercise
Name:
Section: 10AM 11AM (circle one)
Due Mon., Aug. 11th
Rock Name Rock
Type
Comment extrusive; oceanic crust material; vesicular; mafic; fine grains clastic; small grains intrusive; continental crust material; distinct mineral crystals; felsic; coarse grains clastic; large grains foliated and platy; parent rock is shale conspicuously foliated; parent rock is likely granite (text says can sometimes be from clastic secimentary rocks) non-foliated; parent rock is sandstone extrusive; glassy chemically precipitated or biological; no visible strata clastic; varied grain sizes biological
See if you can match the rock in front of you with the descriptions provided in the tables above.
Your rock may be any of the following types- granite, coal, conglomerate, slate, basalt, quartzite, sandstone, gneiss, obsidian, shale, and limestone
The terms below can help you identify the rock type and/or name.
Igneous Rock types:
Intrusive= Intrusive igneous rock bodies are called plutons and form from cooling slowly in the crust.
Extrusive= Extrusive igneous rocks are formed when magma cools on the surface and forms
fine-grained rocks
Felsic= A light colored intrusive igneous rock rich in feldspars and quartz.
Felsic materials contain high levels of SiO2, Na, and K, and low levels of Fe, Mg, and Ca.
Mafic= Igneous rocks made of dark minerals that are rich in iron and magnesium

Sedimentary Rock Types:
Clastic = the accumulated particles of broken rock and skeletal remains
Chemically precipitated = rock composed of pre-existing rock particles cemented together by interlocking crystals formed from dissolved compounds
Biological/organics- made from compressed biological/organic materials (fossils, coal, oil, et cetera)