Format of exam:  36 multiple choice questions. 5 images

Terms to know:  vesicular, aphanitic, phaneritic, fragmental, breccia, pyroclastic, felsic, intermediate, mafic, ultramafic, lopolith, laccolith, stock, sill, dike, batholith, neck, fractional crystallization, partial melting, assimilation, pahoehoe, aa, block flow, lahar, eruption column, fire fountain, pyroclastic flow.

You should know the crystallization sequence described by Bowen (Bowen's reaction series)--this is given on page 96 of your lab book and is also on the "in-class exercises" web page of this site.  Which minerals crystallize first; which crystallize last?

You should understand how melting occurs:  pressure relief melting (at mid-ocean ridges and hot spots) always produces basaltic magma; melting via addition of water lowers the solidus temperature (at subduction zones) and generally produces intermediate composition melts.  Heat transfer can only melt rocks that are more silica rich than the magma from which the heat is being transferred and results in bimodal volcanism at continental hot spots.

You should know the different volcano types, what they look like, and what they are made of:  shield volcanoes (basalt); stratovolcanoes/composite volcanoes (mainly intermediate composition lavas and ash--so andesitic); cinder cones (scoria), domes (mainly intermediate and felsic lava-so andesite and rhyolite).  You should know that a pillow structure indicates that the lava cooled under water.

You should be able to come up with the name for any of the igneous rocks in the chart below.  Understand the difference between crystalline rocks and noncrystalline (vesicular, fragmental, glassy) rocks.
 

Make sure you understand the difference between a MINERAL and a ROCK!!!

Classification of igneous rocks
 

Crystalline-means	made from many	individual mineral	grains that grew in	a melt
Composition >>>  Texture (below)	Felsic	Intermediate	Mafic	Ultramafic
aphanitic (fine-grained)	rhyolite	andesite	basalt	komatiite
phaneritic  (coarse-grained)	granite	diorite	gabbro	peridotite
Minerals you'd	expect to find in	this composition	crystalline rock	.
	quartz, potassium   feldspar,   plagioclase   feldspar	amphibole,    plagioclase    feldspar	pyroxene,    plagioclase    feldspar	olivine
Other rocks - such	as those made from	glass or fragments	of rocks or ash	.
glassy	obsidian	obsidian	obsidian
"frothy" (more  holes than rock) also called vesicular	pumice	pumice	scoria
large fragments  (>2mm) (rocks)	breccia	breccia	breccia
small fragments  (<=2mm) (ash)	tuff	tuff	tuff

Extra stuff:  A basalt containing holes (more rock than holes) is called a vesicular basalt.
 

You should be able to distinguish between mechanical weathering (which breaks material into smaller fragments without making any chemical changes) from chemical weathering (which alters the chemistry of the material)

Mechanical weathering we discussed includes: abrasion, salt cracking, frost action/wedging, activity by organisms, pressure release/exfoliation, thermal expansion and contraction.

Chemical weathering we discussed includes: hydrolysis/hydration, oxidation, dissolution -- you should be able to recognize each when written as a chemical reaction by looking at the products.  Dissolution will not have any solids among the products.  Oxidation will have at least one product that is a solid containing Fe and O in its formula, and Hydrolysis/hydration will contain at least one solid mineral in its products that contains an OH in its formula.

You should know what the products of chemical weathering are:
if the rock contains minerals that have iron (such as the pyroxene or amphibole or olivine in a basalt or gabbro), then you will get hematite (an iron oxide)
if the rock contains a mineral with aluminum and silicon, such as feldspar (which is pretty much any igneous rock), then you will get a clay mineral
if the rock contains quartz (such as a granite, but definitely NOT a basalt), then you will get quartz grains
Those are basically the three solids that you expect.  You will also get ions/atoms in solution in all cases.

Sedimentary Rocks:

some of the descriptions of rocks may say a "clastic rock which feels smooth when rubbed between fingergs"-- you should think shale - see below in chart.  Be able to distinguish between clay and silt sized sediments.  Understand that cross-bedding indicated wind or stream flow direction.  Understand what happens when a clastic sediment becomes mature (rounding and sorting) and that this involves transport by wind and/or water, but not ice.  You should understand the criteria by which each of the rock types are classified (grain size for clastic, for example).

Classification for clastic/detrital sedimentary rocks (classified on the basis of grain size)

Grain size	Name of Rock
Gravel (includes boulders, cobbles, pebbles, granules	if grains are angular:  breccia   if grains are rounded:  conglomerate
Sand - will feel gritty when rubbed between fingers	sandstone   - if contains more than 90% quartz:  quartz sandstone   - if contains more than 25% feldspar:  arkose   - if poorly sorted with a lot of mud:  graaywacke
Mud - will feel smooth or powerdery when rubbed between             fingers    - includes silt (feels gritty against teeth)    - includes clay (feels smooth against teeth)	if breaks along flat surfaces (fissile): shale

Classification of chemical sedimentary rocks (classified on the basis of mineralogy)

made from silica (SiO2)	made from calcite (CaCO3)  all will react with HCl	made from other minerals
chert - microcrystalline quartz  (hard and tends to show conchoidal fracture)  diatomite - made from diatom shells (easily confused with chalk)	limestone - generic name  oolitic limestone - spherical grains like tiny beads  chalk - made from shells of tiny plankton  coquina - made from visible shells or shell fragments  travertine - forms in caves and often has a banded appearance	dolostone - made from dolomite  rock salt - made from halite  rock gypsum - made from gypsum

And then there is coal - peat to lignite to bituminous coal.