Essay about Geology exam 1

Submitted By jlkane123
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Pages: 9

Geology Exam 1
The earth is a dynamic planet it is constantly evolving and we can see that on geologic time scale

Chapter 5
1. What is a mineral? A naturally occurring solid formed by geologic process that has crystalline structure and definite chemical composition
2. What are the 8 most abundant minerals in the earths crust? (98.5%)
a. Oxygen
b. Silicon
c. Aluminum
d. Iron
e. Calcium
f. Sodium
g. Potassium
h. Magnesium
3. What is an ion? An atom with a net electric charge due to the loss or gain of one or more electrons.
4. What is a cation? An atom with a net positive charge
5. What is an anion? An atom with a net negative charge
6. The different types of chemical bonds:
a. Ionic bond: oppositely charged atoms bond to become stable atom with a net charge
b. Covalent bond: the sharing of electrons that causes an atom to bond together (strongest bond)
i. Carbon atoms bond with carbon atoms to create diamond which is the hardest mineral
c. Van Der Waal: forms when asymmetries develop in distribution of electrons about the nucleus and atoms arrange with weak opposite charges (weakest bond)
d. Metallic Bonds: outer electrons wander freely through metals
i. Good for energy and heat
7. What is Silicon-Oxygen Tetrahedron? 4 oxygen atoms bonded to 1 silicon which are the two most abundant minerals in earths crust with net charge 4- so attracts positively charged
8. How many oxygen anions are shared with other tetrahedral and the complexity of the structure?
a. Isolated Tetrahedral structure – simplest, each stand alone
i. Mineral: olivine

b. Single-chain structure – each share 2 Oxygen with neighboring
i. Mineral: pyroxene
c. Double chain structure- each share 2 or 3 Oxygen
i. Mineral amphibole
d. Two-dimensional sheet structure- each share 3 Oxygen
i. Mica minerals
e. Three-dimensional framework structure –most complex, share all 4 oxygen’s so neutral
i. Quartz, feldspars
9. What are halides? Halite is an example of a halide mineral
10. What are oxides? Hematite is an example of an oxide mineral
11. What are sulfides? Pyrite is an example of a sulfide mineral
12. What are carbonates? Calcite is an example of a carbonate mineral
13. What are native elements? Sulfur is an example of a native element
14. What are sulfates? Gypsum is an example of a sulfate mineral
15. Know that minerals can be distinguished by their characteristic physical and chemical properties
a. Crystal form
b. Hardness (know Mohs scale of hardness)
c. Cleavage
d. Specific gravity (density)

e. Color
f. Streak
g. Luster
h. Fracture

Chapter 6 and 9
1. What is a rock? A naturally occurring combination of minerals defined by its origin
2. What basis are 3 major rock groups subdivided? Origin
3. What is the origin of a igneous rock? The cooling and subsequent crystallization solidification of magma
4. What is magma? A hot (>1100 C) liquid melt of elements
5. What are the general characteristics of mafic (basaltic) magmas? Low silica, high magnesium and iron, and dark in color
6. What are the general characteristics of silicic (felsic) magmas? high silica, potassium, sodium, low magnesium and iron, and light in color
7. What are the principal gases dissolved in magma?
a. Water vapor, carbon dioxide, nitrogen oxide, sulfur oxide, chlorine, hydrogen, argon
8. What is viscosity? The resistance to flow; Si and O cause magma to lump together and have viscosity; The higher viscosity, the more eruptive style
9. What two factors do we use to subdivide the igneous rocks? Texture and composition
10. What does the texture of an igneous rock tell you about it's cooling history? How fast it cooled relates to size of crystals
11. What do these terms mean?
a. Phaneritic: slow cooling of magma; macroscopic minerals
b. Aphanitic: fast cooling; microscopic minerals
c. Porphyritic: mixed crystal size- slow then fast cooling
d. Vesicular: has holes which indicates released gases
i. Vesicles: spherical, tubular, or oval holes
e. Glassy: cant see crystals so