Exam #3 (11/5) Flashcards
(83 cards)
1
Q
Where do we find volcanoes?
A
- convergent boundaries
- divergent boundaries
- hot spots
2
Q
What comes out of volcanoes?
A
- dust
- ash
- cinders
- block and bombs
3
Q
volcanic bomb:
A
- elongated shape
- tear drop
- bigger than cinder
- > 64mm
4
Q
volcanic blocks:
A
- mostly rounded
- 65 mm
5
Q
What is a fumarole?
A
small vents that emit only gases and smoke
6
Q
What is lava?
A
molten materials present at Earth’s surface
7
Q
What are the 2 types of lava?
A
- Aa
2. Pahoehoe
8
Q
dissolved gases:
A
As pressure is reduced, the gases escape
9
Q
Aa lava flow:
A
Rough texture, due to gases still being present when solidifying
10
Q
Pahoehoe:
A
smoother, “ropey” texture
11
Q
Lava viscosity
A
- aka thickness of lava
- higher viscosity= greater resistance to flow
- silica content can change viscosity
- (increase silica, increase viscosity)
12
Q
Lava viscosity will effect what?
A
- the explosiveness of a volcano
- gas content
13
Q
Mafic explosion:
A
- low explosion
- low viscosity
14
Q
Felsic explosion:
A
- extremely explosive
- high viscosity
15
Q
Crater:
A
summit depression < 1km diameter
16
Q
Caldera:
A
- summit depression > 1km diameter
- produced by collapse following massive explosion
17
Q
vent:
A
opening to the magma chamber
18
Q
Shield Volcano:
A
- largest
- made of basalt
- low gas content
- low explosiveness/ viscosity
- ex. Mauna Loa
19
Q
Cinder Cone Volcano:
A
- Around 500m high and 500m in diameter
- very short life spans (weeks to months)
- only one eruption cycle
- high gas pressure
- basalt, pumice
- moderately explosive
- ex. South of Young Valley, AZ
20
Q
Conical Composite Volcano (Strato)
A
- layered from multiple eruptions
- long lived
- continental subduction zones
- felsic lava with a lot of gas
- high viscosity/gas pressure
- highly explosive
- ex. Mt Saint Helens, Mt vesuvius
- found around pacific plate
21
Q
lava domes
A
- occur inside of existing volcanoes (mostly strato)
- hot and unstable
- ex. inside Mt. Saint Helens
22
Q
Caldera
A
- large magma body supports large region
- sudden deflation from rapid expulsion
- usually ends up as a significant depression
- ex. Crater Lake & Long Valley caldera
23
Q
Fissure eruption
A
“fountain but does not pile up enough to make a volcano
24
Q
pyroclastic flows:
A
- massive, hot as and dust cloud racing at speeds over 100 mph.
- biggest killers from eruptions
25
pluton
cooled magma at depth
26
stock
pluton exposed over a small area
27
sill
horizontal, emplaced magma body
28
dike
cuts layers of rock at an angle
29
volcanic neck
exterior of volcano removed while internal pipe remains
30
xenoliths
pieces of "country rock" which fall into the magma body
31
Weathering
the breakdown of tock and minerals into smaller and smaller pieces
32
Erosion
the group of natural processes by which weathered materials are transported
33
What are the 3 main processes?
- erosion
- transport
- deposition
34
siWhat is the major key to weathering and erosion?
Water
35
Susceptibility to weathering is dependent on what?
the strength of molecular bonds
36
rocks former at _____ temps are more likely to weather.
lower
37
the _____ covalent bond tetrahedra, the ____ susceptible to weathering
less; more
38
Parent material:
starting off, before weathering
39
Daughter material:
comes from weathering of parent
40
What do quartz break down to?
Quarts can only breakdown to quartz
41
How are igneous rocks formed?
when molten materials solidify
42
Felsic rocks are not typically dark in content due to high iron content
False
43
Karst topography
the dissolution of limestone by groundwater which produces cavernous areas below ground
44
Which will weather at a faster rate, olivine or quarts?
Quartz: lower temperature,
45
Detrital sedimentary rocks are classified based on their _____ composition
chemical
46
bioturbation
life digging into sediments and rocks (animals, humans)
47
List grades of coal in proper order (lowest to highest)
- peat
- lignite
- bituminous
- Anthracite
48
What can feldspars and amphiboles be broken down into?
clay minerals
49
Agents of transportation
- water
- wind
- ice
- anything that can move materials
50
rounding:
corners of transported materials are knocked off as grains slam into each other
51
sorting:
as things travel they come more well sorted based on grain size and density
52
deposition
where transported materials end up
base level: lakes, ponds, local basins
ultimate base levels: ocean
53
lithification
after deposition, rocks can be made through compaction and cementation
54
pedogenesis
soil formation
55
5 factors of pedogenesis:
parent material, time, climate, plants and animals, topography
56
sedimentary rock:
rock made out of bits and pieces of other rocks
57
diagnesis
chemical, physical, and biological changes that take place after sediments are deposited
58
detrital sedimentary rocks, coarsest grain size
- conglomerate (well-rounded)
| - breccia (poorly rounded)
59
detrital sedimentary rocks, moderate grain size
-sandstone
60
detrital sedimentary rocks, fine grain size
- siltstone
| - shale
61
2 common cements
- calcium carbonate
| - silica
62
Chemical sedimentary rocks, silica
chert, flint, jasper, diatomite
63
Chemical sedimentary rocks, evaporites
halite, gypsum
64
stages of coal formation
1. burial (peat)
2. Greater burial (lignite)
3. Metamorphism (bituminous)
4. Stress (anthracite)
65
depositional environment
The are characterized by similar physical processes that result in similar types of sediments being deposited; where sediments are deposited and make sedimentary rocks
66
What are the two types of depositional environments?
1. continental (non-marine)
2. oceans (marine)
- nearshore (waves)
- offshore (currents)
67
examples of continental depositional environments
- deserts
- alluvial fans
- glacial deposits
- rivers
68
Where do we find reefs?
continental shelf in a continental margin
69
bedding
when sediments of different grain sizes or compositions are deposited on top of one another
70
connetic living:
larger grains are at the top
71
laminated bedding
quiet, low-energy environment, usually no animals
72
mixed bedding
mixed usually by animals
73
what defines a sedimentary facies
- the nature of the sediment
- the sedimentary structure
- what fossils used to liver there
74
outcrops
exposed bed rock on earth's surface
75
The units sharing similarities in their heterogeneity:
-formations, members, beds, laminations
76
Steno's laws
rules for determining the order in which rocks were deposited in:
1. superposition (stuff on top is newer than stuff on bottom)
2. original horizontally
3. lateral continuity
4. principle of cross-cutting relationships
77
What do fossils tell us?
age of rock, community dynamics, types of environment
78
half-life
tome needed for 1/2 pf parent to decay
79
Basalt
magic, extrusive, igneous rock formed from the rapid cooling of magnesium-rich and iron-rich lava
80
Organic reefs
carbonate structures created by carbonate secreting organisms
81
Continental shelf
located in the shallow waters off continental shores, where sedimentation is controlled by relatively gentle currents
82
continental margin and slope
deeper waters at and off the edges of the continents where sediment is deposited by turbidity currents
83
deep sea
floors of the deep ocean not affected by wave activity
