Types of rocks Flashcards
(63 cards)
1
Q
Sedimentary Rocks
A
formed by fluids (air/water)
Only on the surface of the earth
2
Q
Two groups
A
- Clastics (pieces of rocks)
- Chemical/ Biogenic (organic compounds or fossilized microbes)
3
Q
Material rocks come from
A
weathering (breaking up)
erosion (transport)
4
Q
Weathering
A
- breaking down material (exposed to the elements)
5
Q
Erosion
A
- plate tectonics
- base level (local or ocean)
6
Q
Physical weathering
A
- makes the rocks smaller (sledgehammer breaking apart the rock)
- surface area of rocks (multiplies as it gets smaller)
7
Q
Chemical weathering
A
- alter the chemical composition
- Water is exposed to rocks gets transported to a different location
8
Q
Types of weathering
A
- Jointing (removing the surface or the pressure of rocks causes the rocks to fracture in crosshatching pattern) (physical)
- Freeze-Thaw wedging (more water enters the cracks to expands more) (physical)
- Root wedging (roots gets into the cracks and expands more) (physical)
- Salt wedging (water dissolved in halite rocks) (chemical)
- Dissolution (combination of physical and chemical combinations)
9
Q
What breaks down first
A
edges (get rounded)
surfaces that are exposed
halite and olivine
10
Q
Clastic sedimentary rock
A
- getting pieces of rocks and glued together
- clasts and “cement”
- diagenesis (glues sentiments together)
11
Q
Three categories of grain sizes
A
- mud/silt
- sand
- gravel/pebble/cobbles
12
Q
trends in size
A
source (mix and angler)
sink (well sorted and smooth)
13
Q
maturity
A
changes chemically
immature (felsic and matic)
mature (same size and composition)
14
Q
Large sedimentary rocks
A
anything larger than 2 mm
- breccia (angler near mountains)
- conglomerate (rounder near mountain streams)
15
Q
Sand size
A
anything between 2-1/16 mm
- Lithic (mixed composition and immature) (landslides)
- Arkose ( mix of 2 or 3 materials pink potassium feldspar) (Alluvial fans)
- Quartz (only one mineral and mature) (can be red from iron or other red minerals) (beaches)
16
Q
Fine grained
A
less than 1/16 mm (flood deposits or lakes)
- mud stone
- shale
17
Q
Chemical sedimentary (evaporates)
A
formed from evaporation
- salts (halite, gypsum)
18
Q
Biochemical sedimentary
A
formed from animal shells
- pelagic ooze (calcite, quartz)
- pelagic (limestone (tropic and mid latitude))
- Siliceous (chert-quartz (polar))
19
Q
What happens when water gets cooler
A
hold more CO2 causing carbolic acid
- will dissolve calcite
20
Q
Limestone
A
warmer oceans
shallow waters
21
Q
Chert
A
Quartz/silica
- cold polar areas
- high acid
22
Q
Coal and oil shale
A
organic carbon
- swampy
- near a coast line
- warm
- high amount of organic matter
23
Q
Biogenic Fossils
A
preserve structures
imprints
petrified wood
24
Q
Bedding and Stratification
A
form in layers Grand canyon (strati-graphic)
25
Stratigraphy (original horizontal)
states that sediment is deposited in a layer that is horizontal and parallel to Earth's surface
26
Stratigraphy (superposition)
states that in any sequence of strata, the order of deposition is from the bottom to top
27
Stratigraphy (lateral continuity
states that a layer of sediment will extend horizontally as far as it was carried, thinning laterally
28
Stratigraphic (correlation)
is the determination of equivalence in age of the secession of strata found in tow of more different areas
29
Cross-cutting relationships
states that and geologic feature must be older than any feature that cuts into
30
cross bedding
sand moves up and down to form a new layer which causes a wedge shape in the direction of water or wind when looking at a cross section
- 20 degrees of less by water
- 20 degrees or more by wind
31
Ripples and dunes
ripples
- small (maybe a foot high)
- shape shows direction
- asymmetrical (unidirectional) moving in one direction (in river settings)
- symmetrical (bidirectional) moving back and forth (in tidal regions or coast lines)
dunes
-large (2/3 the high of the flow)
32
Mud-cracks
shows that it a wet and dry environment (wet then dries extremely fast)
33
Glacial Environments
no rounding
| no souring
34
Mountain streams Environments
big rocks
| rounding
35
Alluvial fans Environments
prone to landslides
36
Desert
sand stones
37
River
sandstone and mud stone
38
Lake
mud stone deposits
white (winter)
black (summer)
39
Coastal
quarts sandstone
40
Marine Delta
Chert and limestone
41
Sedimentary basins
the rock form in low basin areas with water
42
Metamorphic
- pre-existing rock
- change by pressure and temperature
- causes physical and/or chemical change
- compression and shear
- hot water
43
Protoliths
first rock
| - what we started out before pressure and temp.
44
Recrystallization
making the crystals grow bigger (start and end with the same mineral)
45
Phase Change
Rearranging the atoms in the crystals (Start and end with different minerals)
46
Neocrystallization
change the texture
47
Plastic Deformation
- can be squished or stretched
- add deferential stress
- tells the pressure to the stress and forms perpendicular
48
Shear
applying the stress in different direction in pulling
49
Preferred orientation
```
equant grains (the shaped doesn't change)
inequant grains (the pressure is differential and perpendicular)
```
50
Foliation
the differential pressure aligns to the pressure that forms a linear pattern
51
non-foliated
all grains are equal size or change shape
52
foliated
the grains are uneven size and grew in shape
53
Blueshist
subduction
| - rapped rise in pressure and slow rise in temp
54
Mountain belt
collision
| - steady rise in pressure and temp
55
Contact
Intrusions
| - rapped rise in temp and slow rise in pressure
56
Index minerals
helps map out certain temp and pressure
57
Pro-grade metamorphism
increase pressure and temp.
58
Retrograde metamorphism
decrease pressure and temp.
59
Hydrothermal
rocks goes into ground and heats up the water and hot water rises and reacts with the rocks
60
Burial metamorphism
large deposition systems sand turning into sandstone and lastly quartzite
61
Contact
either small or large alteration
closer to the heat source going to have higher grade metamorphism
far away from heat source going to have low grade metamorphism
62
Dynamic
driven by motion and plate tectonics
| - boudings (point show the motion of alteration)
63
Shock
metier impact
| either small or large
