Ch.6: Sedimentary Rocks

Question 1

Types of chemical weathering

Answer 1

Hydrolysis: feldspars → clay
Oxidation: Fe-silicates → Fe-oxide
Dissolution: carbonates

Question 2

Hydrolysis

Answer 2

ions in water replace minerals and force them
into solution

feldspars → clay

Question 3

Oxidation

Answer 3

Important in iron-bearing minerals

Fe-silicates → Fe-oxide

Question 4

Dissolution

Answer 4

Of salts, carbonates, even silicates

By water, usually acidic

Question 5

Chemical stability

Answer 5

minerals weather in reverse order of Bowen’s Series

Question 6

Types of physical weathering

Answer 6

Exfoliation sheeting
Columnar jointing
Frost action
Talus piles

Question 7

Exfoliation, sheeting

Answer 7

large-scale process; pressure release on granite batholith as
it’s uplifted and gets closer to the surface
removing layers from big domes

Question 8

Columnar jointing

Answer 8

cooling and contraction of surface basalt flow

Question 9

Frost action

Answer 9

wedging apart of rock as water freezes in joints

Question 10

Talus piles

Answer 10

pile of physically-weathered rock at base of cliff

Question 11

Spheroidal weathering

Answer 11

combination of chemical and physical weathering of rock along
joints to form round shapes and boulders that are “born” rounded, not rounded by
transportation

Question 12

Differential weathering

Answer 12

landforms (like hogbacks and flatirons) and features formed by
one rock weathering more readily than another

Question 13

Processes that produce

sedimentary rocks

Answer 13

1. weathering: physical and chemical
2. erosion: remove sediment grains
3. transportation dispersal by water or wind
4. deposition: course material deposited closest to source
5. Lithification: transforms loose sediment into solid rock by burial, compaction, cementation

Question 14

Transportation

Answer 14

with increased transportation, detrital grains get smaller and rounder
fine grained farther from source

Question 15

Lithification

Answer 15

transforms loose sediment into solid rock by

1. burial: more sediment is added to prevoius layers
2. compaction: overburden weight reduces pore spcae
3. cementation: mineral grow in pores “glue” sediments

Question 16

Depositional environments

Answer 16

non-marine; shoreline; shallow marine; deep marin
sediments accumulate in an environment above
sea level, like a desert, river, beach, etc.
Or below sea level, like a continental shelf, deep marine
basin, etc.

Question 17

Original Horizontality and Superposition

Answer 17

Principle of Original Horizontality – Bedding was
originally deposited as a horizontal layer
• Principle of Superposition: oldest layer is on
bottom, youngest on top

Question 18

Ripple marks

Answer 18

current (one direction of flow) oscillatory (back-and forth current)
similar to sand dunes

Question 19

Cross-bedding

Answer 19

indicate paleocurrent direction, stratigraphic up

Question 20

Graded bedding

Answer 20

stratigraphic up
from turbidity currents
sediment moves down slope, water loses viscosity, grains settle out
grains on top are more fine grained

Question 21

Clastic

Answer 21

cementation of grains from weathering
loose rock fragments-clasts- cemented together)
created by
weathering (generation of detritus via rock disintegration)
erosion (removal of sediment grains from parent rock)
transportation (dispersal by gravity, wind, water, and ice)
deposition (settling out of the transporting fluid)
lithification (transformation into solid rock)

Question 22

Organic

Answer 22

accumulation of organic material

coal: remains of fossil vegetation

Question 23

chemical

Answer 23

percipitation from water

calcite, limestone, or silica

Question 24

Submarine fans/underwater landslide

Answer 24

graywackes

Question 25

Landslide

Answer 25

Breccia

Question 26

Desert

Answer 26

Ankrose

Question 27

High energy beach

Answer 27

Quartz sandstone

Question 28

Warm tropical beach/Swamp or low energy beach

Answer 28

shale

Question 29

Beach, river, desert, etc.

Answer 29

sandstone