Geology Test 1 - Sedimentary Processes And Rocks (4)

Front 1

weathering

Back 1

rocks disintegrate because they are exposed to earth's surface

Front 2

2 types of weathering

Back 2

physical and chemical

Front 3

physical weathering

Back 3

break rock into smaller and smaller fragments

falling rocks chipping off others, abrasion by sand, water freezing in fractures, plant roots causing cracks

Front 4

chemical weathering

Back 4

dissolving rocks or some of the minerals in rocks

causes the remaining pieces to come apart in pieces

Front 5

transportation

Back 5

debris from weathered rocks is moved

Front 6

main form of transportation

Back 6

water

Front 7

high energy streams move _____

Back 7

large boulders

Front 8

slow moving streams carry ______

Back 8

small debris

Front 9

sediment

Back 9

material moved by water

Front 10

some forms of transportation

Back 10

water, wind, glaciers

Front 11

deposition

Back 11

when the thing that is moving the sediment loses energy, the sediment gets deposited somewhere

Front 12

compaction

Back 12

reduction in pore (open) space between grains in sediment

sediment can get really thick so the pressure causes compaction of sediment grains

Front 13

lithification

Back 13

sediment converted into rocks

deep burial, elevated temperature and pressure, presence of water

new minerals might grow

Front 14

2 groups of sedimentary rocks

Back 14

clastic (detrital) and chemical/biochemical

Front 15

clastic (detrital) sedimentary rocks

Back 15

composed of fragments (clasts) or pre-existing rocks

classified based on size of clasts

Front 16

chemical and biochemical sedimentary rocks

Back 16

chemical elements that have been acquired mainly as a result of chemical weathering

some of these dissolved minerals can be precipitated directly from water

Front 17

6 types of sedimentary rocks, by grain size (big to small)

Back 17

conglomerate, breccia, sandstone, siltstone, shale, mudstome

Front 18

size of clasts reflects ______

Back 18

energy of transporting agent

Front 19

clasts tend to be more _____ and less ______ when transported farther from source

Back 19

more round, less angular

Front 20

5 common structures in sedimentary rocks

Back 20

1) Bedding
2) cross bedding
3) graded bedding
4) ripple marks
5) mud cracks

Front 21

Bedding

Back 21

stratification (layering)

most prominent structure

represents surfaces on which deposition occurred

horizontal

Front 22

cross bedding

Back 22

sloping depositional surfaces

like surface of dunes and delta fronts

Front 23

graded bedding

Back 23

stratification in a bed of sedimentary rocks

coarsest clasts occur at bottom

clast size decreases toward top of bed

Front 24

what is graded bedding a result of

Back 24

different settling velocities for different size clasts (larger and heavier clasts settle out first(

Front 25

each graded bed represents

Back 25

a single and sudden depositional event

Front 26

ripple marks

Back 26

small dune-like features

Front 27

ripple marks generally form in

Back 27

shallow waters

Front 28

size of ripple marks are related to

Back 28

velocities of current that form them

Front 29

shapes of ripple marks are related to

Back 29

current direction

Front 30

mud cracks

Back 30

form when deposits of mud dry out

as it dries, it shrinks and polygonal desiccation cracks form

next layer of fine sediment will fill in and cover cracks, preserving them

Front 31

where do mud cracks form

Back 31

areas that experience frequent wetting by shallow water and drying