Sedimentary Environments

Question 1

Why do we care about the sedimentary rock environments of the past?

Answer 1

Tells us about Earth’s past surface

Question 2

What are the three main groups of clastic sedimentary rocks?

Answer 2

Conglomerate and breccia
Sandstone
Siltstone and shale

Question 3

What are the three main groups of chemical sedimentary rocks?

Answer 3

Limestone
Coal
Evaporites

Question 4

Made of blocks and pebbles, hard to erode. These form steep cliffs

Answer 4

Conglomerate and breccia

Question 5

Made of quartz sand, also hard to erode. These form cliffs

Answer 5

Sandstone

Question 6

Made of fine mud and clay, easy to erode. These form gentle slopes.

Answer 6

Siltstone and shale

Question 7

Jagged blocks of sediment = very short transport distance

Answer 7

Breccia (high energy)

Question 8

Rounded pebbles = more movement during transport

Answer 8

Conglomerate: high energy

Question 9

Poorly sorted, jagged, and dirty sand: some transport by…..

Answer 9

River or delta channels (sandstone moderate energy)

Question 10

Well sorted, rounded, and clean sand: lots of transport in…

Answer 10

Sand bars and along beaches (sandstone moderate energy)

Question 11

Very well-sorted, fine-grained, and frosted sand: lots of transport by the wind in…

Answer 11

Deserts (sandstone moderate energy)

Question 12

Shale or silt with sea-shells:

Answer 12

Shallow marine shelf (siltstone/shale: low energy)

Question 13

Shale or silt with plant fossils or nearby coal layers:

Answer 13

river floodplain (siltstone/shale: low energy)

Question 14

Shale or silt with a mixture of sea shells and plant fossils:

Answer 14

delta bays (between channels)
(siltstone/shale: low energy)

Question 15

Made of calcite shells, forms cliffs in dry climates, but dissolves and forms slopes in wet ones

Answer 15

Limestone

Question 16

Soft, erodes away

Answer 16

Coal

Question 17

Only visible in desert climates

Answer 17

Evaporites

Question 18

Tropical ocean =

Answer 18

Limestone

Question 19

Swamps =

Answer 19

Coal

Question 20

Evaporites =

Answer 20

Deserts and Dried Seas

Question 21

Desert playa lakes form unusual salts like ____ when they evaporate

Answer 21

Borax

Question 22

Hot dry climates make ___ and ____ deposit in thick layers as ocean water dries

Answer 22

Gypsum

Halite

Question 23

Jagged Breccia (high energy) are formed by?

Answer 23

Rockslides or glaciers (rocks frozen can’t be rounded)

Question 24

Rounded Conglomerate (high energy) are formed by?

Answer 24

Flash Floods, Stormy Beaches, or Waterfalls

Question 25

Used to be a beach? (Grand Canyon

Answer 25

Tapeats Sandstone

Question 26

Used to be sea level?

Answer 26

Bright Angel Shelf

Question 27

Used to be a clear warm ocean? (Grand Canyon)

Answer 27

Muav Limestone