Chapter V: Sedimentary Enviornments

Question 1

What kinds of nonmarine sedimentary deposits reflect arid environmental conditions?

Answer 1

gravelly alluvial fans; cross-bedded gravels and sands; shallow playa lakes and salt flats; dunes of clean, cross bedded sand; mudcracks;

Question 2

What kinds of nonmarine sedimentary deposits reflect cold environmental conditions?

Answer 2

Glacial sedimentary deposits

Question 3

What kinds of deposits indicate the presence of rugged terrain in the vicinity of a nonmarine depositional basin?

Answer 3

coarse grained alluvial fans;

Question 4

In what nonmarine setting do gravelly sediments often accumulate?

Answer 4

Mountains, in braided streams/alluvial fans;

Question 5

What patterns of occurrence and sedimentary structures are shown by; meandering rivers, deltas, and turbidity currents?

Answer 5

Meandering Rivers:
graded beds; point-bar deposition; muddy flood plain sediments;

Deltas:
upward-coarsening sequence; shallow water sands over deeper water muds; barrier islands;

Turbidity Currents: 
graded beds (turbidites); calcareous and siliceous ooze;

Question 6

What are the depositional environments of a barrier island-lagoon complex?

Answer 6

cross-bedded tidal deltas; tidal flats

Question 7

What features typify sediments that accumulate in the centers of lakes?

Answer 7

thin horizontal layers; few burrows; absence of marine fossils

Question 8

How do stromatolites form?

Answer 8

Cyanobacteria traps mud then grows through it, forming layer after layer which accumulate to form stromatolites

Question 9

Describe the kind of rock found in a typical organic reef.

Answer 9

Carbonate sedimentary rock. Calcium Carbonate

Question 10

Where is a lagoon in relation to a barrier reef? In relation to an atoll?

Answer 10

Lagoons lie behind long barrier islands and within atolls

Question 11

Which features of carbonate rocks suggest intertidal or supratidal deposition?

Answer 11

algal lamentation and stromatolites

Question 12

what types of sediments and sedimentary structures usually reflect deposition in a deep-sea setting?

Answer 12

pelagic sediments; calcareous ooze; silicous ooze; formed into turbidites

Question 13

siliceous ooze

Answer 13

carpets deep sea floors; made of skeletons of two groups of organisims, phytoplankton (nontropical) and radiolarians

Question 14

Glacial Features

Answer 14

scoured, scratched rock surfaces (striations); poorly sorted gravelly sediment (glacial till); dropstones; associated lake deposits with annual layers;
moraines, lithified till;

Question 15

humus

Answer 15

organic matter which gives topsoil its black color

Question 16

caliche

Answer 16

precipitated deposits of calcium carbonate (warm climates)

Question 17

oxisols

Answer 17

soils rich in iron oxide

Question 18

varves

Answer 18

annual pairs of coarse grained/fine grained layers in lake beds

Question 19

playa lakes

Answer 19

lakes in areas with interior drainage, usually temporary

Question 20

braided streams

Answer 20

complex network of streams on an alluvial fan

Question 21

tempestites

Answer 21

thin, sandy beds produced by storms over usually muddy shelves

Question 22

talus

Answer 22

rubble pile fallen from the wave-swept reef front

Question 23

oolites

Answer 23

spherical sediment formed by ooids