SEDIMENTARY (2)

Question 1

igneous rocks

Answer 1

rocks that form when hot, molten rock crystallizes and solidifies

Question 2

extrusive rocks

Answer 2

cooled from lava

Question 3

intrusive rocks

Answer 3

cooled from magma

Question 4

magma

Answer 4

hot molten material from deep within earths’ crust and mantle

Question 5

metamorphic rock

Answer 5

rocks that are produced when any parent (original) rock (either igneous, metamorphic, sedimentary) undergoes a solid state change

Question 6

sedimentary rock

Answer 6

formed from the compaction and cementation of sediment composed of grains (fragments) of other rocks, clay minerals, precipitated minerals, and biologically produced grains and minerals

Question 7

clastic

Answer 7

sedimentary rocks that have formed from accumulations of preexisting rock fragments as a result of weathering and transport

Question 8

organic

Answer 8

sedimentary rocks composed of skeletal and other remains of organisms

Question 9

inorganic

Answer 9

sedimentary rocks formed as precipitates from an aqueous solution

Question 10

rock cycle

Answer 10

how earth materials are recycled

Question 11

conglomerate

Answer 11

clastic sedimentary rock that contains at least 25% grains larger than sand

> 2mm, poorly sorted, rounded to sub-rounded, pebble to gravel-sized grains, high energy environment, medium travel

Question 12

sandstone

Answer 12

clastic sedimentary rock characterized by sand-sized grains

1/16-2mm

Question 13

siltstone

Answer 13

a type of mudstone that is somewhat coarser grained and intermediate in grain size between clay and sand, composed of silt

generally not fissile like shale, but grains can be seen with a hand lens

Question 14

shale

Answer 14

fine-grained clastic sedimentary rocks composed mostly of a mixture of clay and silt-sized particles and often gray to black in color

easily breaks into flat slab-like pieces

Question 15

fossiliferous shale

Answer 15

shale that bears fossils

Question 16

limestone

Answer 16

organic sedimentary rock made of calcium carbonate (CaCO3) that comprises many varieties produced both organically and inorganically

Question 17

chalk

Answer 17

limestone formed in the deep ocean from the carbonate shells of foraminifera and coccoliths

Question 18

reef limestone/rock

Answer 18

limestone that can form either on the reef itself and consist of mounds of coral growing vertically through time, or piles of coral rubble on the sides of the reef

Question 19

coquina

Answer 19

formed when millions of clam shells are concentrated on a beach or just below the low tide line and become cemented to each other

Question 20

evaporites

Answer 20

deposits that form in shallow bodies of water in arid regions that are undergoing rapid evaporation

Question 21

halite

Answer 21

the most familiar evaporite material, also known as rock salt

Question 22

gypsum

Answer 22

evaporite mineral also known as calcium sulfate used for sheetrock and plaster of paris

Question 23

speleothems

Answer 23

cave deposits formed by the precipitation of dissolved calcium carbonate

Question 24

graded bedding

Answer 24

caused by changes in flow velocity during a debris flow, which is usually a mix of mud, sand, gravel, and often boulders and woody debris

Question 25

cross bedding

Answer 25

consists of inclined “lines” that slant at an angle between 5-20 degrees XXX from the base of the bed

typically only preserved in sandstone

Question 26

ripples

Answer 26

small bedrooms that form in sand and on occasion silt

Question 27

asymmetrical ripples

Answer 27

ripples that have a shallow windward side and a steel leeward side

formed from a unidirectional current like a river

Question 28

symmetrical ripples

Answer 28

ripples that are the same slope on either side because of an oscillating or bidirectional current

waves going back and forth on the beach

Question 29

mudcracks

Answer 29

cracked structures that form only in clay and siltstone

Question 30

varves

Answer 30

light-dark seasonal bands in shale or siltstone that are deposits in shallow bodies of water that are somewhat restricted in terms of circulation (fjords and lakes)

Question 31

glacial striations

Answer 31

technically erosional features, but included because they tell about ancient climate

Question 32

rounding

Answer 32

refers to the shape of an individual sand grain, pebble, cobble, etc

rounded, subrounded, angular, subangular

Question 33

grain size

Answer 33

refers to the diameter of the clastic particle

gravel-coarse sand-medium sand-fine sand-silt-clay

Question 34

sorting

Answer 34

refers to grain size distribution across a sample

big range=poorly

Question 35

textural maturity

Answer 35

refers to how much transport the sediment has undergone since it was first weathered out of a rock