Ch 7 Vocabulary

Front 1

bedding plane

Back 1

a nearly flat surface that separates two beds of sedimentary rock, each bedding plane marks the end of one deposit and the beginning of another having different characteristics

Front 2

chemical sedimentary rock

Back 2

sedimentary rock consisting of material that was precipitated from water by either inorganic or organic means

Front 3

detrital sedimentary rocks

Back 3

rocks that form from the accumulation of materials that originate and are transported as solid particles derived from both mechanical and chemical weathering

Front 4

depositational environment aka sedimentary environment

Back 4

a geographic setting where sediment accumulates. each site is characterized by a particular combination of geologic processes and environmental conditions

Front 5

graded bed

Back 5

sediment layer characterized by a decrease in sediment size from bottom to top

Front 6

strate (beds)

Back 6

parallel layers of sedimentary rocks

Front 7

classic texture

Back 7

a sedimentary rock texture consisting of broken fragments of preexisting rock

Front 8

crystalline texture aka nonclastic texture

Back 8

a term for the texture of sedimentary rocks in which the minerals form a pattern of interlocking crystals

Front 9

facies

Back 9

a portion of a rock unit that possesses a distinctive set of characteristics that distinguishes it from other parts of the same unit

Front 10

lithification

Back 10

the process, generally involving cementation and/or compaction, of converting sediments to solid rock

Front 11

salt flat

Back 11

a white crust on the ground that is produced when water evaporates and leaves behind its dissolved materials

Front 12

turbidity curent

Back 12

a downslope movement of dense, sediment-laden water created when sand and mud on the continental shelf and slope are dislodged and thrown into suspension

Front 13

biochemical

Back 13

a type of chemical that forms when material dissolved in water is evaporated by water-dwelling organisms.

exa. shells

Front 14

compaction

Back 14

a type of lithification in which the weight of overlying material compresses more deeply buried sediment. it is most important in the fine grained sedimentary rocks such as shale

Front 15

diagensis

Back 15

a collective for all the chemical, physical, and biological changes that take place after sediments are deposited and during and after lithification

Front 16

fissility

Back 16

the property of splitting easily into thin layers along closely spaced, parallel surfaces, such as bedding planes in shale

Front 17

mud crack

Back 17

a feature in some sedimentary rocks that forms when wet mud dries out, shrinks and cracks

Front 18

sediment

Back 18

unconsolidated particles created by the weathering and erosion of rock by chemical precipitation from solution in water or from the secretions of organisms and transported by water, wind and glaciers

Front 19

bioturbation

Back 19

the reworking of soils and sediments by animals or plants. its effects include changing texture of sediments (diagenetic), bioirrigation and displacement of microorganisms and non-living particles

Front 20

cementation

Back 20

one way in which sedimentary rocks are lithified. as material precipitates from water that percolates through the sediment, open spaces are filled and particles are joined into a solid mass

Front 21

cross-bedding

Back 21

a structure in which relatively thin layers are inclined at an angle to the main bedding. formed by currents of wind or water

Front 22

evaporite

Back 22

a sedimentary rock formed of material deposited from solution by evaporation of the water

Front 23

fossil

Back 23

the traces or remains of organisms preserved from the geologic past

Front 24

ripple marks

Back 24

small waves of sand that develop on the surface of a sediment layer by the action of moving water or air

Front 25

sorting

Back 25

the degree of similarity in particle size in sediment or sedimentary rock

Front 26

organic sedimentary rock

Back 26

sedimentary rock composed of organic carbon from the remains of plants that died and accumulated on the floor of a swamp

exa. coal

Front 27

organic reef

Back 27

sedimentary rock structure of significant dimensions erected by, and composed almost exclusively of the remains of corals, algae, bryozoans, sponges and other sedentary or colonial organisms