Geology Ch. 11-16

Front 1

On what do stream flow and velocity depend on?

Back 1

gradient (steepness), discharge (volume of water flowing down a stream), and channel characteristics (shape and roughness)

Front 2

What is the base level (ultimate and temporary)?

Back 2

deepest level to which a stream can erode

Ultimate- cannot erode below sea level

temporary- resisting erosion

Front 3

how are meanders formed?

Back 3

formed by lateral erosion which create a series of bends

Front 4

define point bar

Back 4

when sediment is deposited in the slower water on the inside of the meander

Front 5

define oxbow lake

Back 5

a u-shaped body of water created where a meander loop is cut off from a stream and the ends of the meander become plugged with sediment

Front 6

why are some streams braided?

Back 6

it forms where the supply of sediment exceeds the stream's capacity; more sediment is available than the stream can carry

Front 7

how do streams depend of erosion?

Back 7

streams erode soil and bedrock, flowing water carries the eroded sediment downslope

Front 8

stream erosion and sediment transport depend on_______.

Back 8

a stream's energy

Front 9

define Bed load

Back 9

the total mass of a stream's sediment load that is transported along the bottom or in intermittent contact with the bottom of the streambed

Front 10

define dissolve load

Back 10

the total mass of ions dissolved in and carried by a stream at any one time; the ions are derived from chemical weathering

Front 11

define suspended load

Back 11

the total mass of a stream's sediment load that is carried within the flow by turbulence and is free from contact with the streambed

Front 12

define drainage basin

Back 12

the region that is drained by a single stream

Front 13

define alluvial fan

Back 13

a fan-shaped accumulation of sediment created where a steep mountain stream rapidly slows down as it reaches a relatively flat plain

Front 14

define delta

Back 14

a fan-shaped accumulation of sediment formed where a stream enters a lake or ocean

Front 15

define distributaries

Back 15

channels that split from the main stream feeding a delta or alluvial fan and spread out across its surface, depositing sediment in the process

Front 16

how are lakes formed?

Back 16

lakes can be formed by tectonic movements, glaciers, volcanic activity, dissolution of bedrock, erosion, and deposition of rivers, and meteorites

Front 17

what is an oligotrophic lake?

Back 17

a deep lake characterized by nearly pure water but with low concentrations of nutrients, thus sustaining relatively few living organisms

Front 18

what is an eutrophic lake?

Back 18

a relatively shallow lake characterized by abundant nutrients, thus sustaining multiple living organisms

Front 19

what is the thermocline?

Back 19

boundary between warm and cool layers; occurs in temperate climates during the summer and where colder autumn weather cools the surface water.

Front 20

what is turnover?

Back 20

process that occurs in the fall and spring in temperate climates in which a lake's surface water changes temp in response to seasonal weather changes and convection mixes the water to equalize temp throughout the lake

Front 21

define porosity

Back 21

the proportional volume of pores or open space within a material; indicates the maximum possible volume of fluid that could be held within the material

Front 22

define permeability

Back 22

the ability of solid materials such as rock to transmit water or another fluid through its pore network

Front 23

difference in permeability between sedimentary, and igneous rocks

Back 23

sedimentary rock is more porous and therefore more permeable than igneous rock

Front 24

define water table

Back 24

the top surface of the zone of saturation; the water table separates this zone from the aeration zone above