periglacial environments

Question 1

what was periglacial originally used to describe

Answer 1

places near to or on the fringe of ice sheets or glaciers

Question 2

what has the definition of periglacial changed to

Answer 2

areas with
- with permafrost
- with some seasonal temp variation
- mean temp in the summer is ABOVE 0
- freeze/thaw cycle dominates the landform creations
- distinctive ecosystem adapted to the periglacial envi

Question 3

is the periglacial zone easy to live in

Answer 3

NO very hard to thrive

Question 4

what process dominants the landform creating process in periglacial area

Answer 4

freeze-thaw

Question 5

what is permafrost

Answer 5

permanently frozen ground where soil temps have remained BELOW 0 for AT LEAST 2 years

Question 6

how long must soil temps remain below 0 for it to be considered permafrost

Answer 6

at least 2 years

Question 7

what are the kinds of permafrost

Answer 7

1. continuous
2. discontinuous
3. sporadic

Question 8

how deep can continuous permafrost reach

Answer 8

up to 1500 meters

Question 9

what is the mean annual air temp for permafrost to be deemed continuous permafrost

Answer 9

below -5 degrees ALL YEAR ROUND

Question 10

how does summer temps affect continuous permafrost

Answer 10

only results in very superficial surface melting = very little if any melting of permafrost

Question 11

where does continuous permafrost NOT extend

Answer 11

in all areas EXCEPT under bodies of water

Question 12

what is continuous permafrost

Answer 12

a sheet of continuous frozen material ALL YEAR ROUND

Question 13

what type of permafrost occurs in slight warm areas

Answer 13

discontinuous permafrost

Question 14

describe a landscape with discontinuous permafrost

Answer 14

islands of permanently frozen ground SEPARATED by small pockets of unfrozen LESS COLD areas

Question 15

why is zones with discontinuous permafrost slight warmer than continuous permafrost

Answer 15

because these zones have surface water bodies which warm the surrounding area based on water’s specific heat capacity

Question 16

what is the mean annual temp for discontinuous permafrost zones

Answer 16

between -1 and -5 degrees

Question 17

where does the continuous permafrost zone coincide

Answer 17

approximately with the 10C isotherm (where July temps do NOT rise above 10 degrees)

Question 18

what mean annual temp supports sporadic permafrost

Answer 18

it being JUST BELOW 0 degrees

Question 19

what does sporadic permafrost zones look like

Answer 19

isolated areas of permanently frozen ground remain BELOW the surface

Question 20

what are summer temps for supporting sporadic permafrost

Answer 20

above 0 degrees

Question 21

what are the two horizons in a permafrost profile

Answer 21

1. active layer
2. talik

Question 22

contrast the active layer and talik layer for permafrost

Answer 22

active layer
- very mobile layer based on summer temps melting surface layer of permafrost

talik layer
- unfrozen material within the permafrost zone often UNDER bodies of water

Question 23

what is the depth of zero annual amplitude

Answer 23

maximum depth affected by the annual temp variation

Question 24

how does the depth of zero annual amplitude vary

Answer 24

based on air temp and type of soil

Question 25

describe how above and below the zero annual amplitude affect permafrost differently

Answer 25

above the line permafrost is affected by temperature and will melt slightly in the summer below the line permafrost will remain stable and frozen all year round

Question 26

why is there so much water in permafrost zones

Answer 26

because there is no well established drainage system with the ground being frozen and water not being able to penetrate (so it sits ontop of the ground instead)

Question 27

Felsenmeer

Answer 27

exposed rock surfaces that have been quickly broken up by frost action so that much rock is buried under a cover of angular shattered boulders

Question 28

where is Felsenmeer common in Canada

Answer 28

Northern Manitoba

Question 29

what are two landscape features caused by frost wedging in permafrost zones

Answer 29

1. Felsenmeer 2. Patterned Ground

Question 30

what are two types of patterned ground

Answer 30

1. stone circles 2. ice-wedge polygons

Question 31

Stone circles

Answer 31

A type of patterned ground that consist of circular arrangements of slabs and small domes of mud with stony rims

Question 32

how were stone circles sorted to form the unique circle formations

Answer 32

based on many freeze/thaw cycles that sorted the surface debris where finer matter was heaved to the surface and coarser fragments around the edges

Question 32

how are stone circles produced

Answer 32

by the churning action of frost forming in UNSORTED glacial TILL and regolith

Question 33

what type of patterned ground in this is periglacial environments

Answer 33

stone circles

Question 34

what type of patterned ground in this is periglacial environments

Answer 34

ice wedge polygon

Question 35

where do ice wedge polygons occur

Answer 35

in permafrost peatlands

Question 36

what is an example of where to find ice wedge polygons

Answer 36

Hudson Bay Lowlands

Question 37

what do polygons mark in periglacial environments

Answer 37

location of massive ice wedges extending from the surface down 2 or 3 meters

Question 38

what are pingos

Answer 38

vegetated, ice cored mounds commonly formed above ponds or lakes

Question 39

how wide can pingos be

Answer 39

up to 100 meters across

Question 40

what happens in a pingo when the ice core grows TOO large

Answer 40

it will rupture the sediment cover and become exposed

Question 41

what are under pingos

Answer 41

large ice wedges

Question 42

what is this called in a periglacial environment

Answer 42

pingo

Question 43

what manner do pingos grow in

Answer 43

cyclic

Question 44

what type of system can a pingo form in

Answer 44

open AND closed

Question 45

open system pingo

Answer 45

those that receive water CONTINUOUSLY from ground water

Question 46

closed system pingos

Answer 46

form in regions with LIMITED GROUND WATER available SO use more melting permafrost

Question 47

Is this an open or closed Pingo

Answer 47

open system pingo

Question 48

Is this an open or closed Pingo

Answer 48

closed system pingo

Question 49

what are palsas

Answer 49

peat mounds with lenses of ice underneath

Question 50

where do palsas form

Answer 50

near surface water

Question 51

what periglacial feature is this

Answer 51

palsas

Question 52

what kind of topography is formed when permafrost MELTS

Answer 52

THERMOKARST topography

Question 53

what is thermokarst

Answer 53

the process where landforms result from the thawing of ice-rich permafrost and/or melting of massive ice

Question 54

what is thermokarst unique to

Answer 54

erosional process UNIQUE to permafrost with EXCESS ice

Question 55

what is thermokarst terrain characterized by

Answer 55

very irregular surfaces of marshy hollows and small hummocks formed when ice rich permafrost thaws

Question 56

does thermokarst have anything to do with ground or bedrock weathering

Answer 56

NO

Question 57

is there a lot of water in thermokarst topography

Answer 57

YES - based on huge amounts of ice melting

Question 58

how deep does permafrost penetrate in cryosolic soils

Answer 58

1 to 2 meters of the surface

Question 59

describe the soil characteristics if Cryosolic soils

Answer 59

mostly mineral with few organic soils because very little life can thrive can be either wet OR dry

Question 60

what are two characterizing features of cryosolic soils

Answer 60

1. always found in cold climates 2. frozen soil conditions for MOST of the year (needs to be thawed at some point)

Question 61

is the soil profile of cryosolic soils little or big

Answer 61

little based on the soil taking so long to form

Question 62

what is a dead give away form Cryosolic soils

Answer 62

horizons being mixed with a flame like structure based on cryoturbation (uneven freeze thaw)

Question 63

what are impacts of thawing permafrost

Answer 63

1. affects infrasture able to be built based on ground being unstable 2. ecosystems are changing and organisms have to adapt 3. leaking water to the oceans which affect water levels 4. frees methane into the atmosphere = increases global warming