GEOG 216 Lecture Notes - Lecture 12: Frost Heaving, Periglaciation, Patterned Ground
18 May 2018
School
Department
Course
Professor
Range&of&forms&that&processes&are&responsible&for
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Repetitive&things&in&nature&–what&do&they&denote?
Something&that&is&sufficiently&common&environmentally&that&it's&acting&
over&the&entire&landscape
○
What&acts&in&a&uniform&fashion?&Climate
○
Cold&–not&absolute,&but&rate&of&temperature&change
○
•
Exercise& 4:&glacial& landforms&–recommended&reading:	,&Strahler&and&
Archibald,&2005,&"Permafrost"
•
Periglacial&(near-glacial)&environments&–cold&non-glacial
•
Frost&action
•
Permafrost
•
Ground&ice& and&ice& wedges
•
North-facing&slopes&should&receive&less&solar&radiation&than&south-facing&slopes
•
Provide&interpretation&of&data
•
Cold&non-glacial&environments&=&peri-glacial
Glaciers& exist&where&mean&annual&air&temperature&(MAAT)&are&sufficiently&
cold&to&favor&the&preservation&of&snow&
○
•
Freezing&and&frost&action
T>0°rees&C&in&phase&of&"pure"&liquid&water&at&sea&level&=&ice
○
•
Heave&by&needle&ice&–solifluction/gelefluction
•
Frost&action:&frost&heave
Frost&heave&is&due&to&the&volumetric&expansion&of&water&in&the&soil&when&it&
turns&to&ice
○
It&sorts&clasts&by&preferentially&heaving&and&reorienting&larger&stones
○
•
Patterned&ground&–regular&geometric&patterns&on&the&ground&surface&–
generally&thought&to&be&polygenic&in&origin&–frost&heave&is&a&key&process
•
Permafrost&distribution
Two&basic&zones:
Continuous
§
Discontinuous
Sporadic
□
Widespread
□
§
Also,&alpine&and&subsea&permafrost
§
○
•
Ground&ice
When&ground/soil&drops&below&0C&all&of&the&water&contained&in&the&pores&
or&as&groundwater&will&begin&to&freeze;&ground&ice&is&defined&as&"all&ice&
occurring&beneath&the&surface&of&the&ground"
○
Ground&ice& comprises&an&important&component&of&permafrost&sediments&
and&plays&a&significant&role&in&the&evolution&of&periglacial& landscapes
○
Russian&approach&–sedimentary/igneous&ice,&etc.&–geological
○
•
12.2:%Permafrost%and%periglacial%geomorphology
Thursday,& April&5,&2018
10:06&AM
