Lecture 27 more glaciers

Today:

Chapter 12:

Glaciers & glaciation


Today’s Lecture:
Chapter 22:
Glacial erosion.

Fig. 22.01 b

Glacial deposition.

Causes of glaciation.

Stephen
Chapter
23

Marshak

Aspects of global change.


Glacial deposits
 Sediments of glacial
origin are called “drift”.
 Deposits 10-100’s m thick
 Consist of materials

dropped when ice melts.
Deposited by

Unstratifed drift: glaciers
(Called Till or tillite)
Stratified drift:

melt water streams
or lakes.
(Example: Glacial varves)


Fig. 22.21 c
W. W. Norton

Glacial deposits are called drift…


Fig. 22.22 a
Stephen Marshak

Unstratified glacial drift is called till…


Glacial Erratic


Fig. 22.22 c
Courtesy Duncan Heron

Stratified glacial Lake deposits


Loess…
Fine grained
glacial material
(rock flour)
redistributed by
the wind.


How to find a meteorite…

Fig. 22.14
W. W. Norton


Glacial deposits
● Moraines

end moraine: ridge of till at end of stable glacier.
recessional moraine: a series of terminal moraines
formed when a glacier recedes in steps.
ground moraine: blanket of till left when
a glacier retreats rapidly.
lateral moraine: till deposited along the side of glacier.
medial moraine: formed where two or more
glaciers merge.

Glacial deposits

● Lateral moraines:
formed along
margins of glacier.



GLACIERS

Glacial deposits
● Medial Moraines
Medial moraines: Joining of two or more glaciers.


Fig. 22.21 a
W. W. Norton


Glacial deposits
Unstratified drift

● Moraines

End moraine: ridge of till at end of stable glacier
Recessional moraine: all other end moraines


Fig. 22.23 b
W. W. Norton

Fig. 22.24
W. W. Norton. Adapted from
Tarbuck and Lutgens, 1996


Glacial deposits
Stratified drift:

● outwash plains
● kettle lakes
● eskers


Kettle lakes…

Fig. 22.26 a
W. W. Norton


Fig. 22.26 b
W. W. Norton



Glacial deposits
Stratified drift landforms

● outwash plains

● kettle lakes
● eskers


Fig. 22.23 a
W. W. Norton


Fig. 22.27
W. W. Norton


GLACIERS

Glacial deposits

Stratified drift landforms

● outwash plains
● kettle lakes
● eskers