Alpine Glacier Basics

[upbeat music]

Professor: Alright guys, so this
video is going to get into the basics of

Alpine Glaciers remember we talked about
Alpine Glaciers before break and we said

that Alpine Glaciers are glaciers that
were exclusively in the mountains.

We'll talk about continental glaciers a
little bit later on.

During this video you should make sure
you get some good notes on these things

here, we're going to do some intro and
basic stuff, but we're going to mainly

focus on the erosional features of
Alpine Glaciers and we'll also get into

what happens after the ice melts in a
glacier, what do you see in the ground

after all that ice melt in the glacier.

We'll talk about what Moraines are, get a
quick introduction, again make sure you

get really good notes here, we're going to
cover those notes again in class, we'll

look at a whole bunch of examples in
class, a whole bunch of pictures, I don't

have any fancy demos or anything to put
into this video to incorporate like

the last few, uh, just because, well, you
know, we're not in the mountains here,

we're in flat lands so it's hard for me
pull all that stuff together.

So, let's go ahead and get into it, if you
have any questions feel free to

send me an email, I'll get back to you
as soon as I can.

Alright, let's take a look at this
glacial landscape here, all of this was

formed by ice, everything you're taking a
look at here and something you need to

keep in mind here is that these mountains
didn't start out sharp and jagged

like this, these mountains transformed
into this kind of landscape over many

thousands of years of weathering because
of the glaciers that covered

this whole area.

Now, the glaciers that you're looking at
right now are much smaller

than they used to be, how can I tell?

Because I'm looking at this big, massive,
view shaped valley right here.

A glacier bulldozed its way down the
side of the mountain and made this big,

huge U-shaped valley, that's something
that's very characteristic of glaciers

is as they move down the mountain in
response to gravidity and internal

plastic flow, basil slip, the things we've
talked about in class, they bulldoze a

huge U-shaped valley going down the side
of the mountain, there's another one here

off to the left, and you can also tell
a glacier came down here because

of the big mountain water channel, so a
glacier was here, the terminus is about

right here, right now, but it covers all
of this at one time and that's kind-of

what's difficult to imagine here,
is that this was once a rounded top

mountain and then a glacier came by and
through erosional processes, like ice

wedging and abrasion, it knocked all that
down and made these

sharp jagged peaks.

What we are going to do is, we're going to
go ahead and identify what some of the

things in here are, define some vocab
words and we going to come back to the

picture and see if you can spot them out.

Alright, so let's go ahead and get
into it, get your notes ready.

Alright, so let's go ahead and get into
some of this vocab, we're going to cover a

few things here on this slide.

First of all, I already defined it, the
main glacier, this is the biggest part of

the glacier right there, and then we have
some tributary glaciers down here.

So just like rivers, tributary glaciers
are a glacier

that feeds into a larger glacier.

If you didn't get that down from the
previous slide, make sure you got it.

Here's our big U-shaped valley, this big
erosional valley that the, uh,

main glacier formed as it bulldozed its
way down the mountain, and now we're going

to also start with a few of the other
words that are here, like this one right

right, Cirque, C I R Q U E, cirque; and
here's a cirque right up here, and there's

another cirque here, and there's another
cirque over here and what cirques are,

are bowl shaped depressions that form
because of ice wedging.

So what you need to picture is that you
have this rounded mountain and there's

a crack in the mountain, a glacier kind-of
wiggled its way into-- or some water

wiggled its way into that fracture there,
got cold, froze, expand, got bigger,

and then eventually this process is going
to keep on happening where you get this

massive piece of ice embedded into the
side of the mountain.

It's going to make the mountain a little
bit less rounded, it's going to make it

sharp, it's going to make it jagged, but
what you're going to wind up with is this

bowl shaped depression in the side of the
mountain right here

and that's what a cirque is.

Alright, next we have this word right
here, it's called an Arête, it's a French

word which is why it has the little
carrot up there, at least

I think its French.

Um, and an Arête is this ridge right its
these ridges that separate these small

tributary glacial valleys right here,
all these little ridges that we have

going on right here, there are Arêtes,
and these again are erosional ridges

and again, our mountain kind-of started
out like this at some point, erosion took

over and we wound up with these separated
valleys, these separated glacial valleys,

divided by this high ridge right here and
that's what an Arête is, it's in a ridge

that's formed by erosion and it generally
separates smaller glacial valleys.

Let's go ahead and take a look here,
here's an Arête, here's another Arête

coming up, and here's another Arête coming
up, and when they all join you get a horn,

and a horn is basically a pointed top to a
mountain to a glacial mountain.

So here's an Arête coming up here, here's
an Arête coming up here, here's an

Arête coming up here, so this is also
a horn, it's a pointed

top to a glacial mountain.

Now, remember again, it used to be like
this, but erosion took over mainly

ice wedging and abrasion and we wound up
with this pointed top mountain

right here and that would be a horn.