[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.