How is a ocean basin formed
Features of the Ocean Basin
you
hey guys just a quick review of the
ocean basin a lot of people have asked
if I can put a video up showing what the
basic features are of the ocean basin so
here it is remember that test is coming
up soon so knowing these features going
to be really important because we
discussed these features during lab we
had them in lecture these are things
that you should absolutely know alright
let's take a look at this diagram here
and I'm going to concentrate on this
area right here on areas 1 through 4 to
be honest cut now part number 2 we
didn't really talk about they call that
the continental break we didn't really
get there but number 1 let's go ahead
and take this area over here and let's
go ahead and zoom all the way down over
here to the right because this picture
summarizes everything we're going to
talk about this part right here this
flatter part right here that's just
under the oceans this would be like
number 1 in the diagram above this is
your continental shelf
now the continental shelf is simply
defined as the part the shallow
extension of the continents that would
be underwater it's all continental crust
it's all shallow water it's still under
the oceans and it's kind of where you
start to make a transition from being in
land to being into the ocean but really
you're not truly in the ocean yet you're
just kind of that shallow transition
zone now if we go back over here and we
take a look at our diagram we're going
to take a look at number 3 now this
little area right here and let's go
ahead and zoom back in and concentrate
on area number 3 area number 3 is this
part right here this part right here is
called the continental slope now the
continental slope this is a major
transition zone from being in the
continents to being in the oceans this
is we're going to go from continental
cross to oceanic crust it's going to
start to make a transition and where did
that exactly happens depends on where
well I'm be honest which margin you're
talking about so in this diagram I
couldn't tell you where the exactly the
continental crust ends and where the
oceanic crust begins but the point is is
that this is a transition zone between
them and then if we take a look at a
little more detail here we have this
continental rise and I'll put that in a
triangle the continental rise is really
where the ocean truly begins this is
where you're going to find
all your basaltic rocks or all your
oceanic rocks this is also where
sediment from the land is going to wash
off the slope and go down into the ocean
basin I think in the book they talked
about a turbidity currents going ahead
and doing that well if we pan out from
here and we take a look at our bigger
diagram number four right here that
would be your continental rise now the
point is this is that all of these put
together one through four this all makes
up your continental margin where this
guy here number one is the Shelf number
three would be the slope and number four
would be the rise make sure you have
those notes down and then we'll take a
look at the rest of the ocean basin all
right so when we talk about the ocean
basin we're really talking about this
whole part right here this entire thing
the ocean basin is just a generic term
from continental margin to continental
margin and all the features in between
so this whole guy right here is an ocean
basin but the ocean basin has some
features to it it's going to take a look
at some of the flattest parts of the
features now people get this confused a
lot number five right here and number
five right here and number five right
here are all the same thing
those three number 5s are all abyssal
why SS al Plains plai n s and abyssal
plane and like we talked about in class
abyssal Plains are the flattest parts of
the ocean they're essentially
featureless they're not the deepest
parts of the ocean but they really have
nothing going on it's hard for life to
really exist down there and great
abundance because it's so deep within
the ocean sunlight doesn't get down
there very well but there is still life
down there but the main point here is
that these are really the flattest parts
of the ocean alright so let's talk about
the deepest parts of the ocean that
would be number seven right here these
guys here this is the trench the deep
ocean trench and the big thing about
ocean trenches as they formed from
convergence they formed from a
convergent boundary and if we take a
look and zoom in on this diagram down
here on the Left we're going to see that
at work we talked about oceanic crust
subducting underneath another piece of
crust and when that happens we get this
feature right here this little divot or
this pit right were the two pieces of
crust meets where the subduction is
happening this is where the trench will
form and at the trench you'll commonly
get earthquakes and stuff like that we
discussed about all that the melting the
rising of the magma the volcanoes either
on the continents or within the oceans
but the big point here is that these
trenches these form the deepest parts of
the ocean so if we zoom back out and we
take a look here that's why we're
looking at the stuff when we look at
this diagram this feature goes down
lower than anything else in fact this is
also where the lithosphere is the
thinnest the thinnest lithosphere is
found at the oceanic trench the thickest
lithosphere would be found on the
continents on the mountains but this is
where the thinnest little sphere is okay
so let's go ahead now and take a look at
a couple of other features that you find
along the ocean basin one of them is
this guy right here number nine number
nine is a mid-oceanic ridge and I know
it's kind of hard to tell in this
diagram especially since I circled over
it but the top of this feature looks
like this and we talked about
mid-oceanic ridges back when we talked
about plate tectonics we know that these
are divergent boundaries or it trenches
a convergent boundary a mid-oceanic
ridge is a divergent boundary and this
is where oceanic crust is spreading away
from the volcano out towards the edges
of the continents and was a key piece of
evidence that Harry Hammond has used to
prove his idea of plate tectonics
alright let's go ahead and take a look
at number eight number eight is a
seamount now it's hard to tell from this
picture it's either a seamount or it's a
Guyot it's really hard to tell but
they're really similar the only
difference is this here we have a
seamount kind of a rounded or jag
did eroded mountain underneath the water
then a Guyot is very similar except it's
flat-topped and Anatole is very similar
to that where you have a seamount or a
Guyot and it's got a coral ring on top
and that's the big difference so a
seamount is somewhat rounded and a Guyot
is essentially flat and Anatole has that
coral ring along the top and that's the
difference between the three but the
take-home message is this these are all
eroded features found on the basin of
the ocean floor and lastly we have
number 6 over here number 6 is simply an
island and it is a feature of an ocean
basin why because it extends up from the
ocean basin it's not just a little piece
of land floating out there in the middle
of the ocean alright guys so here's a
complete snapshot number one the
continental shelf number three the slope
number four the rise the three of those
things make up a continental margin all
the number fives are abyssal Plains
number six is an island number seven is
a trench number eight would either be a
sea mount or guyot and earned for an
atoll depending if it's rounded flat or
if it has a coral ring number nine is a
mid-oceanic ridge and over here we have
another continental margin we have the
rise the slope and the Shelf leading up
into the continents I hope you found
this review helpful if you have any
questions please feel free to send me a
message on Edmodo or send me an email
one last quick note sorry trenches don't
forget that trenches form from
convergent boundaries and that
mid-oceanic ridges formed from divergent
boundaries and again I hope you found
this video helpful if you have any
questions please feel free to ask me in
class or send me a message on Edmodo
