24 January, 1998

Good morning everybody!  It it 6:30 am and I am on watch.  We will 
continue to collect images of the sea floor today.  Tomorrow we will 
collect more cores and grab samples!

Today we continue our work near Cape Adare.  The information we gather 
will be used by Julia Smith, a graduate student, to help determine how 
big the glaciers got during the last ice age.  The sea floor around along 
the Pennell Coast has shallow flat banks that are about 200 meters (600 
feet) deep.  Next to these flat banks are deep troughs (about 800 meters 
or 2400 feet deep - that's about a half mile deep!) that go from the land 
into the ocean. We can trace these troughs using our imaging systems.  We 
think the glaciers may have flowed through these troughs when the ice was 
bigger. In the troughs we see layers of sediment.  We will core these 
layers later.  Why do we want to survey an area (collect images of the 
sea floor and the layers below the sea floor) before we collect cores?

For those of you who may wish to follow the position of the ship, we are 
at:

70 degrees 32 minutes south latitude
167 degrees 47 minutes east longitude 

I will start writing our position in each of my journals.

We see many different types of ice in Antarctica. All of them are very 
beautiful!

There are huge ICE SHEETS.  Two big ice sheets cover about 97% of 
Antarctica.  They average about 3000 meters thick, or 9000 feet - that 
means the ice is WAY over a mile thick.  The biggest ice sheet is the 
East Antarctic Ice Sheet.  The smaller one is the West Antarctic Ice 
Sheet. Can you find these on a map?  These two ice sheets hold about 70% 
of our world's fresh water!  Ice sheets are ice sheets because they are 
big and cover the land under them.  Ice sheets are a type of glacier - 
just a big type!  They flow very slowly, being pulled by gravity.  These 
ice sheets touch the land beneath them. The Greenland Ice Sheet is 
another ice sheet.

ICE SHELVES are big FLOATING pieces of ice.  They are attached to the 
land.  When ice sheets flow into the ocean, the ice floats, much like ice 
cubes float in a glass of water.  Can you find Ross Ice Shelf on a map?  
Ross Ice Shelf is a floating ice shelf.  The West Antarctic Ice Sheet 
flows into the ocean, and the floating part forms the ice shelf.  The ice 
shelf is the size of Texas!  What other ice shelves do you see in 
Antarctica? Can you find the Ronne/Filchner Ice Shelf in Weddell Sea?  
The West Antarctic Ice Sheet also "feeds" this ice shelf.  How about the 
Amery Ice Shelf?  The largest glacier in the world, the Lambert Glacier, 
feeds the Amery Ice Shelf!

You may see some ICE TONGUES on the map of Antarctica.  These also are 
floating ice.  Look at the coast along Wilkes Land. On most maps of 
Antarctica this is along the bottom of the map. Can you find the Mertz 
and Ninnis Ice Tongues?  Why are they called ice tongues?  Why do you 
think you see ice tongues where you do?  Are they near glaciers?  Ice 
Tongues form where glaciers flow out to sea - they are smaller and more 
narrow than ice shelves.

ICEBERGS "calve" or break off from the ice tongues and ice shelves. These 
can be quite large!  One of the biggest icebergs was twice the size of 
the state of Rhode Island!  When the bergs come from an ice shelf, they 
are flat-topped - these are the biggest! When icebergs break off glaciers 
at the coast, they are very irregular in shape. 

In my next journal I'll write about the different types of SEA ICE - this 
is another type of floating ice but it is thinner and forms in the ocean. 
 One of the mates on the ship has promised to tell me all about the 
different kinds of sea ice we see!

Send some more mail!  Yours truly,

E. Shackleton Bear