Discover 1-2

22

January/February 2018^ DISCOVER^31

FAR RIGHT: MAX VAN WYK DE VRIES

Q

What happens to the iceberg

now?

A

We don't have much information

to go on because this is such a

large iceberg. The Weddell Sea, which

is where all the action is occurring, is

choked with sea ice all year round, so it’s

not an open ocean that things can float

free on. Icebergs have been known to exit

this area — quite big icebergs — and head

up into the Southern Ocean. How quickly

this one will do that is difficult to answer.

It might take years and years.

Q

What can Larsen C’s response

to the calving teach us?

A

There’s a natural experiment going

on here. What happens to an ice shelf

of this size when you take a large piece

out of it?

Q

What’s more scientifically

interesting: the iceberg calving

or what happens next?

A

The thing that doesn’t really interest

us is the calving. As soon as we saw

this rift starting to cut through, we knew

it was going to happen. But the rift itself

— how fast that cut through and what

held it up — is teaching us a lot about

ice shelves. And now we have another

very interesting opportunity to study the

reaction of the ice shelf.

Antarctica’s Fiery

Underbelly

❯

MUCH OF ANTARCTICA is covered with a thick sheet

of ice that obscures what’s below, and it’s tempting

to consider the continent as geologically frozen as

its landscape. But in the land of snow and ice, there’s a

hidden fire.

Reporting their findings in May, geology student Max

Van Wyk de Vries and his colleagues at the University

of Edinburgh used radar surveys to reveal 91 previously

unidentified volcanoes in the West Antarctic Rift System, an

area where plate tectonics are tearing the continent apart.

Some seem to have erupted in the last few millennia.

Scientists aren’t sure how, or even if, the volcanoes will

affect the overlaying ice sheet. Another pressing question:

Will eruptions increase in Antarctica as the ice thins, similar

to Iceland after the Ice Age? What’s clear is that no other

place on Earth contains as

many subglacial volcanoes,

and that’s a real wild card

for researchers attempting to

model the ice sheet’s retreat.

— ERIK KLEMETTI

Elevation (m)

2,000

0

-2,000

-4,000

2

2.5

3

3.5

4

4.5

5

Confidence factor

15.5 miles

A giant

iceberg

calved from

the Larsen C

ice shelf

in July.

Larsen

ice shelf

Volcano

study area

ANTARCTICA

Researchers used radar to map

the landscape underneath

Antarctica’s ice sheet and then

rated how sure they were that

a given feature was a volcano.

(A rating of 5 is most confident.)