Dust flux, Vostok ice core

Dust flux, Vostok ice core
Two dimensional phase space reconstruction of dust flux from the Vostok core over the period 186-4 ka using the time derivative method. Dust flux on the x-axis, rate of change is on the y-axis. From Gipp (2001).
Showing posts with label Antarctica. Show all posts
Showing posts with label Antarctica. Show all posts

Saturday, February 22, 2014

A professional regret

I was asked to send a copy of the 2001 Paleoceanography paper to somebody recently and I noticed this one figure that I wish I could do over again.


The dashed curve in the upper graph should really have been reproduced in the lower one. Unfortunately I was hidebound by my recent discovery that insolation (that is the amount of sunlight received at certain latitudes on earth) drove the rate of change of global ice volume, rather than the ice volume itself, as was commonly supposed. So I likewise compared insolation to the rate of change of temperature in Antarctica, as deduced from the Vostok ice core temperature series.

Here is what it would have looked like had I compared insolation to Antarctic temperatures


It looks like a reasonable comparison, in that geological arm-waving way. It is a bit curious that the Antarctic temperature responds to northern-hemisphere insolation, but that's part of the wonder of the world.

As an aside--just before publication, the journal editor questioned me very closely about the title. He presumably thought it was some kind of joke, and this was a serious journal that published serious science, and titles were definitely no joking matter. I managed to convince him that it was not a joke. But it was!

Tuesday, July 16, 2013

Selecting areas to stake

The British Antarctic Survey unveiled new imagery last month depicting the Antarctic bedrock surface in greater detail than previously.

Via (image may be quite large when clicked).

Love the subglacial tunnel valleys.



The World Complex helped the Brazilians map some potential oil-bearing rocks at the extreme left of the above image.

I'll be staking out the land just above the mountain ridge across the middle of the page. Cu-porphyry. Just in case the ice melts.

Tuesday, July 17, 2012

Brazilian days

In honour of being added to the IKN blog list, I thought I would put up a posting with a little LatAm flavour. I have to go back in time to 1993 when I joined a Brazilian expedition to Antarctica.


It all started at a party. My thesis supervisor knew of this project, and had been invited to assist the Brazilians, but was unable to for some reason. So I asked if I could go. I had had experience in the Canadian Arctic, and so it seemed a reasonable fit. The Brazilian program consisted of academics and Petrobras geologists. I was on one of several teams, and our goal related to developing an understanding of glacially influenced marine sediments, which was to be applied to the Parana Basin in Brazil (a major oil producing region generally only understood from boreholes).

I had initially planned to spend a little time working on my Portugues before flying off to São Paulo--but I was working on another project which didn't finish until late in the evening before my flight. So there I was trying to rest up and study Portuguese on the flight down. I decided to focus on whatever I needed to learn in order to get through the airport, as my instructions were to phone one of the geologists from the airport for a pickup.

To try to understand my mindset at the time: in North America (in January 1993), Brazil was believed to be a dangerous place. Before the trip some friends of mine were taking bets on the likelihood that I would be killed at the first intersection I encountered. Inflation was running at about 25-30% monthly, so managing currency conversion for a long trip was key. I had been told by a colleague that when he was about to begin a stint in Brazil, he arrived planning to transfer money from Canada to a local bank in Brazil, but on the day he arrived the banks were closed by order of the President (possibly the event described here).

My Brazilian colleagues had arranged for me to stay in a room at the USP, which was closed for the holidays. I was asked to wait--there was some political turmoil with the program, and there was some doubt as to whether the trip would go ahead. After awhile I decided to wander around to locate food and amenities, which turned out to be a good idea because my handlers didn't come back for some days.

I chose a street at random and walked along it, eventually arriving at Praca Pan Americana. After narrowly escaping being run down at the traffic circle, I saw the wisdom of crossing the street in the middle of blocks like everyone else seemed to. There was a grocery store, Se. The parking lot was pure chaos. I ended up buying a lot of oranges and bananas, because my guidebook was unclear about whether or not the water was good to drink (it was).

A different street led me past what were probably the student hangouts, at least when the University was open. I had a sandwich at a hole-in-the-wall cafe with the loudest, most exciting futbol game in history blaring over the radio. Further up the street I bought a green coconut, and walked back to the residence. A soft warm rain began to fall. Sublime.

Over the next few days my confidence increased and I wandered farther away from the residence, eating at a variety of hot dog vendors and other hole-in-the-wall cafes with similarly exciting futbol games coming through their radios. I have to say that I never encountered anything but goodwill anywhere I went; not to mention great patience with my ongoing struggle with portuguese. Even the poor bank manager who had to explain to me three times why I couldn't convert foreign currency at the bank. One day, on returning to the residence, two of my Brazilian colleagues were waiting for me, and it was time to go.

We flew by commercial flight to Rio where we stayed one night in a hotel some distance from the beach. My Brazilian colleagues impressed upon me how dangerous it was for us to walk around Rio at night (as there were only seven of us). They all showed  me various methods of hiding cash. I was disappointed when the restaurant was across the street. It was well-lit, and everyone inside was well dressed. Most patrons donated some of their leftovers to children begging on the patio.

The morning featured a sunrise over a mist-shrouded Sugarloaf. We raced off to the military airport in the fastest taxi in the world. Eventually we were packed like sardines into the plane below, and headed south.


Military transport to southern Brazil, en route to Antarctica.

The first leg of the flight was to Pelotas, in the Rio Grande do Sul area. It was a nice old town, with cobblestone streets. Police were armed with batons. At night, the locals sat out on their porches facing the street, and the whole town had a happy vibe.


Street in Pelotas. In the foreground is Victor, a geologist at Petrobras.

The second leg was to Punta Arenas in southern Chile. My initial impressions of the place as we took a bus into the city from the air force base was that it was a lot like Newfoundland--both in topography and in the colour of the houses in the fishing villages.

Chile, on the whole, seemed a lot calmer than Brazil. Currency exchange was easier too.

The last leg of the flight was to the Marsh station on King George Island (the South Shetland Islands). If you talk to a Chilean, you would discover that it was part of Chile. Very few others in the world would agree. But there were families there, who told me their children were born in the local hospital, so it looks like Chile is building a colony.


We were transferred onto the Barão de Teffé, a support vessel for the mission.


Me with my bowling-ball haircut, surrounded by Brazilians. Sadly, these weren't the 
ones coming out to the field with me.


Flying to camp.


Some of our impressive supplies.

Supplies, yes. Very nice. Several cases of wine. Chocolate. Lots of food. My experience in field camps up until then had been dried food, all of which was carried in by hand. I'd never been in a camp like it. I have to say, it was very civilized. After a typical day in the field, we would spend a couple of hours talking about the day, drinking wine, and eating chocolate, while the cook prepared dinner. Sometimes for a change in pace we ate canned palm hearts or sardines. They also had a few cases of cola, and a guarana drink.

I had a very important role at afternoon tea time. It appears to be rude to take the last piece of chocolate, or so I infer from the fact that none of my Brazilian colleagues would take it. No matter how small it became, they would always break it and take only a part. I would eat the last fragment, giving us the excuse to open a new package.

After five weeks, we were picked up again. On one of the first meals back on the ship we were given an apple for dessert, which I ate in about ten seconds. Everyone else at the table ate theirs with knife and fork.


Camp on King George Island.

Saturday, January 15, 2011

Self organization in geological phenomena, part 2: stone and soil stripes

Today the World Complex travels to Antarctica (via the wayback machine, to 1993). (Maps were prepared for some presentation given at about that time).

At the end of the Antarctic peninsula (around 60 W and north of the Antarctic circle) there is a grouping of islands called the South Shetland Islands.




One of the South Shetland Islands is called King George Island. It is dotted with research bases, including Marsh Station and Ferraz Station. The Brazilians had a research base within Admiralty Bay serviced by a naval vessel called the Barão de Teffé.

Brazilian research vessel Barão de Teffé in Admiralty Bay (viewed from shore).

I spent six weeks in the field with a team of Brazilians on a site near Mazurek Point. It was one of the best-supplied field camps I've ever experienced (only Ice Island was better supplied, but the Brazilians outdid us Canadians by supplying abundant--really abundant--wine and chocolate).

Six of us at Marsh Station (the seventh, Jefersòn, took the picture). 
I am at the left, along with Paulo dos Santos, Antonio Rocha-Campos, 
Roland Trompette (famed for his West African work), Ricardo (our mountaineer), 
and Alexandre Uhlein.

 Iceberg with supply helicopter for scale, viewed from our base camp.

The goal of the project was to study the Polonez Cove Formation, which mainly consisted of interbedded diamictites, turbidites and volcaniclastic flows of Oligocene Age. Actually, at the time, the age hadn't been completely established.
 
The base camp was set up on Low Head (that little x near the bottom of the map). Most of the areas of interest were in the numbered sites along the coast running up the right edge of the map.

Wypianski icefall, which will play a role in a later posting, pretty much covered up anything of interest. The interesting rocks were exposed along the coast from Low Head, across Mazurek Point and on up to Lions Rump at the top of the map.

But that irregular area marked SSSI (site of special scientific interest) was off-limits to us, as it was a sea lion breeding area. Unfortunately, there was a very interesting geological transition close to the boundary, where we found a series of stacked debris flows interbedded with turbidites intercalated with a series of volcaniclastic flows coming in from another direction.

But geology sometimes has to yield to biology.

Luckily, we went in summer.

The snow cover was ephemeral. When the snow disappeared, on a slope not far from the base camp you would see these . . .

Soil stripes near Low Head, KGI.

They weren't actually a target of our study, and to be honest, we didn't know what they were. What we observed looked like ripples, with alternations between gravel and lichen- or moss-covered silt. They were oriented perpendicular to the slope and were consistent in thickness and composition over a distance of tens of metres.

Details of soil stripes

Further upslope where the debris was much coarser (fresh angular cobbles), there were similar, albeit larger structures.

Stone stripes, KGI.

I had originally thought this to be a form of fluting, however all of these rocks, which have been shed from the ridge at the top right of this photo, are actually lying on top of ice, albeit a long way down. This patterning is formed by a succession of freeze-thaw cycles, which result in sorting the rocks as they move downlope. Similar images can be seen here.

Formal explanation for these features was published in Nature in 1993, so I had a nice read when I got back home.