Friday, January 29, 2010

The bugs and the paleomagician

We are still on site and drilling. A few icebergs have been sited on the horizon and the Captain and the ice observer are watching their movements. This is important, because we are stuck 800 m into the sea floor with a drill pipe and it takes some time to pull all that pipe and to be able to move out of the way. These icebergs are big: they can be several hundreds of meters to miles long and the ship is dwarfed by such a size. In the mean time we are busy with our science.
This is the Paleontology Lab. Three paleontologists are busy looking for microfossils who can give us an age for the cores we are recovering. In Antarctica, the diatoms (microscopic algae) are the most important group for the shallower depths in the core. They evolve fast and there are many different species, so overlapping age ranges produce good time resolution. Unfortunately at greater depth below the sea floor it doesn't work as well. Upon burial below sediment layers several hundreds of meters below the sea floor where the temperature and pressure is greater, the skeletons of these organisms (called frustules) dissolve. The frustules are made of opal, a type of silica, and have characteristic shapes, which are lost through dissolution at burial. Fortunately we have other microfossil groups that we can work with to provide an age and then there is the paleomagician!
The paleomagnetists measure the magnetic properties of the sediments. The sediments acquire the magnetic properties through the workings of the Earth's magnetic field. Through time the Earth's magnetic field has been shifting from pointing into the Earth at the North Pole (normal polarity, like today), to pointing into the Earth at the South Pole (reverse polarity). Minerals in the sediments align themselves with the Earth's magnetic field during deposition and so a polarity record becomes entombed into the sediment layers below the sea floor. The record of the Earth's polarity reversals is known from areas of seafloor spreading, where volcanic rocks can be dated through radiometric dating (using radioactive decay of elements in minerals). This record is known as the geomagnetic polarity time scale. Paleomagnetists can count magnetic reversals in the cores back in time and try to match the cores to the geomagnetic polarity time scale to provide an age.

One interesting aspect of our current location is that we are almost right on top of the magnetic South Pole. It means that if compass needles were freely suspended they would point straight up. The magnetic North and South Pole do not coincide with the geographic North and South Pole. In fact the magnetic poles are always on the move. The magnetic South Pole is now located off-shore Wilkes Land in our area, but about a century ago it was further inland in Antarctica. Douglas Mawson, an Australian Antarctic explorer tried to find it back then, but he barely survived the trip. He almost died of vitamin A poisoning because his sled fell down a crevasse and he and his pals only had the sled dogs to eat, with their livers rich in vitamin A. His two pals (Ninnis and Mertz) died. His journal is a great read, but I am glad our tip is so much more convenient!

Monday, January 25, 2010

Green mud with burrows and no ice rafted debris

Todays core logging provided some nice animal burrows that were made more than 10 million years ago. As the creature was crawling through the mud, the burrow backfilled, which produced these nice structures. Drilling is continuing at a fast pace and the drill string extends to hundreds of meters below the sea floor. We are now not seeing many large stones or ice-rafted debris, so we may have traveled back into a warmer period already. These rocks show us that the Antarctic climate was changing in the past: from iceberg environments to an environment with no icebergs and a strongly burrowed sea floor. Pretty interesting huh? Let's see what tomorrow will bring...
Also: the video of our second week on the ship can now be viewed here.

Saturday, January 23, 2010

Olive green mud

A core is coming up every hour now and everyone is busy in their labs. Today we logged green mud with diatoms and gravel. Diatoms are microscopic single-celled algae and the gravel indicates the presence of ice bergs. Sedimentologists make visual observations on the cut face of the core and record these on logging sheets and in the database. We also use a microscope to examine smearslides: smears of mud on glass microscope slides. These smears provide an estimate of how much of the sediment is made up of diatoms and other fossil fragments, and how much is made up of minerals, such as quartz and feldspar (see below). The proportions of each component are changing throughout the core and are caused by changes in the paleoenvironment and paleoclimate of Antarctica. Our target at this site is to drill deep into the sea floor and recover rocks from a time when Antarctica was ice-free with forests on its coasts. So far we have seen evidence of ice rafting in the form of pebbles, so we haven't yet traveled far enough in time to reach our goal.




Photomicrograph of a smearslide with abundant diatom fragments.

Friday, January 22, 2010

On to the next site

Unfortunately we had to abandon the first hole (Site WLRIS-6A in the map) after only 31 m of drilling. It was all composed of coarse sand and gravel (see photo) with just a little bit of mud. Coarse-grained sediments are very difficult to drill, because they are not coherent. The drillhole becomes unstable and is caving in, which can cause the drill bit to get stuck in the sea floor. To prevent this, we had to abandon the hole and go to a different site to reach our objectives. The sand and gravel was an unexpected discovery and we are still trying to explain how it got there, although we know it came from Antarctica. Because we are exploring a part of the Antarctic margin where no one has ever drilled before, such surprises are expected. Our next site is to the northwest of WLRIS-6A. We are there now, and drilling has just started. When I wake up tomorrow morning there will be more core and there will be more discoveries. Stay tuned, it will get even better.

Wednesday, January 20, 2010

Core on the floor!

After some problems with APC coring (see drilling equipment class a few posts ago), we have our first core on deck as of this morning. I woke up with the message "core on the floor" on the PA system at 11 AM. Yesterday two attempts were made to launch the piston corer, but one shoe broke off, and the other bent so severely that the drillers couldn't pull it up through the drill pipe. The only solution was to pull all the pipe out and to try again with a rotary core barrel. It was pretty obvious that there was something very hard out there near the sea floor and this morning we found out what it was: gravel. The first core was cut into sections and is currently sitting in the core lab to equilibrate, so that the physical properties will not change while these are measured on the core. After the physical properties have been measured, the core will be split into two halves, and we, the sedimentologists, get to describe the cut face of one half. The other half will be sampled.
The core comes out of the core barrel in a 9 m long plastic tube (see photo taken on "the catwalk"). There the length of the core is measured and it is cut into 1.5 m long sections by the curator and his team. In the photo, you can see co-chief scientist Carlota Escutia (in front) and the core techs placing the second core in the holders. This happened just now. The core feels quite cold when it comes up. This is the main reason that it is necessary to hold the core in a rack in the core lab for a while so that it can get to room temperature first. Temperature effects physical properties, such as density. You may know that most materials expand when they heat up, and this reduces their density.

P.S. For all you teachers and professors out there: feel free to use anything from this blog for your classes. This is for you and your students, so that you can take part in the experience! Feel free to ask questions via the comments as well. I will try to answer them as well as I can or get an expert from the rest of the science team to do it if I can't. Additional resources can be found on joidesresolution.org.

Tuesday, January 19, 2010

On site!

When I woke up this morning I was just in time to witness the deployment of the beacon (see photo) to mark our first drill site. We are at 63° 50.48’S, 138ยบ 49.40’E in 3773 m of water. The beacon is a very important piece of equipment because it plays a role in keeping the ship on site. An automated dynamic positioning system drives a series of thrusters that can move the ship sideways, backward and ahead. The beacon will descend to the sea floor, produce a signal, which is received by the ship. If the ship drifts too far off the site the dynamic positioning will respond and thrusters will automatically turn on to move the ship back into position.

During the deployment of the beacon the drillers were already busy putting together the bottom-hole-assembly (BHA-see the blog a few days ago). A lot of weight was added to the BHA to keep the drill string straight in the deep water that we are in. We are going to start with advanced (hydraulic) piston coring (APC) to refusal and will then continue with the extended core barrel (XCB) in the more compacted sediments at depth beneath the sea floor. The drillers are currently tripping pipe, which can take a while in deep water. They first have to give out 3773 m of pipe to reach the sea floor!

Below are some movies illustrating the drilling preparation activities. If all is well we will have some core tomorrow! It will mean we cannot post to our blogs so much, but I will try to post as much as I can.



Monday, January 18, 2010

Bergy water

The forecasters at the National Snow and Ice Data Center were right: we encountered bergy water (icebergs) in our transit to the coastal drill sites. There were different types of icebergs, as our on board ice observer, Diego Mello, explained to us earlier: tabular, pinnacled, dry-dock, blocky, domed, and wedge icebergs. You can see a large tabular iceberg in the image above. The part that is sticking out above water (only 10% of the iceberg) is 195 ft (~60m) high. Smaller icebergs are present as well and the ones that are smaller than 5 m across are called "growlers". You can see a few growlers in the photos below. They can have very irregular shapes and we can see them come close to the ship.

These icebergs are pieces of glaciers that have broken off where they reached the sea. This is called "calving". Glaciers are "rivers" of ice that flow relatively slowly, usually on the order of 1 to 1000 m per year. When ice flows over the rocky landscape it picks up debris, which become partially embedded in the ice. When a glacier reaches the coastline it thins and begins to float, and eventually it calves to produce icebergs. These icebergs will carry the debris that is embedded in the ice out to sea, where it will fall to the sea
floor as the iceberg melts. This debris is commonly called IRD by geologists (short for ice-rafted debris).

The albatrosses are long gone: they prefer to stay further north, and have been replaced with other birds including penguins, which were sited by others on board. Three of us on top of the bridge and the people on the bridge itself saw one or a few small whales yesterday. We are likely going to see more.

We proceeded to the coast of Wilkes Land until one of the radars broke, the wind started picking up, and it began to snow. These conditions were not safe for drilling so close to the coast, where we need good visibility with all those icebergs around. So we proceeded to one of our off-shore sites, where we will arrive tomorrow. The seas are getting a bit rough now as well. Wave heights have been increasing through the day. Once we made our way north far enough, the snow turned to rain, so it is no longer pleasant to be outside.

It will now not be long until we have core. That will be a good thing, because we are as ready as one can be and cabin fever is kicking in. The movie below is a nice illustration of this (not my creation, but I thought, as many others on board that it was incredible funny):

Sunday, January 17, 2010

Life boat drill at the polar front

We had one of our weekly life boat drills today. What you do is you put your life vest, hard hat, and safety glasses on and proceed to your preassigned life boat after the "abandon ship" alarm goes off. You also take your survival suit with you. These suits have floatation cushions and will keep you warm for a while. There are four lifeboats with more seats than we have people on board. This time we were required to sit in the life boats (see photo) and learn how to start the engine. It was not very complicated and it worked quite well. The life boats have a beacon that sets of an emergency signal so response teams can find the boat. Let's hope we never need to use it!

We have crossed the polar front: yesterday the surface water temperatures dropped from 7 to 0 degrees C (32 F) in 24 hours (sea water freezes at below 0 temperatures, below 32 F). There were two iceberg sitings, but I missed them, one because I was sleeping. There was another one on the radar an hour ago, but the fog is too dense and we didn't see it. We are scheduled to arrive on the Wilkes Land coast tomorrow. The Captain needs to check out the area of the first drill site and see if it is safe. The satellite images show bergy water and some thick sea ice floating around. So: we will certainly see some ice tomorrow. Stay tuned for the pictures and explanations.

Our videographer has made a weekly video report, which you can watch here. It is composed around an interview with our staff scientist, Adam Klaus. Enjoy!

Saturday, January 16, 2010

Drilling equipment class

Staff scientist Adam Klaus took us on a tour of the ship today to introduce us to the drilling operations and equipment. We had to wear hard hats and safety glasses, because of all the moving parts on and around the rig floor. The derrick (right) holds the drill string and once we are on site it will hold the bottom hole assembly composed of the drill bit and core barrel. Pipe will be tripped behind/above the bottom hole assembly enough to reach the sea floor and then to drill into the sea floor. Depending on the types of rocks or sediments cored, different coring equipment will be used. For soft sediments, the advanced piston (APC) corer is used. It is composed of a cutting shoe that is pushed into the sea floor and then takes out 9 m lengths of core. It operates a bit like a syringe. You can see the APC cutting shoe in the image to the left. The APC extends forward through the hole in the center of a drill bit, similar to the one indicated in the photo below. The core will come up through the center of the hole and a core catcher will keep it in place. The core catchers are the small cylinders with the petals in the center in the lower right of the photo. When the sediments are too hard, an extended core barrel (XCB) is used, which will rotate and drill into the sediment. In lithified sedimentary rock, only rotary coring is possible, and most of the work will then be done by the drill bit below with a core barrel behind it (RCB). We will need to learn these terms and abbreviations, because it will affect the preservation of the sediment cores we see.

Friday, January 15, 2010

A nice day with low seas

Today we had nice weather and relatively low seas. I was pleased to see a smile come back on the faces of some of my colleagues who had been sea sick for the last couple of days. We are now slowly drifting towards our work shifts from midnight to noon or noon to midnight (my shift). Once we are on site, expected for Monday evening January 18th, we are going to work around the clock and in two teams we will continuously process core.
The night-shift sedimentologists had a practice run today (see photo above). The two sedimentology teams will take care of visual core description, imaging, and color scanning. All information will be entered in a database. We, the day-shift team, had a practice run yesterday and we are now well-prepared for the first core on deck.
The palynologists are ready too: Joerg Pross and Peter Bijl. They are after the organic-walled cysts of fossil algae called dinoflagellates. These are microscopic photosynthesizing organisms that live in the surface of the ocean. Because these organisms evolved relatively fast, they are good biostratigraphic markers and give us an indication of the age of the rocks we are drilling. Joerg and Peter are working in a special fume hood in the chemistry lab, because they need to use a very strong acid (Hydrofluoric acid) to dissolve the rocks. This is the only way to obtain these microfossils that are so crucial to our studies.


This is really a time of getting everything ready: three more days and we will be on site. Today, I also saw a few people working on the drill rig. You could watch them work from the top of the bridge. The seas were too rough for work on the rig in the previous days. It is easy to forget how big the derrick is that we are carrying on top of the ship! Seeing the man out there puts it all in perspective.
The ice observer Diego Mello is expecting icebergs any time now, so he is watching the radar and the surface of the ocean. We are between 58 and 59 degrees South, which is where icebergs are rare, but easy to miss.

Besides the icebergs there is another interesting geological feature to talk about: we are crossing the boundary between the Indian-Australian plate and the Antarctic plate. The Indian-Australian plate carries part of New Zealand, Australia and India and the Antarctic plate carries the Antarctic continent. The plate boundary is called a divergent plate boundary, because the plates are spreading apart and new ocean crust is formed.
The plate boundary is expressed as a mid-oceanic ridge (indicated in green tints) and has multiple transform faults that intersect the plate margin at high angles. Due to the process of seafloor spreading, India and Australia are moving northward away from Antarctica. This process has been going on for some time. At our first drill, we are going to drill into rocks that are quite old and may date from the Eocene. During this time Antarctica and Australia were much closer than they are today, and if we go even further back in time both continents were part of a supercontinent called Gondwana.

Thursday, January 14, 2010

Antarctic Circumpolar Current

Winds and wave heights have decreased and we are now back on track at 55 degrees South, with the ship pointing southwestward at 8 knots. We are now entering the realm of the Antarctic Circumpolar Current, a strong westward flowing current, driven by the westerlies. The westerlies are winds caused by air flowing from the subtropical highs to the low pressure cells at the Polar Frontal Zone. The winds are diverted westward by the Coriolis force. In contrast, cold katabatic winds that descend northward from the high pressure cells centered above the Antarctic ice sheet are diverted eastward, and drive the polar current near the coastline of Antarctica (large blue arrows). Here in the Antarctic Polar Frontal Zone the surface water temperatures decrease rapidly: we should be seeing icebergs soon....

Wednesday, January 13, 2010

Tuesday, January 12, 2010

High waves are slowing us down

Yesterday in the evening a strong low pressure system suddenly developed in our transit track. We are at the polar front zone near 50 degrees south latitude where cold polar air clashes with warm air from the north and this is where these low pressure systems develop. Last night wave heights were increasing rapidly to more than 10 m (30 ft) and the Captain had to steer the ship away from the developing storm. During the night and morning we were staying in the same location with the bow of the ship heading northwestward at about 4 knots. As of 9:30 AM we are back on track and heading south again. The seas are very rough and wave heights are still approaching 10 m (30 ft) and some people are in their cabins feeling sick, whereas others have taken medication. We also had to tie down the equipment in the labs because the waves come in from the side now and make the ship roll sideways. In the wave height map above you can see where we are heading (see the arrow). Red colors are high waves. The storm will move eastward and the forecast for tomorrow is looking good. Let's hope we can make it through the "screaming 50s" before the next storm arrives....

Monday, January 11, 2010

The roaring 40s

Here we are in the roaring 40s: strong winds and rain. The roaring 40s refers to the latitude at which low pressure systems circle the globe eastward in the Southern Ocean. We are in a storm to the south of New Zealand. We are no longer sheltered by the South Island of New Zealand, because we are too far south, so we feel the full impact of the winds and ocean swell.

Some of my colleagues had to lie down because the ship is suddenly moving a lot more than it did yesterday. I am still not feeling much of a difference; I have never been seasick before, so let's hope I can keep that up.

Outside the weather is mainly miserable. When I was on deck for 10 minutes I saw an albatros or two flying next to the ship and I saw water shooting up through the moonpool: the hole in the center of the ship through which the drillpipe will be lowered when we are on site. You can see the location of the moonpool indicated in the image below. It also shows you where I work, sleep and eat. My cabin is on the Upper Tween Deck, two floors up from the thrusters (more on those later). I share the cabin with Mitsu, a Japanese scientist, who will be on the opposite shift. For more information about the interior of the ship see: http://ship.iodp.tamu.edu/ship.html.

I work in the core lab with the team of sedimentologists and the sedimentology technician. We represent 8 countries: U.S., Japan, New Zealand, Australia, Korea, India, United Kingdom and China (see image below). Today we were instructed on the core flow by the staff scientist and the core curator, so that we know what will happen once core comes up. We also had a lecture from the ice observer and the weather forecaster, two very important people who work with the Captain to ensure our safety in the icy waters around Antarctica. The sea ice conditions at the drillsites on the shelf are looking good based on recent satellite imagery, although we may have to navigate a few decent icebergs of more than a couple of miles long.

Saturday, January 9, 2010

We are on our way!

The ropes were pulled in at 11 AM this morning. The weather was extremely nice and we had a very enjoyable morning sitting on deck watching the preparations for departure. Two small boats were pulling the ship from the quay out to sea. We are now making our way south along the east coast of New Zealand. The seas are still relatively calm, only with some white caps. Fortunately we are still in the shelter of the South Island, but it may be different when we wake up tomorrow morning. The ropes were stored below deck: we will not need them for two months until we return to land in March (to Hobart, Australia).

Friday, January 8, 2010

Antarctica more than 35 million years ago?

This is what Antarctica was like more than 35 million years ago in the Eocene: no ice sheet and a vegetation of tree ferns, Nothofagus trees and shrubs. This is the image that emerges from previous Antarctic drill holes and samples that recovered pollen and spores from the Eocene. Our mission is to find out when and why it changed.

This is a photo from the Wellington botanical garden. New Zealand and Antarctica were once side by side within a supercontinent called Gondwana before tectonic processes sent New Zealand further North. New Zealand has been isolated as a set of islands for a long time and still carries some of that Gondwana flora and fauna.

The science party had the afternoon off yesterday to spend the last couple of hours on shore before departure. We are departing in half an hour as the tide rises. We are so full of fuel that the ship is deep in the water and the Captain did not want to take any chances getting out of port. The weather forecast is still projecting bad weather with up to 45 knot wind gusts for tomorrow as we follow the coast of New Zealand's South Island southward.

Wednesday, January 6, 2010

A day with Zenon


I am part of a science team called the sedimentologists. There are 10 of us and we will work in two shifts: noon to midnight and midnight to noon. We are not on shift yet, because we are still in port. Today we were receiving instruction on the lab equiment and database software from the sedimentology tech, Zenon Matteo (see photo). We also had a meeting to discuss how we are going to operate as a team. I think we are almost ready for the first core now. The Captain told us today that we are still scheduled to depart on the morning of Saturday the 9th (on the 8th in the US and Europe). The weather forecast warns of 40-50 knot winds, so we get to test our sea legs right away!

Tuesday, January 5, 2010

On board the Joides Resolution

After a 29 hour plane travel, I have arrived in Wellington New Zealand. The ship, the Joides Resolution, came into port the day before yesterday and yesterday (January 5th) we were able to move on board. In a few minutes we will have our first meeting with the entire science party (> 30 people), now that everyone has arrived. We are still scheduled to leave Wellington on the 9th, so we will spend a few more days in port. It is nice for us to get over jet lag before heading into the ocean swells. You will notice that the ship has a tower on it called the "derrick". This is where the drill rig is located. If all goes well we are going to drill 5 holes up to more than a kilometer deep on the Antarctic continental margin. We are all getting excited, but it is still a bit unreal: it is Summer here with temperatures in the 70s (20 degrees C), and we are heading for the coldest place on Earth. More later!