We have now reached the last meters of the core of the last drilling site M0080A. After almost four weeks after of core description, we still have some good surprises regarding the facies, structures and sedimentary processes recorded in these beautiful cores.
There are ten scientists involved in the VCD-team, which is split in two parts (morning and evening shifts). While some of them focus their observations on structures (natural or drilling induced deformation such as faults, fractures, biscuiting, etc), the rest of the team is working on the logging, which consists of reporting general sedimentological observations at the bed-scale, descriptions and interpretations on the log sheets and the digital information system. Crossover meetings between both morning and evening shifts lead to good discussions, additional changes and updates, which are necessary to provide the best lithostratigraphic column of each cores.
I cannot believe we went though more than 1645 meters of core description in four weeks. This onshore science party at Bremen was a great first experience of core description, not only as a sedimentologist, but also as a young postdoctoral fellow pursuing research in the Corinth rift.
Measurements on cores take many different guises and require many different experts. Here are just some of the standard things we look at:
We (Erwan, Abah, Giorgios, Mohammad, Mai Linh, Malka Leah, Emilio, Marco, Johanna, Leah, Natalia, Vera, Malgorzata, Nataliya, Laurence and Liane) look at the physical properties of a core (see also Leah’s blog entry):
How magnetic the core is. This tells us not only how much magnetic material the core contains, but by then de-magnetising it, we can get back to the original polarity of the Earth when the sediment was deposited. This gives us a rough timeline that can be applied to the cores.
How porous the core is.
What is the strength of the sediments (i.e. how much force can the sediments take before they fail and deform). We measure this using a torvane and a fall cone.
The gamma density of the core (i.e. how tightly packed or dense is the core material).
The colour reflectance of the cores. By looking at where on the scale each measurement sits with regards to yellow to blue, green to red, and black to white, we can work out what colour reflectance clay has as opposed to sand, giving us an automated way to look at lithology (see also below).
The thermal conductivity of the core material (i.e. how quickly can the core transfer heat, telling us something about how densely packed or “consolidated” the sediment is).
Do all the physical properties help plot the actual cores against the seismic data through a process called Core-Seismic Integration.
We (Mary, Rob, Richard, Casey, Jack, Sofia, Romain, Liliana, Spyros, Shunli and Gino) look at the lithology, that is the physical characteristic of the material in the core:
Is it silt, sand, mud or clay or a mixture of all of those?
Is it all the same or are there layers of different types of different types of sediment?
Are the boundaries between different types of sediments sharp or gradual?
Is it all the same colour or different colours?
Has it been deformed or broken, either by faulting or by the actual drilling process?
What different minerals make up the sediment and so where might they have come from?
We (Clint, Carol, Joana, Simone, Luzie, Silvana, Brit and Christoph) also measure the geochemistry of the pore water – the water trapped between each particle of sand, silt or clay, and its neighbor:
Offshore we measure salinity, the pH, alkalinity and Ammonium.
Onshore we measure for a range of different elements including Calcium, Strontium, Chlorine, Potassium, Magnesium, Phosphate, Sulphate and Ammonium.
We also look at how much organic content is in the sediments.
We (Maria, Aleksandra, Marcie, Asli, Paula, Kostas and Katarina) look for evidence of past life by searching for microfossils – tiny fossils that are 1 millimeter or less in size, under microscopes. The type of microfossil can tell us whether it was land or water at that time, or if it was salty, brackish or freshwater. Certain species also prefer certain water temperatures, again giving us a clue as to what the environment was like in the past:
Diatoms – a type of microalgae
Foraminifera – single celled organisms with a shell or “test”
Nannofossils – a planktonic (floating) organism
We also look for pollens as different tree species can tell us about the climate at the time.
And we can’t forget Lara and Alex – two more student helpers who keep the measuring machine going through copious supplies of coffee and cookies!
As you can see there are a lot of people involved in measuring the cores, but all of these different measurements, when combined, help tell the researchers the story of fault movement, changes in climate, whether the area was terrestrial, a lake, or fully marine, how much sediment was deposited (telling us something about erosion on land), and many other aspects. These measurements give us a fascinating insight into the past.
How do you…? Whilst the OSP is running we will post a series of blog entries, focussing on the different steps involved in processing and sampling the cores to IODP standards.
Being part of an international expedition is not only about the science, it also gives scientists the opportunity to experience other cultures. At the OSP for Expedition 381 not only did we celebrate a Greek national holiday, but also Valentines and Chinese New Year.
Since the OSP is located in Bremen, Germany, the participants of course also experience German Culture – especially when it comes to food and language, sometimes even a combination of both. For example when a dessert sounds as if you’re calling your colleague names (Rote Grütze – very traditional in the north of Germany) and a side dish sounds like you are scolding a child (Knödel – a side dish from southern Germany).
Food is important for the scientists, it feeds the brain cells and brightens up the mood. At lunch times, when in Germany you traditionally eat a hot meal, talk of course revolves around science, but a walk to and from the dining hall also gives the participants the opportunity to let their thoughts wander off.
As many of the OSP participants are finding, the German language is quite complicated. The scientists are doing their best to cope with German wording and trying to order their meals (just pronouncing their favourite kind of roll – Kürbiskernbrötchen for example is hard enough), or even just learning how to say ‘Hi!’. “Moin” in this case is perfect, you can say it at any time. One can also say “Moin Moin”, though some people might get the impression that you are chatty.
Germans do use words such as “Geschirrrückgabestelle” or “Nahrungsmittelunverträglichkeit”, though often it is all in the pronunciation. “Tschüss” just means ‘bye!’, but seemingly it has to be said in a higher voice than normal.
Will one month be long enough for the science team? Probably not!
When the cores are collected offshore, they come up in clear plastic liners which are then divided into a maximum length of 1.5 meters. Those liners are sealed and labelled and then put into a cold dark container. On Mission Specific Platform expeditions the cores are split onshore. They are returned to the IODP Bremen Core Repository for full analysis. The first stage is splitting the cores open – so how do you split a core?
The core splitting is done in the workshop area at the MARUM – Center for Marine Environmental Sciences at the University of Bremen (Germany). It’s a workshop so the odd splashes of water or mud won’t matter!
The core is placed into the splitter, held in a metal trough, with the steadying hand of one of the wonderful student helpers. Ngozi, Sipan, Rezan and Johann ensure over two shifts that the core splitter is working from 7.30 am to 10.30 pm.
As the circular saw blade whirrs into life, it is slowly pulled along the length of the core, making a vertical cut through the plastic liner and core material. Once completed, a sharp knife is run down that cut making sure there are no plastic liner bits still holding it together. After that it is opened and the split core faces are washed with cold water. This removes any mud smears that have been left as the blade passes through. By the way: We are halfway through the core splitting at the onshore science party and now on our second blade.
One core half is designated as an archive half, which means it gets preserved as it is a part of the IODP legacy. Only non-destructive measurements can be performed on this such as digital line scanning and core description. The other half is the designated working half, and this is the one from which all the research samples are taken, as well as any measurements that might damage the core. The cores are loaded onto a trolley and taken to the waiting scientists who are eager to see what story each section will tell them.
How do you…? Whilst the OSP is running we will post a series of blog entries, focussing on the different steps involved in processing and sampling the cores to IODP standards.
Sharing the enthusiasm for science: This month (February) I am working in Bremen (Germany) as part of the onshore science party for the IODP 381 Expedition; Corinth Active Rift Development. My role within the onshore phase of the expedition is working as a technician for the physical properties team, and more specifically, operating the digital line scanner. This is a digital camera attached to a scary looking machine which scans all the drill cores at high resolution once they have been split in half. These high-quality images are then used by the scientists in the core description lab. They are also archived so that there is a digital record of all the split cores.
So far, we have been processing core for 15 days and in that short time I have learnt a lot. I have learnt how to operate the line scanner, how the complex filing system and digital database works, I have become more familiar with Photoshop and now know how an onshore science party works. I have also worked out that it takes four minutes to scan a full 1.5 meter core section and that after taking time to crop the previous image and upload it to the database, this is not enough time to run to the bathroom (which is at the opposite end of the corridor), but is just enough time to grab a swig of coffee and a biscuit from the snacks table which is conveniently placed just outside of my lab! But, some might say more importantly, I now know how to ask if the food is vegetarian in German, I have learnt that German university canteens are chaotic and that tired and cranky geologists can be bribed with chocolate cookies.
The system used to process the core is clearly well practiced and the MARUM-team (MARUM stands for Center for Marine Environmental Sciences) at the University of Bremen know exactly where everyone and everything should be at any given time – at least it feels that way. It is great to see the enthusiasm of the scientists when they see something exciting in newly split core, and to see geologists with a wide range of experience and expertise working alongside each other.
We work hard – eleven hours a day, seven days a week – but everyone is happy to contribute, knowing that they are collecting and processing truly world-class material and data. It is clear that for many of the scientists, having an IODP expedition occur in their geographical area of research is an opportunity that only a select few have the chance to experience, and to be able to be a part of the onshore science party and be some of first to see the core is the icing on the cake. IODP expeditions appear to be a prime example of how collaborative research should work. I doubt there are many examples of so many scientists from all over the world congregating in one place to collect the raw data that they, and many others, will use for future research.
While almost all the other scientists are following the core flow, eagerly waiting for the next core to be split, the Geochemistry Team follows its own schedule.
During the Offshore Phase in November and December 2017, Simone Sauer and Clint Miller were already busily collecting pore water that they squeezed and sucked out of certain core sections. This way, over 260 of water samples have already been collected, which can now be analyzed before enough sediment samples have been taken for further processing.
It is particularly interesting to determine the elemental composition of the pore water, including cations and anions of different elements, in order to better understand diffusion processes, adsorption, absorption, chemical exchange processes between the sediment and the water, as well as microbial reactions.
Offshore, the pore water samples were split up according to the number of analyses that will be performed during the Onshore Science Party and afterwards. This results in over 1200 little bottles, flasks and vials that all need to be sorted, transferred to different vials, resorted and diluted before any analysis can start – an arduous task!
After almost one week of lab work, the Ion Chromatograph, measuring the anions, and the Inductively Coupled Plasma – Optical Emission Spectrometer, measuring the cations, are running non-stop and first results are expected for the weekend. Meanwhile, the phosphate content of 63 samples was determined manually, producing fascinating variations of blue liquids. The results look both promising and surprising and the Geochemists are very excited and eager to spend more time on the interpretation as soon as possible!
Carol Mahoney, Clint Miller, Simone Sauer and Joana Seguin
A stair story… and a bit of math related to my stay in Bremen’s MARUM for IODP Expedition 381….
1) we have to process more than 1.65 kilometers of cores in four weeks 2) the samples I am in charge off are taken every 1.5 meter (around 1100 samples to go!!!)
3) the instrument for the measurement runs four samples at a time 4) one run takes about an hour
5) the sampling room is located on the ground floor and
6) the measurement room on the second floor 7) there are 48 steps to go up – and obviously the same to go down
This means: Each day I climb about 1200 steps!
Also, knowing that:
1) my hotel room is on the 5th floor
2) I decided not to use the elevator (“step mood”)
3) there are 98 steps to go up
This means: These are about 588 additional steps per day, giving a total of more than 1700 steps – although the “best” day so far is actually about 2000 steps.
And this means: Every day I climb higher than the Eiffel tower (1665 steps) or than the Empire State building (1860 steps).
Of course in both cases I could use the lift – but that would definitely be less fun
The preparations at MARUM (http://www.marum.de/en/Research/Partner-to-the-ECORD-Science-Operator.html) started many months ago, when for example we reserved the accommodation for the Science Party, this at a stage when we did not know the exact timing/duration of the OSP or the exact amount of recovered core! We also reserved numerous lab and office spaces ahead of time, as well as measurement slots in a variety of MARUM laboratories (e.g., core sampling, core logging and scanning, geochemistry, geotechnics, mineralogy (XRD), palynology, paleomagnetics, petrophysics), to ensure that sufficient capacity will be available for the OSP for the IODP-MSP standard measurements.
Right after the end of the offshore phase on Dec 18, the expedition data were made available for the Science Party on a MARUM server. This was key, meaning that all science party members could immediately access the information required to revise their preliminary sample requests, which were initially submitted before the offshore phase. The beginning of the New Year was quite exciting as the expedition cores arrived at MARUM on January 3! The two refrigerated containers were unloaded instantly and Alex and Holger safely transported the 21 core boxes, into the reefer of the IODP Bremen Core Repository (BCR) in what seemed to be no time.
Since the Autumn we intensified our preparations, preparing the OSP workstations in a variety of labs, setting up IT hardware in numerous offices and labs, loading the latest curation database version on the computers, testing equipment, checking our stocks of consumables, discussing how to optimise core-flow plans and when and how to integrate outreach activities. Equally important is to arrange procedures and reservations with the Mensa, where everybody has lunch from Monday to Friday! Combined with grocery shopping for coffee breaks and snacks and catering for the weekend meals, it is quite a complex and intense logistical exercise! Nevertheless, we are still working regular hours (ok, some of the time) and not in shifts yet. This will change for all of us later this week!
Successively, during the month of January the sample requests were shared with the Co-Chief scientists Lisa and Donna as well as the EPMs Gareth and Jez. Together with Ursula they form the so-called Sample Allocation Committee (SAC). The SAC establishes a project-specific sampling strategy and makes decisions on project-specific sample requests received before the drilling project, during the drilling project including the OSP, and during the moratorium period, that is twelve months after the end of the OSP.
In these last few days before the start of the OSP the setup of some of the work stations are still to be finalised, but all of us are very excited to finally start splitting and processing the new cores and looking forward to finally meeting the whole Science Party.
Last but not least we are looking forward to continue working and collaborating with the wider ESO team, which comprises colleagues from the BGS, the EPC, and us at MARUM. All of those involved in the OSP – scientists, ESO staff (including the twelve University of Bremen Geosciences student helpers) – comprise a team of more than 70 people, who will closely work on processing and describing the 1645 meters of cores and samples in two shifts over the course of a full month!
Image captions: Beakers all ready for the moisture and density (MAD) analysis on Expedition 381 samples; Ongoing preparations in the core description lab; The core splitter nice and shiny, but still asleep; Earlier stage of microscopes set up in the core description lab; Petrophysics equipment awaiting installation; Patrizia unpacking and assembling microscope equipment; The calm before the storm, scientists’ office not claimed yet (All images U.Röhl, ECORD/IODP)
Exp. 381 core boxes on arrival at MARUM (U.Prange, ECORD/IODP)
The almost a month-long “Pre-OSP” phase started on the 3rd of January 2018 at the MARUM institute in Bremen. The Pre-OSP this time focuses on measuring Thermal Conductivity (TC) of the cores from IODP Expedition 381 – the last measurements that require the cores to be whole – and preparation for the OSP (Onshore Science Party) in February when they will be split.
We, the “TC measuring” team (Laurence, Nataliya, Malgorzata) and Sally (EPC coordinator) arrived at the MARUM – Center for Marine Environmental Sciences in the morning of the 3rd of January, after leaving home on the 2nd – almost right after New Year celebrations! The beginning of the New Year was an exciting one as we were busy preparing our workspace for measurements in the four degrees celsius reefer, testing equipment and finalising plans.
As always, we were warmly welcomed by the MARUM staff, and we spent some time with them chatting over good coffee and cookies during breaks. These two days (2nd and 3rd of January) seem now like a relaxing warm-up before the work on continuous measurements in the following weeks, and the excellent evening dinners we had (traditional German food) seem like an unreal dream because…
…in order to complete TC measurements on the huge number of recovered cores from IODP Expedition 381 Corinth Active Rift Development, measurements are undertaken round the clock… in twelve hour shifts.
Laurence is on shift during the daytime (5 AM to 5 PM), and Nataliya together with Malgorzata work at night (5 PM to 5 AM).
TC measurements are recorded using the full space line source, the VLQ or “needle probe”, inserted into the cores along the same plane that they will be split. Before starting measurements the equipment was checked for calibration and then checked again using dummy cores: one made up of saturated and compacted topsoil and another of water-saturated clean sand. Both very different in terms of TC response…
Cores from IODP Expedition 381 that have been measured thus far have been full of surprises. Results have kept us on our toes in terms of gathering high quality data, and served to heighten our anticipation for finally splitting the cores in February and getting to see with our own eyes what is inside.
One thing that we have learned over the past couple of weeks: the better results – the better mood of the Pre-OSP team members! When we obtained the first measurement with a solid data-set, we started to dance in the reefer! Which is by the way a very good way of keeping yourself warm. That’s it – dancing, some yoga, jumping and jogging around the reefer’s shelfs are the top activities we do to keep ourselves warm during the long periods of time that we have to spend in four degrees Celsius. Though, unloading or re-loading core sections out of and into the transport boxes is a bit more physically engaging way of keeping the circulation flowing. Laurence once counted how many core sections he moved from and out the boxes during one shift and the number exceeds 300! It’s definitely good exercise. We will have some more muscles after Pre-OSP, that is for sure!
We celebrated Laurence’s Birthday on the 15th of January, at 5 am in the reefer in four degrees Celsius. Not everyone gets Birthday wishes at 5 am!
We do not have time to explore Bremen at this time. Twelve hour shifts leave time only for TC measurements and some sleep. Not a lot of sleep by the way, but the results of TC measurements are their own reward!
To be able to drill in the seabed hundreds of meters below the sea surface Fugro Synergy needs to stay in the same position on the surface, sometimes for weeks at a time. As anchors would be impractical in the water depths we work in Fugro Synergy is equipped with a Dynamic Positioning system (DP for short), meaning she is kept in position using her propellers.
The DP system receives input from a number of sensors (DGPS and hydro-acoustic beacons for position, gyro compasses for heading and several wind meters) and then continuously calculates the trust settings (both force and direction) required on the propellers to generate the exact forces needed to counter the outside forces and stay in position. In the generally quiet waters of the Gulf of Corinth we are often able to keep the ship within about 20cm of the set position, though we may move over a meter in the strong squalls that sometimes blow through the Rion strait. On one occasion we recorded a 75kn (140km/u) gust while holding position on the DP.
An interesting piece of history: While DP systems are quite common today in the offshore oil/ gas and wind energy sectors as well as on cruise ships, the first predecessor of the technology was actually developed for a ship used by an early predecessor of the IODP. They used converted barge called the CUSS1 during project Mohole in 1961 that attempted to drill through the earth’s crust where it was thinnest: on the bottom of the ocean. As the water depths were much too deep for anchors the barge was kept over the borehole using 4 thrusters operated manually in combination with a crude sonar system to indicate the position which kept them within around 180m of the site, just enough not to bend the pipe too much. 60 years of improvement in computers, positioning systems, electric drive converters and ship design have helped a lot in making our jobs easier!
The DP system is controlled from the bridge, and while the computer is doing the hard work of constantly correcting the settings of the propellers it is monitored by the one of the duty Dynamic Positioning Operators (DPO). The DPO has to make sure that all parameters stay within limits and also anticipate changes in the weather and other operating conditions. In case of failures the DPO can switch between the multiple systems that provide redundancy, or can take over manually as required; different control modes are available in case of failures from fully automatic, via joystick to control to full manual. As on most ships the DPOs are also the officers in charge of the navigation of the vessel and our normal DP watches consist of a senior and a junior deck officer who are on the bridge together, taking one hour turns at the DP system controls. The chief officer and first officers are changing shifts at midnight and mid-day, while the two 2nd officers are changing at 0600 and 1800 to make sure there is enough overlap between shifts.
Also on the bridge is the survey station, here the surveyor determines the exact position of the borehole. First the position of the ship is fixed using GNSS receivers that can use signals from both GPS and GLONASS satellites which are then corrected using Fugro’s Starfix system to an accuracy of <10cm. The exact position of the Seabed Frame (and drill pipe leading through it) is then fixed using the USBL (ultra-short baseline) hydro-acoustic systems integrated in Synergy’s hull and a transponder mounted on the frame.