How do you measure a core?

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.
IODP OSP EXP 381
Line Scanning. Photo: VDiekamp, ECORD/IODP

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.
IODP OSP EXP 381
Paleontologist Kostas. Photo: VDiekamp, ECORD/IODP

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.

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Culture studies

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.

Happy Chinese New Year
Shunli Li and his wishes for the New Year. Photo: SLi, ECORD/IODP

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!

How do you split a core?

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.

IODP OSP EXP 381
Sipan (left) and Ngozi rinse off the core halves after splitting. Photo: VDiekamp, ECORD/IODP

What is it like to work in an IODP onshore science party?

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.

Leah Nolan

IODP OSP EXP 381
Leah Nolan operating the line scanner. Photo: VDiekamp, ECORD/IODP

Off the coreflow

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

IODP OSP EXP 381 - Geochem
Clint Miller performing phosphate analysis. Photo: VDiekamp, ECORD/IODP
IODP OSP EXP 381 - Geochem
Simone Sauer places samples into the Ion Chromatograph. Photo: VDiekamp, ECORD/IODP

A stair story

Who said science is only brain work?

A stair story… and a bit of math related to my stay in Bremen’s MARUM for IODP Expedition 381….

Knowing that: 
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  

Johanna Lofi

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Steps, lots of steps everywhere – here: Johanna’s Hotel. Photo: JLofi, ECORD/IODP

Τσικνοπέμπτη- Greek tradition in Germany!

It is a very common tradition in Greece to celebrate the second Thursday of the carnival period, known as “Tsiknopempth” (Τσικνοπέμπτη), with a lot of meat, dance and traditional greek spirits!

Accordingly, the late shift had a great idea.IMG_0211 They gathered around in the Greek  taverna  “Meteora” and had a fantastic time and plenty of “gyros” and of course “ouzo”!

The best way of ending up a 11-hours long shift!!

Στην υγειά μας!!