Fun Science: Iceberg Chasing and Laser Lights
One of the 'fun science" activities we have carried out during AMASE 2009 is "iceberg chasing". Naturally this was all for a good scientific reason as we were interested in acquiring sediments trapped in calved icebergs for further characterization. Being in the arctic and around massive ice caps and glaciers it is no surprise that during the time we have been based on Lance we have seen tens of icebergs per day. Some of them are mostly made of blue ice but they sometimes also have layers of sediments and these are the interesting ones!
So the task we have this year is: find a relatively newly calved iceberg, evaluate is it is safe to approach, find an interesting and safely reachable area with sediments, take samples, melt the ice and separate the sediments and than back in the lab study the sediments with different techniques (high resolution microscopy, X-ray diffraction, infrared spectroscopy, etc) with the specific question about the iron minerals.
How do we chase icebergs?
Very very carefully!As usual on AMASE safety is the first rule. Although seemingly a simple task, approaching and sampling floating icebergs can be risky. Depending on the size and shape of an iceberg, even the smallest amount of pressure on it surface could lead to an iceberg to rotate or to flip upside down. Naturally, if this would happen when we approach an iceberg with a zodiac boat that would not be safe. Because 90% of the iceberg's mass is under the water, its real size and shape is not easily evaluated, so we have to approach any iceberg carefully and evaluate whether we can safely obtain samples or not. If we see dirty blue ice, that means that there could be sediments waiting for us. So if the iceberg sampling is considered safe, the person that will take the samples will use an ice axe and a bag to catch the chipped of sections with sediments and ice. However, the 'sampler' will be secured by at least two people on the zodiac and the sampling will take less than five minutes/iceberg.
This year three iceberg chasing trips have been carried out successfully, obtaining a total of samples from different icebergs. These samples will be returned to the University of Leeds where they will be studied further with the aim to provide novel information about the contribution of glacially derived iron-rich sediments to the iron-budget of the arctic ocean and their link to bioproductivity in the current ocean and also with respect to the Last Glacial Maximum (LGM). The samples collected this year will be compared and contrasted with other iceberg samples that have been collected during previous years in Antarctica and the Southern Ocean.
Studying the composition of Martian rocks: building and testing a new concept of Raman spectroscopy
One of the worth mentioning analytical techniques that are being tested during AMASE 2009 is a Raman spectrometer. Two researchers are involved in a very interesting project that will be very important for both expanding the capabilities of the next missions to Mars and also for the detection of signatures of life on the Red Planet: Prof. Fernando Rull, who is the principal investigator of a contact Raman spectrometer for ExoMars, and Antonio Sansano, who is working with Prof. Rull on his PhD thesis. Both are working at the University of Valladolid, Spain, developing two Raman spectrometers that will obtain really valuable information about the chemical and mineralogical composition of the Martian rocks.
Why is the 'secondary radiation' so interesting? Because it can give us plenty of data about the atomic-molecular vibrations of matter that we are illuminating with the laser light, enabling us to obtain structural and compositional information, as well as physical-chemical characteristics of solid, liquid or gaseous samples. Furthermore, one of the great advantages of Raman spectroscopy is that we only have to illuminate our sample with a laser, so -if the power of the laser is not too high- this is a non-destructive technique and the sample needs no prior preparation at all.
Considering the modern developments in spectrometry and optical fibre technology, as well as in miniaturization techniques for both spectrometers and detectors, it is not strange that Raman spectrometers could be really useful for planetary research missions. Although there were plans to include a Raman spectrometer aboard the Mars Exploration Rover missions, the devices were unfortunately discarded because of mass constraints for both probes. So the next mission that will include the first Raman spectrometer on Mars will be the EXOMars rover (ESA, 2019), that will acquire samples up to a maximum depth of 2 metres using a corer. These samples will be ground and transferred into small cache boxes located on a carrousel below various scientific instruments. Both the Raman spectrometer and an infrared microscopy will be the first instruments that will study the solid samples.
However, the Spanish team is not only developing this EXOMars contact Raman; they are working also on another project that is even more thrilling and that was also tested during AMASE 2009: a remote Raman spectrometer which coupled to an optical telescope makes it possible to measure samples located at a distance from 8 to 130 metres away, yet this spectrometer has the same precision as the contact Raman spectrometer. The potential of studying rocks and sediments from afar with an instrument like this would significantly expand the capabilities of a Martian rover or lander, because the combination of panoramic and high resolution cameras with Raman spectrometry would allow analytical information without moving the rover to the sampling areas to be obtained; this would save lots of energy and time. Although this technology is not yet miniaturized it has potential for future Mars sample return missions where this technology could be essential when time/distance, etc. constraints are very tight.