MISIP2018: Gerrit Postema


As of now, my internship experience at MISIP has been roughly composed of two main investigative pathways. We've spent most of our time analyzing four chondrules from two meteorities, Allende and Murchison. Each of our chondrules has been sliced (very carefully) into a fraction that lies on a thin section and a free fragment. The first investigation has been the analysis of our thin section sample through various electron microscopy and focused-beam analysis methods. We constructed high-definition composition maps of each of our thin sections using an SEM and performed some basic composition investigations using EDX to find what the mineral phases are within each thin section and their modal abundance, as well as some bulk chemistry trends. After this, we used an electron microprobe to look at some of the much smaller crystals (with a resolution of about 3 microns) to figure out the later-stage mineral phases and their composition.

The other avenue we've explored is wet chemistry analysis of our free fragments. We've been working in a clean room to dissolve our samples into solutions using some pretty hefty acids, which we then have started to prepare for analysis by mass spectrometry. We've also heavily investigated the isotope dilution process of finding trace element abundances, where our samples are spiked with a known volume of a known solution with a known isotopic concentration of an element, in our case Samarium. This process allows an easier method of measuring the ratios of other trace elements to our spike, which we can then use to determine the true abundance of the trace elements in our sample.

Overall, this internship (so far) has been an experience of working well outside of my experience and comfort zone, but in a manner that is much more rewarding than it is difficult. What I've studied lies much more on the theoretical side of planetary science, largely involving analytic descriptions of the formation processes of chondrules and planets, which didn't include real hands-on research with in-depth SEM investigations or wet chemistry. However, it's been a great experience to be able to explore the real laboratory work that supported/corroborated the analytics I knew. I've studied planetary science, but not in the "real world" dealing with real samples and real lab work, and it's been rewarding to connect these new lab experiences with my more theoretical knowledge.

Gerrit Postema