Landed safely on the 16th of February in Houston, and after having a 2 meat BBQ meal while catching up with an old friend, I got some rest for the work that laid ahead! I was getting ready early Monday morning to go to the Johnson Space Center badging center to collect my international visitors pass. I was picked up by my research collaborator (Dr Timmons Erickson) at the hotel, and he sadly told me that because it is President’s Day the badging office is closed. I immediately thought to myself, “I didn’t consider that the badging office might be closed on President’s Day…”. So unfortunately, I could not get my badge until Tuesday morning. We drove to the nearest Starbucks (because coffee and Wi-Fi go hand in hand nowadays) and I showed Timmons the zircon minerals I wanted to map using the Secondary Electron Microscopy (SEM) machine. He suggested since he could still go on site, he would take my samples and get them polished, so we are ready to start after I get my badge. He also wanted to print off the maps I created, where I marked the location of each zircon in each sample. The maps are backscattered electron (BSE) images. They are created when a sample, in this case a thin slice of a melt rock, is bombarded by a focused beam of electrons. The electrons excite the elements in the rock and they each release energy back to a receiver. Each element releases different amounts of energy, so they appear at different brightness’s. Below is one of my BSE images.
A BSE image of an impact rock with clasts created by a meteorite impact event. The red labels and circles mark the locations of zircon crystals. This sample is from the Mistastin Lake impact structure in Northern Labrador, Canada.
Fast forward to the next day, I got my badge after waiting 15 minutes in the office (not too bad), and then Timmons and I drove over to the SEM laboratory. We immediately dove into our work. For those who are wondering what we are studying and why we are analyzing the zircons, I can tell you very briefly (mainly because a full explanation of the entire project will need a separate blog post). The atomic arrangement and make-up or “microstructure” of zircons changes in size and shape when heated to extreme temperatures (>2000 degrees). Extreme temperatures cause the zircons crystallographic (structure of the mineral) orientations to change. We are able to study these orientations and determine what mineral phases were present before heating. Therefore, we can figure out what the temperatures conditions are during meteorite impact events. The zircon microstructures are mapped using a lab technique called electron backscatter diffraction (EBSD). Electrons are fired at the zircons at a 70 degree tilt angle and are diffracted (they are re-directed) towards a detector. This is a very simplified explanation, and I do realize that I could go into more details about the technique and the data. I have decided to post an audio clip where I talk about the technique and data. I will be releasing a regular blog post after my travels to Baltimore for my research visit week at John Hopkins University.
I still want to keep this “Short Blog” series as short as possible. However, I did not want to end this post without at least showing you a couple of photos. I am posting regularly on Twitter (@GavinOnTheMoon) and my Instagram story (@gavin4science_94).
Until next time, see you guys soon!