Hunting Meteorites in the Atacama

Clara Maurel | EAPS News
Wednesday, December 4, 2019

EAPS graduate student Clara Maurel breaks out of the lab and joins an expedition to collect meteorites, rocks fallen from space that she and other scientists use for their research.

Have you ever seen on the 9th floor of the Green building a dense map of research field sites visited by MIT EAPS scientists? Our department is rich with hundreds of field experiences in remote and grandiose parts of our planet, but truth is, not all of us contribute equally to the densification of this map.

I am a PhD student in planetary sciences. My research goal is to contribute to our understanding of planetary systems formation. I want to address questions such as: How are asteroids made out of dust? How do they grow and evolve? How do they form planets, or why do they not? For this, I study meteorites, which are known to come from the very first asteroids formed at the birth of the solar system. However, despite the “exotic” nature of my samples, the most exotic sample collection site I had been to was the Harvard Museum of Natural History, until recently.

Meteorites have been falling everywhere on Earth for the past 4 billion years; humans have collected them since the beginning of their history. Centuries of meteorite discoveries are now centralized in natural history museums and available upon request. It simply takes an email and, sometimes, a bus ride. It is an undisputed truth in the world of meteoritics: just because you study meteorites does not mean that you will travel the world to find them.

This truth does not apply to Jérôme Gattacceca, planetary scientist at the Centre Européen de Recherche et d’Enseignement des Géosciences de l’Environnement (CEREGE) in France and long-time collaborator of our lab. For years, Jérôme has been taking part in and organizing expeditions to collect meteorites all around the world. One day, in the post scriptum of an email, he casually invited me to join his next expedition to the Atacama Desert. With apprehension but without a hesitation, I jumped on the occasion to participate — my very first field trip.

Deserts are the best places to find meteorites, which are generally richer in metal than most Earth rocks and get rusted away in humid areas. In dry environments, they can be preserved for hundreds of thousands of years. Among all deserts on Earth, the Atacama has the largest number of meteorites per square kilometer. This is partly because in this desert, only a thin sand layer overlays bedrock, which means that meteorites don’t get buried and remain somewhat visible.

The field trip took place at the beginning of November 2019. We were 13 participants: professors, research scientists and graduate students, from different universities in France, Germany, and the UK. Every day, we drove our pickups from the campsite to interesting areas, identified by satellite or during previous searches. Over a period of ten days, we scanned for meteorites at these preselected locations, searching in different areas of the desert. The job consisted of slowly walking in line alongside the other researchers, looking at the ground—a very meditating activity—picking up any rock that seemed out of place.

I handle meteorites quite often for my research. I know what they should look like, in theory: they are dark, dense, possibly a little rusty, and sometimes have a fusion crust resulting from their atmospheric entry. When you are in the field though, that is a whole different story. You have to look for a dark rock in hopefully lighter sand, which can be of any shape and any size. On many terrains, it was easy to get overwhelmed by all the darkish (Earth) rocks on marginally lighter sand. If anyone found a meteorite, we all stopped the search and gathered to readjust our mental picture of what a meteorite should look like. When I found my first meteorite, one of my teammates told me, “Do you realize this rock once was in space and that you are the first person ever to touch it? How awesome is that?!” She was right; it is not something you experience every day.

Nights at the camp certainly helped make this field trip unforgettable. At the end of the day, we all sat around the fire, sipping a camping mug of Chilean wine and cooking unbelievably good food. Laughing and chatting while watching the sunset and rising our heads to see the stars are memories that will stay with me. Some nights, a small group would stroll from the camp with their head-torches to search for meteorites. After walking a few hundred meters, surrounded by emptiness, we would turn off the lights to share a rare moment of quietness.

In total, the group found more than 700 meteorites, representing 60 kilograms of billion-year-old space rocks with sizes ranging from a fava bean to a mango. We carried the rocks out of the desert ourselves. They were then flown back to France for classification and will be available to any researcher upon request. Who knows, maybe we found some rare specimens that will be used for years to come!

Even though this expedition was not directly related to my research, I learned a lot about my “raw” research material. Everyone on the team worked on meteorites, but the vast majority was coming from different research areas, which triggered enriching scientific conversations around the fire and during the breaks. Beyond its scientific interest, this expedition truly was a life-changing experience. First humanly, as I got to live remotely almost 24/7 with my (thankfully) fantastic teammates. Who hasn’t at least once felt lonely in the lab? Field trips are the occasion to bond and connect on a deep level with your peers (should they be grad students or professors), and remind you that cooperation is the crux of our scientific work. Second personally, as I experienced unforgettable moments of profound happiness when sitting alone in the middle of the desert, watching quietly a sunrise, a sunset or the stars.

I am forever indebted to Jérôme Gattacceca for inviting me to join the team, and to the team for making the expedition so enjoyable. Thank you to Claire Nichols, postdoctoral fellow in the EAPS Weiss lab and field trip master; during these two weeks, I surprised myself for being so well prepared (technically and mentally) thanks to our conversations. Finally, I warmly thank the Zonta International association, who awarded me an Amelia Earhart Fellowship that allowed me to participate to this expedition.

Story Image: Clara Maurel finds a meteorite! (Credits: Katherine Joy, The University of Manchester and Vinciane Debaille, Université Libre de Bruxelles)