Erin L. Walton, 1978–2022

Erin Walton

Erin Lindsey Walton Hauck passed away on September 21, 2022, at the age of 44 following a battle with cancer.

Walton was born on August 4, 1978, in Fredericton, New Brunswick, Canada. She grew up with a love and respect for the natural world that would continue all her life. During her undergraduate studies at the University of New Brunswick (UNB), she discovered her passion for geology and the cosmos, which led her to mineralogy, meteorites, and impact processes.

Characterizing the complex shock effects produced during impact events was the overarching theme of her research. Following her documentation of the Benton LL6 chondrite (the only meteorite known from Atlantic Canada) for her undergraduate honors thesis — her first published paper — she continued to her Ph.D. with John Spray at the Planetary and Space Science Centre, UNB. The work involved a study of the effects of shock in martian meteorites — a theme that would be central to her scientific contributions. Her dissertation was nominated by UNB as one of the best in Canada, and she was recognized as one of the brightest university researchers by Maclean’s magazine in 2004.

In 2005, she was competitively awarded a Natural Sciences and Engineering Research Council of Canada (NSERC) Postdoctoral Fellow position, which she took up in the Department of Earth and Atmospheric Sciences at the University of Alberta. In 2007, she secured a Space Science Fellowship from the Canadian Space Agency, which she used to continue her position at the University of Alberta until 2009. At Alberta, she took advantage of experimental petrology facilities — and more microbeam methods — to explore and constrain the crystallization conditions of impact melt pockets in martian meteorites. Working in collaboration with Chris Herd, she published a series of papers that provided insights into how impact melt pockets formed, as well as the mechanics of implantation of the martian atmosphere. Her research using laser probe 39Ar-40Ar on impact melt pockets and veins was important for establishing that implantation of atmospheric argon can significantly modify apparent Ar-Ar isochrons. This was succinctly described, within the context of the then-raging debate about the ages of martian meteorites, in a paper simply entitled “Isotopic and petrographic evidence for young martian basalts” (Geochimica et Cosmochimica Acta, 72, 5819–5837).

In 2009, Walton secured a faculty position at Grant MacEwan College (now MacEwan University), which enabled her to continue research on martian meteorites and to share her passion for mineralogy and petrology with undergraduate students. Recognizing a need to hone her teaching skills, she enrolled in a mentorship program and quickly became known for being an excellent instructor. In her role, she developed four new courses and co-developed six new courses for the new Physical Sciences degree program. All this was achieved while maintaining a full teaching load; securing funding for a Raman instrument; sustaining an active, NSERC-funded research program; and supervising some 20 student projects. Most were undergraduate projects, but there were also several master’s projects, co-supervised with Chris Herd at the University of Alberta, or with Cliff Shaw and John Spray at UNB, thanks to her adjunct professor status at both institutions. She was actively co-supervising some of these student projects as recently as August 2022.

Walton’s research into shock effects expanded to include other meteorite types, and her body of work in this area contributed to an improved understanding of the pressure-temperature-time histories of shock melts, along with the correlation between these effects, the impact process, and by inference, the size of the impact event. In this way, her research was seminal to linking shock effects in meteorites to the geological setting of their parent bodies.

In the past decade, Walton expanded her research to include terrestrial impact structures, recognizing that similar approaches to meteorite studies could be applied to terrestrial rocks. The Steen River (Alberta) impact structure had not been extensively studied since the 1970s. Walton, along with her students and collaborators, applied modern characterization methods to impactites from this structure and brought their study into the twenty-first century. Her research recognized and characterized new types of impactites from Steen River and elucidated new chemical reactions that took place within these rocks that had never been described before. Furthermore, some of the minerals found in the Steen River impact rocks are the same as those found in the rocks from the dinosaur-ending Chixculub impact structure. In 2019, she was awarded a MacEwan University Board of Governors Research Chair in recognition of her research.

Walton loved to get new data, especially from the scanning electron and Raman microscopes, and the electron microprobe, which she used herself at an expert level. The quality of her research contributions sets a high bar — papers typically include at least one hand-drafted illustration of features within a shock metamorphosed rock. This links back to her undergraduate days when John Spray discovered at the back of the class an exceptional artist at work precisely copying and coloring images from the petrographic microscope and hand samples, the quality of which he had not seen before, or has seen since. Walton leaves behind a body of work in the peer-reviewed literature that lays the groundwork for countless future research projects and that will continue to inform and inspire future research.

— Text courtesy of Christopher Herd, John Spray, and Tom Sharp in Meteoritics & Planetary Science