Investigation of subsurface environments and subsurface processes is becoming more and more important in our understanding of planetary evolution, habitability and the search for life. Barbara Sherwood Lollar, University Professor in Earth Sciences and Dr. Norman Keevil Chair in Ore Deposits Geology at the University of Toronto, will discuss her research on this topic in the talk, “Imaging Habitable Worlds – Lessons from the Deep Biosphere and Hydrogeosphere.”
The virtual talk, which is free and open to the public, is scheduled for 4:30 p.m. Thursday, Oct. 28. Attendees can either watch via Zoom or meet in 220 Hammond Building on the University Park campus to watch the virtual talk. The talk is part of the Penn State Department of Geosciences’ fall 2021 colloquium series and was selected as the colloquium’s 125th anniversary celebration talk in honor of the College of Earth and Mineral Sciences 125th anniversary.
The talk will address some of the highlights of recent exploration of the energy-rich “hidden hydrogeosphere” – or systems of water isolated deep underground on long geological time scales – in the Precambrian crust, and connections to deep subsurface life on Earth and beyond to planetary exploration and astrobiology.
Science has long relied on fluid inclusions – microscopic time capsules of fluid and gas encased in host rocks and fracture minerals – to access preserved samples of ore-forming fluids, metamorphic fluids and remnants of the ancient atmosphere and hydrosphere.
Until recently, groundwaters were thought to reflect only much younger periods of water-rock interaction and Earth history, due to dilution with large volumes of younger fluids recharging from surface hydrosphere. However, in the last 10 to 20 years, global investigations of the world’s oldest rocks have revealed ancient groundwaters that have not been exposed to the surface in millions or even billions of years at some sites.
These groundwaters provide unprecedented samples for investigation of the Earth’s ancient hydrosphere and atmosphere and they are opening up new lines of exploration of the biodiversity of extant life in the Earth’s subsurface and planetary habitability. Beyond Earth, these findings have relevance to understanding the role of chemical water-rock reactions, in particular radiolysis, in defining the potential habitability of the subsurface of Mars, as well as that of ocean worlds and icy bodies such as Europa and Enceladus.
Sherwood Lollar is a fellow of the American Geophysical Union, the Geochemical Society and European Association of Geochemistry. She is co-director of the Canadian Institute for Advanced Studies’ research program, Earth 4D: Subsurface Science and Exploration. In 2021, she was elected as an international member of the U.S. National Academy of Engineering.