Neutrons Reveal Hidden Pathways to Geologic Hydrogen and Critical Minerals

To understand why this matters, it helps to begin with the rocks themselves. Ultramafic rocks are distinctive magnesium- and iron-rich rocks formed deep within the Earth. In Canada, they matter for two reasons. They occur in large deposits in parts of British Columbia and Quebec that also host nickel, chromium, cobalt, and other strategic minerals, and they can react with water in ways that generate hydrogen gas naturally. That reaction, known as serpentinization, occurs when water alters ultramafic minerals into new minerals such as serpentine. That is why these rocks have drawn growing interest for their potential to produce low-carbon geologic hydrogen.

The mystery, however, lies in the reaction pathway itself. Because serpentine minerals are more voluminous than the host rock, serpentinization will tend to fill up any empty space with the newly formed minerals. But if serpentinization gradually seals larger fractures, then what hidden pathways would allow water to keep moving through the rock long enough for meaningful quantities of hydrogen to form?

This matters not only for explaining how hydrogen forms underground, but also for revealing whether these hidden pathways could one day support viable hydrogen production or more sustainable recovery of critical minerals. That is the question Prof. Ben Tutolo and his research team at the University of Calgary have been helping to answer.

Using neutron beams, they have shown that serpentinized ultramafic rocks can host intricate pores and channels on the scale of nanometres within the serpentine minerals themselves. These pathways are far too small to be properly understood through conventional imaging alone, but neutrons are exceptionally well suited to the task for two reasons: They can probe rock-fluid interfaces with nanoscale clarity, enabling scientists to explore previously invisible flow pathways. And they are highly sensitive to hydrogen and can reveal how hydrogen-bearing fluids occupy and move through dense materials.

The result was a new picture of serpentinization, in which water can still migrate through a hidden network of microscopic channels even after larger fractures begin to seal, allowing hydrogen-producing reactions to continue.

This insight matters because it clarifies both the promise and the limits of geologic hydrogen. Tutolo’s broader work suggests that these nanoscale pathways make sustained hydrogen generation physically plausible, but also that the natural permeability of serpentinized rocks is so low that useful accumulations of hydrogen may form far too slowly for commercial production without some form of engineering intervention. In other words, the neutron results do more than resolve a geological mystery. They define a practical challenge for anyone hoping to tap geologic, or “orange,” hydrogen in Canada: if this resource is to become a meaningful contributor to a low-carbon energy system, the subsurface may need to be stimulated to enhance fluid flow.

The same findings may also have implications for critical minerals such as nickel, cobalt, chromium, and manganese—elements essential to batteries, advanced alloys, and other clean-energy technologies. By revealing previously unrecognized fluid-accessible pathways inside serpentinized rock, this research supports the idea that some ultramafic formations might one day be treated in place using carefully designed fluids to recover dissolved critical minerals with less blasting, hauling, and surface disturbance than conventional mining. For Canada, which has ambitious critical-minerals goals and is seeking lower-emissions paths for industrial development, such possibilities make neutron-enabled insight into porosity and fluid flow especially significant.

“Neutron beams let us trace the hidden pathways through which water continues to move inside these rocks, even after larger fractures begin to close,” says Tutolo. “That insight is helping us see how Canadian ultramafic rocks could support both geologic hydrogen and critical minerals—and why access to neutron beams is so important for moving discoveries like this toward real-world impact.”

Taken together, these discoveries show how fundamental neutron studies can illuminate a problem with far-reaching practical consequences. By revealing the hidden architecture of serpentinized ultramafic rocks, Tutolo’s research is helping scientists assess how Canadian rock formations might serve both as hydrogen-generating systems and as unconventional sources of critical minerals. Ongoing work by Tutolo and PhD candidate Madeline Bartels is also extending neutron-derived insights to geologic carbon storage systems, enabling scientists to estimate the amount of carbon dioxide that can be stored in ultramafic rock.

Just as importantly, these discoveries underscore the need for reliable Canadian access to neutron beams if work of this kind is to advance quickly enough to inform emerging opportunities in hydrogen, critical minerals, and industrial decarbonization. Without timely access to these irreplaceable tools, promising Canadian ideas will move more slowly from scientific insight to economic and societal benefit.