The Interpretation of Mineralogical and Geochemical Processes: An Interview with Pooja Sheevam, Part V

In Part IV of our conversation with Pooja Sheevam, she discussed how scanning electron microscopy with an energy-dispersive X-ray spectroscopy (SEM-EDS) and bulk X-ray fluorescence (XRF) was applied in the study to learn more about the fluid-rock interactions in the PTA-2 drill core (1,2).

In the final part of this video interview with Sheevam, she discusses the importance of her study in understanding the mineralogical and geochemical processes in Hawaii.

Will Wetzel: Why is it significant that this study was conducted away from active margins, and how does that influence the interpretation of mineralogical and geochemical processes?

Pooja Sheevam: Hawaii, from a geological perspective, is far from an active plate margin, but it is on top of a hotspot. It is significant because it allows us to investigate a geothermal or a hydrothermal system in a geological context that's fundamentally different from a traditional high-temperature geothermal field found along either large rift zones, large fault zones, or even tectonic boundaries. A lot of people like to compare Hawaii to Iceland, and I fully disagree, even though the rocks are similar. Hawaii does not have a large rift province like Iceland does, and Hawaii is moving away from a hot spot, so your rifting is very localized to where it is right now, which is the Kilauea East rift zone. Therefore, the movement of heat and water is fairly different.

Our work contributes to how heat and fluid move by studying the alteration and its occurrences. The bigger picture here is we're contributing to a fraction of assessing the renewable energy potential across these islands, right? It's particularly important for Hawaii, where energy independence is a priority. Microgrid development on individual islands could benefit from localized geothermal resources, but to do that, you have to understand what's going on underground, and so recovering these cores and doing these studies really helps bring light to what is going on under the surface.

Also, just purely from a scientific perspective, the rarity of recovered cores from deep in the subsurface of Hawaii is a unique opportunity. This study is part one of three papers that provide insight on these drill cores, not just because of the hydrothermal or geothermal alteration, but also a history of the volcanic or magnetic input and the subsurface stratigraphy, and the magmatic evolution. And these areas are still unexplored. I think that was not the purview of my research, and in many ways, we're just beginning to scratch the surface. So these cores have raised way more questions than they've answered from the fact that we're seeing variations and alteration types, and styles between the islands. I think there's a need for further drilling, geophysical surveys, and geochemical sampling, and it's exciting that we’re contributing to this big picture. And there's a huge potential for scientific value in the Hawaiian volcanic systems, especially away from the active margins.

This interview with Sheevam is the final part of a five-part interview series. You can watch the previous segments of our conversation with Sheevam below.

Part I

Part II

Part III

Part IV

References

1. Sheevam, P.; Calvin, W. M. Comprehensive characterization and geochemical alteration pathways of drill core from the Humu'ula Groundwater Research Project, Hawaii, USA: I. Pohakuloa Training Area. J. Vol. Geo. Res. 2025, 462, 108311. DOI: 10.1016/j.jvolgeores.2025.108311
2. Wetzel, W. Understanding Fluid-Rock Interactions: An Interview with Pooja Sheevam, Part IV. Spectroscopy. Available at: https://www.spectroscopyonline.com/view/understanding-fluid-rock-interactions-an-interview-with-pooja-sheevam-part-iv (accessed 2025-06-04).