Heat flow as a catalyst for radiogenic helium release in the East Africa Rift System

Mulaya, Ernest; Gluyas, Jon; McCaffrey, Ken; Byrne, David; Ballentine, Chris

Abstract

The Rukwa Rift section of the East Africa Rift System presents a type setting for radiogenic helium accumulation in a petroleum free basin. As a prerequisite for accumulation, a considerable high heat fow anomaly is required from tectonothermal events to drive the release and circulation of radiogenic helium in the continental crust. Here we apply statistical analysis on geochemical data observed in thermal springs and recorded heat flow to account for crustal helium mass balance for each tectono-thermal event in the region. Our results demonstrate anoma-
lously high heat fow~64–99 mW/m2 with a consistent trend of helium isotopic ratio and fuid chemistry in the Rukwa Rift. Mass balance calculation show that the whole crustal volume underlying the East Africa Helium Pool (EAHP) has a capability of producing radiogenic helium of about 9.9× 106 mol/yr (22× 10–6 mol 4 He/m2 yr) while the total radiogenic helium fux ranges between ~2.39 × 106 mol/yr and ~2.68 × 109 mol/yr. The Tanzania Craton contributes largely to radiogenic helium releasing up to 50% of the total capacity in the region. The total 4He emission in the Rukwa Rift Basin is about 4.45× 105
–5.01× 108 mol/yr which is thus equivalent to 19%–21% of the total production capacity in the region. These results imply that the helium accumulation in the EAHP would have started as early as Paleoproterozoic (2.349 Ga). These results provide a qualitative and quantitative insight to assess both helium and geothermal potentiality in the region.

Citation

Mulaya, E., Gluyas, J., McCaffrey, K., Byrne, D., & Ballentine, C. (online). Heat flow as a catalyst for radiogenic helium release in the East Africa Rift System. Acta Geochimica, https://doi.org/10.1007/s11631-025-00780-z

• Journal Article Type: Article
• Acceptance Date: Mar 30, 2025
• Online Publication Date: May 23, 2025
• Deposit Date: May 28, 2025
• Publicly Available Date: Jun 25, 2025
• Journal: Acta Geochimica
• Print ISSN: 2096-0956
• Electronic ISSN: 2365-7499
• Publisher: Springer
• Peer Reviewed: Peer Reviewed
• DOI: https://doi.org/10.1007/s11631-025-00780-z
• Public URL: https://durham-repository.worktribe.com/output/3965815