Abstract
Nyamulagira volcano (eastern Democratic Republic of the Congo) is one of Africa's most active volcanoes and poses a significant threat to the nearby rapidly expanding population centers. Situated in the Virunga Volcanic Province in the western branch of the East African Rift System, Nyamulagira's frequent eruptions offer a valuable opportunity to study effusive rift volcanism. However, understanding its subsurface processes remains challenging, impeding monitoring efforts. Here, we report a comprehensive mineralogical, petrological, and geochemical study of rocks from historical eruptions at Nyamulagira. Mineral textures and compositions show strong spatial and temporal variations. We identify multiple active magma reservoirs in which magma compositions and textures evolve via crystal accumulation, fractional crystallization, magma recharge, mixing, and convection. We distinguish three distinct reservoirs: a deep reservoir at ∼ 22–30 km depth, the main storage region at ∼ 13–18 km depth, and a shallow reservoir at ∼ 2–9 km depth. We propose that differentiation at Nyamulagira integrates olivine and clinopyroxene crystallization and accumulation in the deep reservoir, and fractional crystallization and magma mixing/homogenization in the interconnected intermediate and shallow reservoirs. Primitive magmas from the deep reservoir are predominantly emitted via distal eruptions, whereas more evolved magmas from the shallower reservoirs have been erupted on the flanks or at the summit caldera in recent decades.
Original language | English |
---|---|
Article number | 108264 |
Number of pages | 24 |
Journal | Journal of Volcanology and Geothermal Research |
Volume | 458 |
DOIs | |
Publication status | Published - Feb 2025 |
Bibliographical note
Funding Information:The authors would like to thank Nicolas Delmelle, Elvira Vassilieva and Hermann Nijs for their help with sample preparation and chemical analyses. O.N. and E.K.K. acknowledge support from the KU Leuven for a PhD Fellowship for Researchers from the South. O.N. acknowledges support from the FWO for an Odysseus grant. E.K.K. is grateful to the Goma Volcano Observatory (GVO) and the Universit\u00E9 de Goma for their help in the field work organization. Katcho Karume, Georges Mavonga, C\u00E9lestin Kasereka Mahinda, Honor\u00E9 Ciraba, Jonathan Kambale Kavuke, Niche Mashagiro, Kabeya Mukuna, Zawadi Batumike, Claude Mukanirwa, Michel Kiroha, Salumu Bihango, D\u00E9sir\u00E9 Baseka, Kanzaniye, Bahihi Luuta, Visiha and Mbambaje of GVO are particularly thanked for their assistance during the field work. We thank two anonymous reviewers and Tobias Fischer for the editorial handling of the manuscript.
Publisher Copyright:
© 2024
Keywords
- Continental basalts
- Magmatic differentiation
- Magmatic petrology
- Magmatic reservoirs
- Virunga Volcanic Province