Details

Autor(en) / Beteiligte

• Reiss, M. C.
• Siena, L.
• Muirhead, J. D.

Titel

The Interconnected Magmatic Plumbing System of the Natron Rift

Ist Teil von

• Geophysical research letters, 2022-08, Vol.49 (15), p.n/a

Ort / Verlag

Washington: John Wiley & Sons, Inc

Erscheinungsjahr

2022

Quelle

Wiley Blackwell Single Titles

Beschreibungen/Notizen

• Understanding the magmatic plumbing system of rift volcanoes is essential when examining the interplay between magmatic and tectonic forces. Recent seismicity, volcanic activity, magma emplacement, and volatile release make the Natron basin the ideal location to study these processes in the East African Rift System. Here, we present the first high‐resolution tomographic imaging of Oldoinyo Lengai volcano and surrounding volcanic systems using attenuation mapping. High scattering and absorption features reveal fluid‐filled fracture networks below regions of magmatic volatile release at the surface and a close spatial association between carbonatite volcanism and deeply penetrating, fluid‐filled faults. High‐absorption features appear sensitive to fluids and thermal gradients, revealing a central sill complex and connected plumbing system down to the mid‐crust, which links volcanoes and rift segments across the developing magmatic rift. Plain Language Summary The interplay between magmatic and tectonic forces during rifting is still debated. While they are a key component of rift development, the complex structures of rifts and melt storage systems scatter and absorb seismic waves passing through them: in turn, this deteriorates the quality of the subsurface images we obtain from them. In this study, we use the loss of energy suffered by seismic waves to image the Natron basin, which hosts extinct volcanoes and the only active natrocarbonatite volcano on Earth, Oldoinyo Lengai. The results identify areas of melt storage and fracture networks that feed volatiles and melt to this volcano. Results suggest that carbonatite melts may ascend through the crust efficiently along deep‐seated faults systems, while silicate melts in the region may be primarily sourced from a separate melt reservoir. This reservoir, which is elongate and oriented oblique to the general trend of the rift, may act as a magmatic transfer zone between two rift segments. Key Points First fine‐scale 3D images reveal an interconnected rift plumbing system using scattering and absorption mapping High scattering and absorption mark fluid‐filled faults that degas magmatic fluids and act as potential conduits for carbonatite melts A high absorption melt reservoir feeds eruptions at Oldoinyo Lengai and dike intrusions and acts as a transfer zone between rift segments