Abstract
Magmatically-accreted upper crust along mid-ocean ridges is traditionally considered to consist of lava flows overlying a sheeted-dyke complex. However, how the upper crust is formed at hotspot-influenced ridge segments remains unknown. Using three-dimensional seismic reflection data, here we report images of lava flow layering beneath Axial volcano on the Juan de Fuca Ridge. These lava flow layers dip inward towards the caldera and rift zones, resulting from subsidence caused by magma withdrawal beneath the summit and rift zone extension. Furthermore, our images reveal that the classic, laterally continuous sheeted-dyke complex is absent. Instead, lava flow layers are rotated and brought into direct contact with the magma domain, leading to partial assimilation of these units. Three-dimensional images also show that melt is injected outward along lava flow layers, suggesting that the upper crust at Axial volcano is formed by complex interactions between injected melt sills and lava flow layers.
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Data availability
MCS data for the 3-D cruise is available on the Marine Geoscience Data System at https://www.marine-geo.org/; the cruise information name is MGL1905, https://doi.org/10.7284/908292. Correspondence and requests for materials should be addressed to Satish C. Singh (singh@ipgp.fr).
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Acknowledgements
We thank the officers and crew of the R/V Marcus Langseth and supporting Office of Marine Operations at Lamont-Doherty Earth Observatory, Columbia University. We also thank the around-the-clock shipboard open-participation crew and onshore liaison: Axelle Cap, Brian Oiler, Massimo Bellucci, Matthews Griffiths, Michelle Lee, Morgane Goulain, Shelby Brandt, Tanner Eischen, Victoire Lucas, Samuel Mitchell and Annie Kell. Data-processing software was provided by Aspen Tech, Inc. (Paradigm 22), Bedford, Massachusetts, USA. Echos and Geodepth were used for the three-dimensional binning, stacking and prestack depth migration of the multichannel seismic data. Data presentation of the three-dimensional seismic volume was facilitated through visualization using Matlab. This project was funded through the National Science Foundation awards: OCE-1658021 (G.M.K.), OCE-1658199 (A.F.A.), and OCE-1658018 (A.J.H.). H.W. and W.X. were funded by Chinese Scholarship Council. S.C.S. was in part supported by ERC Advanced Grant MohoLAB 101141564. IPGP contribution number 4298.
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A.F.A. and A.J.H. collected the 3-D dataset onboard the R/V Marcus Langseth; 3D PSDM was performed by H.W. and 2D FWI was performed by W.X., under the supervision of S.C.S., H.C., and G.M.K. Interpretation of the datasets was undertaken by S.C.S., H.C., G.M.K. and H.W. and manuscript was written by S.C.S., G.M.K., H.C., and H.W. with input from A.F.A. and A.J.H.
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Wu, H., Xie, W., Singh, S.C. et al. Oceanic upper crustal accretion by melt sill and lava flow interaction at Axial volcano. Nat Commun (2026). https://doi.org/10.1038/s41467-026-70033-x
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DOI: https://doi.org/10.1038/s41467-026-70033-x
