G. Helffrich M. Cosca D. Vance D. Hoffmann D.N. Schmidt R. Ramalho 2010 <p><span>On the Beagle voyage, Charles Darwin first noted the creation and subsidence of ocean islands</span>^{<a id="ref-link-section-d52660e398" title="Darwin, C. R. The Structure and Distribution of Coral Reefs (Smith Elder, 1842)." href="https://www.nature.com/articles/ngeo982#ref-CR1" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 1" data-mce-href="https://www.nature.com/articles/ngeo982#ref-CR1">1</a>}<span>, establishing in geology’s infancy that island freeboard changes with time. Hotspot ocean islands have an obvious mechanism for freeboard change through the growth of the bathymetric anomaly, or swell</span>^{<a id="ref-link-section-d52660e402" title="Crough, S. T. Thermal origin of mid-plate hot-spot swells. Geophys. J. R. Astron. Soc. 55, 451–469 (1978)." href="https://www.nature.com/articles/ngeo982#ref-CR2" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 2" data-mce-href="https://www.nature.com/articles/ngeo982#ref-CR2">2</a>}<span>, on which the islands rest. Models for swell development indicate that flexural</span>^{<a id="ref-link-section-d52660e406" title="Grigg, R. &amp; Jones, A. Uplift caused by lithospheric flexure in the Hawaiian Archipelago as revealed by elevated coral deposits. Mar. Geol. 141, 11–25 (1997)." href="https://www.nature.com/articles/ngeo982#ref-CR9" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 9" data-mce-href="https://www.nature.com/articles/ngeo982#ref-CR9">9</a>}<span>, thermal</span>^{<a id="ref-link-section-d52660e410" title="Crough, S. T. Thermal origin of mid-plate hot-spot swells. Geophys. J. R. Astron. Soc. 55, 451–469 (1978)." href="https://www.nature.com/articles/ngeo982#ref-CR2" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 2" data-mce-href="https://www.nature.com/articles/ngeo982#ref-CR2">2</a>,<a id="ref-link-section-d52660e413" title="Detrick, R. S. &amp; Crough, S. T. Island subsidence, hot spots and lithospheric thinning. J. Geophys. Res. 83, 1236–1244 (1978)." href="https://www.nature.com/articles/ngeo982#ref-CR3" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 3" data-mce-href="https://www.nature.com/articles/ngeo982#ref-CR3">3</a>}<span>&nbsp;or dynamic pressure</span>^{<a id="ref-link-section-d52660e417" title="Davies, G. F. Ocean bathymetry and mantle convection 1. Large-scale flow and hotspots. J. Geophys. Res. 93, 10467–10480 (1988)." href="https://www.nature.com/articles/ngeo982#ref-CR4" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 4" data-mce-href="https://www.nature.com/articles/ngeo982#ref-CR4">4</a>,<a id="ref-link-section-d52660e420" title="Olson, P. in Magma Transport and Storage (ed. Ryan, M. P.) 33–51 (John Wiley, 1990)." href="https://www.nature.com/articles/ngeo982#ref-CR5" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 5" data-mce-href="https://www.nature.com/articles/ngeo982#ref-CR5">5</a>,<a id="ref-link-section-d52660e423" title="Sleep, N. H. Hotspots and mantle plumes: Some phenomenology. J.&nbsp;Geophys.&nbsp;Res. 95, 6715–6736 (1990)." href="https://www.nature.com/articles/ngeo982#ref-CR6" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 6" data-mce-href="https://www.nature.com/articles/ngeo982#ref-CR6">6</a>,<a id="ref-link-section-d52660e426" title="Ribe, N. M. &amp; Christensen, U. R. The dynamical origin of Hawaiian volcanism. Earth Planet. Sci. Lett. 171, 517–531 (1999)." href="https://www.nature.com/articles/ngeo982#ref-CR8" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 8" data-mce-href="https://www.nature.com/articles/ngeo982#ref-CR8">8</a>}<span>&nbsp;contributions, as well as spreading of melt residue from the hotspot</span>^{<a id="ref-link-section-d52660e431" title="Morgan, J. P., Morgan, W. J. &amp; Price, E. Hotspot melting generates both hotspot volcanism and a hotspot swell? J. Geophys. Res. 100, 8045–8062 (1995)." href="https://www.nature.com/articles/ngeo982#ref-CR7" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 7" data-mce-href="https://www.nature.com/articles/ngeo982#ref-CR7">7</a>}<span>, can all contribute to island uplift. Here we test various models for swell development using the uplift histories for the islands of the Cape Verde hotspot, derived from isotopic dating of marine terraces and subaerial to submarine lava-flow morphologies. The island uplift histories, in conjunction with inter-island spacing, uplift rate and timing differences, rule out flexural, thermal or dynamic pressure contributions. We also find that uplift cannot be reconciled with models that advocate the spreading of melt residue in swell development unless swell growth is episodic. Instead, we infer from the uplift histories that two processes have acted to raise the islands during the past 6 Myr. During an initial phase, mantle processes acted to build the swell. Subsequently, magmatic intrusions at the island edifice caused 350 m of local uplift at the scale of individual islands. Finally, swell-wide uplift contributed a further 100 m of surface rise.</span></p> application/pdf 10.1038/ngeo982 en Nature Publishing Group Episodic swell growth inferred from variable uplift of the Cape Verde hotspot islands article