Cape Verde hotspot

Cape Verde hotspot
Name	Cape Verde hotspot
Location	Atlantic Ocean, off West Africa
Type	Intraplate volcanic hotspot
Coordinates	16°N 23°W (approx.)
Age	Neogene to Present
Activity	Active (historical eruptions on Fogo)

Cape Verde hotspot is an intraplate volcanic center beneath the eastern North Atlantic responsible for the volcanic islands of the Cape Verde archipelago. The hotspot underlies the Bissagos Islands region near the western African margin and has produced oceanic islands with basaltic to phonolitic volcanism, notably on Fogo (island), Santo Antão, São Vicente, São Nicolau, Santiago (Cape Verde), Boavista, Sal (island), and Brava. Studies integrate evidence from plate reconstructions tied to the African Plate, seismic tomography anchored by data from the IRIS (seismology) network, and geochemical analyses compared with hotspots such as Iceland hotspot, Azores hotspot, Canary hotspot, and Galápagos hotspot.

Geology and tectonic setting

The hotspot sits within the eastern North Atlantic basin competing in interpretations between a deep-mantle plume model and a shallower, lithospheric-controlled upwelling; seismic tomography studies using arrays from Portuguese Institute of the Sea and Atmosphere and the National Oceanography Centre (UK) detect low-velocity anomalies beneath the archipelago that are compared with anomalies beneath Reykjanes Ridge and the Mid-Atlantic Ridge. The tectonic context includes proximity to the African Plate–Nubian Plate boundary debates, the passive margin formed during the breakup of Pangea and rifting linked to the formation of the Central Atlantic Magmatic Province, and transform or fracture zones such as the Gloria Fault and Santo Antão Fault. Regional seismicity recorded by the Instituto de Investigação e Desenvolvimento (Cape Verde) and international observatories shows volcano-tectonic events similar to those cataloged at Montserrat and La Palma.

Volcanism and landforms

Surface expressions include shield volcanoes, stratovolcanoes, fissure-fed flows, tuff rings, and cinder cones comparable to morphologies on Hawaiʻi and Iceland. Fogo features a caldera, the Pico do Fogo stratovolcano, whose eruptions in 1995 and 2014 produced lava flows that impacted São Filipe and agricultural terraces similar to historic devastation at Pelee (1902) and Krakatoa (1883). Onshore products range from olivine-phyric basalts to evolved phonolites that created volcanic edifices, lahars affecting watersheds studied in analog with Mount St. Helens and Eyjafjallajökull. Offshore, submarine edifices, guyots, and hyaloclastite deposits mapped by the NOAA and the Institut Français de Recherche pour l'Exploitation de la Mer resemble seafloor features imaged near the Azores and Madeira.

Geochemistry and mantle source

Geochemical signatures include enriched mantle 1 (EM1), enriched mantle 2 (EM2), and primitive mantle (FOZO/PIBI) components inferred from isotopic systems such as Sr–Nd–Pb–Hf measured at laboratories like Scripps Institution of Oceanography and University of Oxford. Trace-element ratios and He–Ne isotopes show elevated 3He/4He ratios in some samples, aligning with hypothesized deep-mantle plume sources akin to Hawaii and contrasting with enriched signatures seen at the Canary Islands. Geochemical heterogeneity across islands mirrors mixing between recycled oceanic crust components, subcontinental lithospheric contributions, and enriched plume material discussed in publications from Max Planck Institute for Chemistry and CNRS. Petrogenesis models invoke fractional crystallization, crustal assimilation, and low-pressure crystal fractionation documented by experimental petrology groups at ETH Zurich.

Age progression and hotspot track

Absolute ages from K–Ar and 40Ar/39Ar dating produced at facilities such as Geological Survey of Denmark and Greenland and USGS indicate span from early Neogene to Holocene, with older volcanic centers to the east/southeast and younger centers at Fogo and Brava. Unlike the classic linear track of the Hawaiian–Emperor seamount chain, the age pattern is discontinuous and shows overlapping episodes similar to the Azores and Canary provinces, complicating plate-motion reconstructions relative to fixed-plume models proposed in studies by researchers at University of Cambridge and Massachusetts Institute of Technology. Regional tectonic reorganization events recorded in stratigraphy are correlated with episodes documented in the Senegal Basin and West African Craton evolution.

Interaction with lithosphere and tectonics

The hotspot’s magmatism is modified by variably thick oceanic lithosphere, fracture-controlled magma ascent along transform zones, and flexural response of the plate leading to subsidence and uplift patterns analogous to observations at Reykjanes and Icelandic rift zones. Crustal contamination and magma storage are influenced by the composition and thickness of the Cape Verde oceanic crust investigated with seismic reflection profiles by institutions like Woods Hole Oceanographic Institution and the Gulf Coast Repository. Geodynamic modeling from groups at University of Barcelona and Institut de Physique du Globe de Paris evaluates plume–lithosphere coupling, downward mantle flow, and the role of small-scale convection similar to processes inferred for the Canary Isles.

Human history and impacts

Human settlement and historical impacts involve connections to Portuguese Empire colonization, transatlantic maritime routes linked to Age of Discovery, and economic activities such as salt extraction on Boavista comparable to saltworks in Cape Verde (country). Volcanic hazards have caused evacuations, agricultural loss, and urban damage documented in municipal archives of São Filipe and national emergency reports modeled after procedures from UN Office for Disaster Risk Reduction. Cultural responses include oral histories preserved by institutions like the Museu Etnográfico da Praia and adaptations in island agriculture resembling terraces seen in the Madeira Islands and Azores.

Research history and methods

Investigations combine petrology, geochemistry, geochronology, seismic tomography, marine geophysics, and remote sensing employed by teams from University of Lisbon, University of Cape Verde, Plymouth Marine Laboratory, Imperial College London, GEOMAR Helmholtz Centre for Ocean Research Kiel, and Tokyo Institute of Technology. Key methods include 40Ar/39Ar dating, Sr–Nd–Pb–Hf isotope analyses, seismic receiver functions, magnetotellurics, multibeam bathymetry, and gravity surveys comparable to approaches used in studies of Iceland and Azores. Ongoing collaborations through programs funded by the European Research Council and the National Science Foundation support drilling proposals linked to the International Ocean Discovery Program and multidisciplinary field campaigns modeled on campaigns at Kerguelen and Hawaii Volcano Observatory.

Category:Volcanism of the Atlantic Ocean Category:Hotspots