Mantle plume heterogeneity versus shallow-level interactions: A case study, the São Nicolau Island, Cape Verde archipelago

Millet, Marc-Alban; Doucelance, Régis; Schiano, Pierre; David, Karine; Bosq, Chantal

doi:10.1016/j.jvolgeores.2008.04.003

Cited by 47 publications

(40 citation statements)

References 59 publications

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“…The volcanic islands and seamounts of Cape Verde are dominantly mafic with minor felsic volcanism (Gerlach et al 1988;Davies et al 1989;Doucelance et al 2003;Kokfelt et al 1998;Holm et al 2006;Millet et al 2008;Martins et al 2009;Dyhr and Holm 2010). The Cape Verde volcanic rocks are typically highly alkaline, being basanitic to nephelinitic in nature (Gerlach et al 1988; Davies et al 1989).…”

Section: Geological Settingmentioning

confidence: 99%

“…Little or no evidence for crustal assimilation has been recorded in studies of mafic lavas from Cape Verde, probably a consequence of the limited potential for interaction with sediments or crust in the oceanic setting. Although interaction between magmas, oceanic crust and lithosphere has been postulated in the formation of the lavas of São Nicolau (Millet et al 2008). The few studies that have investigated felsic lavas from the dominantly mafic centres (Santo Antão and Boa Vista) suggest magmatic evolution mainly through processes of fractional crystallisation to generate relatively minor volumes of evolved magma (Holm et al 2006;Dyhr and Holm 2010).…”

Section: Geological Settingmentioning

confidence: 99%

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Magmatic evolution of the Cadamosto Seamount, Cape Verde: beyond the spatial extent of EM1

Barker

Troll

Ellam

et al. 2011

Contrib Mineral Petrol

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The Cadamosto Seamount is an unusual volcanic centre from Cape Verde, characterised by dominantly evolved volcanics, in contrast to the typically mafic volcanic centres at Cape Verde that exhibit only minor volumes of evolved volcanics. The magmatic evolution of Cadamosto Seamount is investigated to quantify the role of magma-crust interaction and thus provide a perspective on evolved end-member volcanism of Cape Verde. The preservation of mantle source signatures by Nd-Pb isotopes despite extensive magmatic differentiation provides new insights into the spatial distribution of mantle heterogeneity in the Cape Verde archipelago. Magmatic differentiation from nephelinite to phonolite involves fractional crystallisation of clinopyroxene, titanite, apatite, biotite and feldspathoids, with extensive feldspathoid accumulation being recorded in some evolved samples. Clinopyroxene crystallisation pressures of 0.38-0.17 GPa for the nephelinites constrain this extensive fractional crystallisation to the oceanic lithosphere, where no crustal assimilants or rafts of subcontinental lithospheric mantle are available. In turn, magma-crust interaction has influenced the Sr, O and S isotopes of the groundmass and late crystallising feldspathoids, which formed at shallow crustal depths reflecting the availability of oceanic sediments and anhydrite precipitated in the ocean crust. The Nd-Pb isotopes have not been affected by these processes of magmacrust interaction and hence preserve the mantle source signature. The Cadamosto Seamount samples have high 206 Pb/ 204 Pb ([19.5), high eNd (?6 to ?7) and negative D8/ 4Pb, showing affinity with the northern Cape Verde islands as opposed to the adjacent southern islands. Hence, the Cadamosto Seamount in the west is located spatially beyond the EM1-like component found further east. This heterogeneity is not encountered in the oceanic lithosphere beneath the Cadamosto Seamount despite greater extents of fractional crystallisation at oceanic lithospheric depths than the islands of Fogo and Santiago. Our data provide new evidence for the complex geometry of the chemically zoned Cape Verde mantle source.

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Section: Geological Settingmentioning

confidence: 99%

Section: Geological Settingmentioning

confidence: 99%

Magmatic evolution of the Cadamosto Seamount, Cape Verde: beyond the spatial extent of EM1

Barker

Troll

Ellam

et al. 2011

Contrib Mineral Petrol

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“…The volcanism is a result of the interaction of a mantle plume with the fractured lithosphere [36,37]. Santiago Island is a shield volcano, with periods of intense volcanic activity, the emission of alkaline basaltic lava flows, and subaerial pyroclastic materials, separated by erosion and sedimentations periods [38].…”

Section: Geographic Geologic and Climate Settings And Soil Typesmentioning

confidence: 99%

“…The used skin adherence factor (SAF) was 0.2 mg·cm −2 and 0.07 mg·cm −2 for children and adults, respectively, and the dermal absorption factor (DA) was 0.003 for As and 0.001 for other elements [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46]. InhR is the inhalation rate taken as 7.6 m 3 ·d −1 and 20 m 3 ·d −1 for children and adults, respectively, and the particle emission factor (PEF) is 1.36 × 10 9 m 3 ·kg −1 .…”

Section: Risk Assessmentmentioning

confidence: 99%

The Cancer and Non-Cancer Risk of Santiago Island (Cape Verde) Population due to Potential Toxic Elements Exposure from Soils

Pinto

Silva

et al. 2017

Geosciences

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Abstract:The hazard index (HI) and carcinogenic risk due to the exposure of some potentially toxic elements to the Santiago Island (Cape Verde) population were calculated, considering soil ingestion, inhalation, and dermal contact as exposure pathways. The topsoil of Santiago Island, compared with that of the upper continental crust, is enriched with Co, Cr, Cu, Ni, V, Zn, Mn, and Cd. Hazard indices (HIs) for these metals and the As exposures to the Santiago Island population were calculated, and these calculations were performed for children and adults. For children, HIs were higher than 1 for Co, Cr, and Mn. Therefore, there is an indication of potential non-carcinogenic risk for children, due to the high Co (HI = 2.995), Cr (HI = 1.329), and Mn (HI = 1.126) values in these soils. For the other elements, in adults, there is no potential non-carcinogenic risk. Cancer risk for As, Cd, Cr, and Ni exposures, in adults and children, was calculated, and the results are mainly lower than the carcinogenic target risk of 1 × 10 −6 for As, Cd, and Ni. However, in adults, cancer risk is higher than the carcinogenic target risk for Cr. Regarding As, for children, the fraction due to Risk ingestion represents 51.6%, while Risk inhalation represents 48.0% and Risk dermalcontact represents only 0.4% of the total risk. For adults, Risk inhalation represents 81.3%, Risk ingestion represents 16.6%, and Risk dermal contact represents 2.1%. These results reflect the higher daily ingestion dose for children and the higher inhalation rate and higher dermal contact surface for adults. For the other elements, the cancer risk due to Cr, Ni, and Cd inhalation is always higher for adults than it is for children, reflecting the higher inhalation rate for adults.

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“…Mainly based on Sr, Nd, and Pb isotopes, Cape Verde magmas have been considered to incorporate the contribution of ancient recycled crustal materials (e.g., Gerlach et al 1988;Doucelance et al 2003;Holm et al 2006;Millet et al 2008;Martins et al 2010). Whether or not these magmas result from a mantle plume deeply rooted in the lower mantle is hardly assessed by such isotope systems.…”

Section: Introductionmentioning

confidence: 99%

Primary and secondary processes constraining the noble gas isotopic signatures of carbonatites and silicate rocks from Brava Island: evidence for a lower mantle origin of the Cape Verde plume

Mourão

Moreira

Mata

et al. 2011

Contrib Mineral Petrol

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We present and discuss noble gas compositions of minerals from silicate rocks (olivines) and carbonatites (apatites and calcites) from Brava Island. The presence of an almost ubiquitous atmosphere-derived fingerprint is explained as reflecting contamination by seawater. Because of the high U and Th content in apatites, which are responsible for 4 He production by a-decay, the high measured 4 He/ 3 He ratios do not represent magmatic signatures. In contrast, low values of 4 He/ 3 He in calcites (C61,223; R/R a B 11.80) and olivines (C56,240; R/R a B 12.85) are considered to be representative of signatures trapped at the time of crystallization, given that there are no evidences for significant cosmogenic additions. These relatively low 4 He/ 3 He ratios depicted by silicate and carbonatite rocks imply the contribution of a reservoir that evolved under low (U ? Th)/ 3 He; this is considered a strong evidence for the genesis of Brava by a mantle plume deeply anchored in the lower mantle. The inferred low 4

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Mantle plume heterogeneity versus shallow-level interactions: A case study, the São Nicolau Island, Cape Verde archipelago

Cited by 47 publications

References 59 publications

Magmatic evolution of the Cadamosto Seamount, Cape Verde: beyond the spatial extent of EM1

Magmatic evolution of the Cadamosto Seamount, Cape Verde: beyond the spatial extent of EM1

The Cancer and Non-Cancer Risk of Santiago Island (Cape Verde) Population due to Potential Toxic Elements Exposure from Soils

Primary and secondary processes constraining the noble gas isotopic signatures of carbonatites and silicate rocks from Brava Island: evidence for a lower mantle origin of the Cape Verde plume

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