The Plio-Quaternary magmatic feeding system beneath Gran Canaria (Canary Islands, Spain): constraints from thermobarometric studies

Abstract

A complete framework of chronostratigraphic, petrographic, geochemical and thermobarometric data allows a reinterpretation of the evolution of the Plio-Quaternary volcanism in Gran Canaria. Bulk-rock and mineral chemistry has been used to define P – T crystallization paths, based on clinopyroxene–melt thermobarometry. Mafic magmas mainly crystallized at mantle depths (17–22 km) with secondary fractionation at crustal levels (1.5–8.0 km), suggesting multistage magma ascent. Crystallization of evolved magmas took place at crustal depths (3–15 km). The complexity of the magmatic plumbing system increased in the last 1 Ma, as shown by the presence of reverse zoned clinopyroxenes in the lavas, with green diopside–hedenbergite cores surrounded by brown diopsidic rims. Petrographic and chemical features of such clinopyroxenes support a xenocrystic origin of the green cores, related to magma mixing or mingling processes between pre-existing colder evolved magmas and new batches of hot basic magmas. The evolution of the magmatic feeding system beneath Gran Canaria was affected by the long-term uplift of the island as a result of lithospheric flexure caused by loading of the neighbouring island of Tenerife. This uplift favoured the generation of giant landslides and nesting of the recent volcanic activity (the last 1 Ma) within landslide basins. The association of rifts, giant landslides and nested volcanism with a higher degree of magmatic differentiation is proposed to constrain the plumbing system model.

Radon in Groundwater of the Northeastern Gran Canaria Aquifer

“…On the surface basaltic, basanitic and trachybasaltic lavas of the Roque Nublo and Post-Roque Nublo volcanism, and sediments of Las Palmas Detritic Formation mainly occur. Miocene trachytic and phonolitic lavas crop out, usually in the coastal areas and at the bottom of ravines, where alluvial deposits are also observed [21,23]. The main mineral phases in Basic volcanic rocks consist of diopside, olivine and labradorite, whereas in Salic volcanic rocks andesine, kaersutite, anorthoclase and hauyne are found [23,24].…”

“…Miocene trachytic and phonolitic lavas crop out, usually in the coastal areas and at the bottom of ravines, where alluvial deposits are also observed [21,23]. The main mineral phases in Basic volcanic rocks consist of diopside, olivine and labradorite, whereas in Salic volcanic rocks andesine, kaersutite, anorthoclase and hauyne are found [23,24]. On the other hand, secondary mineral phases, such as weathering cover or fillings of fractures and vesicles on volcanic rocks, include calcite, dolomite, gypsum and clays (illite, and smectites, usually montmorillonites), and zeolites (analcime, chabazite, phillipsite).…”

Factors controlling the morphology of monogenetic basaltic volcanoes: The Holocene volcanism of Gran Canaria (Canary Islands, Spain)

“…The studied lava flows show similar petrographical and geochemical characteristics Aulinas et al, 2010), therefore, it may be inferred that their viscous behaviour was similar. On the other hand, they were generated during Strombolian eruptions, comparable to those observed in historical eruptions of the Canary Islands Archipelago (Hernández-Pacheco, 1987;Romero, 1991;Carracedo et al, 2007;Rodriguez-Gonzalez et al, 2009).…”

“…Olivine and clinopyroxene phenocrysts are observed over a microcrystalline mesostasis. Geochemically they are very similar, within the compositional range of tephrite-basanite rocks, and, to a lesser degree, of basalt and foidite rocks (Rodriguez-Gonzalez, 2009;Rodriguez-Gonzalez et al, 2009;Aulinas et al, 2010).…”

GIS methods applied to the degradation of monogenetic volcanic fields: A case study of the Holocene volcanism of Gran Canaria (Canary Islands, Spain)

“…8.0-5.5 Ma, including the most prominent sedimentary deposits of the island known as Las Palmas Detritic Formation), and a rejuvenated stage (ca. 5.5 Ma to present, including the Roque Nublo stratovolcano and the Post-Roque Nublo volcanism) (Perez-Torrado et al, 1995;Carracedo et al, 2002;Guillou et al, 2004;Aulinas et al, 2010). The distribution of volcanism in the island has imprinted a contrasting geomorphology between southern (almost exclusively juvenile volcanism) and northern (predominantly rejuvenated volcanism) flanks (Fig.…”