Paleocene radiolarians fromXenoliths hosted in Holocene lavas of Lanzarote (Canary Islands)

Bustillo, Ma Ángeles; Nishimura, Akiko; Araña, Vicente; Hattori, Isamu

doi:10.1016/s0016-6995(94)80005-7

Cited by 10 publications

(5 citation statements)

References 3 publications

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“… The sedimentary package underneath the eastern Canaries is well characterised from onshore exposure, drilling campaigns and seismic investigations 3 4 8 9 10 11 14 15 17 23 26 31 32 33 34 35 36 37 38 39 40 41 , while the age and nature of the sedimentary strata underneath the western Canaries is unknown. The eruption of nannofossil-bearing sedimentary relicts at the westernmost island of El Hierro in 2011 now defines the age range of the sedimentary layers beneath El Hierro to between Cretaceous and Pliocene.…”

Section: Figurementioning

confidence: 99%

Nannofossils in 2011 El Hierro eruptive products reinstate plume model for Canary Islands

Zaczek

Troll

Cachão

et al. 2015

Sci Rep

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The origin and life cycle of ocean islands have been debated since the early days of Geology. In the case of the Canary archipelago, its proximity to the Atlas orogen led to initial fracture-controlled models for island genesis, while later workers cited a Miocene-Quaternary east-west age-progression to support an underlying mantle-plume. The recent discovery of submarine Cretaceous volcanic rocks near the westernmost island of El Hierro now questions this systematic age-progression within the archipelago. If a mantle-plume is indeed responsible for the Canaries, the onshore volcanic age-progression should be complemented by progressively younger pre-island sedimentary strata towards the west, however, direct age constraints for the westernmost pre-island sediments are lacking. Here we report on new age data obtained from calcareous nannofossils in sedimentary xenoliths erupted during the 2011 El Hierro events, which date the sub-island sedimentary rocks to between late Cretaceous and Pliocene in age. This age-range includes substantially younger pre-volcanic sedimentary rocks than the Jurassic to Miocene strata known from the older eastern islands and now reinstate the mantle-plume hypothesis as the most plausible explanation for Canary volcanism. The recently discovered Cretaceous submarine volcanic rocks in the region are, in turn, part of an older, fracture-related tectonic episode.

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Section: Figurementioning

confidence: 99%

Nannofossils in 2011 El Hierro eruptive products reinstate plume model for Canary Islands

Zaczek

Troll

Cachão

et al. 2015

Sci Rep

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“…Other xenoliths, of sedimentary origin, are calcsilicate and silica rocks, and to a lesser extent sandstones, limestones and claystones (Ortiz, Araña & Valverde, 1986;Araña & Ortiz, 1991;Araña & Bustillo, 1992;Bustillo et al 1994). Extensive sampling and study of Timanfaya sedimentary xenoliths A. APARICIO AND OTHERS (most ofthem metamorphosed) are presented in this paper.…”

Section: Introductionmentioning

confidence: 92%

“…Bustillo et al (1994) described characteristics in some of them that denote the existence of sedimentary structures, including fine stratification, current ripples, erosive contacts and detrital grains, etc., which have almost completely disappeared where there has been a high degree of thermal transformation. Bustillo et al (1994) described characteristics in some of them that denote the existence of sedimentary structures, including fine stratification, current ripples, erosive contacts and detrital grains, etc., which have almost completely disappeared where there has been a high degree of thermal transformation.…”

Section: Petrologymentioning

confidence: 99%

Metasedimentary xenoliths in the lavas of the Timanfaya eruption (1730–1736, Lanzarote, Canary Islands): metamorphism and contamination processes

et al. 2006

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We report on the investigation of contact metamorphism provoked by the emplacement of a shallow magma chamber during the Timanfaya eruption of Lanzarote from 1730 to 1736 AD. The study was carried out on metamorphic xenoliths from basaltic Timanfaya lavas, and shows how the primary basanitic magma was contaminated by sedimentary and metamorphic rocks. Mineralogical and chemical studies allowed the definition of several xenolith types. Silica xenoliths (quartz, tridymite, cristobalite or a mixture of these, constituting more than 50 % of the xenolith) and calc-silicate xenoliths (wollastonite, sometimes the 2M type, diopside, forsterite or mixture of these, constituting more than 50 % of the xenolith) are the most frequent. Other minerals recognized were calcite, dolomite, augite, enstatite, hypersthene, spinel and scapolite. The mineralogy and some textures of the metamorphic forsteritic xenoliths are identical to those found in ultrabasic xenoliths (dunites) and point to a possible metamorphic origin for some of them. Major and trace elements showed a diversity of composition, controlled by the mineralogy. The REE composition of the metamorphic xenoliths is high, compared with the sedimentary xenoliths not affected by metamorphism. The mineral assemblages define metamorphic facies of low, medium and high grade, depending on the distance of the sedimentary rocks from the magma chamber border. The IGPETWIN-MIXING program was used to verify the contamination process, taking the xenoliths as representative of the sedimentary/metamorphic rocks that were melted. The results indicated that sedimentary/metamorphic rock contamination of a basanitic magma can produce tholeiitic compositions.

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“…Los enclaves de naturaleza ígnea, principalmente de origen mantélico, han sido ampliamente abordados por Neumann et al (1995Neumann et al ( , 2000; Schmincke et al (1998), entre otros. Sin embargo, los enclaves de naturaleza sedimentaria únicamente han sido considerados en detalle por Araña & Bustillo (1992), Bustillo et al (1994) y Aparicio et al (2006). Estos últimos, describen el origen y composición de metasedimentos englobados en las lavas de Timanfaya, distinguiéndose dos tipos de enclaves: unos de composición silícea cuya mineralogía está compuesta por cuarzo, tridimita y cristobalita, y otros de naturaleza calcosilícea, presentando wollastonita, diópsido y forsterita, además de otros términos intermedios.…”

Section: Los Enclaves Y Alteraciones De Montaña Señalounclassified

Las alteraciones silíceas de las lavas de Montaña Señalo, erupción de Timanfaya (1730-1736) (Lanzarote, Islas Canarias)

Carmona¹,

Ruiz²,

Páez³

et al. 2009

Estud. geol.

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IntroducciónPara la formación de un depósito hidrotermal, es necesario por un lado una fuente de calor y por otro una circulación eficiente de fluidos, capaces de movilizar componentes de las rocas por las que atraviesa hacia otros lugares. Si estas aguas son capaces de alcanzar la superficie y contienen la carga quími-ca suficiente, las nuevas condiciones termodinámi-cas hacen que se puedan generar depósitos y alteraciones características, identificables tanto texturalmente como en composición y contenido mineral. RESUMENLa presencia de alteraciones de origen hidrotermal entre las lavas de la erupción de Timanfaya (1730-36), con altas proporciones del cuarzo y ópalo, indica la circulación efectiva de fluidos calientes. El origen de estos fluidos estaría en zonas profundas por debajo de la isla, donde se produciría la disolución de la sílice a partir de areniscas y radiolaritas, movilizándose de esta manera este componente hacia la superficie en forma de coloides de Si(OH) 4 . El estudio en profundidad del ópalo indica la presencia de fases tipo A-inicio de CT y C. Si se tiene en cuenta el tiempo en el que se producen estas transformaciones en la evolución diagenética de esta fase amorfa (10.000-50.000 años), indicaría la presencia de un proceso acelerador que podría estar relacionado con una importante circulación de fluidos o con procesos de alteración meteórica capaces, de producir estas transformaciones en unas lavas de menos de 300 años.Palabras clave: alteración hidrotermal, ópalo-A, ópalo-C, sistema hidrológico, erupción Timanfaya, Lanzarote. ABSTRACTThe presence of hydrothermal alterations within the lavas of Timanfaya eruption (1730-1736), with high proportions of quartz and opal, suggests the effective circulation of hot fluids. The source of these fluids would be located under the island, where silica would be dissolved from sandstones and radiolarites, moving this way towards the surface as Si(OH) 4 colloids. Study of opal indicates the presence of Ainitial CT and C phases in the collected samples which, considering the time needed for producing this phase transformations in the diagenetic evolution of opal (10,000-50,000 years), suggests an accelerating process, probably related with either the presence of fluid circulation or weathering processes. Such circumstances are necessary for explaining the presence of such components affecting 300 years old lavas.

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Paleocene radiolarians fromXenoliths hosted in Holocene lavas of Lanzarote (Canary Islands)

Cited by 10 publications

References 3 publications

Nannofossils in 2011 El Hierro eruptive products reinstate plume model for Canary Islands

Nannofossils in 2011 El Hierro eruptive products reinstate plume model for Canary Islands

Metasedimentary xenoliths in the lavas of the Timanfaya eruption (1730–1736, Lanzarote, Canary Islands): metamorphism and contamination processes

Las alteraciones silíceas de las lavas de Montaña Señalo, erupción de Timanfaya (1730-1736) (Lanzarote, Islas Canarias)

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