Genesis of the Roque Nublo ignimbrites, Gran Canaria, Canary IslandsReportar como inadecuado




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Colaborador: Perez-Torrado, Francisco-JoseMartí, JoanDay, SimonMangas, José

Materias : IgnimbritasCanariasRoque NubloGran Canaria

Fecha de publicación : 1997

Fecha de depósito: 8-oct-2009

Tipo de documento: Artículo

En : Volcanism and volcanic hazards in inmature intraplate oceanic islands : International Workshop, September 15-18 ; programme and abstracts, pp. 115-117





Fuente: https://acceda.ulpgc.es


Introducción



Genesis of the Roque Nublo Ignim brites, Gran Canaria, Canary Islands. Francisca José P e r e z - ~ o r r a d o ,Joan Martí , Simon Day34 and José M a n g a s i . 1: Dep-pl.Fisica-Geoiogia, Universidad de Las PaEnzas de G r m Canaria, .Si)nin. 2: htstitur de Cieilcies dc la Tierra - h u m e Almera-, Barcelona, Sppaii~. 3: Dept.
qf Geography 8 Geology, Chelfenhanl and Gloucester CHE, Cheltenham, L1.K 4: Greig Fester Ceutre for Hazard Research, Oniversity College Loudon, U.K. The Roque Nublo group (Pliocene, ca.
5,5 to 2,7 Ma) is the product of one of the main episodes i i i the subaerial construction of Gran Canaria.
This is characterised by the constructiori of a central volcanic complex, the Roque Nublo stratovolcano, which reaclied a heiglit of at least 2500 in in tlie central asea of the isIand.
The evolution of this stratovolcario involved maginas o f alkali basaltbasanite to trachyíe-phonolite compositions and a great variety of eruptive mechanisins.
The most distinctive lithology in the Roque Nublo volcanic sequence are pyroclastic breccia deposits, tlle Roque Nublo ignimbrites.
Tliese are especially abundant in tlie Tirajana and El Montanon formatioris, which represent rnost of thc later activity of the volcano (see Pérez-Torrado et al., Growth m d destre~ctionby laterai coiiapsc of tiw Roque iVubio oceanic idanu srrarovolcario, Gran Canaria, Canary hlands, this volume). The Roque Iiublo ignimbrites sliow a number of distinctive lithological features.
They are highlyindurated, matrix - supported breccias with a polymict clast assemblage.
Two main types of clast are present: lithic clasts derivecl from near - surface volcznic formations witliin the Roque Ncblo Group (35-55% of the total roclc volume) and juvcnile fragments (1.530%).
The lithic clasts are unrisually abundant for rocks of pyroclastic origin.
The juvenile clasts include abundant purnice fragments with irregular, angular to ragged oudines, high crystal content and 1ow vesicularity ( 50%) com...






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