Geochemistry of submarine mafic lavas from Pantelleria Island, Sicily Channel (Contributo in atti di convegno)

Type
Label
  • Geochemistry of submarine mafic lavas from Pantelleria Island, Sicily Channel (Contributo in atti di convegno) (literal)
Anno
  • 2014-01-01T00:00:00+01:00 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#doi
  • 10.3301/ROL.2014.140 (literal)
Alternative label
  • Calarco M., Chiocci F. L., Conte A.M., Fonseca F., Martorelli E., Perinelli C., Sposato A. (2014)
    Geochemistry of submarine mafic lavas from Pantelleria Island, Sicily Channel
    in SGI-SIMP, 2014
    (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
  • Calarco M., Chiocci F. L., Conte A.M., Fonseca F., Martorelli E., Perinelli C., Sposato A. (literal)
Rivista
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  • D'Appolonia S.p.A. Genova, Sapienza Università di Roma, IGG-CNR, Sapienza Università di Roma, IGAG-CNR, Sapienza Università di Roma, IGAG-CNR (literal)
Titolo
  • Geochemistry of submarine mafic lavas from Pantelleria Island, Sicily Channel (literal)
Abstract
  • Detailed investigations of the submarine portions of Pantelleria were carried out in 2006 and 2008 (aboard R\V Urania) using a 50 kHz multibeam bathymetric system and collecting seafloor samples by dredging, grabbing and coring. In particular, more than 50 dredge samples including scoriaceous and massive lavas were recovered on the NW portion of the volcano. Here, numerous volcanic centers were identified, including the vent of the last known eruption (1891). The NW monogenetic volcanic field likely formed during a discontinuous activity punctuated by several eruptions close in space and, probably, in time. In order to reconstruct the submarine volcanic activity of Pantelleria, several mafic lava collected from these volcanic cones and along the NW slope have been analyzed in their petrography and geochemistry and compared with the literature data of analogous subaerial products from the NW of the island. Samples from the cones are scoriaceous basalts and basanites with sub-aphyric to porphyric texture (P.I.~5-15vol%) in which plagioclase, clinopyroxene±olivine±oxides occur as phenocrysts, microphenocrysts and microlites. Vesicles of most of these samples are totally or partially filled with secondary minerals (i.e., carbonate and/or motukoreaite). In addition, the composition of scoriaceous lavas is similar to those of 1891 products (Conte et al., 2014). The massive lavas from the slope are weakly porphyritic basalts (P.I.<=10vol%) with phenocrysts of plagioclase>olivine> clinopyroxene and ± oxides, set in a microcrystalline groundmass made up of the same minerals. Their higher olivine amount respect to the scoriaceous products, along with the higher Mg# and Cr and Ni contents, testify a more primitive character. Noteworthy, the massive basalts are characterized by a lower TiO2 and P2O5 contents than those of the scoriaceous lavas (TiO2~2.55wt%-P2O5~0.55wt% and TiO2~4.3wt%-P2O5~1.80wt%, respectively). The chemical differences observed between submarine massive and scoriaceous lavas were found respectively in the older (~120 to 50 ka) and younger (~30 to 10 ka) mafic sub-aerial products outcropping in the NW part of Pantelleria, which are characterized by higher TiO2 (>3wt%) and P2O5 (>1wt%) contents, and lower TiO2 (<3wt%) and P2O5 (<0.7wt%) contents, respectively. Therefore, we infer that the massive basalts from the NW submarine slope were fed by magmas similar to the younger sub-aerial products and the scoriaceous lavas of the NW volcanic field, including the historical 1891 eruption products, were fed by a reservoir filled by a magma geochemically very similar to that which had fed the older sub-aerial mafic units. (literal)
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