The Quaternary pyroclastic succession of southeast Tenerife, Canary Islands: Explosive eruptions, related caldera subsidence, and sector collapse

Brown, R. J., Barry, T. L., Branney, M. J., Pringle, M. S. and Bryan, S. E. (2003) The Quaternary pyroclastic succession of southeast Tenerife, Canary Islands: Explosive eruptions, related caldera subsidence, and sector collapse. Geological Magazine, 140 3: 265-288. doi:10.1017/S0016756802007252


Author Brown, R. J.
Barry, T. L.
Branney, M. J.
Pringle, M. S.
Bryan, S. E.
Title The Quaternary pyroclastic succession of southeast Tenerife, Canary Islands: Explosive eruptions, related caldera subsidence, and sector collapse
Journal name Geological Magazine   Check publisher's open access policy
ISSN 0016-7568
Publication date 2003-05-01
Sub-type Article (original research)
DOI 10.1017/S0016756802007252
Open Access Status DOI
Volume 140
Issue 3
Start page 265
End page 288
Total pages 24
Place of publication London, UK
Publisher Cambridge University Press
Language eng
Subject C1
260103 Vulcanology
780104 Earth sciences
0403 Geology
Abstract A much-revised Quaternary stratigraphy is presented for ignimbrites and pumice fall deposits of the Bandas del Sur, in southern Tenerife. New Ar-41/Ar-39 data obtained for the Arico, Granadilla, Fasnia, Poris, La Caleta and Abrigo formations are presented, allowing correlation with previously dated offshore marine ashfall layers and volcaniclastic sediments. We also provide a minimum age of 287 +/- 7 ka for a major sector collapse event at the Gaimar valley. The Bandas del Sur succession includes more than seven widespread ignimbrite sheets that have similar characteristics, including widespread basal Plinian layers, predominantly phonolite composition, ignimbrites with similar extensive geographic distributions, thin condensed veneers with abundant diffuse bedding and complex lateral and vertical grading patterns, lateral gradations into localized massive facies within palaeo-wadis, and widespread lithic breccia layers that probably record caldera-forming eruptions. Each ignimbrite sheet records substantial bypassing of pyroclastic material into the ocean. The succession indicates that Las Canadas volcano underwent a series of major explosive eruptions, each starting with a Plinian phase followed by emplacement of ignimbrites and thin ash layers, some of coignimbrite origin. Several of the ignimbrite sheets are compositionally zoned and contain subordinate mafic pumices and banded pumices indicative of magma mingling immediately prior to eruption. Because passage of each pyroclastic density current was characterized by phases of non-deposition and erosion, the entire course of each eruption is incompletely recorded at any one location, accounting for some previously perceived differences between the units. Because each current passed into the ocean, estimating eruption volumes is virtually impossible. Nevertheless, the consistent widespread distributions and the presence of lithic breccias within most of the ignimbrite sheets suggest that at least seven caldera collapse eruptions are recorded in the Bandas del Sur succession and probably formed a complex, nested collapse structure. Detailed field relationships show that extensive ignimbrite sheets (e.g. the Arico, Poris and La Caleta formations) relate to previously unrecognized caldera collapse events. We envisage that the evolution of the nested Las Cahadas caldera is more complex than previously thought and involved a protracted history of successive ignimbrite-related caldera collapse events, and large sector collapse events, interspersed with edifice-building phases.
Keyword Geosciences, Multidisciplinary
Ignimbrite
Tenerife
Explosive Eruptions
Phreatomagmatism
Quaternary
Volcanism
Q-Index Code C1

 
Versions
Version Filter Type
Citation counts: TR Web of Science Citation Count  Cited 47 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 48 times in Scopus Article | Citations
Google Scholar Search Google Scholar
Created: Wed, 15 Aug 2007, 12:19:10 EST