@article{BecerrilUbideSudoetal.2016, author = {Becerril, Laura and Ubide, Teresa and Sudo, Masafumi and Marti, Joan and Galindo, Ines and Gale, Carlos and Maria Morales, Jose and Yepes, Jorge and Lago, Marceliano}, title = {Geochronological constraints on the evolution of El Hierro (Canary Islands)}, series = {Journal of African earth sciences}, volume = {113}, journal = {Journal of African earth sciences}, publisher = {Elsevier}, address = {Oxford}, issn = {1464-343X}, doi = {10.1016/j.jafrearsci.2015.10.012}, pages = {88 -- 94}, year = {2016}, abstract = {New age data have been obtained to time constrain the recent Quaternary volcanism of El Hierro (Canary Islands) and to estimate its recurrence rate. We have carried out Ar-40/Ar-39 geochronology on samples spanning the entire volcanostratigraphic sequence of the island and C-14 geochronology on the most recent eruption on the northeast rift of the island: 2280 +/- 30 yr BP. We combine the new absolute data with a revision of published ages onshore, some of which were identified through geomorphological criteria (relative data). We present a revised and updated chronology of volcanism for the last 33 ka that we use to estimate the maximum eruptive recurrence of the island. The number of events per year determined is 9.7 x 10(-4) for the emerged part of the island, which means that, as a minimum, one eruption has occurred approximately every 1000 years. This highlights the need of more geochronological data to better constrain the eruptive recurrence of El Hierro. (C) 2015 Elsevier Ltd. All rights reserved.}, language = {en} } @article{GuzmanStreckerMartietal.2017, author = {Guzman, Silvina and Strecker, Manfred and Marti, Joan and Petrinovic, Ivan A. and Schildgen, Taylor F. and Grosse, Pablo and Montero-Lopez, Carolina and Neri, Marco and Carniel, Roberto and D. Hongn, Fernando and Muruaga, Claudia and Sudo, Masafumi}, title = {Construction and degradation of a broad volcanic massif: The Vicuna Pampa volcanic complex, southern Central Andes, NW Argentina}, series = {Geological Society of America bulletin}, volume = {129}, journal = {Geological Society of America bulletin}, publisher = {American Institute of Physics}, address = {Boulder}, issn = {0016-7606}, doi = {10.1130/B31631.1}, pages = {750 -- 766}, year = {2017}, abstract = {The Vicuna Pampa volcanic complex, at the SE edge of the arid Puna Plateau of the Central Andes, records the interplay between volcanic construction and degra-dational processes. The low-sloping Vicuna Pampa volcanic complex, with a 1200-m-deep, southeastward-opening depression, was previously interpreted as a collapse caldera based on morphological considerations. However, characteristic features associated with collapse calderas do not exist, and close inspection instead suggests that the Vicuna Pampa volcanic complex is a strongly eroded, broad, massif-type composite volcano of mainly basaltic to trachyandesitic composition. Construction of the Vicuna Pampa volcanic complex occurred during two distinct cycles separated by the development of the depression. The first and main cycle took place at ca. 12 Ma and was dominated by lava flows and subordinate scoria cones and domes. The second cycle, possibly late Miocene in age, affected the SW portion of the depression with the emplacement of domes. We interpret the central depression as the result of a possible sector collapse and subsequent intense fluvial erosion during middle to late Miocene time, facilitated by faulting, steepened topography, and wetter climate conditions compared to today. We estimate that similar to 65\% of the initial edifice of similar to 240 km(3) was degraded. The efficiency of degradation processes for removing mass from the Vicuna Pampa volcanic complex is surprising, considering that today the region is arid, and the stream channels within the complex are predominantly transport limited, forming a series of coalesced, aggraded alluvial fans and eolian infill. Hence, the Vicuna Pampa volcanic complex records the effects of past degradation efficiency that differs substantially from that of today.}, language = {en} }