Silvina Guzman, Manfred Strecker, Joan Marti, Ivan A. Petrinovic, Taylor F. Schildgen, Pablo Grosse, Carolina Montero-Lopez, Marco Neri, Roberto Carniel, Fernando D. Hongn, Claudia Muruaga, Masafumi Sudo
- 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 asThe 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.…
MetadatenAuthor details: | Silvina GuzmanORCiD, Manfred StreckerORCiDGND, Joan Marti, Ivan A. Petrinovic, Taylor F. SchildgenORCiD, Pablo Grosse, Carolina Montero-LopezORCiD, Marco NeriORCiD, Roberto Carniel, Fernando D. Hongn, Claudia Muruaga, Masafumi SudoORCiDGND |
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DOI: | https://doi.org/10.1130/B31631.1 |
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ISSN: | 0016-7606 |
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ISSN: | 1943-2674 |
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Title of parent work (English): | Geological Society of America bulletin |
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Publisher: | American Institute of Physics |
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Place of publishing: | Boulder |
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Publication type: | Article |
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Language: | English |
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Year of first publication: | 2017 |
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Publication year: | 2017 |
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Release date: | 2020/04/20 |
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Volume: | 129 |
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Number of pages: | 17 |
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First page: | 750 |
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Last Page: | 766 |
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Funding institution: | Agencia Nacional de Promocion Cientifica y Tecnica [PICT 2012-0419, PICT 2011-0407]; Consejo Nacional de Investigaciones Cientificas y Tecnicas [PIP 489, PIP 286]; Consejo de Investigacion de la Universidad Nacional de Salta [CIUNSa 1810]; STRATEGY initiative [IGRK 1820]; German Science Foundation (Deutsche Forschungsgemeinschaft) [STR 373/34-1] |
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Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Geowissenschaften |
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Peer review: | Referiert |
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