TY  - JOUR
A1  - Guzman, Silvina
A1  - Strecker, Manfred
A1  - Marti, Joan
A1  - Petrinovic, Ivan A.
A1  - Schildgen, Taylor F.
A1  - Grosse, Pablo
A1  - Montero-Lopez, Carolina
A1  - Neri, Marco
A1  - Carniel, Roberto
A1  - D. Hongn, Fernando
A1  - Muruaga, Claudia
A1  - Sudo, Masafumi
T1  - Construction and degradation of a broad volcanic massif: The Vicuna Pampa volcanic complex, southern Central Andes, NW Argentina
JF  - Geological Society of America bulletin
N2  - 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.
Y1  - 2017
U6  - https://doi.org/10.1130/B31631.1
SN  - 0016-7606
SN  - 1943-2674
VL  - 129
SP  - 750
EP  - 766
PB  - American Institute of Physics
CY  - Boulder
ER  -