@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} } @article{MonteroLopezStreckerSchildgenetal.2014, author = {Montero-Lopez, Carolina and Strecker, Manfred and Schildgen, Taylor F. and Hongn, Fernando D. and Guzman, Silvina and Bookhagen, Bodo and Sudo, Masafumi}, title = {Local high relief at the southern margin of the Andean plateau by 9 Ma: evidence from ignimbritic valley fills and river incision}, series = {Terra nova}, volume = {26}, journal = {Terra nova}, number = {6}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0954-4879}, doi = {10.1111/ter.12120}, pages = {454 -- 460}, year = {2014}, abstract = {A valley-filling ignimbrite re-exposed through subsequent river incision at the southern margin of the Andean (Puna) plateau preserves pristine geological evidence of pre-late Miocene palaeotopography in the north western Argentine Andes. Our new Ar-40/(39) Ar dating of the Las Papas Ignimbrites yields a plateau age of 9.24 +/- 0.03 Ma, indicating valley-relief and orographic-barrier conditions comparable to the present-day. A later infill of Plio-Pleistocene coarse conglomerates has been linked to wetter conditions, but resulted in no additional net incision of the Las Papas valley, considering that the base of the ignimbrite remains unexposed in the valley bottom. Our observations indicate that at least 550 m of local plateau margin relief (and likely > 2 km) existed by 9 Ma at the southern Puna margin, which likely aided the efficiency of the orographic barrier to rainfall along the eastern and south eastern flanks of the Puna and causes aridity in the plateau interior.}, language = {en} } @article{OzsayinCinerRojayetal.2013, author = {Ozsayin, Erman and Ciner, T. Attila and Rojay, F. Bora and Dirik, R. Kadir and Melnick, Daniel and Fernandez-Blanco, David and Bertotti, Giovanni and Schildgen, Taylor F. and Garcin, Yannick and Strecker, Manfred and Sudo, Masafumi}, title = {Plio-Quaternary extensional tectonics of the Central Anatolian Plateau a case study from the Tuz Golu Basin, Turkey}, series = {Turkish journal of earth sciences = T{\"u}rk yerbilimleri dergisi}, volume = {22}, journal = {Turkish journal of earth sciences = T{\"u}rk yerbilimleri dergisi}, number = {5}, publisher = {T{\"u}bitak}, address = {Ankara}, issn = {1300-0985}, doi = {10.3906/yer-1210-5}, pages = {691 -- 714}, year = {2013}, abstract = {The Tuz Golu Basin is the largest sedimentary depression located at the center of the Central Anatolian Plateau, an extensive, low-relief region with elevations of ca. 1 km located between the Pontide and Tauride mountains. Presently, the basin morphology and sedimentation processes are mainly controlled by the extensional Tuz Golu Fault Zone in the east and the transtensional Inonu-Eskisehir Fault System in the west. The purpose of this study is to contribute to the understanding of the Plio-Quaternary deformation history and to refine the timing of the latest extensional phase of the Tuz Golu Basin. Field observations, kinematic analyses, interpretations of seismic reflection lines, and Ar-40/Ar-39 dating of a key ignimbrite layer suggest that a regional phase of NNW-SSE to NE-SW contraction ended by 6.81 +/- 0.24 Ma and was followed by N-S to NE-SW extension during the Pliocene-Quaternary periods. Based on sedimentological and chronostratigraphic markers, the average vertical displacement rates over the past 5 or 3 Ma with respect to the central part of Tuz Golu Lake are 0.03 to 0.05 mm/year for the fault system at the western flank of the basin and 0.08 to 0.13 mm/year at the eastern flank. Paleo-shorelines of the Tuz Golu Lake, vestiges of higher lake levels related to Quaternary climate change, are important strain markers and were formed during Last Glacial Maximum conditions as indicated by a radiocarbon age of 21.8 +/- 0.4 ka BP obtained from a stromatolitic crust. Geomorphic observations and deformed lacustrine shorelines suggest that the main strand of the Tuz Golu Fault Zone straddling the foothills of the Sereflikochisar-Aksaray range has not been active during the Holocene. Instead, deformation appears to have migrated towards the interior of the basin along an offshore fault that runs immediately west of Sereflikochisar Peninsula. This basinward migration of deformation is probably associated with various processes acting at the lithospheric scale, such as plateau uplift and/or microplate extrusion.}, language = {en} }