Periglacial activity in the Central and Southern Andes

The Andes Mountain range runs along the western margin of South America for ~7500 km, from the Sierra Nevada de Santa Marta, next to the Caribbean Sea, to Cape Horn, at the southern tip of the continent. Based on structural differences, the Northern Andes (11ºN-1ºS), Central Andes (1º-47ºS) and Southern Andes (47º-68ºS) have been differentiated. In the Central Andes the mountain range is divided into Western and Eastern Andes, between which the Altiplano, a plateau of 300x500 km and 3800- 4900 m surrounded by peaks that reach 6000 m in altitude. Only the Himalayas and Tibet are higher and larger than Andes-Altiplano. Glaciers are preserved on many peaks of the Andes, and on their slopes, there are moraines revealing a much larger glacial extent in the past. Today, in the deglaciated areas there are extensive periglacial landscapes. However, the extent to which altitude and latitude modify periglacial forms and processes has not yet been investigated. Our team aims to make a first approach to the problem by analyzing three representative Study areas of a north- south transect of the Central and Southern Andes: Nevado Coropuna volcanic complex (16ºS, 73ºW, 6377 m), in the Arequipa region (Peru); Cerro Aconcagua (33ºS, 70ºW, 6960 m), in Mendoza (Argentina) and Cerro Alvear (54ºS, 68ºW, 1490 m), in the Argentinean side of Tierra del Fuego. In the last 20 years we have identified different periglacial processes linked to permafrost, such as: rock glaciers, protalus ramparts, debris lobes, patterned grounds including tundra polygons associated with active ice wedges, cryo-ejected clast, tors, nivation hollows or boulder (clast) pavements. This periglacial activity probably records aspects of current interests, as climate change, interhemispheric teleconnections, or ENSO phenomenon, which modify snow cover. Understanding this record is an interesting geomorphological challenge that we begin to address by presenting this work

Geoarchaeological reconstruction of Caverna de Las Brujas (Mendoza, Argentina) for the archaeological intervention

Archaeological prospection and excavation in the Caverna de las Brujas (southern part of the province of Mendoza, Argentina) has offered the first known data on human presence in this cave. This is of great interest for understanding the evolution of peopling in the southern Mendoza province during the Holocene. Four archaeological pits were excavated, two in the gallery known as the Sala de la Virgen and another two near the cave entrance. Three volcanic ash levels were dated by TL techniques (7780±600, 4700±500; 765 ±200 years) and a level with enough organic material was dated by 14C analysis (3695±65 years BP). The available data is sufficient to establish the origin and make a geomorphological reconstruction of the Holocene levels. At the same time, a hypothetical model is proposed that uses geomorphological criteria to predict the stratigraphy of the unexcavated lower levels at the cave entrance. The aim of thismodel is to help direct future archaeological excavations of the cave's oldest deposits.Fil: Peña Monné, José Luis. Universidad de Zaragoza. Departamento de Geografía y Ordenación del Territorio; EspañaFil: Sancho Marcén, Carlos. Universidad de Zaragoza. Departamento de Ciencias de la Tierra; EspañaFil: Duran, Victor Alberto. Universidad Nacional de Cuyo. Facultad de Filosofia y Letras. Centro Interdisciplinario de Estudios Regionales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mendoza; ArgentinaFil: Mikkan, Raul. Universidad Nacional de Cuyo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mendoza; Argentin

MODIS Image-derived ice surface temperature assessment in the southern patagonian icefield

Ice surface temperature (IST) is one of the most relevant parameters when it comes to estimating the effects of climate change on glaciers. This study aims to estimate the IST for the Southern Patagonian Icefield (SPI) during the 2001–2016 period and, in so doing, to contribute to the assessment of the MOD11A1 product in this area. We evaluated IST performance by comparing it with that of automatic weather stations (AWSs). In addition, the glaciological significance of the results is presented through 1) IST trends, 2) annual IST anomalies, 3) IST behavior at different altitudes and orientations and 4) a comparison with Santa Cruz River flow records. The correlation coefficients obtained between the IST and AWSs ranged between 0.66 and 0.85. In addition, we report on the mean absolute differences between them, ranging between 0.6 ± 3.6°C and 9.4 ± 1.9°C. In this sense, we observed the lowest differences at the AWSs that were located in a homogeneous environment. Stated in glaciological terms: 1) only 1% of the pixels had a statically significant IST trend (p-value ≤ 0.05): between 0.01 and 0.05°C/month; 2) we found that most of the IST anomalies ranged between –1 and 1°C throughout the period of this study; 3) the results suggest that the altimetric gradient was the most influential variable of the IST, mostly in north-oriented glaciers; and 4) the SPI IST showed an annual periodicity, which, in turn, shows a high correlation with the Santa Cruz River flow (R = 0.86). This study is the first in estimating the SPI’s IST and contributes to enhance our knowledge of glacier dynamics and, therefore, the management of the water resource. Despite this, some MOD11 filtering is required in regions with high cloud cover frequency.Fil: Lo Vecchio Repetto, Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Lannutti, Esteban Damián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Lenzano, María Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Mikkan, Raul. Universidad Nacional de Cuyo. Facultad de Filosofía y Letras; ArgentinaFil: Vacaflor, Paulina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Lenzano, Luis Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentin