DOCSLIB.ORG

This Article Appeared in a Journal Published by Elsevier. the Attached

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
This Article Appeared in a Journal Published by Elsevier. the Attached This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier’s archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/copyright Author's personal copy Quaternary International 253 (2012) 80e90 Contents lists available at SciVerse ScienceDirect Quaternary International journal homepage: www.elsevier.com/locate/quaint Geomorphology, tectonism and Quaternary landscape evolution of the central Andes of San Juan (30Se69W), Argentina Laura P. Perucca a,b,*, Liliana M. Martos b a CONICET, Gabinete de Neotectónica, INGEO-FCEFyN-UNSJ, Av. Ignacio de La Roza y Meglioli, 5400 San Juan, Argentina b Departamento Geología, FCEFyN-UNSJ, Av. Ignacio de La Roza y Meglioli, 5400 San Juan, Argentina article info abstract Article history: The northesouth trending valley of Iglesia is a regional tectonic depression limited to the west by the Available online 23 August 2011 Cordillera Frontal Unit and to the east by Precordillera Occidental Mountain Units. The forms of the resulting landscape in the region are the result of glacial, periglacial, fluvial and alluvial action, aggra- dational and deggradational processes, as well as neotectonic activity and climatic changes. The generation of large Quaternary alluvial fan aggradational surfaces is related to previous climatic conditions, colder and more humid than the present ones. Abundant snowfalls and rains during the Pleistocene made possible detritus deposition, generating alluvial covers whose thickness increases toward the east. These climatic conditions alternated with arid periods, during which vertical erosion of streams prevailed, forming a landscape of stepped levels. In addition, the presence of faults with Quaternary tectonic activity indicates, a strong structural control in the evolution of the landscape during the PleistoceneeHolocene periods, effectively starting vertical erosion and finishing a cycle of erosion-accumulation and the beginning of the following one. Ó 2011 Elsevier Ltd and INQUA. All rights reserved. 1. Introduction occasionally overflowing during intense rainfalls in summer, or in those years of higher snow precipitation in the Cordillera Frontal Between 32 and 52S, a wide region in Argentina with arid and area. The action of mechanic weathering and mainly wind action semi-arid climatic conditions is developed with a narrow strip of promotes glaciplanation processes, good development of desert maximum aridity, named the Arid Diagonal (Bruniard, 1982) pavement, desert varnish and cryoclastic phenomena. extending from the Atlantic coast at 44S to the north to 27S along This paper will propose a paleoclimatic analysis aimed at the eastern flank of the Andes. understanding its influence on the evolution of the landscape, Landscape evolution in semi-arid areas of this portion of the adding the control of the active tectonics of the Pleistoce- Andes can take on distinctive characteristics of their own. These neeHolocene as a main factor in such development. The main regions are clearly marked by low annual precipitation, distinctive constraint in the analysis of these mountain paleoenvironments is vegetation, and characteristic ephemeral processes of erosion and/ the lack of previous geological and paleoecological data on the or deposition, which water and wind are the most important Pleistocene/Holocene conditions. Most of the existing studies are driving agents. centered on the glacial chronology of several valleys of the However, deposits and landforms recognized in the region Cordillera, hundreds of kilometers south of the study area, as suggest past climate conditions much different from today’s. general paleoclimatic interpretations, whereas very little is known Different accumulation and erosion landforms identified in the area about the paleoenvironmental conditions at this latitude. There- indicate changes in climatic conditions, leading to greater aridifi- fore, this work is a contribution to current knowledge of the region. cation during the Late Holocene. These changes in turn lead to The methodology applied in the analysis of the area is based on decreased transport capacity of rivers, and to dominating aeolian the interpretation and digital analysis of the geomorphological processes. Fluvial activity is restricted to rivers and streams, features of the land surface. 1:30,000 scale aerial photographs provided by the Secretaría de Minería de la Provincia and Landsat TM images with 30 and 15 m of resolution were used to that effect. * Corresponding author. CONICET, Gabinete de Neotectónica, INGEO-FCEFyN- A slope analysis map was prepared in a GIS environment with UNSJ, Av. Ignacio de La Roza y Meglioli, 5400 San Juan, Argentina. E-mail addresses: [email protected] (L.P. Perucca), lmartos@unsj-cuim. the creation of a digital terrain model (DTM). Altitudes were edu.ar (L.M. Martos). obtained as a result of the partial digitization of topographic charts 1040-6182/$ e see front matter Ó 2011 Elsevier Ltd and INQUA. All rights reserved. doi:10.1016/j.quaint.2011.08.009 Author's personal copy L.P. Perucca, L.M. Martos / Quaternary International 253 (2012) 80e90 81 provided by the Instituto Geográfico Militar. Field work consisted of Previous studies proposed that the Iglesia basin includes a detailed analysis of the most relevant landforms and natural a Neogene sequence up to 3.5 km thick in its center, thinning to the trenches. east and west, and also to the north and south, and interpreted the basin as a piggyback basin that developed during the eastward 2. Environmental setting of the study area advance of Precordillera thrusts (Beer et al., 1990; Jordan et al., 1993). Siame et al. (2006) found that at 30S both the Iglesia The area under study is located in the central western region of Valley and the Precordillera can be seen as a crustal-scale trans- the San Juan province, between 30 and 30 200S and 69 and 69 pressive zone, whose deformation is distributed with a dextral 300W(Fig. 1a). From east to west, it covers a portion of the western strike-slip along El Tigre Fault zone. This phenomenon is closely border of the Precordillera Occidental, the Iglesia Valley and the related to the Precordillera fold-and-thrust belt. eastern portion of the Cordillera Frontal. Based on the analysis of seismic profiles in the Iglesia Valley and In the Precordillera, the main mountain outcrops trend north- several outcrops in a cross-section along the Jáchal river, Alvarez- esouth, at the Sierra Negra, whose peaks reach 3500 m asl. The Marrón et al. (2006) interpreted a positive flower-type structure most important ranges in the Andean Cordillera are the Colangüil during the Neogene for this region. The authors considered that and the Agua Negra, both exceeding 5000 m asl. these models would not totally reflect the structural arrangement Surface drainage is constituted by the Blanco River and its of fault and thrust belt proposed by others (Allmendinger et al., perennial tributaries, among which the most important are the 1990; Jordan et al., 1993). Colangüil and the Agua Negra creeks both coming from the According to Siame et al. (2006), the Precordillera mountain Cordillera Fontal. To the east, other tributaries coming from the belt, which is nearly 400 km long and 80 km wide, is a thrust-and- Precordillera Occidental, is the Carrizal creek and coming from the fold belt separated from the Cordillera Frontal by an NeS piggyback south, the Iglesia Creek. basin: the Calingasta-Iglesia Valley. Allmendinger et al. (1990) The harshness of the present climate is manifested by extreme suggested that, between 29 and 31S latitude, the Cordillera winter temperatures in the Cordillera (to À30 C), wide tempera- Frontal is uplifted as a ramp-anticline over a mid-crustal ture variations, minimum humidity, winter snow precipitation and décollement. very scarce pluvial precipitation (Minetti et al.,1986). The climate in Outcrops in the Cordillera Frontal area consist of sandstones and the Precordillera Occidental and Iglesia Valley is arid-desert, with siltstones with an Upper CarboniferouseLower Permian age (Agua large daily and annual temperature variations, atmospheric trans- Negra Formation), Permian granites and granodiorites. Mesozoic parency and low humidity. The rainfall regime is continental, with granites of the Batholith of Colangüil, Neogene continental sedi- summer rains and only with very low average frequency of days mentary rocks (Iglesia Group) and PleistoceneeHolocene deposits with rain. According to the classification of Köppen (1936) it is of (Fig. 2) are present in the Valley (Cardó et al., 2000, 2001). type BWK (average annual temperature of 15.7 C in Rodeo, but In Precordillera Occidental, the oldest statigraphic units are above 18 C during the warmest month. January >23 C) (Minetti Ordovician and Devonian sedimentites (Yerba Loca and Punilla et al., 1986). From a climatic viewpoint, this area may be classi- Formations) covered by Upper Paleozoic deposits (Malimán fied as hyper-arid (120 > p > 60 mm)
Load more

Recommended publications
  • 1 ENSO-Triggered Floods in South America
    Hydrol. Earth Syst. Sci. Discuss., https://doi.org/10.5194/hess-2018-107 Manuscript under review for journal Hydrol. Earth Syst. Sci. Discussion started: 3 April 2018 c Author(s) 2018. CC BY 4.0 License. 1 ENSO-triggered floods in South America: 2 correlation between maximum monthly discharges during strong events 3 Federico Ignacio Isla 4 Instituto de Geología de Costas y del Cuaternario (UNMDP-CIC) 5 Instituto de Investigaciones Marinas y Costeras (UNMDP-CONICET) 6 Funes 3350, Mar del Plata 7600, Argentina, +54.223.4754060, [email protected] 7 8 Abstract 9 ENSO-triggered floods altered completely the annual discharge of many watersheds of South America. Anomalous 10 years as 1941, 1982-83, 1997-98 and 2015-16 signified enormous fluvial discharges draining towards the Pacific 11 Ocean, but also to the Atlantic. These floods affected large cities built on medium-latitudinal Andes (Lima, Quito, 12 Salta), but also those located at floodplains, as Porto Alegre, Blumenau, Curitiba, Asunción, Santa Fe and Buenos 13 Aires. Maximum discharge months are particular and easily distinguished along time series from watersheds located 14 at the South American Arid Diagonal. At watersheds conditioned by precipitations delivered from the Atlantic or 15 Pacific anti-cyclonic centers, the ENSO-triggered floods are more difficult to discern. The floods of 1941 affected 16 70,000 inhabitants in Porto Alegre. In 1983, Blumenau city was flooded during several days; and the Paraná River 17 multiplied 15 times the width of its middle floodplain. That year, the Colorado River in Northern Patagonia 18 connected for the last time to the Desagûadero – Chadileuvú - Curacó system and its delta received saline water for 19 the last time.
    [Show full text]
  • The Ichnology of the Winterhouse Formation
    The ichnology of the Winterhouse Formation By ©Robyn Rebecca Reynolds, B.Sc. (Hons) A thesis submitted to the School of Graduate Studies in partial fulfilment of the requirements for the degree of Master of Science Department of Earth Sciences Memorial University of Newfoundland October, 2015 St. John’s Newfoundland Abstract The Upper Ordovician Winterhouse Formation of Western Newfoundland contains a, hitherto undescribed, well-preserved and diverse assemblage of trace fossils. This study provides the first systematic ichnological review of the area. 20 ichnotaxa are documented herein from the mudstone and sandstone storm deposits of the formation. A detailed morphologic three-dimensional reconstruction and analysis of a complex Parahaentzschelinia-like burrow system that is prolific throughout the formation is also undertaken. This analysis allows for a reconsideration of the trace-maker’s ethology and paleobiology, and highlights a need for a systematic ichnotaxonomic review of Parahaentzschelinia. Additional reconstructions of natural mineral-filled fractures associated with Parahaentzschelinia-like burrows in the cemented silt-rich fine-grained sandstones illustrate that the burrows create planes of weakness within the cemented sandstone, along which natural fractures preferentially propagate. This suggests that these trace fossils create mechanical heterogeneities that can steer fracture development, and can potentially have a dramatic effect on reservoir charactertstics in bioturbated reservoirs where induced fracturing techniques may be employed. ii Acknowledgements Firstly I would like to thank my supervisor, Dr. Duncan McIlroy, for providing me with this opportunity, and for your support and mentorship throughout the past three years. In addition to everything I have learned from you about ichnology and sedimentology, your approach to research and your method of supervising/teaching has made me a stronger, more independent, and confident scientist.
    [Show full text]
  • PDF Linkchapter
    Index Page numbers in italic denote Figures. Page numbers in bold denote Tables. Abanico extensional basin 2, 4, 68, 70, 71, 72, 420 Andacollo Group 132, 133, 134 basin width analogue modelling 4, 84, 95, 99 Andean margin Abanico Formation 39, 40, 71, 163 kinematic model 67–68 accommodation systems tracts 226, 227, 228, 234, thermomechanical model 65, 67 235, 237 Andean Orogen accretionary prism, Choapa Metamorphic Complex development 1, 3 20–21, 25 deformation 1, 3, 4 Aconcagua fold and thrust belt 18, 41, 69, 70, 72, 96, tectonic and surface processes 1, 3 97–98 elevation 3 deformation 74, 76 geodynamics and evolution 3–5 out-of-sequence structures 99–100 tectonic cycles 13–43 Aconcagua mountain 3, 40, 348, 349 uplift and erosion 7–8 landslides 7, 331, 332, 333, 346–365 Andean tectonic cycle 14,29–43 as source of hummocky deposits 360–362 Cretaceous 32–36 TCN 36Cl dating 363 early period 30–35 aeolian deposits, Frontal Cordillera piedmont 299, Jurassic 29–32 302–303 late period 35–43 Aetostreon 206, 207, 209, 212 andesite aggradation 226, 227, 234, 236 Agrio Formation 205, 206, 207, 209, 210 cycles, Frontal Cordillera piedmont 296–300 Chachahue´n Group 214 Agrio fold and thrust belt 215, 216 Neuque´n Basin 161, 162 Agrio Formation 133, 134, 147–148, 203, Angualasto Group 20, 22, 23 205–213, 206 apatite ammonoids 205, 206–211 fission track dating 40, 71, 396, 438 stratigraphy 33, 205–211 (U–Th)/He thermochronology 40, 75, 387–397 Agua de la Mula Member 133, 134, 205, 211, 213 Ar/Ar age Agua de los Burros Fault 424, 435 Abanico Formation
    [Show full text]
  • The Eoorthid Brachiopod Apheoorthina in the Lower Ordovician of NW Argentina and the Dispersal Pathways Along Western Gondwana
    The eoorthid brachiopod Apheoorthina in the Lower Ordovician of NW Argentina and the dispersal pathways along western Gondwana DIEGO F. MUÑOZ and JUAN L. BENEDETTO Muñoz, D.F. and Benedetto, J.L. 2016. The eoorthid brachiopod Apheoorthina in the Lower Ordovician of NW Argentina and the dispersal pathways along western Gondwana. Acta Palaeontologica Polonica 61 (3): 633–644. The eoorthid brachiopod Apheoorthina is reported for the first time from the Lower Ordovician of NW Argentina. It is represented by a species similar to A. ferrigena from the Tremadocian of the Prague Basin, increasing the faunal af- finities between the Central Andean Basin and the South European microcontinents, in particular the Bohemian region (Perunica). Nine out of the fourteen brachiopod genera reported from the Tremadocian of the Central Andean Basin (~64%) are shared with the Mediterranean region, four of which (~28%) have been recorded in the Prague Basin, and two (Kvania and Apheoorthina) are restricted to the Central Andes and Perunica. Dispersal pathways around Gondwana are analyzed in the light of major factors affecting large-scale distribution of brachiopods (environment, larval capacity for dispersal, oceanic currents). The presence in Apheoorthina aff. ferrigena of a well-preserved larval protegulum measuring 420 μm in width and 210 μm in length strongly suggests that this species had planktotrophic larvae capable of long-distance dispersal. According to recent ocean-atmosphere general circulation models for the Ordovician Period, the Central Andean margin was dominated by the cold-water Antarctica Current. Despite the complex non-zonal pattern produced by current deflections around the peri-Gondwanan microcontinents, the general westward circulation sense favoured larval dispersal from the Andean region to North Africa, Avalonia, the Armorican Terrane Assemblage, and Perunica.
    [Show full text]
  • Implications for the Bolivian Orocline
    6th International Symposium on Andean Geodynamics (ISAG 2005, Barcelona), Extended Abstracts: 693·696 Preliminary paleomagnetic results from the Cambrian Mesôn Group: Implications for the Bolivian Orocline Cecilia Mariel Spagnuolo 1, Augusto Ernesto Rapalini 1, & Ricardo Alfredo Astini 2 1 INGEODAV, Dpto de Cs. Geolâgicas, FCEyN, Universidad de Buenos Aires, Argentina 2 Dpto de Cs. Geolâgicas, Universidad Nacional de Cérdoba, Argentina The Andean chain changes its strike near )80S. This region is called the " Bo livian Orocline", which comprises part of Bolivia, Pen], Chile and Argentina and is characterized by counterclockwise rotations north of the bend and clockwise rotations south of it (Somoza et al ., 1996; Beek, 1998; Randalll, 1998). Despite its name, it is not considered at present as a true orocline as was defined by Carey (1958). Current models suggest that the present curvature is the result of an original geometrie feature which has been enhanced by Andean tectonism (Kley, 1999). Several different hypothesis about the mechanisms that have caused the systematic rotations detected by paleomagnetism have been proposed, but no general consensus has been yet attained. Because of the lack of Lower Paleozoic paleomagnetic data from Northwestern Argentina, a reconnaissance paleomagnetic survey was carried out on the Meson Group, exposed along the Iruya River in the province of Salta (22°49'S-22°50'S y 64°50'W-65°00'W), near the Matancillas anticline. .....'" tN t . o \" REFERENCES Figura 1. Puneoviseana Formation Thrusts Geologie map of Mataneillas Meson Group Lithologie contact Angular diserodance Antieline. Santa Rosita Foramtion .. Anticlinal laid Secondary lault . Quaternary • Buildings The Meson Group (Turner, 1960) is charac terized by extensive outcrops in Northwestern Argentina.
    [Show full text]
  • Climate Modeling in Las Leñas, Central Andes of Argentina
    Glacier - climate modeling in Las Leñas, Central Andes of Argentina Master’s Thesis Faculty of Science University of Bern presented by Philippe Wäger 2009 Supervisor: Prof. Dr. Heinz Veit Institute of Geography and Oeschger Centre for Climate Change Research Advisor: Dr. Christoph Kull Institute of Geography and Organ consultatif sur les changements climatiques OcCC Abstract Studies investigating late Pleistocene glaciations in the Chilean Lake District (~40-43°S) and in Patagonia have been carried out for several decades and have led to a well established glacial chronology. Knowledge about the timing of late Pleistocene glaciations in the arid Central Andes (~15-30°S) and the mechanisms triggering them has also strongly increased in the past years, although it still remains limited compared to regions in the Northern Hemisphere. The Southern Central Andes between 31-40°S are only poorly investigated so far, which is mainly due to the remoteness of the formerly glaciated valleys and poor age control. The present study is located in Las Leñas at 35°S, where late Pleistocene glaciation has left impressive and quite well preserved moraines. A glacier-climate model (Kull 1999) was applied to investigate the climate conditions that have triggered this local last glacial maximum (LLGM) advance. The model used was originally built to investigate glacio-climatological conditions in a summer precipitation regime, and all previous studies working with it were located in the arid Central Andes between ~17- 30°S. Regarding the methodology applied, the present study has established the southernmost study site so far, and the first lying in midlatitudes with dominant and regular winter precipitation from the Westerlies.
    [Show full text]
  • Debris Flows Occurrence in the Semiarid Central Andes Under Climate Change Scenario
    geosciences Review Debris Flows Occurrence in the Semiarid Central Andes under Climate Change Scenario Stella M. Moreiras 1,2,* , Sergio A. Sepúlveda 3,4 , Mariana Correas-González 1 , Carolina Lauro 1 , Iván Vergara 5, Pilar Jeanneret 1, Sebastián Junquera-Torrado 1 , Jaime G. Cuevas 6, Antonio Maldonado 6,7, José L. Antinao 8 and Marisol Lara 3 1 Instituto Argentino de Nivología, Glaciología & Ciencias Ambientales, CONICET, Mendoza M5500, Argentina; [email protected] (M.C.-G.); [email protected] (C.L.); [email protected] (P.J.); [email protected] (S.J.-T.) 2 Catedra de Edafología, Facultad de Ciencias Agrarias, Universidad Nacional de Cuyo, Mendoza M5528AHB, Argentina 3 Departamento de Geología, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Santiago 8320000, Chile; [email protected] (S.A.S.); [email protected] (M.L.) 4 Instituto de Ciencias de la Ingeniería, Universidad de O0Higgins, Rancagua 2820000, Chile 5 Grupo de Estudios Ambientales–IPATEC, San Carlos de Bariloche 8400, Argentina; [email protected] 6 Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Universidad de La Serena, Coquimbo 1780000, Chile; [email protected] (J.G.C.); [email protected] (A.M.) 7 Departamento de Biología Marina, Universidad Católica del Norte, Larrondo 1281, Coquimbo 1780000, Chile 8 Indiana Geological and Water Survey, Indiana University, Bloomington, IN 47404, USA; [email protected] * Correspondence: [email protected]; Tel.: +54-26-1524-4256 Citation: Moreiras, S.M.; Sepúlveda, Abstract: This review paper compiles research related to debris flows and hyperconcentrated flows S.A.; Correas-González, M.; Lauro, C.; in the central Andes (30◦–33◦ S), updating the knowledge of these phenomena in this semiarid region.
    [Show full text]
  • Distribution of Ostracods in West-Central Argentina Related to Host-Water Chemistry and Climate: Implications for Paleolimnology
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Servicio de Difusión de la Creación Intelectual J Paleolimnol (2017) 58:101–117 DOI 10.1007/s10933-017-9963-1 ORIGINAL PAPER Distribution of ostracods in west-central Argentina related to host-water chemistry and climate: implications for paleolimnology D. Sabina D’Ambrosio . Adriana García . Analía R. Díaz . Allan R. Chivas . María C. Claps Received: 6 October 2016 / Accepted: 24 March 2017 / Published online: 30 March 2017 © Springer Science+Business Media Dordrecht 2017 Abstract Ecological and biogeographical studies of multivariate analysis of the data indicated that Neotropical non-marine ostracods are rare, although salinity is the most significant variable segregating such information is needed to develop reliable two ostracod groups. Limnocythere aff. staplini is the paleoecological and paleoclimatic reconstructions only species that develops abundant populations in for the region. An extensive, yet little explored South the saline ephemeral Laguna Llancanelo during American area of paleoclimatic interest, is the arid- almost all seasons, and is accompanied by scarce semiarid ecotone (Arid Diagonal) that separates arid Cypridopsis vidua in summer. The latter species is Patagonia from subtropical/tropical northern South abundant in freshwater lotic sites, where Ilyocypris America, and lies at the intersection of the Pacific and ramirezi, Herpetocypris helenae, and Cyprididae Atlantic atmospheric circulation systems. This study indet. are also found in large numbers. Darwinula focused on the Laguna Llancanelo basin, Argentina, a stevensoni, Penthesilenula incae, Heterocypris incon- Ramsar site located within the Arid Diagonal, and gruens, Chlamydotheca arcuata, Chlamydotheca sp., was designed to build a modern dataset using Herpetocypris helenae, and Potamocypris smarag- ostracods (diversity, spatial distribution, seasonality, dina prefer freshwater lentic conditions (springs), habitat preferences) and water chemistry.
    [Show full text]
  • Holdridge Life Zone Map: Republic of Argentina María R
    United States Department of Agriculture Holdridge Life Zone Map: Republic of Argentina María R. Derguy, Jorge L. Frangi, Andrea A. Drozd, Marcelo F. Arturi, and Sebastián Martinuzzi Forest International Institute General Technical November Service of Tropical Forestry Report IITF-GTR-51 2019 In accordance with Federal civil rights law and U.S. Department of Agriculture (USDA) civil rights regulations and policies, the USDA, its Agencies, offices, and employees, and institutions participating in or administering USDA programs are prohibited from discriminating based on race, color, national origin, religion, sex, gender identity (including gender expression), sexual orientation, disability, age, marital status, family/parental status, income derived from a public assistance program, political beliefs, or reprisal or retaliation for prior civil rights activity, in any program or activity conducted or funded by USDA (not all bases apply to all programs). Remedies and complaint filing deadlines vary by program or incident. Persons with disabilities who require alternative means of communication for program information (e.g., Braille, large print, audiotape, American Sign Language, etc.) should contact the responsible Agency or USDA’s TARGET Center at (202) 720-2600 (voice and TTY) or contact USDA through the Federal Relay Service at (800) 877-8339. Additionally, program information may be made available in languages other than English. To file a program discrimination complaint, complete the USDA Program Discrimination Complaint Form, AD-3027, found online at http://www.ascr.usda.gov/complaint_filing_cust.html and at any USDA office or write a letter addressed to USDA and provide in the letter all of the information requested in the form.
    [Show full text]
  • Glacier Changes in the Semi-Arid Huasco Valley, Chile, Between 1986 and 2016
    geosciences Article Glacier Changes in the Semi-Arid Huasco Valley, Chile, between 1986 and 2016 Katharina Hess 1,*, Susanne Schmidt 2,* , Marcus Nüsser 1,2 , Carina Zang 1 and Juliane Dame 1,2 1 Heidelberg Center for the Environment (HCE), Heidelberg University, 69120 Heidelberg, Germany; [email protected] (M.N.); [email protected] (C.Z.); [email protected] (J.D.) 2 Department of Geography, South Asia Institute (SAI), Heidelberg University, 69115 Heidelberg, Germany * Correspondence: [email protected] (K.H.); [email protected] (S.S.); Tel.: +49-(0)6221-54-15240 (S.S.) Received: 30 July 2020; Accepted: 26 October 2020; Published: 29 October 2020 Abstract: In the semi-arid and arid regions of the Chilean Andes, meltwater from the cryosphere is a key resource for the local economy and population. In this setting, climate change and economic activities foster water scarcity and resource conflicts. The study presents a detailed glacier and rock glacier inventory for the Huasco valley (28–29◦ S) in northern Chile based on a multi-temporal remote sensing approach. The results indicate a glacier-covered area of 16.35 3.06 km2 (n = 167) and, ± additionally, 50 rock glaciers covering an area of about 8.6 km2 in 2016. About 81% of the ice-bodies are smaller than 0.1 km2, and only four glaciers are larger than 1 km2. The change analysis reveals a more or less stable period between 1986 and 2000 and a drastic decline in the glacier-covered area by about 35% between 2000 and 2016.
    [Show full text]
  • Flora Ano Vegetation of Northern Chilean Andes
    El Altiplano. Ciencia y conciencia en los Andes FLORA ANO VEGETATION OF NORTHERN CHILEAN ANDES MARY T. KALIN ARROYO (1), FRANCISCO A. SQUEO (2), HEINZ VEIT (3), LOHENGRIN CAVIERES (1), PEDRO LEON (1), ELIANA BELMONTE (4). (1) Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile. (2) Departamento de Biología, Facultad de Ciencias, Universidad de La Serena, Casilla 599, La Serena, Chile. (3) Lehrstuhl für Geomorphologie, Universitat Bayreuth, Germany. (4) Universidad de Tarapacá, Arica, Chile. Correspondence to: Dr. Francisco A. Squeo, Depto. Biología, Universidad de La Serena, Casilla 599, La Serena- Chile • Fax: 56 (51) 204383, Phone: 56 (51) 204369-401, E-mail: [email protected] ABSTRACT In northern Chilean Andes two rainfall patterns are found: a summer rain region (17°-24°S) anda winter rain region (25°·32°S). The transition between both rain regions (24°-25°S) correspond also with the driest area ('arid diagonal'). The Andes Mountains started to emerge in the Upper Tertiary. The existence of high mountains in the Miocene/Piiocene, together with the likely birth of the cold Humboldt-curren! at about this time, led to an aridization of northern Chilean Andes. The Quatemary with its generally dry conditions is charac­ terized by the occurrence of relativa moist phases during the glacials. The models, concerning the northwards or southwards shift of climatic belts (e.g., the westerlies) during glacial periods, are discussed. The flora of northern Chilean Andes include 865 plant species, 21% of these especies are endemic to Chile. In the winter rain region exist twice higher endemism than the summer rain region.
    [Show full text]
  • Glacier Inventory and Recent Glacier Variations in the Andes of Chile, South America
    Annals of Glaciology 58(75pt2) 2017 doi: 10.1017/aog.2017.28 166 © The Author(s) 2017. This is an Open Access article, distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives licence (http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is unaltered and is properly cited. The written permission of Cambridge University Press must be obtained for commercial re-use or in order to create a derivative work. Glacier inventory and recent glacier variations in the Andes of Chile, South America Gonzalo BARCAZA,1 Samuel U. NUSSBAUMER,2,3 Guillermo TAPIA,1 Javier VALDÉS,1 Juan-Luis GARCÍA,4 Yohan VIDELA,5 Amapola ALBORNOZ,6 Víctor ARIAS7 1Dirección General de Aguas, Ministerio de Obras Públicas, Santiago, Chile. E-mail: [email protected] 2Department of Geography, University of Zurich, Zurich, Switzerland 3Department of Geosciences, University of Fribourg, Fribourg, Switzerland 4Institute of Geography, Pontificia Universidad Católica de Chile, Santiago, Chile 5Centre for Hydrology, University of Saskatchewan, Saskatoon, Canada 6Department of Geology, University of Concepción, Concepción, Chile 7Department of Geology, University of Chile, Santiago, Chile ABSTRACT. The first satellite-derived inventory of glaciers and rock glaciers in Chile, created from Landsat TM/ETM+ images spanning between 2000 and 2003 using a semi-automated procedure, is pre- sented in a single standardized format. Large glacierized areas in the Altiplano, Palena Province and the periphery of the Patagonian icefields are inventoried. The Chilean glacierized area is 23 708 ± 1185 km2, including ∼3200 km2 of both debris-covered glaciers and rock glaciers.
    [Show full text]