Cartografía xeomorfolóxica da actividade glaciar durante o Plistoceno na serra dos Ancares (Galicia, noroeste da Península Ibérica)

• Autores: Augusto Pérez Alberti
• Localización: Nemus: revista de l'Ateneu de Natura, ISSN 1697-2694, Nº. 14, 2024, págs. 15-29
• Idioma: gallego
• Títulos paralelos:
  • Geomorphological mapping of glacial activity during the Pleistocene in Serra dos Ancares (Northwest of the Iberian Peninsula)
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• Resumen
  • galego

    A serra dos Ancares atópase ao norte do val do río Sil e esténdese entre o pico Miravalles (1967m) e o pico Penarrubia (1822 m). A serra actúa como divisoria hidrográfica entre as concas dos ríos Navia e Sil e artéllase arredor dunha estreita crista alongada en dirección NL-SO, onde se sitúan os picos de maior altitude.

    Os xeos na serra dos Ancares chegaron a ocupar unha extensión de 141,6 km2 . Resultado da súa actividade é a gran diversidade de formas e depósitos xerados durante o Plistoceno superior. A pegada do xeo evidénciase pola extensión e magnitude das formas de erosión e de acumulación. Entre as primeiras sobresaen os vales en U ou en berce, os circos, anfiteatros, ombreiros ou as rochas ovelladas e estriadas. Entre as segundas sobresae un amplo cortexo de moreas glaciares e depósitos fluvioglaciares.

    A investigación levada a cabo en diferentes etapas baseouse nun intenso traballo de campo e de gabinete. As pescudas sobre o terreo permitiron localizar, analizar e describir formas e depósitos. A cartografía mediante SIX empregando modelos dixitais de elevacións de alta resolución proporcionou unha maior precisión na situación das moreas glaciares, e a súa xeolocalización precisa facilitou a posterior cartografía detallada que se levou a cabo no gabinete, o cal permitiu reconstruír tres fases glaciares: máximo glaciar, que habería que situar cronoloxicamente entre arredor dos 44 e 27 ka; último máximo glaciar global, que se situaría entre os 19 e 26,5 ka e deglaciación, que se daría entre os 19 e 11 ka

  • English

    The Serra dos Ancares is located to the north of the Sil river valley and stretches between the Miravalles Peak (1,967 m) and the Penarrubia Peak (1,822 m). The mountain range acts as a watershed between the basins of the rivers Navia and Sil and is articulated around a narrow-elongated ridge in a NE-SW direction, where the highest peaks are located.

    The ice cover in the Serra dos Ancares reached an extension of 141.6 km2 . The result of its activity is the great diversity of forms and deposits generated during the Upper Pleistocene. The traces of the ice are evidenced by the extent and magnitude of the forms of erosion and accumulation. Among the former, the U-shaped or cradle-shaped valleys, cirques, amphitheatres, shoulder ridges or the boulders and striated rocks stand out. The latter include a wide range of glacial moraines and fluvioglacial deposits.

    The research carried out in different stages was based on intensive field and desk research. Field research allowed us to locate, analyse and describe forms and deposits. GIS mapping using high-resolution digital elevation models gave a more precise location of the glacial moraines and their precise geo-localisation facilitated the subsequent detailed mapping carried out in the office, which allowed the reconstruction of three glacial phases: Glacial Maximum, which should be placed chronologically between about 44 and 27 ka. Last Global Glacial Maximum, which would be between 19 and 26.5 ka and Deglaciation, which would occur between 19 and 11 ka.