Post‐little ice age patterned ground development on two pyrenean proglacial areas: from deglaciation to periglaciation

Abstract

This study aims to observe post‐Little Ice Age glacier retreat and the constitutive patterned ground development at two French Pyrenean glacier forelands (Taillon Glacier and Pays Baché Glacier). Periglacial feature observations are associated with periods of deglaciation using aerial photos and archive files. Four conclusions are drawn. (1) The two glaciers have lost respectively 68% and 92% of their surface since 1850, which corroborates observations on other Pyrenean glaciers. (2) Patterned ground can develop very rapidly, sometimes only 10 years after deglaciation. (3) Patterned ground size does not systematically increase as a function of the time elapsed since deglaciation. (4) All the forms, even those developing near the Little Ice Age moraines, are active. We propose that the location, activity and size of patterned ground are more probably linked to drift characteristics and local wetness conditions than to the time elapsed since deglaciation.

Effect of Climate on Morphology and Development of Sorted Circles and Polygons

“…This is an order of magnitude longer than previous estimates based on sorted patterns across glacial chronosequences (e.g. Ballantyne and Matthews, ; Haugland, ; Feuillet and Mercier, ). The latter are valid particularly for small‐scale sorted patterns and mid‐latitude alpine climates, characterised by well‐developed seasonal and diurnal temperature variations and numerous freeze–thaw cycles.…”

“…Sorted patterns commonly develop in front of retreating glaciers (Ballantyne and Matthews, ; Haugland, ) and perennial or late‐lying snow patches (Kling, ). Because these settings often provide favourable ground material properties, moisture supply, ground thermal regime and topography for patterned‐ground formation, sorted circles and polygons can rapidly emerge and develop within a few decades (Ballantyne and Matthews, ; Matthews et al , ; Feuillet and Mercier, ). In Svalbard, the LIA ended rapidly in the early 20th century (Hagen et al , ; Svendsen and Mangerud, ; Isaksson et al , ) and, since then, land‐terminating glaciers in the northern Billefjorden have continuously retreated at a rate of 5–15 m yr −1 and exposed extensive areas (Rachlewicz et al , ).…”

Los efectos geoecológicos del cambio global en el Pirineo Central español: una revisión a distintas escalas espaciales y temporales

“…y hasta un total de 13 glaciares rocosos están todavía en activo (Lugon et al, 2004). Suelos poligonales se están formando en el frente deglaciado del Taillón en tan sólo 10 años (Feuillet & Mercier, 2012), y se rehacen cada día en otoño en pequeños rellanos del fondo del circo de Marboré. Vicente-Serrano et al (2007) y López han comprobado además la existencia de una tendencia negativa en la precipitación en el Pirineo durante la segunda mitad del siglo xx, sobre todo en primavera y verano, y un aumento en la duración de las rachas secas, que se puede explicar por un desplazamiento del cinturón de altas presiones subtropicales hacia el norte, y por el descenso de precipitaciones convectivas.…”

Holocene and ‘Little Ice Age’ glacial activity in the Marboré Cirque, Monte Perdido Massif, Central Spanish Pyrenees

“…According to Del Barrio et al (1990), the actual 0ºC isotherm is located at 2726 m. Feuillet and Mercier (2012) established the 0ºC isotherm at approximately 2650 m, noting that the mean annual temperature is -1.3ºC on the Midi de Bigorre Peak (2877 m). To the east, in the Maladeta Glacier, the Equilibrium Line Altitude (ELA) is located between 2956 and 2959 m; in 1820-1830, it was estimated to lie about 255 m lower than that (Chueca Cía et al, 2005).…”