Surge glaciers during the Little Ice Age in the Pyrenees

Abstract

Historical moraine complexes and erosional features are interesting elements to discern the historical climate changes and evolution, with a complex chronologies that help us to understand the dynamics and glacier evolution during the Little Ice Age (LIA). The existence of landforms as crevasses-squeeze ridges, hummocky moraines and flutes, related to different glacier advances and retreats, allows understanding in a better way the LIA glacier evolution in the Pyrenees. The aim of this work is to show how many LIA moraine complexes have traces of fast flow ice; when the surge dynamic happened; his extent and the environmental meaning. Based on glacier landsystem analysis we have established a work hypothesis on the fast flow or surge dynamic glaciers during the LIA, with geomorphological features, as flutes and push and hummocky moraines, at least in 17 LIA glacier complexes. The analysis of morphosquences by fieldwork, photo interpretation and historical sources in 8 selected LIA moraine complexes have been compared with previous climatic reconstructions creating a hypothesis about the response of the LIA glaciers to the short time changes in temperature and moisture.The glacier cirques with fast flow features are found in the highest mountains with summits above 3000 m., mainly northern oriented (88%) and without a significant lithology. The studied complexes (Central Infierno, Eastern Infierno, Oulettes de Gaube, Monte Perdido, Marboré, La Paúl, Literola and Tempestades) show 4 morphological units: a frontal moraine system (U1); a more voluminous moraine (U2); a little push and hummocky moraines complex linking with flutes (U3); and minor arcs up valley (U4). The U3 belongs to a fast flow stage or surging and by morphostratigraphy we can point out that the surge processes were produced between 1820 and 1840, at the end of the LIA. We related it with a possible climatic response to sudden cooling and the increase of winter precipitation with melt-water availability and quick ice melting during the summer, generating hydrodynamic changes in the small glaciers and quick dynamic response.

Periglacial environments and frozen ground in the central Pyrenean high mountain area: Ground thermal regime and distribution of landforms and processes

“…Glaciers shaped the high Pyrenees during the Pleistocene, some longer than 40 km in the central portion during the Last Glacial Maximum (LGM) . The Dryas was also important, and at least two stages with small glaciers shaped the highest cirques during the Lateglacial . During the Little Ice Age (LIA) glaciers occupied cirques and fashioned moraine complexes .…”

“…26,36,51,52 The Dryas was also important, and at least two stages with small glaciers shaped the highest cirques during the Lateglacial. 27,[53][54][55] During the Little Ice Age (LIA) glaciers occupied cirques and fashioned moraine complexes. 27,[56][57][58] Paraglacial and periglacial environments have made up the high mountain region for the last 12 ka, 51 so all massifs studied have LIA moraine complexes and are in areas occupied by Dryas period moraine systems ( Figure 2).…”

Geomatic Methods Applied to the Change Study of the La Paúl Rock Glacier, Spanish Pyrenees

“…The GNSS-RTK and TLS measurements show that the rock glacier is active, with displacements of similar magnitude to other Pyrenean rock glaciers. The complex history of the rock glacier, with part of its north-western portion eroded during the LIA (Serrano and Martín-Moreno, 2018), exhibit its resilience capacity, in both ideal and marginal conditions, in the high temperate mountain. In this case, the La Paúl rock glacier is previous to the LIA, when the advance of the La Paúl glacier modified its eastern sector incorporating part of the rock glacier body to the lateral and frontal moraine.…”

Post‐little ice age paraglacial processes and landforms in the high Iberian mountains: A review

“…Subsequently, glaciers started retreating, although in at least 16 cirques there was a period of glacier expansion after approximately 1830 and prior to 1850 CE that formed moraine complexes with flutes, push, and hummocky moraines that deformed previous ones. This has been interpreted as a short‐lived stage of fast flow glacier advance or surging glaciers that occurred before post‐LIA warming that favoured widespread glacier retreat (Serrano & Martín‐Moreno, ). However, at the end of 19th century there were small glacier advances as illustrated by naturalists and cartographers, with glaciers next to the frontal moraines at Vignemale, Infierno, Maladeta, Posets, and Monte Perdido massifs (Russell, ; Schrader, ).…”