![]() ![]() The paleolakes are recorded either by non-dissected infilled basins or by hanging and incised lacustrine terraces that persisted for thousands of years. These relict lake basins are related to the blockage of drainages by postglacial earthflows and slides, mainly developed on Paleozoic slates. The production of a cartographic landslide inventory in the glaciated headwaters of the upper Gállego River, Axial Zone of the Spanish Pyrenees, revealed several paleolakes. However, post-LIA warming led to glacier disappearance in the Cantabrian Mountains, Sierra Nevada and most massifs of the Pyrenees, together with an accelerated shrinkage of the small glaciers still existing in this range at elevations near 3000 m. Temperature increase recorded during the Holocene conditioned the melting of glaciers, which only reappeared in the highest massifs during the coldest periods, such as the LIA. A massive glacial retreat occurred in all ranges at 19-20 ka, but the long-term deglaciation process was interrupted by cold intervals, such as the Oldest and Younger Dryas, which favoured glacial expansion in the highest mountains. 30 ka in Sierra Nevada and NW ranges, and (almost) synchronously to the LGM in the Central Range and Iberian Range. The maximum glacial expansion of this last Pleistocene glaciation stage occurred well before the global Last Glacial Maximum (LGM) between 30 and 60 ka in the Cantabrian Mountains and Pyrenees, at ca. However, most of the glacial records correspond to the Last Glacial Cycle and subsequent Termination. In some ranges, there is evidence of Middle Pleistocene glaciations, one potentially correlating with marine isotope stage (MIS) 12 and another correlating with MIS 6 with glaciation dated to ca. Depending on the combination of temperatures and moisture conditions, more or less ice was stored. In all cases, glaciers remained confined within the mountain systems and did not reach the surrounding lowlands. During Quaternary cold stages, ice accumulated in the head valleys of these mountain ranges and glaciers flowed down-valleys. The data were geographically divided considering the mountain systems where glacial evidence exists: Pyrenees, Cantabrian Range, NW ranges, Central Range, Iberian Range and Sierra Nevada. To this purpose, the chronological framework was divided in six periods: glaciations prior to the Last Glacial Cycle (Middle Pleistocene), Last Glacial Cycle (Late Pleistocene), Termination-1, Holocene, Little Ice Age (LIA) and present-day. The objective of this research is to summarize the current knowledge on the spatial and temporal patterns of glacial activity in the Iberian mountains during the Late Quaternary. ![]() The wide range of glacial landforms and deposits distributed across different Iberian ranges suggests the occurrence of several past periods with larger glacial systems. The only glaciers existing today in the Iberian Peninsula are small features located in the Pyrenees, though their number and extension has undergone significant changes over the Late Quaternary. The dates obtained for the last glacial cycle (20–18 ka) are similar to other chronolo-gies for Mediterranean mountains, and confirm the occur-rence of an early MIE in the Central Pyrenees that does not coincide with the global LGM. Other minor internal moraines were related to the 7–8 m terrace. Moraine M2 was clearly linked to the fluvioglacial 20 m terrace. The dif-ference in age between M1 moraine and the 60 m fluviogla-cial terrace suggests that the latter belongs to an earlier glacial stage (MIS 8). From a topographical point of view, moraine M1 appears to be linked to the 60 m fluvioglacial terrace, dated in a tributary of the Aragón River at 263 21 ka. The main moraines (M1 and M2) correspond to two glacial stages (oxygen isotopic stages MIS 6 and MIS 4), dated at 171 22 ka and 68 7 ka, respec-tively. Six frontal arcs and three lateral morainic ridges were identified in the Villanúa basin terminal glacial complex. New morpho-logical studies and absolute ages for moraines and fluvial terraces in the Aragón Valley allow a correlation with other Pyrenean glaciers and provide solid chronologies about the asynchroneity between global last glacial maximum (LGM) and the maximum ice extent (MIE). The Aragón Valley glacier (Central Western Pyrenees) has been studied since the late nineteenth century and has become one of the best areas in the Pyrenees to study the occurrence of Pleistocene glaciations and the relation-ships between moraines and fluvial terraces. Deposits in the Aragón Valley, central-western Pyrenees: chronology of the Pyrenean late Pleistocene glaciers. ![]()
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