Llanquihue glaciation

The last glacial period and its associated glaciation is known in southern Chile as the Llanquihue glaciation (Glaciación de Llanquihue). Its type area lies west of Llanquihue Lake where various drifts or end moraine systems belonging to the last glacial period have been identified. The glaciation is the last episode of existence of the Patagonian Ice Sheet. Around Nahuel Huapi Lake the equivalent glaciation is known as the Nahuel Huapi Drift. The preceding interglacial is known as the Valdivia interglacial after its type locality of Valdivia. The characteristics of the glaciation differ according to latitude. In Central Chile, south of Atacama Desert, the extent of the Llanquihue glaciation was controlled by precipitation which increases to the south. Maximum glaciers advances were not synchronous across the whole latitudinal gradient as they were triggered by north and southward shifts in the moisture-bringing Westerlies and its storm tracks. Glaciers in Central Chile were particularly sensitive to shifts in the precipitation pattern and those to the south in southern Chile (39–43° S) were sensitive to both precipitation and temperature, correlating better with global temperature trends. During large glacier advances the Llanquihue glaciation in Chile showed a marked difference north and south of latitude 41.5° S. To the south Andean valley glacier lobes coalesced and spread out occupying what is today the sea of Chiloé and other marine basins. At times the ice reached all the way across to the foot of the Chilean Coast Range in Chiloé. This meant that the region south of 41.5° S was subject to a proper ice sheet glaciation during large glacier advances. In contrast during times of glacier advance Andean valley glaciers entering the Chilean Central Valley in the Chilean Lake District (39–41.5° S) spread out forming large but separate glacier lobes, meaning that the glaciation remained restricted by topography being a glaciation of valley glaciers, or in other words one of Alpine type.