Potrok Aike

Potrok Aike is a maar (a broad volcanic crater) in the Patagonian province of Santa Cruz, Argentina, which contains a brackish lake. It has a roughly square shape and is about 3.5 kilometres (2.2 mi) wide. The lake is fed by groundwater and occasional inflows through dry valleys, and its water levels have fluctuated over the course of its 770,000 year long history between overflow and near desiccation. Recent (past 51,000 years) climatic variability has left a series of terraces and shorelines, both around the lake and submerged under its waters. The variability is driven mainly by changes in wind speed, which change the evaporation rates. Usually, cold periods correlate to higher and warm periods to lower water levels in Potrok Aike.

The lake is embedded in a dry steppe region, and is one of the few open water bodies there. It has been studied as a site for long drill cores and palaeoclimate records of the PASADO/SALSA project, which in 2002 and 2003 took about half a kilometre of drill cores from the lake. These drill cores were used to reconstruct the climate (temperature, wind and precipitation) and environment of the region, including volcanic activity and changes in Earth's magnetic field.

The region around Potrok Aike was periodically glaciated before the maar formed, but later glaciations did no longer reach it. Sparse volcanic activity built the Pali-Aike volcanic field, which was active until 10,000 years ago east of Potrok Aike. About 12,500 years ago humans first arrived in Patagonia. They used the resources around Potrok Aike, including rockshelters to dismember animal kills. The lake itself is inhabited by algae and underwater plants.