An international team of scientists has been attracted to coordinate the Potrok Aike Maar Lake Sediment Archive Drilling Project (PASADO) which has been submitted in the framework of the International Continental Scientific Drilling Program (ICDP). The main objective of PASADO is to develop an environmental, climatic and volcanological science network focussing on (A) quantitative climate reconstruction in combination with proxy-model intercomparison and (B) investigation of the phreatomagmatic formation and analysis of early sedimentation in a young maar-diatreme structure. Within PASADO it is proposed to recover long sediment cores from Laguna Potrok Aike, a 770,000 year old maar lake in the dry steppe of southern Patagonia, Argentina (52°S, 70°W; max. depth: 100 m; diameter: 3470 m). Seismic surveys demonstrate that at least 400 m of pelagic sediments were deposited in the lake centre underlain by an unknown thickness of volcaniclastic breccias. Based on seismic data, three drilling sites were selected: (1) from the deepest part of the lake to (i) obtain a continuous and high-resolution record of climatic and environmental changes and (ii) unveil the phreatomagmatic history including more precise age constrains for the maar-diatreme formation from the volcaniclastic sediments below, (2) from a subaquatic lake level terrace at 35 m water depth to constrain the range of lake level variations and (3) from an angle hole passing through lacustrine sediments and the crater wall into the basement rocks (molasse sandstones) to study the impact of explosive volcanism, post-eruptive structural evolution and early processes of sedimentation in a mid-Pleistocene maar. It is anticipated that this site will develop into a key site of the Southern Hemisphere that will improve our understanding of climatic teleconnections and inter-hemispheric differences. Moreover, this region close to the Andean volcanic chain is subject to shifts in polar and mid-latitude pressure fields and affected by the El Niño Southern Oscillation (ENSO) as well as by the Antarctic Oscillation (AAO). This lacustrine Patagonian archive thus can potentially provide unique terrestrial records of variations in climate, hydrology and deposition of airborne particles. Furthermore, such a record acts as a cornerstone for palaeodata-model comparison. Links will also be established to ice cores from Antarctica and to marine records from the Southern Oceans where dust and tephra of Patagonian provenance have been detected.