Sedimentology (2007, in press) Lacustrine sedimentation in active volcanic settings: The Late Quaternary depositional evolution of Lake Chungará (Northern Chile) Sáez, A.1*, Valero-Garcés, B.L.2, Moreno, A.2, Bao, R.3, Pueyo, J.J.1, González-Sampériz, P.2, Giralt, S.4, Taberner, C.4, Herrera, C.5, and Gibert, R.O.1 1 Facultat de Geologia, Universitat de Barcelona, c/ Martí Franques s/n, 08028 Barcelona (Spain) 2 Instituto Pirenaico de Ecología. Consejo Superior de Investigaciones Científicas. Apdo 202, 50080 Zaragoza (Spain) 3 Facultade de Ciencias, Universidade da Coruña, Campus da Zapateira s/n, 15071 A Coruña (Spain) 4 Instituto de Ciencias de la Tierra 'Jaume Almera' - CSIC, c/ Lluís Sole Sabaris s/n, 08028 Barcelona (Spain) 5 Departamento de Ciencias Geológicas, Universidad Católica del Norte, Casilla 1280, Antofagasta (Chile) (*) E-mail:
[email protected] ABSTRACT Lake Chungará is the largest (22.5 Km2) and deepest (40 m) lacustrine ecosystem in the Chilean Altiplano and its location in an active volcanic setting provides an opportunity to evaluate environmental (volcanic versus climatic) controls on lacustrine sedimentation. The Late Quaternary depositional history of Lake Chungará (18º15' S, 69º09 W, 4520 m a.s.l.) is reconstructed by means of a multiproxy study of 15 Kullenberg cores and seismic data. The chronological framework is supported by 10 14C AMS and 1 230Th/234U dates. Lake Chungará was formed prior to 12.8 cal. kyr BP following the partial collapse of the Parinacota volcano that impounded the Lauca river. The sedimentary architecture of the lacustrine sequence has been controlled by (1) the strong inherited palaeo-relief, and (2) changes in the accommodation, caused by lake level fluctuations and tectonic subsidence.