Laguna Potrok Aike (51° 58'S, 70° 23'W), is a ~770 ka maar lake in southern Patagonia (Province of Santa Cruz, Argentina). In the austral spring 2008, the PASADO international team of scientists cored Laguna Potrok Aike using the GLAD800 equipment in order to obtain a high-resolution geological archive for paleoenvironmental reconstructions. Two long sedimentary sequences of approximately 100 meters each were recovered close to the center of the lake at 100 m water depth. In the field, the magnetic susceptibility was measured using a Multi Sensor Core Logger at 2 cm intervals. At the Paleo and Environmental Magnetism Laboratory of ISMER in Rimouski (Québec, Canada), core catcher samples (core 5022 2A) were analyzed using an alternating gradient force magnetometer to determine the magnetic mineralogy and grain size. In the framework of the PASADO project, the aim of this paleomagnetic study is to 1) reconstruct the first full paleomagnetic vector (inclination, declination and relative paleointensity) recorded from southern South America and presumably back to Oxygen Isotope Stage 5, 2) use magnetostratigraphy as a chronostratigraphic tool in Laguna Potrok Aike in addition to radiocarbon and optical (OSL) dating as well as tephrochronology and 3) develop high-resolution magnetic proxies of paleoenvironmental changes in southern Patagonia. Here we present the paleomagnetic study outline, the magnetic susceptibility profiles obtained in the field and preliminary laboratory results as a first step to characterize the magnetic mineralogy and grain size.
Helmholtz Research Programs > PACES I (2009-2013) > TOPIC 3: Lessons from the Past > WP 3.2: Tectonic, Climate and Biosphere Development from Greenhouse to Icehouse