Osorno–Llanquihue Basin

The Osorno–Llanquihue Basin (Cuenca Osorno-Llanquihue) is a sedimentary basin located in south-central Chile in the forearc region of the Andes. From north to south the basin spans and area from Catamutún to Reloncaví Sound (40–42° S). The deepest part of the basin lie to the east. The lower levels of the basin are occupied by coal-bearing Cheuquemó Formation among other units while the Miocene-aged marine Santo Domingo Formation makes up much of the upper stratigraphy. The uppermost levels are made of sediments of Quaternary age of glacial, glaci-fluvial, glaci-lacustrine and volcanic character. The thickness of Quaternary sediments is greater to the south reaching almost 1300 m in Puerto Montt. Sediments in the western part of the basin are roughly estimated to have reached 70 °C during burial and diagenesis.