Río Biobío
In the 110 km between Gorbea and Paillaco ("c". 39–40° S) the Central Valley is inexistent as the region is instead crossed by a series of east-west mountainous ridges and broad fluvial valleys. South of this region the Central Valley re-appears in the south to extend into Osorno and Puerto Montt (41°30' S). This southern section is 190 km long from north to south. The Central Valley south of Bío Bío River has been influenced by volcanism and past glaciations giving origin to the ñadis and moraines that cover parts of the valley.