 This "Ladoga–Pasha structure", as it known, hosts Jotnian sediments.During the Pleistocene glaciations the depression was partially stripped of its sedimentary rock fill by glacial overdeepening.During the Last Glacial Maximum, about 17,000 years BP, the lake served likely as a channel that concentrated ice of the Fennoscandian Ice Sheet into an ice stream that fed glacier lobes further east.