Quaternary Heritage and Landscape in the Témiscouata–Madawaska Valley, Eastern Québec

The Quaternary heritage and landscape of the Temiscouata–Madawaska Valley consists of an assemblage of landforms and deposits associated with former stabilizations of glacial margins during the Late Pleistocene development of an ice-free corridor in the Notre-Dame Ice Cap (NDIC), through which Glacial Lake Madawaska developed. This lake occupied an area of more than 500 km2 in the Temiscouata–Madawaska valley from late-glacial times to the middle of the Holocene, depositing a thick series of varves. The contact between Madawaska Lake and the ice margin of the NDIC contributed to the acceleration of deglaciation and the fragmentation of NDIC into two local ice caps: the Lejeune Ice Cap (LIC) and the Pohenegamook Ice Cap (PIC). In the Bas-Saint-Laurent and particularly in the Temiscouata–Madawaska valley, the Quaternary landscape is the product of the coexistence of an Appalachian ice margin and the glacial lake Madawaska.