Late-glacial stratigraphy and history of the Gulf of St. Lawrence: Discussion
The cruise of the C.S.S. Hudson in 1990 was a memorable introduction to marine geoscience and North Atlantic storms. Land- and sea-based geologists were thrown together to link land and sea sedimentary records and get a better understanding of the complex glaciation of Atlantic Canada.

Atlantic Canada is an amalgam of distinctive tectonic terranes, where lithic markers can be used to reconstruct glacial flow patterns (e.g., Stea and Pe-Piper 1999). Provenance analysis can also help to establish correlations between terrestrial and marine stratigraphic records. Once offshore ice margins and onshore flow lines are linked up, former Pleistocene glaciers can be modelled. Stea et al. (1998) used these methods to develop an ice advance and retreat history of Maritime Canada. The Gulf of St. Lawrence region was a critical area for the reconstruction, and little data was available. Josenhans and Lehman (1999) have made a significant advance in the understanding of the marine record to complete the link with the terrestrial records in the Gulf of St. Lawrence.

While on the cruise, I logged piston cores and examined the lithologies of large (1t) IKU grab samples from the till units in the Gulf of St. Lawrence that were mapped using high-resolution seismic data (Stea 1991). Much of that lithic data was not presented in the summary paper by Josenhans and Lehman (1999), which is unfortunate because of its important ramifications for ice reconstructions. The lithic data and terrestrial radiocarbon dates from the surrounding land areas imply a much greater thickness and extent of late-glacial ice than in the model presented by Josenhans and Lehman (1999). I will briefly review the pebble lithological results, addressing the questions of ice-flow paths and ice thickness, then discuss contradictions between the Josenhans–Lehman model of deglaciation of the Gulf of St. Lawrence and the Stea et …