In the early VCGI study and mapping in the Memphremagog Basin an active ice margin represented by numerous Ice Marginal Channels was identified and distinguished from an associated stagnant ice margin, both in relatively close proximity, the former at an elevation slightly above the latter. Further, the evidence indicates, as discussed elsewhere and as just suggested, that recession of the active ice margin at some times and locations took place to a new and lower position at an elevation slightly below the stagnant ice margin, while this stagnant margin was still developing (likely due to the insulating property of sediment cover associated with stagnant ice deposits), with meltwater from the stagnant margin draining downgradient to the new active ice margin, where it was diverted along the new active ice margin as a Drainage Line. As previously mentioned, this indicates a complex temporal and spatial relationship between active and stagnant ice margins and led to the concept of a “hybrid” margin, and a Style condition referred to as “Everything, Everywhere, All at Once and Continuing.” This is an intentional play on words to signify the extraordinary complexity. Similar hybrid margins have been identified elsewhere, notably for example in the vicinity of the mouth of the Winooski Basin, which likewise is spatially and temporally complex.
It is believed that all T levels and times were “hybrid margins,” which is to say that they all include both active and stagnant ice margins portions, but the nature of the markings and the inter-relationships of these features varied greatly. However, in many places the information is insufficient to individually recognize and delineate such hybrid components and therefore to recognize and parse such temporal and spatial relationships.The distinction between active ice margins versus stagnant ice margins is important to the deciphering of deglacial history as reported here.