Late Wisconsinan Mountain Glaciation in the Northern Presidential Range, New Hampshire

New field evidence from the White Mountains of New Hampshire supports a proposed late Wisconsinan phase of combined alpine and continental glaciation. A till sheet mantling the lower north slopes of the Presidential Range is of unquestionable southerly provenance and can be traced from its source in three north-opening cirques. No cirque moraines were found, but in the adjacent lowlands, low elevation moraines, ice-contact terrains, proglacial lake sediments, and till provenance suggest that active cirque glaciation was coincident with the nunatak phase of continental ice retreat. Calculations based on theoretical late Wisconsinan ice-sheet profiles and a reasonable rate of ice-front retreat yield a rough estimate of 500 yr for the duration of the proposed nunatak phase of combined glaciation. This model accommodates evidence cited by both proponents and opponents of late Wisconsinan cirque glaciation in the White Mountains, and thus offers a resolution of this long-standing controversy in the Quaternary glacial history of New England.