FIELD EVIDENCE FOR READVANCES – THE LUZERNE EXAMPLE

Connally and Cadwell (2002) depict a Luzerne readvance margin that includes much of Washington County, NY, to the 3000ft Taconic summits along the NY-VT border. No readvance is shown in the Mettawee and Vermont Valleys of southwestern VT although glaciological considerations make this likely. My mapping in VT and NY does NOT support this readvance (De Simone, 2007, 2005, 2004, 2001, 1985). There are no exposures of deformed sediment with evidence of ice override. The readvance ended in an east-west segment of the Batten Kill Valley but no evidence for ice override exists here. There is no “plethora of stagnant ice features probably left by wasting ice” from the readvance. There is no evidence of “forced drainage eastward into the Batten Kill drainage system.”

The Luzerne hypothesis suggests ice obliterated earlier Lake Albany (AB) deposits yet left no readvance till. It is more plausible the higher waters of Lake Albany were never present since the lake lowered to Quaker Springs (QS). Furthermore, higher northern Hudson Valley deltas positively correlate to QS, not to AB.

The Hidden Valley moraine is the western limit of readvance; there are no cited exposures to document ice override. Nearby outwash and kame terraces are considered the result of stagnation zone retreat. Could these deposits mark simple recession of H-C ice, not a western limit of readvance?

The type sections of the Luzerne have been interpreted as middle and late Wisconsinan tills separated by lacustrines (Woodworth, 1905). My study suggests sediment flow diamictons as another alternative interpretation. Thus, the body of evidence does not support the occurrence of a Luzerne readvance.

Interpreted glacial history in the Hudson-Champlain (H-C) lowlands has traditionally included readvance hypotheses such as the 20km Rosendale, 48km Middleburg, 32km Delmar, 50km Luzerne and the Bridport. These hypotheses have often been accepted rather than severely tested. C-14 dates from “readvance” moraines constrain ice retreat but these moraines may represent still stands in retreat of the H-C lobe, not limits of readvances. Readvances should be positively correlated to the paleoclimatic record documented by marine and ice core data. Testing of other readvance hypotheses is warranted to produce a better understanding of H-C ice retreat, including any surges.