Final Wisconsinan glaciation of the Wallkill Valley was accomplished by the Wallkill Valley lobe that advanced as far south as the Ogdens-burg-Culvers Gap moraine in New Jersey. As the ice margin retreated northward to the Pellets Island and New Hampton moraines, a proglacial lake was impounded with an outlet at 500 ft. Next, the ice margin retreated to the Wallkill moraine and a new lake outlet was established at 400 ft. Kettle ice in the New Hampton moraine then melted and drained into the 400 ft lake, and pollen sedimentation in New Hampton Bog No. 1 commenced.

Analysis of the pollen spectra in New Hampton No. 1 indicates the presence of pollen subzones that are correlated with dated sequences in southern New England and southern New York. Correlation with the Herb Pollen Zone is based on the presence of cold climate indicator pollen even though nonarboreal pollen (NAP) comprises only 11 percent of the spectrum. A radiocarbon date of 12,850 ± 250 years B.P. between the A1-A2 and A3 subzones confirms correlation and suggests that sedimentation in the T1 subzone began about 15,000 years B.P. Using the most recent sedimentation rate for Rogers Lake, the basal sediments are calculated to be 14,850 yrs old. A spruce rise in the T2 subzone is tentatively correlated with the Rosendale re-advance in the Hudson Valley and the Middle-town re-advance in Connecticut.

The initial advance into the Wallkill Valley is correlated with the early Woodfordian Kent glaciation of Ohio, Pennsylvania, and western New York. The mid-Woodfordian recessional deposits probably correlate in part with the Valley Heads drift of western New York.

First Page Preview

First page PDF preview
You do not currently have access to this article.