GEOMORPHIC HISTORY DETERMINED FROM CORING AT AN ARCHAEOLOGICALLY SENSITIVE SITE ALONG THE WYNANTS KILL, TROY, NY

Data from drilling, trenching, shovel test pits and a geomorphology survey were combined to interpret the geomorphic history and landscape development associated with an archaeological site along the lower Wynants Kill. Concern for sensitive archaeological deposits necessitated alternative methodologies. The site was beneath a wedge of iron-rich fill that limited usefulness of some remote sensing methodologies. Consequently, drilling at 12 locations using a hollow stem auger was done.

Our goal was to delineate the extent of a T3 fluvial terrace that contains Pre-Contact artifacts. Multiple cross sections were constructed approximately perpendicular to the Wynants Kill to discern the lateral extent of the buried terrace. Analysis of 6 cross sections provided a detailed view of the bedrock surface and overlying sediment. Three lower terraces - T3a, T2 and T1 - were recognized and formed by Holocene downcutting of the Wynants Kill. The creek stepped down and migrated north to its present position. The stratigraphy of each package of terrace sediment was a typical fining upwards sequence of alluvium 1-3 meters thick and a preserved soil profile often containing a distinct A horizon was revealed in the cores. A basal coarser grained channel to bar facies was overlain by a finer overbank flood plain facies. The lateral extent of the artifact-bearing T3-T3a terrace set was determined from the drilling program. We used this information to formulate specific recommendations for the proposed development and future archaeological investigations. The geomorphological study proved very useful in the interpretation of the archaeological deposits.

South of the site, the topography steps up to the T4 or highest terrace associated with the Wynants Kill and the flank of a hill as seen on older topographic maps. The hill has the appearance of a drumlin but reconnaissance mapping revealed the hill to be composed of rhythmically bedded glaciolacustrine silt-clay from Lake Albany I and II. During later Lakes Coveville and Fort Ann time, the project area experienced high discharge flows and events that eroded the sediment cover and left the hill as an erosional remnant. There is a distinct channel that carried a part of this high discharge flow to the east of the project area completing the hydrodynamic shape of the hill.