In the master core (S-2009) basal sandy silt (till) is overlain by reddish-brown
varved clay (core depth 745-708 cm) in which 29 annual varves were identified (Fig.
Comments: The site is on a deep
varved clay deposit (Connecticut Valley
Varved Clay) on the University of Massachusetts, Amherst campus.
(2005) recorded an only 4.5 m thick
varved clay layer between the Warthanian (Late Saalian) till and the Eemian sediments in the Licze core in northern Poland.
Consequently, the formation of bottom deposits may have been influenced by currents and wave activity, but the erosion areas are located near the deposition area--inside the bay (till and
varved clay exposed on the seafloor) or on bordering peninsulas (bedrock).
Within 1.5 km north of the city boundary, 2-3 m thick lenses of
varved clay were found in the lower part of the sand layer.
Fine sand, silt, and
varved clay, typical of ice lakes, facilitated drawing up the contours of ancient lakes (Fig.
Proglacial
varved clay is outcropping in the northern part of the lake bottom.
In the southern part of the lake glaciolacustrine
varved clay was not distinguished within the corings (Fig.
The lowermost unit A consists of brownish-grey proglacial
varved clay which lies on top of Late Weichselian till.
Laminated clayey deposits (Photo 1E) or brecciated
varved clay inclusions and coarse-clastic diamicton lenses are found in this depositional unit.
Studies of
varved clays in West Virginia by Janssen and McCoy (1953) placed the minimum duration of Lake Tight at 6,500 years.
Van Asch, "Factors controlling the movement of a landslide in
varved clays near La Mure (French Alps)," Bulletin de la Societe Geologique de France, vol.