These deposits originate from glacial meltwater, either deposited by streams, through settling in glacial lakes or in glacial marine environments. Stratified drift deposits are commonly located in major river valleys, where glacial meltwater drainage channels have persisted into modern times, and in dry valleys more common in the uplands where the deposits are remnants of ancient glacial drainage. These deposits are primarily comprised of one or more vertically stacked units of gravel, sand, and fine-grained deposits known as fines. For example, a coarse-grained stratified drift deposit can be comprised of solely gravel or gravel on the surface overlying sand below (e.g. vertically stacked).
Connecticut Stratified Drift is derived from the Surficial Aquifer Texture compilation extracted from the Surficial Materials Map of Connecticut (Stone et al 1992). Areas of surficial aquifer texture defined as coarse grained deposits either on the surface or in the subsurface are combined to create a single, coarse-grained stratified drift mapping unit. Stratified drift as coarse grained fluvial deposits, are variably sorted, and may or may not have a strongly layered appearance. Areas of surficial aquifer texture defined as fine grained deposits either on the surface or in the subsurface are combined to create a single, fine-grained stratified drift mapping unit.
Course-Grained stratified drift deposits include the Coarse and the Fine overlying Coarse surficial texture classes. The Coarse texture class is comprised of the following surficial material deposits: Sand, Gravel, Sand and Gravel, Alluvium overlying Sand, Alluvium overlying Sand and Gravel, Alluvium overlying Sand and Gravel overlying Sand, Gravel overlying Sand, Gravel overlying Sand and Gravel, Gravel overlying Sand and Gravel overlying Sand, Sand and Gravel overlying Sand, Sand and Gravel overlying Sand overlying Sand and Gravel, Sand overlying Gravel, Sand overlying Sand and Gravel, Swamp overlying Sand, Swamp overlying Sand and Gravel, Swamp overlying Sand overlying Sand and Gravel. The Fine overlying Coarse surficial texture class is comprised of the following surficial material deposits: Alluvium overlying Fines overlying Gravel, Alluvium overlying Fines overlying Sand, Alluvium overlying Fines overlying Sand and Gravel, Fines overlying Gravel, Fines overlying Sand, Fines overlying Sand and Gravel, Sand and Gravel overlying Fines overlying Sand and Gravel, Sand overlying Fines overlying Sand and Gravel, Swamp overlying Fines overlying Sand.
Fine-Grained stratified drift deposits include the Fines and the Coarse overlying Fines surficial texture classes. The Fines texture class is comprised of the following surficial material deposits: Fines, Alluvium overlying Fines, Salt Marsh overlying Fines, and Swamp overlying Fines. The Coarse overlying Fine surficial texture class is comprised of the following surficial material deposits: Alluvium overlying Sand and Gravel overlying Fines, Alluvium overlying Sand and Gravel overlying Sand overlying Fines, Alluvium overlying Sand overlying Fines, Gravel overlying Fines, Gravel overlying Sand overlying Fines, Salt Marsh overlying Sand overlying Fines, Sand and Gravel overlying Fines, Sand and Gravel overlying Sand overlying Fines, Sand overlying Fines, Swamp overlying Sand overlying Fines.
The Surficial Aquifer Texture Map was prepared from the Surficial Materials Map of Connecticut (Stone, J.R., Schafer, J.P., London, E.H. and Thompson, W.B., 1992, U.S. Geological Survey special map, 2 sheets, scale 1:125,000) to describe unconsolidated areas of the subsurface with similar properties relative to ground water flow. Surficial aquifers are unconsolidated geologic deposits capable of yielding a sufficient quantity of groundwater to wells. Surficial aquifer textures were identified from original surficial materials mapping for use in ground water applications. These are qualitative interpretations of material properties relative to groun
