CT ECO Basic Data Guide

Quaternary Geology

Example of Quaternary Geology

Description

Quaternary Geology is 1:24,000-scale data that illustrates the geologic features formed in Connecticut during the Quaternary Period, which spans from 2.588 ± 0.005 million years ago to the present and includes the Pleistocene (glacial) and Holocene (postglacial) Epochs. The Quaternary Period has been a time of development of many details of the Connecticut landscape and all surficial deposits. At least twice in the last Pleistocene, continental ice sheets swept across Connecticut from the north. Their effects are of pervasive importance to present-day occupants of the land.

The Quaternary Geology information illustrates the geologic history and the distribution of depositional environments during the emplacement of unconsolidated glacial and postglacial surficial deposits and the landforms resulting from those events in Connecticut. These deposits range from a few feet to several hundred feet in thickness, overlie the bedrock surface and underlie the organic soil layer of Connecticut. Quaternary Geology is mapped without regard for any organic soil layer that may overly the deposit.

For additional documentation including a description of the unconsolidated glacial and postglacial surficial deposits shown on the map, refer to the CT ECO Complete Resource Guide for Quaternary Geology.

The Connecticut Quaternary Geology information was initially compiled at 1:24,000 scale (1 inch = 2,000 feet) then recompiled for a statewide 1:125,000-scale map, Quaternary Geology Map of Connecticut and Long Island Sound Basin (PDF, 56 Mb) 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, and pamphlet, 71 p. A companion map, the Surficial Materials Map of Connecticut (PDF, 26 Mb) Stone, J.R., Schafer, J.P., London, E.H., DiGiacomo-Cohen, M.L., Lewis, R.L., and Thompson, W.B., 2005, U.S. Geological Survey Scientific Investigation Map 2784, 2 sheets, scale 1:125,000, emphasizes the surface and subsurface texture (grain-size distribution) of these materials. The quaternary geology and surficial material features portrayed on these two maps are very closely related; each contributes to the interpretation of the other.

Purpose

Connecticut Quaternary Geology is 1:24,000-scale data suitable for geologic and environmental mapping and analysis purposes. It is not intended for maps printed at map scales greater or more detailed than 1:24,000 scale (1 inch = 2,000 feet). The 1:24,000-scale Quaternary Geology features and the 1:24,000-scale Surficial Material features are very closely related; each contributes to the interpretation of the other. The Quaternary Geology data is complemented by the Surficial Geology data in that the grain-size distribution (texture) of individual Quaternary Geology deposits is defined and described the Surficial Materials data. For example, the Surficial Materials data specifies the texture (grain size) for a given Quaternary Geology Sediment of Dammed Pond deposit as either comprised of Sand, Gravel, Sand and Gravel, Sand and Gravel overlying Sand, Sand overlying Sand and Gravel, Sand overlying Fines, or another similar combination. Not all Quaternary Geology deposits exhibit the same grain size.

Quaternary Geology Map of Connecticut and Long Island Sound Basin (PDF, 56 Mb) provides information on the geologic history and the distribution of depositional environments during the emplacement of unconsolidated glacial and postglacial surficial deposits and the landforms resulting from those events in Connecticut, whereas the Surficial Materials Map of Connecticut (PDF, 26 Mb) emphasizes the surface and subsurface texture (grain-size distribution) of these materials.

Use Limitations

Quaternary Geology is not intended for maps printed at map scales greater or more detailed than 1:24,000 scale (1 inch = 2,000 feet.). It is not intended for analysis with other digital data compiled at scales greater or more detailed than 1:24,000 scale. This information is based on 7.5 minute U.S. Geological Survey 1:24,000-scale topographic quadrangle maps with a 10-ft contour interval. Surficial geologic maps exist in various forms (either published, open-filed, or unpublished) for 98 quadrangles. The authors of the Quaternary Geology Map of Connecticut and Long Island Sound Basin (PDF, 56 Mb) reviewed all of these maps, and did reconnaissance mapping in the remaining quadrangles. In the course of compiling this large body of data to create both the statewide Surficial Materials Map and the statewide Quaternary Geology Map, the authors applied a consistent interpretive rationale; the result is that, in some cases, the original studies have been reworked or revised.

Dataset Information

Additional Documentation

Originators

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