Surficial deposits and materials in the eastern and central United States (east of 102 degrees west longitude)

Metadata Updated: May 1, 2019

The surficial geologic map of the Eastern and Central United States depicts the areal distribution of surficial geologic deposits and other materials that accumulated or formed during the past 2+ million years, the period that includes all activities of the human species. These materials are at the surface of the earth. They make up the "ground" on which we walk, the "dirt" in which we dig foundations, and the “soil” in which we grow crops. Most of our human activity is related in one way or another to these surface materials that are referred to collectively by many geologists as regolith, the mantle of fragmental and generally unconsolidated material that overlies the bedrock foundation of the continent. The map is based on 31 published maps in the U.S. Geological Survey's Quaternary Geologic Atlas of the United States map series (U.S. Geological Survey Miscellaneous Investigations Series I-1420). It was compiled at 1:1,000,000 scale, to be viewed as a digital map at 1:2,000,000 nominal scale and to be printed as a conventional paper map at 1:2,500,000 scale. This map is not a map of soils as recognized and classified in agriculture. Rather, it is a generalized map of soils as recognized in engineering geology, or of substrata or parent materials in which agricultural, agronomic, or pedologic soils are formed. Where surficial deposits or materials are thick, agricultural soils are developed only in the upper part of the engineering soils. Where they are very thin, agricultural soils are developed through the entire thickness of a surficial deposit or material. The surficial geologic map provides a broad overview of the areal distribution of surficial deposits and materials. It identifies and depicts more than 150 types of deposits and materials. In general, the map units are divided into two major categories, surface deposits and residual materials. Surface deposits are materials that accumulated or were emplaced after component particles were transported by ice, water, wind, or gravity. The glacial sediments that cover the surface in much of the northern United States east of the Rocky Mountains are in this category, as are the gravel, sand, silt, and clay that were deposited in past and present streams, lakes, and oceans. In contrast, residual materials formed in place, without significant transport of component particles by ice, water, wind, or gravity. They are products of modification or alteration of pre-existing surficial deposits, surficial materials, or bedrock. For example, intense weathering of solid rock, or even stream deposits, by chemical processes may produce a residual surficial material that is greatly transformed from its original physical and chemical state. In recent years, surficial deposits and materials have become the focus of much interest by scientists, environmentalists, governmental agencies, and the general public. They are the foundations of ecosystems, the materials that support plant growth and animal habitat, and the materials through which travels much of the water required for our agriculture, our industry, and our general well being. They also are materials that easily can become contaminated by pesticides, fertilizers, and toxic wastes. In this context, the value of the surficial geologic map is evident The map and its digital database provide information about four major aspects of the surficial materials, through description of more than 150 types of materials and depiction of their areal distribution. The map unit descriptions provide information about (1) genesis (processes of origin) or environments of deposition (for example, deposits related to glaciation (glacial deposits), flowing water (alluvial deposits), lakes (lacustrine deposits), wind (eolian deposits), or gravity (mass-movement deposits)), (2) age (for example, how long ago the deposits accumulated or were emplaced or how long specific processes have been acting on the materials), (3) properties (the chemical, physical, and mechanical or engineering characteristics of the materials), and (4) thickness or depth to underlying deposits or materials or to bedrock. This approach provides information appropriate for a broad user base. The map is useful to national, state, and other governmental agencies, to engineering and construction companies, to environmental organizations and consultants, to academic scientists and institutions, and to the layman who merely wishes to learn more about the materials that conceal the bedrock. The map can facilitate regional and national overviews of (1) geologic hazards, including areas of swelling clay and areas of landslide deposits and landslide-prone materials, (2) natural resources, including aggregate for concrete and road building, peat, clay, and shallow sources for groundwater, and (3) areas of special environmental concern, including areas of intense erosion and areas of potential contamination of soil and groundwater. The map also includes lines depicting the maximum limits of glacial advance during selected time periods.

Access & Use Information

License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

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Metadata Date June 13, 2016
Metadata Created Date May 1, 2019
Metadata Updated Date May 1, 2019
Reference Date(s) January 1, 2003 (publication)
Frequency Of Update asNeeded

Metadata Source

Harvested from DOI CKAN Harvest Source

Graphic Preview

Reduced-size image of the entire map sheet, 400x383 pixels, 87k bytes

Additional Metadata

Resource Type Dataset
Metadata Date June 13, 2016
Metadata Created Date May 1, 2019
Metadata Updated Date May 1, 2019
Reference Date(s) January 1, 2003 (publication)
Responsible Party U.S. Geological Survey (Point of Contact)
Contact Email
Access Constraints Use Constraints: None. Acknowledgment of the U.S. Geological Survey will be appreciated in products derived from these data., Access Constraints: None
Bbox East Long -66.955
Bbox North Lat 49.386
Bbox South Lat 24.518
Bbox West Long -102.000
Coupled Resource
Frequency Of Update asNeeded
Graphic Preview Description Reduced-size image of the entire map sheet, 400x383 pixels, 87k bytes
Graphic Preview File
Graphic Preview Type GIF
Harvest Object Id b4a4f18b-030b-4956-b60e-b8e31c98396f
Harvest Source Id 34ce571b-cb98-4e0b-979f-30f9ecc452c5
Harvest Source Title DOI CKAN Harvest Source
Licence Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made by the U.S. Geological Survey regarding the utility of the data on any other system, nor shall the act of distribution constitute any such warranty. No responsibility is assumed by the U.S. Geological Survey in the use of these data.
Metadata Language
Metadata Type geospatial
Progress completed
Spatial Data Service Type
Spatial Reference System
Spatial Harvester true
Temporal Extent Begin 1998-03-01
Temporal Extent End 2000-06-01

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