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National Geologic Map Database

The National Geologic Map Database is collaborating with State Geological Surveys, to provide assistance in addressing local and regional stratigraphic nomenclature issues within a State, and between adjacent States. Our goals are to: (1) support reexamination of each State's stratigraphic column(s); (2) encourage scientific discussion among States that may lead to changes in nomenclature and(or) agreement on stratigraphic equivalence across State boundaries; (3) facilitate publication of changes in stratigraphic nomenclature and detailed descriptions of the geology; and (4) support development of long-term management of stratigraphic information that will benefit future research and applications.

Start year and lead agency Title
2020 -- Delaware Geological Survey MAtStrat I: Middle Atlantic Coastal Plain stratigraphic correlations -- Delaware, Maryland, New Jersey, and Virginia
2020 -- Oregon Department of Geology and Mineral Industries Oregon stratigraphic compilation
2021 -- Geological Survey of Alabama East Gulf Coastal Plain stratigraphic correlations -- Alabama, Florida, and Mississippi
2021 -- Delaware Geological Survey MAtStrat II: Stratigraphic correlations in the coastal aquifer systems of the Middle Atlantic Coastal Plain (late Miocene to early Pleistocene) -- Delaware, Maryland, New Jersey, and Virginia
2021 -- Kansas Geological Survey Pennsylvanian stratigraphic correlations in the Midcontinent -- Iowa, Kansas, Missouri, Nebraska, and Oklahoma
2021 -- Kentucky Geological Survey Categorizing and documenting geologic map discontinuities
2021 -- Maine Geological Survey Identifying stratigraphic problems in New England
2021 -- Pennsylvania Geological Survey Building a modern stratigraphic framework for Pennsylvania
2022 -- Geological Survey of Alabama Northern Gulf of Mexico Basin stratigraphic correlations -- Alabama, Arkansas, Louisiana, Mississippi, Tennessee, and Texas
2023 -- South Carolina Geological Survey Southeastern Atlantic Coastal Plain stratigraphic correlations -- Florida, Georgia, North Carolina, South Carolina, and Virginia
2023 -- Illinois State Geological Survey Mesozoic and Cenozoic stratigraphic correlations in the northern part of the Mississippi Embayment -- Illinois, Kentucky, and Missouri
2023 -- Delaware Geological Survey MAtStrat data framework: Documenting Middle Atlantic Coastal Plain stratigraphic research and data management -- Delaware, Maryland, New Jersey, and Virginia


MAtStrat I: Middle Atlantic Coastal Plain stratigraphic correlations -- Delaware, Maryland, New Jersey, and Virginia
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Brief description

The Delaware Geological Survey (DGS) is leading a multi-state, multi-organization initiative aimed at establishing a regional understanding of the equivalencies of formation names across state lines in the Middle Atlantic Coastal Plain province (New Jersey-Delaware-Maryland-Virginia). This project, the Middle Atlantic Coastal Plain Stratigraphic Reconciliation Initiative or "MAtStrat", was developed as a cooperative effort of regional experts from state geological survey organizations, water resource agencies, universities, and the USGS. The DGS has established an informal Middle Atlantic Coastal Plain Stratigraphy Working Group and coordinated workshops to identify important questions of stratigraphic equivalency between the states and to develop plans to resolve those questions. The results of the project are expected to benefit surficial geological mapping efforts in the region as well as the management of groundwater resources. Mapping will be improved by resolution of longstanding issues of formation name equivalencies at state boundaries where surficial geological maps created by different agencies can appear to conflict. Understanding of the connectivity of aquifer systems beneath these states will be improved as we clarify the equivalency of geologic names for groundwater-bearing formations between the states. Products under development include correlation charts, regional cross sections, an extensive collaborative data store, documentation of methodologies, and a summary report.

Proposals, reports, and related information:


Oregon stratigraphic compilation
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Brief description

The published Oregon Geologic Data Compilation (OGDC) is not a traditional compilation map with consistent linework and geologic units across the state. Instead, it is a variable-scale collage of the best-available geologic mapping within the state, with their original linework and units retained. The current version, OGDC-7, mosaics 342 source maps with 7,240 source-map units. Source-map units are classified into a terrane/group–formation–member–unit hierarchy and assigned values of rock type, age, and lithology that results in more than 2,000 unique compilation units.

This DOGAMI-USGS co-op project is developing a consistent stratigraphic framework for all 2,000 units in OGDC-7, thereby making this compilation far more useful. We are establishing regional and statewide stratigraphic correlations and producing time-rock charts for the entire state. We will reduce the terrane/group –formation –member–unit hierarchy to about 500 unique formation-level names statewide. This includes assigning formal or informal formation-level names to source-map units that are classified only at the terrane/group level in OGDC-7. We are building time-rock charts at the formation level for NW Oregon, SW Oregon, the Cascade Mountains, NE Oregon, and SE Oregon, and a single chart at the terrane/group level for the state.

Proposals, reports, and related information


East Gulf Coastal Plain stratigraphic correlations -- Alabama, Florida, and Mississippi
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Brief description

The Geological Survey of Alabama is coordinating an East Gulf Coastal Plain Stratigraphic Working Group that will allow participating entities to cooperatively develop a consistent regional stratigraphic nomenclatural framework and advance USGS and State Geological Survey goals such as applicability to petroleum and groundwater issues. The Working Group will create and publish updated regional stratigraphic charts and cross sections.

Proposals, reports, and related information


MAtStrat II: Stratigraphic correlations in the coastal aquifer systems of the Middle Atlantic Coastal Plain (late Miocene to early Pleistocene) -- Delaware, Maryland, New Jersey, and Virginia
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Brief description

As a result of the initial finding of the MAtStrat I Cooperative, the Delaware Geological Survey conducted a MAtStrat II project to address unresolved issues in the stratigraphically complex late Miocene to early Pleistocene sediments in Middle Atlantic Coastal Plain from southeastern Virginia to Cape May, New Jersey. These strata contain important aquifers that are used by public water systems, agriculture, industry, and household consumers in the region, including growing municipalities with large summer tourist populations located along the Atlantic Coast. The project goal was to examine in detail all available core and sample material in the area to develop a regional stratigraphic framework of the units. This was accomplished by 1) collection of all available stratigraphic data both published and unpublished, 2) identification of available core material, 3) construction of regional cross sections, 4) a multi-state workshop to refine the cross sections and correlations, and 5) identification of additional work needed. Drilling was undertaken to address data gaps in critical areas. A 470-foot continuous wireline corehole was drilled in the middle of the region near Berlin, Maryland. Split-spoon coreholes were drilled further north nearer the Maryland-Delaware border and further south at the Maryland-Virginia border. Combined with the compilation of older data, the new cores clarify the nature of the north-to-south stratigraphic changes in this part of the study area. In addition, the project served as an excellent opportunity to train university students in methods to describe sediment in detail, and to familiarize them with drilling techniques.



Pennsylvanian stratigraphic correlations in the Midcontinent -- Iowa, Kansas, Missouri, Nebraska, and Oklahoma
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Brief description

The midcontinent region of the United States (Kansas, Oklahoma, Missouri, Nebraska, and Iowa) has been a natural laboratory for the development of stratigraphic methods over the last 120+ years. This rich, long history has produced a voluminous literature that has been of great benefit to regional mining, aggregate, and petroleum industries. Unfortunately, however, the use, definition, and stratigraphic position of many Pennsylvanian rock units has varied between States and frequently changed through time, resulting in complexity and confusion in terms of stratigraphic nomenclature, correlation, and geologic mapping. The goal of this project was to develop a unified, regional understanding of Pennsylvanian stratigraphy across State boundaries. In order to achieve this goal, a regional working group, organized by the Kansas Geological Survey, was established. The group is composed of experts from geological surveys and academic institutions in Kansas, Missouri, Nebraska, Oklahoma, and Iowa.

Proposals, reports, and related information
  • Nomenclatural history of Pennsylvanian strata in Kansas (KGS Open-file Report 2022-5 or NGMDB page)
  • Lithostratigraphic Correlations of the Upper Desmoinesian and Missourian Stages (Pennsylvanian) in Eastern Kansas (KGS Open-file Report 2022-3)


Categorizing and documenting geologic map discontinuities
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Brief description

The Kentucky Geological Survey is identifying and categorizing stratigraphic discontinuities across map boundaries, and recommending if and how these discontinuities should be dealt with. A documentation protocol for geologic map discontinuities in digital geologic map compilations will be developed, using Kentucky's statewide 1:24,000 digital geologic map as the foundation of the effort.



Identifying stratigraphic problems in New England
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Brief description

Ongoing study of the New England Appalachians continues to improve our understanding of the regional tectonic framework. While the basic concept of New England as a Paleozoic plate tectonic collision zone was established in the 1970's, recent advances in high-precision geochronology have allowed workers to recognize an increasingly complex array of continental fragments, microcontinents, island arcs, sedimentary basins, and other stratigraphic elements that are now incorporated in an intricately deformed, repeatedly metamorphosed, and highly intruded orogenic system.

The six New England states are currently represented by state bedrock maps that were compiled at different scales by different authors at different times ranging from 1983 to 2011. Each map not only represents the state of knowledge at the time it was made, but also is a reflection of the tectonic framework as understood by the compilers. For these reasons there are inconsistencies of many types across state boundaries. In addition, more recent detailed work has shown places in every state where the maps need to be updated.

Before attempting to launch an effort to address some of the hundreds of regional and local stratigraphic issues that have accumulated over the past 40 years, this initial collaborative project of the New England States Geologic Mapping Coalition (NESGMC) seeks to review the existing state of knowledge and understanding, identify areas where we can see that regional and local stratigraphic problems exist, especially ones that affect cross-border areas, and offer recommendations for addressing them. The goal will be to provide a context for guiding meaningful stratigraphic research.

Proposals, reports, and related information


Building a modern stratigraphic framework for Pennsylvania
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Brief description

The Pennsylvania Geological Survey has completed the initial compilation of the Pennsylvania Universal Bedrock Geologic Units Table through an in-depth literature review of current formal and informal bedrock geologic units that appear on agency maps and reports. The review revealed previous inconsistencies that had yet to be resolved and new inconsistencies that had not yet been discovered. Following an internal review of these discrepancies, feedback from the geologic community was sought. Through this continuous open discussion with professionals throughout the community, fostered by the survey’s stratigraphic forum series, the inconsistencies in nomenclature and correlation across Pennsylvania were addressed. This project provided the opportunity to identify areas, both geographically and stratigraphically, in which knowledge is generally lacking. While quick resolutions were sometimes possible, many questions were more complex and will ultimately require additional research or field work. The ability to pinpoint the areas in which understanding is lacking will help to guide future research at the survey. The continuation of the modernization of Pennsylvania’s stratigraphic framework include pinpointing the area of the State, or the general location, in which each unit can be found (geographic extent) and continuing to work through the stratigraphic column into younger units, including unconsolidated deposits.

The results of this project will provide the foundation on which to build a series of updated stratigraphic columns for regions of the state. The results also provide a framework for the Pennsylvania Geological Survey plans to build an inventory of outcrop and subsurface core sections that will allow geologists to examine representative examples of the formations in different regions. The nomenclature changes recommended as a result of this investigation will be formalized through publication of geological reports or documentation through USGS's Professional Paper series "Stratigraphic Notes". All nomenclature updates will be delivered to NGMDB for inclusion in Geolex. The information that comprises the new stratigraphic framework will be released to the public through Pennsylvania Geologic Data Exploration (PaGEODE) website.



Northern Gulf of Mexico Basin stratigraphic correlations -- Alabama, Arkansas, Louisiana, Mississippi, Tennessee, and Texas
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Brief description

The Geological Survey of Alabama is leading the extension of its East Gulf Coastal Plain initiative, to focus on stratigraphic units in the West Gulf Coastal Plain, including deposits in the Mississippi Embayment. Significant outcrop and subcrop differences in Mesozoic and Cenozoic strata are present throughout the stratigraphic section in these regions that comprise the northeastern, central, and western part of the northern Gulf of Mexico basin and these are reflected in the different nomenclature used by each state.

An initial workshop was convened in Baton Rouge, LA, by members of the working group that included representatives from each of the state participants. Working group discussions focused on the overall project goals, the status of the East Gulf Coast Stratigraphic Initiative and Working Group investigations and methodology, ongoing stratigraphic investigations in each state, ideas on specific stratigraphic intervals in contention, and state participant's needs in order to accomplish the goals. It was agreed that a second workshop would be convened during Fall of 2023 to discuss progress, identify additional units of contention and agreement, and to discuss any problems or issues that have arisen during the project. An additional workshop may be held in southern Arkansas in the Spring of 2024 to follow up on the Fall meeting items and to visit type section outcrops in the area.



Southeastern Atlantic Coastal Plain stratigraphic correlations -- Florida, Georgia, North Carolina, South Carolina, and Virginia
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Brief description

The South Carolina Geological Survey is leading a Southeastern Atlantic Coastal Plain working group, to include the geological surveys of Virginia, North Carolina, South Carolina, and Florida. Representation from Georgia will come from interested universities. The purpose is to address stratigraphic issues, in part to facilitate the orderly development of interstate stratigraphic correlations.



Mesozoic and Cenozoic stratigraphic correlations in the northern part of the Mississippi Embayment -- Illinois, Kentucky, and Missouri
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Brief description

The Illinois State Geological Survey will develop a unified geological nomenclature of the Midcontinent stratigraphy of the Coastal Plains province of Illinois, Kentucky and Missouri. Outcrop and subcrop differences in nomenclature from Mesozoic and Cenozoic strata are present throughout the stratigraphic sections of the upper Mississippi Embayment region of southern Illinois, southeastern Missouri, and western Kentucky. The project will convene a Midcontinent Coastal Plains Province working group, managed by the Illinois State Geological Survey and comprised of stratigraphic experts from the three states, to address interstate stratigraphic frameworks, terminology discrepancies, and resolve 'state-line faults'.



MAtStrat data framework: Documenting Middle Atlantic Coastal Plain stratigraphic research and data management -- Delaware, Maryland, New Jersey, and Virginia
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Brief description

The Delaware Geological Survey will be documenting and sharing the data framework used for the two previous MAtStrat Cooperative Agreements. The project has two goals: 1) to document how MAtStrat data and information types were collected, organized, and stored, and 2) to transform the project data framework into a collaborative data-sharing hub for Middle Atlantic Coastal Plain stratigraphic equivalency researchers that provides access to data assembled during the MAtStrat project and standards for addition of future data.


Questions? Please contact the NGMDB.