The Northeast Bedrock Mapping Project consists of scientists conducting geologic mapping and scientific research of complexly deformed crystalline igneous and metamorphic rocks in the Northeastern United States. Current mapping activities are focused in New Hampshire, Vermont, Connecticut, and New York. The Project produces high-quality, multi-purpose digital geologic maps and accompanying databases and reports to solve diverse problems in high-priority areas. The research is part of a Federal component of the National Cooperative Geologic Mapping Program called FEDMAP. FEDMAP geologic mapping advances nationwide geologic mapping and associated research as mandated by the National Geologic Mapping Act of 1992 (Public Law 102-285). The FEDMAP program produces world-class digital geologic maps and 3D framework models based on state-of-the art observation and scientific interpretation directed by high priority national issues.
The goal of this project is to produce high quality 1:24,000-scale bedrock geologic maps that improve our understanding of crystalline bedrock in the Northeast United States. New mapping is focused in areas where limited detailed or modern mapping exists. The new maps contribute to framework studies to help characterize the distribution or mineral resources and address outstanding questions about the tectonic evolution of mountain belts and the behavior of groundwater and groundwater contaminants in fractured rock. The large scale geologic maps include detailed fracture information that can be used to characterize the recharge potential of bedrock lithologies and identify potential pathways for groundwater and contaminant flow. Geologic mapping activities are supported by modern geochemistry and geochronology in scientifically appropriate areas.
The project concentrates its mapping activities in selected areas such that they serve a five-fold purpose: 1) conduct modern mapping for mineral resource potential, 2) answer outstanding questions on the nature and timing of the tectonic evolution and framework of metamorphic and igneous rocks, 3) improve our understanding of the distribution, flow paths, and contaminant sources of groundwater in fractured bedrock, 4) maximize the production of geologic maps and associated computer databases, and 5) educate and train a new generation of bedrock mappers.
Below are data release products associated with this project.
Data release for depth to bedrock derived from Hydrogeology of Southeastern Connecticut by Melvin (1974)
Data release for depth to bedrock from Connecticut Water Resources Bulletins
Data release for depth to bedrock from Rhode Island Water Resources Maps
Photoluminescence Imaging of Whole Zircon Grains on a Petrographic Microscope - An Underused Aide for Geochronologic Studies
Electron microprobe analyses of feldspars and petrographic, geochemical, and geochronologic data from the Hawkeye Granite Gneiss and Lyon Mountain Granite Gneiss in the Adirondacks of New York (ver. 2.0, May 2023)
Bedrock geologic map of the Crown Point quadrangle, Essex County, New York, and Addison County, Vermont
Bedrock geologic map of the Springfield 7.5- x 15-minute quadrangle, Windsor County, Vermont, and Sullivan County, New Hampshire
Bedrock geologic map of the Mount Ascutney 7.5- x 15-minute quadrangle, Windsor County, Vermont, and Sullivan County, New Hampshire
Bedrock geologic map of the Hartland and North Hartland quadrangles, Windsor County, Vermont, and Sullivan and Grafton Counties, New Hampshire
Below are publications associated with this project.
An apparent dip calculator for spreadsheets
Age and tectonic setting of the Quinebaug-Marlboro belt and implications for the history of Ganderian crustal fragments in southeastern New England, USA
Integrated geophysical imaging of rare-earth-element-bearing iron oxide-apatite deposits in the eastern Adirondack Highlands, New York
Photoluminescence imaging of whole zircon grains on a petrographic microscope—An underused aide for geochronologic studies
The refractory nature of zircon to temperature and pressure allows even a single zircon grain to preserve a rich history of magmatic, metamorphic, and hydrothermal processes. Isotopic dating of micro-domains exposed in cross-sections of zircon grains allows us to interrogate this history. Unfortunately, our ability to select the zircon grains in a heavy mineral concentrate that records the most ge
Geochronology of the Oliverian Plutonic Suite and the Ammonoosuc Volcanics in the Bronson Hill arc: Western New Hampshire, USA
U-Pb zircon geochronology by sensitive high-resolution ion microprobe–reverse geometry (SHRIMP-RG) on 11 plutonic rocks and two volcanic rocks from the Bronson Hill arc in western New Hampshire yielded Early to Late Ordovician ages ranging from 475 to 445 Ma. Ages from Oliverian Plutonic Suite rocks that intrude a largely mafic lower section of the Ammonoosuc Volcanics ranged from 474.8 ± 5.2 to 4
Geochemistry and geophysics of iron oxide-apatite deposits and associated waste piles with implications for potential rare earth element resources from ore and historic mine waste in the eastern Adirondack Highlands, New York, USA
Syn-collisional exhumation of hot middle crust in the Adirondack Mountains (New York, USA): Implications for extensional orogenesis in the southern Grenville province
Bedrock geologic map of the Littleton and Lower Waterford quadrangles, Essex and Caledonia Counties, Vermont, and Grafton County, New Hampshire
Bedrock geologic map of the Lisbon quadrangle, and parts of the Sugar Hill and East Haverhill quadrangles, Grafton County, New Hampshire
Bedrock geologic map of the Miles Pond and Concord quadrangles, Essex and Caledonia Counties, Vermont, and Grafton County, New Hampshire
A transect through Vermont’s most famous volcano – Mount Ascutney: GSNH Summer 2017 Field Trip
Reaction softening by dissolution–precipitation creep in a retrograde greenschist facies ductile shear zone, New Hampshire, USA
We describe strain localization by a mixed process of reaction and microstructural softening in a lower greenschist facies ductile fault zone that transposes and replaces middle to upper amphibolite facies fabrics and mineral assemblages in the host schist of the Littleton Formation near Claremont, New Hampshire. Here, Na-poor muscovite and chlorite progressively replace first staurolite, then gar
Below are partners associated with this project.
- Overview
The Northeast Bedrock Mapping Project consists of scientists conducting geologic mapping and scientific research of complexly deformed crystalline igneous and metamorphic rocks in the Northeastern United States. Current mapping activities are focused in New Hampshire, Vermont, Connecticut, and New York. The Project produces high-quality, multi-purpose digital geologic maps and accompanying databases and reports to solve diverse problems in high-priority areas. The research is part of a Federal component of the National Cooperative Geologic Mapping Program called FEDMAP. FEDMAP geologic mapping advances nationwide geologic mapping and associated research as mandated by the National Geologic Mapping Act of 1992 (Public Law 102-285). The FEDMAP program produces world-class digital geologic maps and 3D framework models based on state-of-the art observation and scientific interpretation directed by high priority national issues.
Arthur Merschat conducts geologic mapping of exposed bedrock outcrops along the shore of Paradox Lake in Schroon, NY. (Credit: Gregory Walsh, USGS. Public domain.) The goal of this project is to produce high quality 1:24,000-scale bedrock geologic maps that improve our understanding of crystalline bedrock in the Northeast United States. New mapping is focused in areas where limited detailed or modern mapping exists. The new maps contribute to framework studies to help characterize the distribution or mineral resources and address outstanding questions about the tectonic evolution of mountain belts and the behavior of groundwater and groundwater contaminants in fractured rock. The large scale geologic maps include detailed fracture information that can be used to characterize the recharge potential of bedrock lithologies and identify potential pathways for groundwater and contaminant flow. Geologic mapping activities are supported by modern geochemistry and geochronology in scientifically appropriate areas.
The project concentrates its mapping activities in selected areas such that they serve a five-fold purpose: 1) conduct modern mapping for mineral resource potential, 2) answer outstanding questions on the nature and timing of the tectonic evolution and framework of metamorphic and igneous rocks, 3) improve our understanding of the distribution, flow paths, and contaminant sources of groundwater in fractured bedrock, 4) maximize the production of geologic maps and associated computer databases, and 5) educate and train a new generation of bedrock mappers.
- Data
Below are data release products associated with this project.
Data release for depth to bedrock derived from Hydrogeology of Southeastern Connecticut by Melvin (1974)
This data release consists of a single ESRI shapefile, Hydrogeo_SECTpts, with geologic information from the previously published Hydrogeology of Southeastern Connecticut (Melvin, 1974). Test boring location points digitized from georeferenced area maps (1:24,000 scale) are attributed with associated well log information: town, identification numbers, altitude, depth to bottom, and remarks regardinData release for depth to bedrock from Connecticut Water Resources Bulletins
This data release consists of information from published tables in Connecticut Water Resources Bulletins (WRBs) transcribed into tabular digital format. Information about wells and test holes in the WRBs used in this data release consists of geographic location, depth to consolidated rock (bedrock depth), and depth of the well or test hole. The WRBs, published between 1966 and 1980 by the U.S. GeoData release for depth to bedrock from Rhode Island Water Resources Maps
This data release, RI_WRpts.gdb, consists of information from Rhode Island Ground-water maps published by the Rhode Island Water Resources Coordinating Board, the Rhode Island Port and Industrial Development Commission, Rhode Island Industrial Commission, and the Rhode Island Development Council; in cooperation with the U.S. Geological Survey. The point data on these maps have been digitized intoPhotoluminescence Imaging of Whole Zircon Grains on a Petrographic Microscope - An Underused Aide for Geochronologic Studies
The refractory nature of zircon to temperature and pressure allows even a single zircon grain to preserve a rich history of magmatic, metamorphic, and hydrothermal processes. Isotopic dating of micro-domains exposed in cross-sections of zircon grains allows us to interrogate this history. Unfortunately, our ability to select the zircon grains in a heavy mineral concentrate that records the most geElectron microprobe analyses of feldspars and petrographic, geochemical, and geochronologic data from the Hawkeye Granite Gneiss and Lyon Mountain Granite Gneiss in the Adirondacks of New York (ver. 2.0, May 2023)
Iron oxide-apatite (IOA) deposits of the Adirondack Mountains of New York locally contain elevated rare earth element (REE) concentrations (e.g. Taylor and others, 2019). Critical to evaluating resource potential is understanding the genesis of the IOA deposits that host the REE-rich minerals. As part of this effort, the U.S. Geological Survey (USGS) is conducting bedrock geologic mapping, geoch - Maps
Bedrock geologic map of the Crown Point quadrangle, Essex County, New York, and Addison County, Vermont
The bedrock geology of the 7.5-minute Crown Point quadrangle consists of deformed and metamorphosed Mesoproterozoic gneisses of the Adirondack Highlands unconformably overlain by weakly deformed lower Paleozoic sedimentary rocks of the Champlain Valley. The Mesoproterozoic rocks occur on the eastern edge of the Adirondack Highlands and represent an extension of the Grenville Province of Laurentia.Bedrock geologic map of the Springfield 7.5- x 15-minute quadrangle, Windsor County, Vermont, and Sullivan County, New Hampshire
The bedrock geology of the 7.5- by 15-minute Springfield quadrangle consists of highly deformed and metamorphosed Mesoproterozoic through Devonian metasedimentary and meta-igneous rocks. In the west, Mesoproterozoic gneisses of the Mount Holly Complex are the oldest rocks and form the eastern side of the Chester dome. The Moretown slice structurally overlies the Chester dome along the Keyes MountaBedrock geologic map of the Mount Ascutney 7.5- x 15-minute quadrangle, Windsor County, Vermont, and Sullivan County, New Hampshire
The bedrock geology of the Mount Ascutney 7.5- x 15-minute quadrangle consists of highly deformed and metamorphosed Mesoproterozoic through Devonian metasedimentary and meta-igneous rocks intruded by rocks of the Mesozoic White Mountain Igneous Suite. In the west, Mesoproterozoic gneisses of the Mount Holly Complex are the oldest rocks and form the northeastern flank of the Chester dome. The allocBedrock geologic map of the Hartland and North Hartland quadrangles, Windsor County, Vermont, and Sullivan and Grafton Counties, New Hampshire
The bedrock geology of the 7.5-minute Hartland and North Hartland quadrangles, Vermont-New Hampshire, consists of highly deformed and metamorphosed lower Paleozoic metasedimentary, metavolcanic, and metaplutonic rocks of the Bronson Hill anticlinorium (BHA) and the Connecticut Valley trough (CVT). Rocks of the Orfordville anticlinorium on this map occupy the western part of the broader BHA. In the - Publications
Below are publications associated with this project.
An apparent dip calculator for spreadsheets
This report and spreadsheet calculator contain Microsoft Excel-based equations that are useful in structural geology to calculate plunge or apparent dip when measuring lineations on a plane. The spreadsheet allows users to measure the trend or the plunge of a lineation and calculate the corresponding unknown value of trend or plunge. The spreadsheet provides the user with two options:Option 1: CalAuthorsGregory J. WalshAge and tectonic setting of the Quinebaug-Marlboro belt and implications for the history of Ganderian crustal fragments in southeastern New England, USA
Crustal fragments underlain by high-grade rocks represent a challenge to plate reconstructions, and integrated mapping, geochronology, and geochemistry enable the unravelling of the temporal and spatial history of exotic crustal blocks. The Quinebaug-Marlboro belt (QMB) is an enigmatic fragment on the trailing edge of the peri-Gondwanan Ganderian margin of southeastern New England. SHRIMP U-Pb geoAuthorsGregory J. Walsh, John N. Aleinikoff, Robert A. Ayuso, Robert P. WintschIntegrated geophysical imaging of rare-earth-element-bearing iron oxide-apatite deposits in the eastern Adirondack Highlands, New York
The eastern Adirondack Highlands of northern New York host dozens of iron oxide-apatite (IOA) deposits containing magnetite and rare earth element (REE)-bearing apatite. We use new aeromagnetic, aeroradiometric, ground gravity, and sample petrophysical and geochemical data to image and understand these deposits and their geologic framework. Aeromagnetic total field data reflect highly magnetic leuAuthorsAnjana K. Shah, Ryan D. Taylor, Gregory J. Walsh, Jeffrey PhillipsPhotoluminescence imaging of whole zircon grains on a petrographic microscope—An underused aide for geochronologic studies
The refractory nature of zircon to temperature and pressure allows even a single zircon grain to preserve a rich history of magmatic, metamorphic, and hydrothermal processes. Isotopic dating of micro-domains exposed in cross-sections of zircon grains allows us to interrogate this history. Unfortunately, our ability to select the zircon grains in a heavy mineral concentrate that records the most ge
AuthorsRyan J. McAleer, Aaron M. Jubb, Paul C. Hackley, Gregory J. Walsh, Arthur J. Merschat, Sean P. Regan, William C. Burton, Jorge A. VazquezGeochronology of the Oliverian Plutonic Suite and the Ammonoosuc Volcanics in the Bronson Hill arc: Western New Hampshire, USA
U-Pb zircon geochronology by sensitive high-resolution ion microprobe–reverse geometry (SHRIMP-RG) on 11 plutonic rocks and two volcanic rocks from the Bronson Hill arc in western New Hampshire yielded Early to Late Ordovician ages ranging from 475 to 445 Ma. Ages from Oliverian Plutonic Suite rocks that intrude a largely mafic lower section of the Ammonoosuc Volcanics ranged from 474.8 ± 5.2 to 4
AuthorsPeter M. Valley, Gregory J. Walsh, Arthur J. Merschat, Ryan J. McAleerGeochemistry and geophysics of iron oxide-apatite deposits and associated waste piles with implications for potential rare earth element resources from ore and historic mine waste in the eastern Adirondack Highlands, New York, USA
The iron oxide-apatite (IOA) deposits of the eastern Adirondack Highlands, New York, are historical high-grade magnetite mines that contain variable concentrations of rare earth element (REE)-bearing apatite crystals. The majority of the deposits are hosted within sodically altered Lyon Mountain granite gneiss, although some deposits occur within paragneiss, gabbro, anorthosite, or potassically alAuthorsRyan Taylor, Anjana K. Shah, Gregory J. Walsh, Cliff D. TaylorSyn-collisional exhumation of hot middle crust in the Adirondack Mountains (New York, USA): Implications for extensional orogenesis in the southern Grenville province
Extensional deformation in the lower to middle continental crust is increasingly recognized and shown to have significant impact on crustal architecture, magma emplacement, fluid flow, and ore deposits. Application of the concept of extensional strain to ancient orogenic systems, like the Grenville province of eastern North America, has helped decipher the structural evolution of these regions. ThAuthorsSean Regan, Gregory J. Walsh, Michael L. Williams, Jeffrey R. Chiarenzelli, Megan E. Toft, Ryan J. McAleerBedrock geologic map of the Littleton and Lower Waterford quadrangles, Essex and Caledonia Counties, Vermont, and Grafton County, New Hampshire
The bedrock geologic map of the Littleton and Lower Waterford quadrangles covers an area of approximately 107 square miles (277 square kilometers) north and south of the Connecticut River in east-central Vermont and adjacent New Hampshire. This map was created as part of a larger effort to produce a new bedrock geologic map of Vermont through the collection of field data at a scale of 1:24,000. AAuthorsDouglas W. RankinBedrock geologic map of the Lisbon quadrangle, and parts of the Sugar Hill and East Haverhill quadrangles, Grafton County, New Hampshire
The bedrock geologic map of the Lisbon quadrangle, and parts of the Sugar Hill and East Haverhill quadrangles, Grafton County, New Hampshire, covers an area of approximately 73 square miles (189 square kilometers) in west-central New Hampshire. This map was created as part of a larger effort to produce a new bedrock geologic map of Vermont through the collection of field data at a scale of 1:24,00AuthorsDouglas W. RankinBedrock geologic map of the Miles Pond and Concord quadrangles, Essex and Caledonia Counties, Vermont, and Grafton County, New Hampshire
The bedrock geologic map of the Miles Pond and Concord quadrangles covers an area of approximately 107 square miles (276 square kilometers) in east-central Vermont and adjacent New Hampshire, north of and along the Connecticut River. This map was created as part of a larger effort to produce a new bedrock geologic map of Vermont through the collection of field data at a scale of 1:24,000. The majoAuthorsDouglas W. RankinA transect through Vermont’s most famous volcano – Mount Ascutney: GSNH Summer 2017 Field Trip
No abstract available.AuthorsGregory J. WalshReaction softening by dissolution–precipitation creep in a retrograde greenschist facies ductile shear zone, New Hampshire, USA
We describe strain localization by a mixed process of reaction and microstructural softening in a lower greenschist facies ductile fault zone that transposes and replaces middle to upper amphibolite facies fabrics and mineral assemblages in the host schist of the Littleton Formation near Claremont, New Hampshire. Here, Na-poor muscovite and chlorite progressively replace first staurolite, then gar
AuthorsRyan J. McAleer, David L. Bish, Michael J. Kunk, Karri R. Sicard, Peter M. Valley, Gregory J. Walsh, Bryan A. Wathen, R. P. Wintsch - Partners
Below are partners associated with this project.