The USGS is conducting geologic mapping and scientific research of complexly deformed crystalline igneous and metamorphic rocks in the Northeastern United States. Current mapping activities are focused on 1:24,000-scale mapping in New Hampshire, Vermont, Connecticut, and New York, plus regionwide 1:500,000-scale compilation of the bedrock geology of New England. 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.
Media
Sources/Usage: Public Domain. View Media Details
The goal of this project is to produce high quality 1:24,000-scale to 1:500,000-scale bedrock geologic maps that improve our understanding of crystalline bedrock in the Northeast United States. New detailed mapping is focused in areas where limited detailed or modern mapping exists. Compilation mapping aims to synthesize the geology of the region, address stratigraphic problems, develop stratigraphic correlations, and reconcile small-scale, cross-border edge-match issues that exist between the state geologic maps.
The new maps contribute to framework studies to help characterize the distribution natural 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, geochronology, paleontology, and petrology in scientifically appropriate areas.
Below are data release products associated with this project.
Generalized lithology for lithogeochemical classification of the bedrock of Vermont
This data release provides a generalized lithology look-up table for the lithogeochemical classification of Vermont's bedrock geologic map units. The table is defined from the mapped bedrock geologic units published by Ratcliffe and others (2011) and the generalized lithology of rock group A and rock group B for lithogeochemical classification as defined by Robinson and Kapo (2003). The...
Database of historical anthracite coal-mining infrastructure at the northern end of the Lackawanna syncline, Wayne, Susquehanna, and Lackawanna counties, Pennsylvania
Abandoned railroads and infrastructure from the anthracite coal mining industry are significant features in abandoned mine lands and are an important part of history; however, these features are often lost and masked by the passage of time and the regrowth of forests. The application of modern light detection and ranging (lidar) topographic analysis, combined with ground-truthing "boots...
Whole rock geochemistry and uranium-lead isotopic data from Mesoproterozoic rocks in the Eagle Lake quadrangle, Essex County, New York
This data release includes whole rock (WR) geochemical data, and uranium-lead isotopic data collected using a sensitive high resolution ion microprobe-reverse geometry (SHRIMP-RG) instrument; the SHRIMP-RG is a type of secondary ion mass spectrometer (SIMS). Whole rock geochemistry data were analyzed at Bureau Veritas Commodities Canada Ltd. Laboratories in Vancouver, British Columbia...
Electron microprobe and 40Ar/39Ar isotopic data from west-central New Hampshire
This dataset accompanies planned publication 'Unmixing multiple metamorphic muscovite age populations with powder X-ray diffraction and 40Ar/39Ar analysis'. The 40Ar/39Ar and electron microprobe data are from samples adjacent to a lower greenschist facies shear zone in western New Hampshire. The geochronology coupled with the electron microprobe data provide a petrochronologic framework...
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...
Data 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...
Data 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...
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...
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)
Iron oxide-apatite (IOA) deposits of the Adirondack Mountains of New York locally contain elevated 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, geochronology...
Petrophysical data collected on outcrops and rock samples from the eastern Adirondack Highlands, New York
Petrophysical data were collected in the eastern Adirondack Highlands during several field campaigns in 2016-2017. This data release provides magnetic susceptibility, gamma spectrometry, and density measurements on rock outcrops, hand samples, and during walking surveys. Rock types for the outcrops and samples were identified using standard field methods. Locations of the outcrops or...
GIS and Data Tables for Focus Areas for Potential Domestic Nonfuel Sources of Rare Earth Elements
In response to Executive Order 13817 of December 20, 2017, the U.S. Geological Survey (USGS) coordinated with the Bureau of Land Management (BLM) to identify 35 nonfuel minerals or mineral materials considered critical to the economic and national security of the United States (U.S.). Acquiring information on possible domestic sources of these critical minerals is the basis of the USGS...
Geochemistry of ore, host rock, and mine waste pile samples of iron oxide-apatite (IOA) deposits of the eastern Adirondack Highlands, New York, in relation to potential rare earth elements resources, 2016-2018
Thirty-four ore, twenty-nine mine waste, seven host rock, two pegmatite, and one slag sample were collected from iron oxide-apatite (IOA) mines in the eastern Adirondack Highlands near Mineville and Ticonderoga, New York, from March 2016 to August 2018. The waste pile samples included twenty-five samples collected from rubble-sized mine waste piles and four samples from processed...
Bedrock geologic map of the Woodstock quadrangle, Grafton County, New Hampshire
The bedrock geology of the Woodstock 7.5-minute quadrangle consists of highly deformed metasedimentary rocks of the Central Maine trough, including the Silurian Rangeley and Perry Mountain Formations and the Devonian Littleton Formation. The central, northern, and eastern parts of the quadrangle are underlain by the oldest rocks in the area, the Rangeley Formation. In the southwest and...
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...
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...
Bedrock 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...
Bedrock 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...
Below are publications associated with this project.
Filter Total Items: 14
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...
Authors
Gregory J. Walsh
Age 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...
Authors
Gregory J. Walsh, John N. Aleinikoff, Robert A. Ayuso, Robert P. Wintsch
Unmixing multiple metamorphic muscovite age populations with powder X-ray diffraction and 40Ar/39Ar analysis
A combination of modal estimates from powder X-ray diffraction (XRD) experiments and argon isotopic data shows that muscovite 40Ar/39Ar total gas age correlates with muscovite composition near the retrograde Bald Mountain shear zone (BMSZ) in Claremont, New Hampshire, and that the shear zone was active at ∼245 Ma. Petrologic study demonstrates that chemical disequilibrium is preserved in...
Authors
Ryan J. McAleer, David L. Bish, Michael J. Kunk, Peter M. Valley, Gregory J. Walsh, Robert P. Wintsch
Integrated 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...
Authors
Anjana K. Shah, Ryan D. Taylor, Gregory J. Walsh, Jeffrey Phillips
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...
Authors
Ryan J. McAleer, Aaron M. Jubb, Paul C. Hackley, Gregory J. Walsh, Arthur J. Merschat, Sean Regan, William C. Burton, Jorge A. Vazquez
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...
Authors
Peter M. Valley, Gregory J. Walsh, Arthur J. Merschat, Ryan J. McAleer
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
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...
Authors
Ryan D. Taylor, Anjana K. Shah, Gregory J. Walsh, Cliff D. Taylor
Syn-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...
Authors
Sean Regan, Gregory J. Walsh, Michael S. Williams, Jeffrey R. Chiarenzelli, Megan E. Toft, Ryan J. McAleer
Bedrock 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...
Authors
Douglas W. Rankin
Bedrock 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...
Authors
Douglas W. Rankin
Bedrock 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...
Authors
Douglas W. Rankin
A transect through Vermont’s most famous volcano – Mount Ascutney: GSNH Summer 2017 Field Trip
No abstract available.
Authors
Gregory J. Walsh
Below are partners associated with this project.
The USGS is conducting geologic mapping and scientific research of complexly deformed crystalline igneous and metamorphic rocks in the Northeastern United States. Current mapping activities are focused on 1:24,000-scale mapping in New Hampshire, Vermont, Connecticut, and New York, plus regionwide 1:500,000-scale compilation of the bedrock geology of New England. 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.
Media
Sources/Usage: Public Domain. View Media Details
The goal of this project is to produce high quality 1:24,000-scale to 1:500,000-scale bedrock geologic maps that improve our understanding of crystalline bedrock in the Northeast United States. New detailed mapping is focused in areas where limited detailed or modern mapping exists. Compilation mapping aims to synthesize the geology of the region, address stratigraphic problems, develop stratigraphic correlations, and reconcile small-scale, cross-border edge-match issues that exist between the state geologic maps.
The new maps contribute to framework studies to help characterize the distribution natural 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, geochronology, paleontology, and petrology in scientifically appropriate areas.
Below are data release products associated with this project.
Generalized lithology for lithogeochemical classification of the bedrock of Vermont
This data release provides a generalized lithology look-up table for the lithogeochemical classification of Vermont's bedrock geologic map units. The table is defined from the mapped bedrock geologic units published by Ratcliffe and others (2011) and the generalized lithology of rock group A and rock group B for lithogeochemical classification as defined by Robinson and Kapo (2003). The...
Database of historical anthracite coal-mining infrastructure at the northern end of the Lackawanna syncline, Wayne, Susquehanna, and Lackawanna counties, Pennsylvania
Abandoned railroads and infrastructure from the anthracite coal mining industry are significant features in abandoned mine lands and are an important part of history; however, these features are often lost and masked by the passage of time and the regrowth of forests. The application of modern light detection and ranging (lidar) topographic analysis, combined with ground-truthing "boots...
Whole rock geochemistry and uranium-lead isotopic data from Mesoproterozoic rocks in the Eagle Lake quadrangle, Essex County, New York
This data release includes whole rock (WR) geochemical data, and uranium-lead isotopic data collected using a sensitive high resolution ion microprobe-reverse geometry (SHRIMP-RG) instrument; the SHRIMP-RG is a type of secondary ion mass spectrometer (SIMS). Whole rock geochemistry data were analyzed at Bureau Veritas Commodities Canada Ltd. Laboratories in Vancouver, British Columbia...
Electron microprobe and 40Ar/39Ar isotopic data from west-central New Hampshire
This dataset accompanies planned publication 'Unmixing multiple metamorphic muscovite age populations with powder X-ray diffraction and 40Ar/39Ar analysis'. The 40Ar/39Ar and electron microprobe data are from samples adjacent to a lower greenschist facies shear zone in western New Hampshire. The geochronology coupled with the electron microprobe data provide a petrochronologic framework...
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...
Data 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...
Data 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...
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...
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)
Iron oxide-apatite (IOA) deposits of the Adirondack Mountains of New York locally contain elevated 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, geochronology...
Petrophysical data collected on outcrops and rock samples from the eastern Adirondack Highlands, New York
Petrophysical data were collected in the eastern Adirondack Highlands during several field campaigns in 2016-2017. This data release provides magnetic susceptibility, gamma spectrometry, and density measurements on rock outcrops, hand samples, and during walking surveys. Rock types for the outcrops and samples were identified using standard field methods. Locations of the outcrops or...
GIS and Data Tables for Focus Areas for Potential Domestic Nonfuel Sources of Rare Earth Elements
In response to Executive Order 13817 of December 20, 2017, the U.S. Geological Survey (USGS) coordinated with the Bureau of Land Management (BLM) to identify 35 nonfuel minerals or mineral materials considered critical to the economic and national security of the United States (U.S.). Acquiring information on possible domestic sources of these critical minerals is the basis of the USGS...
Geochemistry of ore, host rock, and mine waste pile samples of iron oxide-apatite (IOA) deposits of the eastern Adirondack Highlands, New York, in relation to potential rare earth elements resources, 2016-2018
Thirty-four ore, twenty-nine mine waste, seven host rock, two pegmatite, and one slag sample were collected from iron oxide-apatite (IOA) mines in the eastern Adirondack Highlands near Mineville and Ticonderoga, New York, from March 2016 to August 2018. The waste pile samples included twenty-five samples collected from rubble-sized mine waste piles and four samples from processed...
Bedrock geologic map of the Woodstock quadrangle, Grafton County, New Hampshire
The bedrock geology of the Woodstock 7.5-minute quadrangle consists of highly deformed metasedimentary rocks of the Central Maine trough, including the Silurian Rangeley and Perry Mountain Formations and the Devonian Littleton Formation. The central, northern, and eastern parts of the quadrangle are underlain by the oldest rocks in the area, the Rangeley Formation. In the southwest and...
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...
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...
Bedrock 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...
Bedrock 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...
Below are publications associated with this project.
Filter Total Items: 14
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...
Authors
Gregory J. Walsh
Age 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...
Authors
Gregory J. Walsh, John N. Aleinikoff, Robert A. Ayuso, Robert P. Wintsch
Unmixing multiple metamorphic muscovite age populations with powder X-ray diffraction and 40Ar/39Ar analysis
A combination of modal estimates from powder X-ray diffraction (XRD) experiments and argon isotopic data shows that muscovite 40Ar/39Ar total gas age correlates with muscovite composition near the retrograde Bald Mountain shear zone (BMSZ) in Claremont, New Hampshire, and that the shear zone was active at ∼245 Ma. Petrologic study demonstrates that chemical disequilibrium is preserved in...
Authors
Ryan J. McAleer, David L. Bish, Michael J. Kunk, Peter M. Valley, Gregory J. Walsh, Robert P. Wintsch
Integrated 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...
Authors
Anjana K. Shah, Ryan D. Taylor, Gregory J. Walsh, Jeffrey Phillips
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...
Authors
Ryan J. McAleer, Aaron M. Jubb, Paul C. Hackley, Gregory J. Walsh, Arthur J. Merschat, Sean Regan, William C. Burton, Jorge A. Vazquez
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...
Authors
Peter M. Valley, Gregory J. Walsh, Arthur J. Merschat, Ryan J. McAleer
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
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...
Authors
Ryan D. Taylor, Anjana K. Shah, Gregory J. Walsh, Cliff D. Taylor
Syn-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...
Authors
Sean Regan, Gregory J. Walsh, Michael S. Williams, Jeffrey R. Chiarenzelli, Megan E. Toft, Ryan J. McAleer
Bedrock 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...
Authors
Douglas W. Rankin
Bedrock 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...
Authors
Douglas W. Rankin
Bedrock 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...
Authors
Douglas W. Rankin
A transect through Vermont’s most famous volcano – Mount Ascutney: GSNH Summer 2017 Field Trip
No abstract available.
Authors
Gregory J. Walsh
Below are partners associated with this project.