Gregory Walsh
I am a Project Leader and a Supervisory Research Geologist with the Florence Bascom Geoscience Center. I manage bedrock geologic mapping activities for the USGS in the northeastern United States. I managed two international mapping projects in Morocco, the completion of the new bedrock geologic map of Vermont, and I conducted mapping Madagascar.
I have expertise in geologic mapping, structural geology, geochronology, tectonics, digital cartography, and GIS. I specialize in the mapping, structure, and tectonics of complexly deformed rocks, the integration of geologic data with hydrogeologic and mineral resource assessment studies, and the use of GIS as a mapping and analysis tool. I have trained students and geologists in geologic mapping, GIS, GPS, digital mapping, and U-Pb geochronology by SHRIMP. The Publications listed on the tab below is automatically generated and incomplete. Please contact me if you would like a copy of my current CV.
Professional Experience
1992-Present, Research Geologist, U.S. Geological Survey, Reston, Virginia and Montpelier, Vermont
1990-1992, Consulting Geologist, Heindel and Noyes, Inc., Burlington, Vermont
1988-1990, Contractor, Vermont Agency of Natural Resources, Waterbury, Vermont
1986-1988, Teaching Assistant, University of Vermont, Department of Geology, Burlington, Vermont
1986, NAGT Intern Geologist, U.S. Geological Survey, Menlo Park, California
Education and Certifications
M.S. in Geology / University of Vermont, Burlington, Vermont USA, 1989
B.S. in Geology / University of Massachusetts, Amherst, Massachusetts, 1986
Affiliations and Memberships*
2013-Present, Fellow, Geological Society of America
1988-2013, Member, Geological Society of America
2013-2014, Elected Vice-Chair, Geological Society of America, Northeastern Section Management Board
2014-2015, Chair, Geological Society of America, Northeastern Section Management Board
2015-2016, Past-Chair, Geological Society of America, Northeastern Section Management Board
2012-Present, Member, Connecticut Geological Society
1998-Present, Member, New Hampshire Geological Society
1992-Present, Member, Vermont Geological Society
Honors and Awards
Dean’s List five semesters (1982-1986)
Amoco Geophysics Award (1985)
NAGT – USGS Student Internship (1985)
L.R. Wilson Award, UMASS Amherst (1986)
Charles G. Doll Award, Vermont Geological Society (1988)
Twenty-one USGS performance awards (1997-2021)
Elected GSA Fellow (2013)
Science and Products
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 Miles Pond and Concord 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
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
Identification of groundwater nitrate contamination from explosives used in road construction: Isotopic, chemical, and hydrologic evidence
Geochemistry and origin of metamorphosed mafic rocks from the Lower Paleozoic Moretown and Cram Hill Formations of North-Central Vermont: Delamination magmatism in the western New England appalachians
Neoproterozoic–Cambrian stratigraphic framework of the Anti-Atlas and Ouzellagh promontory (High Atlas), Morocco
Telescoping metamorphic isograds: Evidence from 40Ar/39A dating in the Orange-Milford belt, southern Connecticut
Unraveling Alleghanian orogenesis in southern Connecticut: The history of the Lyme Dome
A transect through the base of the Bronson Hill Terrane in western New Hampshire
Neoproterozoic tectonic evolution of the Jebel Saghro and Bou Azzer - El Graara inliers, eastern and central Anti-Atlas, Morocco
Science and Products
- Science
- Data
- Maps
Filter Total Items: 13
- Multimedia
- Publications
Filter Total Items: 77
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 1:24,000. AAuthorsDouglas 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. 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. 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. WintschIdentification of groundwater nitrate contamination from explosives used in road construction: Isotopic, chemical, and hydrologic evidence
Explosives used in construction have been implicated as sources of NO3– contamination in groundwater, but direct forensic evidence is limited. Identification of blasting-related NO3– can be complicated by other NO3– sources, including agriculture and wastewater disposal, and by hydrogeologic factors affecting NO3– transport and stability. Here we describe a study that used hydrogeology, chemistry,AuthorsJames R. Degnan, John Karl Böhlke, Krystle Pelham, David M. Langlais, Gregory J. WalshGeochemistry and origin of metamorphosed mafic rocks from the Lower Paleozoic Moretown and Cram Hill Formations of North-Central Vermont: Delamination magmatism in the western New England appalachians
The Moretown Formation, exposed as a north-trending unit that extends from northern Vermont to Connecticut, is located along a critical Appalachian litho-tectonic zone between the paleomargin of Laurentia and accreted oceanic terranes. Remnants of magmatic activity, in part preserved as metamorphosed mafic rocks in the Moretown Formation and the overlying Cram Hill Formation, are a key to furtherAuthorsRaymond Coish, Jonathan Kim, Evan Twelker, Scott P. Zolkos, Gregory J. WalshNeoproterozoic–Cambrian stratigraphic framework of the Anti-Atlas and Ouzellagh promontory (High Atlas), Morocco
In the last two decades, great progress has been made in the geochronological, chrono- and chemostratigraphic control of the Neoproterozoic and Cambrian from the Anti-Atlas Ranges and the Ouzellagh promontory (High Atlas). As a result, the Neoproterozoic is lithostratigraphically subdivided into: (i) the Lkest-Taghdout Group (broadly interpreted at c. 800–690 Ma) representative of rift-to-passiveAuthorsJose Javier Alvaro, Fouad Benziane, Robert Thomas, Gregory J. Walsh, Abdelaziz YazidiTelescoping metamorphic isograds: Evidence from 40Ar/39A dating in the Orange-Milford belt, southern Connecticut
New 40Ar/39Ar ages for hornblende and muscovite from the Orange-Milford belt in southern Connecticut reflect cooling from Acadian amphibolite facies metamorphism between ∼380 to 360 Ma followed by retrograde recrystallization of fabric-forming muscovite and chlorite during lower greenschist facies Alleghanian transpression at ∼280 Ma. Reported field temperature and pressure gradients are improbablAuthorsMichael J. Kunk, Gregory J. Walsh, Martha L. Growdon, Robert P. WintschUnraveling Alleghanian orogenesis in southern Connecticut: The history of the Lyme Dome
No abstract available.AuthorsGregory J. Walsh, John N. Aleinikoff, Robert P. WintschA transect through the base of the Bronson Hill Terrane in western New Hampshire
This trip will present the preliminary results of ongoing bedrock mapping in the North Hartland and Claremont North 7.5-minute quadrangles in western New Hampshire. The trip will travel from the Lebanon pluton to just north of the Sugar River pluton (Fig. 1) with the aim of examining the lower structural levels of the Bronson Hill anticlinorium (BHA), and the nature of the boundary with the rocksAuthorsGregory J. Walsh, Peter M. Valley, Karri R. SicardNeoproterozoic tectonic evolution of the Jebel Saghro and Bou Azzer - El Graara inliers, eastern and central Anti-Atlas, Morocco
New mapping, geochemistry, and 17 U–Pb SHRIMP zircon ages from rocks of the Sirwa, Bou Azzer–El Graara, and Jebel Saghro inliers constrain the Neoproterozoic evolution of the eastern Anti-Atlas during Pan-African orogenesis. In the Sirwa inlier, Tonian quartzite from the pre Pan-African passive margin deposits of the Mimount Formation contains detrital zircon derived entirely from the West AfricanAuthorsGregory J. Walsh, John N. Aleinikoff, Richard W. Harrison, William C. Burton, James E. Quick, Foudad Benziane, Abdelaziz Yazidi, Abderrahim Saadane
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government