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
Filter Total Items: 17
No Result Found
Filter Total Items: 15
Filter Total Items: 81
Telescoping metamorphic isograds: Evidence from 40Ar/39A dating in the Orange-Milford belt, southern Connecticut Telescoping 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
Authors
Michael Kunk, Gregory Walsh, Martha Growdon, Robert Wintsch
Unraveling Alleghanian orogenesis in southern Connecticut: The history of the Lyme Dome Unraveling Alleghanian orogenesis in southern Connecticut: The history of the Lyme Dome
No abstract available.
Authors
Gregory Walsh, John Aleinikoff, Robert Wintsch
A transect through the base of the Bronson Hill Terrane in western New Hampshire A 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...
Authors
Gregory Walsh, Peter Valley, Karri Sicard
Neoproterozoic tectonic evolution of the Jebel Saghro and Bou Azzer - El Graara inliers, eastern and central Anti-Atlas, Morocco Neoproterozoic 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...
Authors
Gregory Walsh, John Aleinikoff, Richard W. Harrison, William Burton, James Quick, Foudad Benziane, Abdelaziz Yazidi, Abderrahim Saadane
A transect across the basement massifs of the central Green Mountains, Vermont A transect across the basement massifs of the central Green Mountains, Vermont
No abstract available.
Authors
Gregory Walsh, Nicholas Ratcliffe, Michael Kunk
Traverse of the major fault systems of the Taconian deformational front, the Vermont Valley and core of the Green Mountain massif, southern Vermont Traverse of the major fault systems of the Taconian deformational front, the Vermont Valley and core of the Green Mountain massif, southern Vermont
No abstract available.
Authors
Nicholas Ratcliffe, Michael Kunk, William Burton, Gregory Walsh
Cover sequences at the northern margin of the Antongil Craton, NE Madagascar Cover sequences at the northern margin of the Antongil Craton, NE Madagascar
The island of Madagascar is a collage of Precambrian, generally high-grade metamorphic basement domains, that are locally overlain by unmetamorphosed sedimentary rocks and poorly understood low-grade metasediments. In the Antalaha area of NE Madagascar, two distinct cover sequences rest on high-grade metamorphic and igneous basement rocks of the Archaean Antongil craton and the...
Authors
W. Bauer, G. J. Walsh, B. De Waele, Ronald J. Thomas, M. Horstwood, L. Bracciali, D. Schofield, U. Wollenberg, D. J. Lidke, I.T. Rasaona, M.H. Rabarimanana
Provisional zircon and monazite uranium-lead geochronology for selected rocks from Vermont Provisional zircon and monazite uranium-lead geochronology for selected rocks from Vermont
This report presents the results of zircon and monazite uranium-lead (U-Pb) geochronologic analyses of 24 rock samples. The samples in this study were collected from mapped exposures identified while conducting either new, detailed (1:24,000-scale) geologic quadrangle mapping or reconnaissance mapping, both of which were used for compilation of the bedrock geologic map of Vermont. All of...
Authors
John Aleinikoff, Nicholas Ratcliffe, Gregory Walsh
Polyphase Neoproterozoic orogenesis within the east Africa- Antarctica orogenic belt in central and northern Madagascar Polyphase Neoproterozoic orogenesis within the east Africa- Antarctica orogenic belt in central and northern Madagascar
Our recent geological survey of the basement of central and northern Madagascar allowed us to re-evaluate the evolution of this part of the East Africa-Antarctica Orogen (EAAO). Five crustal domains are recognized, characterized by distinctive lithologies and histories of sedimentation, magmatism, deformation and metamorphism, and separated by tectonic and/or unconformable contacts. Four...
Authors
R. Key, P. E. J. Pitfield, Ronald J. Thomas, K. Goodenough, D. Waele, D. Schofield, W. Bauer, M. Horstwood, M.T. Styles, J. Conrad, J. Encarnacion, D. J. Lidke, E. O’connor, C. Potter, R. Smith, G. J. Walsh, A.V. Ralison, T. Randriamananjara, J. Rafahatelo, M. Rabarimanana
Silurian-Devonian age and tectonic setting of the Connecticut Valley-Gaspé trough of Vermont using U-Pb SHRIMP analyses of detrital zircons Silurian-Devonian age and tectonic setting of the Connecticut Valley-Gaspé trough of Vermont using U-Pb SHRIMP analyses of detrital zircons
U-Pb SHRIMP ages of detrital zircons from metasedimentary rocks of the Connecticut Valley-Gaspe' trough in Vermont corroborate a Silurian-Devonian age of deposition for these strata and constrain their provenances. Ages of randomly selected detrital zircons obtained from quartzites within the Waits River and Gile Mountain Formations range from Archean to Devonian with Mesoproterozoic
Authors
C. McWilliams, Gregory Walsh, Robert Wintsch
Geological evolution of the Antongil Craton, NE Madagascar Geological evolution of the Antongil Craton, NE Madagascar
The Antongil Craton, along with the Masora and Antananarivo cratons, make up the fundamental Archaean building blocks of the island of Madagascar. They were juxtaposed during the late-Neoproterozoic to early Palaeozoic assembly of Gondwana. In this paper we give a synthesis of the geology of the Antongil Craton and present previously published and new geochemical and U-Pb zircon analyses...
Authors
D. Schofield, Ronald J. Thomas, K. Goodenough, B. De Waele, P. E. J. Pitfield, R. Key, W. Bauer, G. J. Walsh, D. J. Lidke, A.V. Ralison, M. Rabarimanana, J. Rafahatelo, T. Randriamananjara
Road to the kingdom: A bedrock transect across the Pre-Silurian Rowe-Hawley Belt in central Vermont Road to the kingdom: A bedrock transect across the Pre-Silurian Rowe-Hawley Belt in central Vermont
No abstract available.
Authors
Jonathan Kim, Marjorie Gale, R. Coish, Jo Laird, Gregory Walsh
Science and Products
Filter Total Items: 17
No Result Found
Filter Total Items: 15
Filter Total Items: 81
Telescoping metamorphic isograds: Evidence from 40Ar/39A dating in the Orange-Milford belt, southern Connecticut Telescoping 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
Authors
Michael Kunk, Gregory Walsh, Martha Growdon, Robert Wintsch
Unraveling Alleghanian orogenesis in southern Connecticut: The history of the Lyme Dome Unraveling Alleghanian orogenesis in southern Connecticut: The history of the Lyme Dome
No abstract available.
Authors
Gregory Walsh, John Aleinikoff, Robert Wintsch
A transect through the base of the Bronson Hill Terrane in western New Hampshire A 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...
Authors
Gregory Walsh, Peter Valley, Karri Sicard
Neoproterozoic tectonic evolution of the Jebel Saghro and Bou Azzer - El Graara inliers, eastern and central Anti-Atlas, Morocco Neoproterozoic 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...
Authors
Gregory Walsh, John Aleinikoff, Richard W. Harrison, William Burton, James Quick, Foudad Benziane, Abdelaziz Yazidi, Abderrahim Saadane
A transect across the basement massifs of the central Green Mountains, Vermont A transect across the basement massifs of the central Green Mountains, Vermont
No abstract available.
Authors
Gregory Walsh, Nicholas Ratcliffe, Michael Kunk
Traverse of the major fault systems of the Taconian deformational front, the Vermont Valley and core of the Green Mountain massif, southern Vermont Traverse of the major fault systems of the Taconian deformational front, the Vermont Valley and core of the Green Mountain massif, southern Vermont
No abstract available.
Authors
Nicholas Ratcliffe, Michael Kunk, William Burton, Gregory Walsh
Cover sequences at the northern margin of the Antongil Craton, NE Madagascar Cover sequences at the northern margin of the Antongil Craton, NE Madagascar
The island of Madagascar is a collage of Precambrian, generally high-grade metamorphic basement domains, that are locally overlain by unmetamorphosed sedimentary rocks and poorly understood low-grade metasediments. In the Antalaha area of NE Madagascar, two distinct cover sequences rest on high-grade metamorphic and igneous basement rocks of the Archaean Antongil craton and the...
Authors
W. Bauer, G. J. Walsh, B. De Waele, Ronald J. Thomas, M. Horstwood, L. Bracciali, D. Schofield, U. Wollenberg, D. J. Lidke, I.T. Rasaona, M.H. Rabarimanana
Provisional zircon and monazite uranium-lead geochronology for selected rocks from Vermont Provisional zircon and monazite uranium-lead geochronology for selected rocks from Vermont
This report presents the results of zircon and monazite uranium-lead (U-Pb) geochronologic analyses of 24 rock samples. The samples in this study were collected from mapped exposures identified while conducting either new, detailed (1:24,000-scale) geologic quadrangle mapping or reconnaissance mapping, both of which were used for compilation of the bedrock geologic map of Vermont. All of...
Authors
John Aleinikoff, Nicholas Ratcliffe, Gregory Walsh
Polyphase Neoproterozoic orogenesis within the east Africa- Antarctica orogenic belt in central and northern Madagascar Polyphase Neoproterozoic orogenesis within the east Africa- Antarctica orogenic belt in central and northern Madagascar
Our recent geological survey of the basement of central and northern Madagascar allowed us to re-evaluate the evolution of this part of the East Africa-Antarctica Orogen (EAAO). Five crustal domains are recognized, characterized by distinctive lithologies and histories of sedimentation, magmatism, deformation and metamorphism, and separated by tectonic and/or unconformable contacts. Four...
Authors
R. Key, P. E. J. Pitfield, Ronald J. Thomas, K. Goodenough, D. Waele, D. Schofield, W. Bauer, M. Horstwood, M.T. Styles, J. Conrad, J. Encarnacion, D. J. Lidke, E. O’connor, C. Potter, R. Smith, G. J. Walsh, A.V. Ralison, T. Randriamananjara, J. Rafahatelo, M. Rabarimanana
Silurian-Devonian age and tectonic setting of the Connecticut Valley-Gaspé trough of Vermont using U-Pb SHRIMP analyses of detrital zircons Silurian-Devonian age and tectonic setting of the Connecticut Valley-Gaspé trough of Vermont using U-Pb SHRIMP analyses of detrital zircons
U-Pb SHRIMP ages of detrital zircons from metasedimentary rocks of the Connecticut Valley-Gaspe' trough in Vermont corroborate a Silurian-Devonian age of deposition for these strata and constrain their provenances. Ages of randomly selected detrital zircons obtained from quartzites within the Waits River and Gile Mountain Formations range from Archean to Devonian with Mesoproterozoic
Authors
C. McWilliams, Gregory Walsh, Robert Wintsch
Geological evolution of the Antongil Craton, NE Madagascar Geological evolution of the Antongil Craton, NE Madagascar
The Antongil Craton, along with the Masora and Antananarivo cratons, make up the fundamental Archaean building blocks of the island of Madagascar. They were juxtaposed during the late-Neoproterozoic to early Palaeozoic assembly of Gondwana. In this paper we give a synthesis of the geology of the Antongil Craton and present previously published and new geochemical and U-Pb zircon analyses...
Authors
D. Schofield, Ronald J. Thomas, K. Goodenough, B. De Waele, P. E. J. Pitfield, R. Key, W. Bauer, G. J. Walsh, D. J. Lidke, A.V. Ralison, M. Rabarimanana, J. Rafahatelo, T. Randriamananjara
Road to the kingdom: A bedrock transect across the Pre-Silurian Rowe-Hawley Belt in central Vermont Road to the kingdom: A bedrock transect across the Pre-Silurian Rowe-Hawley Belt in central Vermont
No abstract available.
Authors
Jonathan Kim, Marjorie Gale, R. Coish, Jo Laird, Gregory Walsh
*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