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Person

Gregory J Walsh

Research Geologist
Florence Bascom Geoscience Center

Email: gwalsh@usgs.gov
Office Phone: 802-828-4528
Fax: 802-828-4465
ORCID: 0000-0003-4264-8836

Location
Federal Bldg USPOandct
87 State Street
Room 228
Montpelier , VT 05602-2956
US

Supervisor: Christopher E Bernhardt
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Magnetic susceptibility was measured on outcropping rock in the eastern Adirondack Mountains, New York. A Terraplus KT-20 was used for the measurements. The corresponding rock type was identified using standard field geologic approaches. Locations of the outcrops were determined using a handheld GPS.
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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 on the ground" mapping, enable recovery of the location of these historical features. Waste rock piles and abandoned mine lands from historical mining locally appear as distinct features on the landscape depicted on the percent slope map. Abandoned, and in many places demolished, infrastructure such as breakers, turntables, rail...
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This collection contains unpublished hand drawn geologic maps, field maps, traverse maps, sample location maps, and cross sections of Traveler Mountain and vicinity, central Maine. The maps were created by Douglas W. Rankin between 1955 and 1961 (date is indicated if known) and scanned in 2016. Most maps use a 7.5-minute topographic quadrangle as a base. Some compiled maps of larger areas are a composite of several 7.5-minute quadrangle maps and latitude and longitude values are indicated on the map. Please contact the Eastern Geology and Paleoclimate Science Center for additional information and access to original copies.
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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 geochronologic information is limited by our inability to predict internal zonation from observations of whole zircon grains. Here we document the use of a petrographic microscope to observe and image the photoluminescence (PL) response of whole zircon grains excited under ultraviolet (UV) light, and the utility of this PL...
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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 tailings piles. The ore from historic iron mines of the eastern Adirondack Highlands, New York, contain abundant quantities of rare earth element (REE)-bearing apatite crystals. These apatite crystals are especially enriched in Y, La, Ce, and Nd. In-ground ore, mine waste piles, and tailings piles could contain apatite...
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