Florence Bascom Geoscience Center

Publications

Filter Total Items: 529
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Year Published: 2020

Geologic and mineral map (modified from the 1975 original map compilation by A.S. Shadchinev and others) and hyperspectral surface materials maps of the Ghorband, Salang, and Panjsher River Basins; Kapisa, Panjsher, Parwan, and Baghlan Provinces, Afghanistan

IntroductionThe geologic map and cross sections are a redrafted and modified version of the Geologic map and map of mineral resources of the basins of Ghorband, Salang, and Panjsher; located in the Kapisa, Panjsher, Parwan, and Baghlan Provinces, Afghanistan. The original map and cross sections are contained in an unpublished Soviet report no....

Stettner, Will R.; Koroleva, Natalia E.; Masonic, Linda M.; Shields, David A.
Stettner, W.R., Koroleva, N.E., Masonic, L.M., and Shields, D.A., comps., 2020, Geologic and mineral map (modified from the 1975 original map compilation by A.S. Shadchinev and others) and hyperspectral surface materials maps of the Ghorband, Salang, and Panjsher River Basins; Kapisa, Panjsher, Parwan, and Baghlan Provinces, Afghanistan: U.S. Geological Survey Open-File Report 2020–1101, 2 sheets, scale 1:100,000, https://doi.org/10.3133/ofr20201101.

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Year Published: 2020

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...

McAleer, Ryan J.; Jubb, Aaron M.; Hackley, Paul C.; Walsh, Gregory J.; Merschat, Arthur J.; Regan, Sean P.; Burton, William C.; Vazquez, Jorge A.

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Year Published: 2020

High sensitivity of Bering Sea winter sea ice to winter insolation and carbon dioxide over the last 5,500 years

Anomalously low winter sea ice extent and early retreat in CE 2018 and 2019 challenge previous notions that winter sea ice in the Bering Sea has been stable over the instrumental record, although long-term records remain limited. Here, we use a record of peat cellulose oxygen isotopes from St. Matthew Island along with isotope-enabled general...

Jones, Miriam C.; Berkelhammer, Max ; Keller, Katherine; Yoshimura, Kei; Wooller, Matthew J.

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Year Published: 2020

Large stocks of peatland carbon and nitrogen are vulnerable to permafrost thaw

Over many millennia, northern peatlands have accumulated large amounts of carbon and nitrogen, thus cooling the global climate. Over shorter timescales, peatland disturbances can trigger losses of peat and release of greenhouses gases. Despite their importance to the global climate, peatlands remain poorly mapped, and the vulnerability of...

Hugelius, Gustaf; Loisel, Julie; Chadburn, Sarah; Jackson, Robert B.; Jones, Miriam C.; MacDonald, Glen; Marushchak, Maija; Olefeldt, David; Packalen, Maara S.; Siewert, Matthias B.; Treat, Claire C.; Turetsky, Merritt; Voigt, Carolina; Yu, Zicheng

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Year Published: 2020

Sediment dynamics and implications for management: State of the science from long‐term research in the Chesapeake Bay watershed, USA

This review aims to synthesize the current knowledge of sediment dynamics using insights from long‐term research conducted in the watershed draining to the Chesapeake Bay, the largest estuary in the U.S., to inform management actions to restore the estuary and its watershed. The sediment dynamics of the Chesapeake are typical of many impaired...

Noe, Gregory B.; Cashman, Matthew J.; Skalak, Katherine; Gellis, Allen; Hopkins, Kristina G.; Moyer, Douglas; Webber, James S.; Benthem, Adam; Maloney, Kelly O.; Brakebill, John; Sekellick, Andrew; Langland, Michael J.; Zhang, Qian; Shenk, Gary Wynee; Keisman, Jennifer L.D.; Hupp, Cliff R.

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Year Published: 2020

Evaluating elevation change thresholds between structure-from-motion DEMs derived from historical aerial photos and 3DEP LiDAR data

This study created digital terrain models (DTMs) from historical aerial images using Structure from Motion (SfM) for a variety of image dates, resolutions, and photo scales. Accuracy assessments were performed on the SfM DTMs, and they were compared to the United States Geological Survey’s three-dimensional digital elevation program (3DEP) light...

Chirico, Peter; DeWitt, Jessica D.; Bergstresser, Sarah E.

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Year Published: 2020

Major-element compositional data and thermal data for drill core from Kīlauea Iki lava lake, plus analyses of glasses from scoria of the 1959 summit eruption of Kīlauea Volcano, Hawaii

This report presents electron microprobe data on glasses and selected crystalline phases from Kīlauea Iki lava lake and glasses from the 1959 summit eruption of Kīlauea Volcano, Hawaii. Some of these data have been published previously, but the complete set has not been published before. In addition, this report includes electron microprobe data...

Helz, Rosalind Tuthill
Helz, R.T., 2020, Major-element compositional data and thermal data for drill core from Kīlauea Iki lava lake, plus analyses of glasses from scoria of the 1959 summit eruption of Kīlauea Volcano, Hawaii: U.S. Geological Survey Open-File Report 2020–1012, 48 p., https://doi.org/10.3133/ofr20201012.

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Year Published: 2020

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...

Walsh, Gregory J.; Valley, Peter M.; Thompson, Peter J.; Ratcliffe, Nicholas M.; Proctor, Brooks P.; Sicard, Karri R.
Walsh, G.J., Valley, P.M., Thompson, P.J., Ratcliffe, N.M., Proctor, B.P., and Sicard, K.R., 2020, Bedrock geologic map of the Mount Ascutney 7.5- x 15-minute quadrangle, Windsor County, Vermont, and Sullivan County, New Hampshire (ver. 1.1, April 2020): U.S. Geological Survey Scientific Investigations Map 3440, 2 sheets, scale 1:24,000, https://doi.org/10.3133/sim3440.

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Year Published: 2020

40Ar/39Ar and U-Pb SIMS zircon ages of Ediacaran dikes from the Arabian-Nubian Shield of south Jordan

A spectacular feature of the Arabian-Nubian Shield (ANS) is the abundance of well-exposed and extensive Neoproterozoic dike swarms of multiple generations. These dikes are generally categorized into metamorphosed and unmetamorphosed post-orogenic dike swarms. The unmetamorphosed dikes in the northern ANS can be grouped into an old and young...

Ghanem, Hind; McAleer, Ryan J.; Jarrar, Ghaleb; Al Hseinat, Mu'ayyad; Whitehouse, Martin

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Year Published: 2020

Geology of the Trout Rock caves (Hamilton Cave, Trout Cave, New Trout Cave) in Pendleton County, West Virginia (USA), and implications regarding the origin of maze caves

The Trout Rock caves (Hamilton Cave, Trout Cave, New Trout Cave) are located in a hill named Cave Knob that overlooks the South Branch of the Potomac River in Pendleton County, West Virginia (U.S.A). The geologic structure of this hill is a northeasttrending anticline, and the caves are located at different elevations primarily along the contact...

Swezey, Christopher S.; Brent, Emily L

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Year Published: 2020

Foreward: Geology Field Trips in and around the U.S. Capital

The first annual meeting of the Geological Society of America (GSA) was held in 1888 in Ithaca, New York (Fairchild, 1932), but official Sections of GSA formed much later. During the spring of 1949, a symposium in Knoxville, Tennessee, on mineral resources of the southeastern United States became the catalyst for the creation of the Southeastern...

Swezey, Christopher S.; Carter, Mark W.

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Year Published: 2020

Mapping the extent and methods of small-scale emerald mining in the Panjshir Valley, Afghanistan

Emerald mining in the Panjshir Valley, Afghanistan, has occurred for thousands of years, yet few records exist documenting the detailed spatial extent, techniques, or productivity of small-scale miners. This study proposes new methods to map and monitor the extent and changes in small-scale mining in remote and inaccessible terrain by integrating...

DeWitt, Jessica D.; Chirico, Peter; O'Pry, Kelsey; Bergstresser, Sarah E.