Publications
Filter Total Items: 890
10Be/9Be and 26Al/10Be support a late Miocene burial age for basal Gray Fossil Site sediments 10Be/9Be and 26Al/10Be support a late Miocene burial age for basal Gray Fossil Site sediments
We provide 2 independent radioisotopic age estimates for cored basal sediments of the Gray Fossil Site using cosmogenic nuclides. The first estimate uses meteoric 10Be/9Be from the bottom of the GFS-1 core, as well as from modern local grasses, to constrain the deposition of basal GFS sinkhole complex sediments to 6.60 ± 0.85 Ma. We corroborated this age estimate using in-situ 10Be and...
Authors
William Elijah Odom, Darryl E. Granger, Steven C. Wallace
Calcareous nannofossil biostratigraphy and floral response to environmental changes recorded in the Pliocene Yorktown Formation, southeastern Virginia, USA Calcareous nannofossil biostratigraphy and floral response to environmental changes recorded in the Pliocene Yorktown Formation, southeastern Virginia, USA
The Pliocene Yorktown Formation, deposited on the U.S. Mid-Atlantic Coastal Plain, has played an important role in advancing our knowledge of Pliocene paleoclimate. To refine the age and paleoenvironment of the Yorktown Formation, we analyzed the calcareous nannofossil assemblage and compared it with variations in lithology and calculated sea surface temperature (SST) from previous...
Authors
Masayuki Utsunomiya, Harry J. Dowsett
Alteration mapping in granitic gneiss using handheld geophysical and geochemical instruments: Implications for iron oxide-apatite and rare earth elements exploration Alteration mapping in granitic gneiss using handheld geophysical and geochemical instruments: Implications for iron oxide-apatite and rare earth elements exploration
The Adirondack Mountains of New York, U.S.A. contain iron oxide-apatite (IOA) mineral deposits with variable concentrations of rare earth elements (REE). The IOA mineral deposits are typically hosted in the Lyon Mountain Granite Gneiss and are spatially correlated with extensive Na metasomatism (albitization) of the surrounding country rocks, although some mineral deposits also occur in...
Authors
Kaitlyn A. Suarez, Michael L. Williams, Gregory J. Walsh, Daniel E. Harlov, Michael J. Jercinovic, Daniel J. Tjapkes, Ian William Hillenbrand
Rapid Holocene deposition in the Mackenzie Trough and Barrow Canyon areas in the western Arctic Ocean Rapid Holocene deposition in the Mackenzie Trough and Barrow Canyon areas in the western Arctic Ocean
The Arctic Ocean and terrestrial environment have recently been reported to be changing drastically, but it is unclear whether these changes are similar to natural variations in the past or how sudden and large the changes are compared to natural variations. This premise served as motivation to collect sediment cores during the summer of 2022 at four sites on the Canadian continental...
Authors
Masanobu Yamamoto, Kenta Suzuki, Masafumi Murayama, Laura Gemery, Koji Seike, Leonid Polyak, Young Jin Joe, Shoma Uchida, Minoru Kobayashi, J. Onodera, Keiji Horikawa, Yuhji Yamamoto, Takayuki Omori, Michinobu Kuwae, Tomohisa Irino, Yutaka Watanabe, Motoyo Itoh, Eiji Watanabe
The conundrum of taxonomic uniformitarianism in planktic foraminifera The conundrum of taxonomic uniformitarianism in planktic foraminifera
Planktic foraminiferal species distributions in the modern ocean track environmental features like sea surface temperature (SST). Species shift their distributions as the marine environment changes, providing an analogue for past behaviour. Stationarity of species' ecological tolerances is therefore a first-order assumption of all palaeoenvironmental reconstructions based upon modern...
Authors
Harry J. Dowsett, Marci M. Robinson, Kevin M. Foley, Whittney Spivey
A review of abrupt permafrost thaw: Definitions, usage, and a proposed conceptual framework A review of abrupt permafrost thaw: Definitions, usage, and a proposed conceptual framework
Purpose of Review We review how ‘abrupt thaw’ has been used in published studies, compare these definitions to abrupt processes in other Earth science disciplines, and provide a definitive framework for how abrupt thaw should be used in the context of permafrost science.Recent Findings We address several aspects of permafrost systems necessary for abrupt thaw to occur and propose a...
Authors
Hailey Webb, Matthias Fuchs, Benjamin W. Abbott, Thomas A. Douglas, Clayton D. Elder, Jessica G. Ernakovich, Eugenie Euskirchen, Mathias Göckede, Guido Grosse, Gustaf Hugelius, Miriam C. Jones, Charles Koven, Heather Kropp, Emma Lathrop, Wenwen Li, Michael M. Loranty, Susan M Natali, David Olefeldt, Christina Schädel, Edward A.G. Schuur, Oliver Sonnentag, Jens Strauss, Anna-Maria Virkkala, Merritt R. Turetsky
Cryptic ice wedge networks in Holocene peat, Yukon-Kuskokwim Delta, Alaska Cryptic ice wedge networks in Holocene peat, Yukon-Kuskokwim Delta, Alaska
The Yukon-Kuskokwim Delta (YKD), covering ~75,000 km2 of Alaska's discontinuous permafrost zone, has a historic (1902–2023) mean annual air temperature of ~−1°C and was previously thought to lack ice wedge networks. However, our recent investigations near Bethel, Alaska, revealed numerous near-surface ice wedges. Using 20 cm resolution aerial orthoimagery from 2018, we identified ~50...
Authors
Benjamin M. Jones, Mikhail Z. Kanevskiy, Melissa K. Ward Jones, Phillip R. Wilson, Isaiah Ditmer, Benjamin V. Gaglioti, Eric S. Klein, Rodrigo C. Rangel, Kristi L. Wallace, Miriam C. Jones, Matthew J. Wooller, Yuri Shur
Over, under, and through: Hydrologic connectivity and the future of coastal landscape salinization Over, under, and through: Hydrologic connectivity and the future of coastal landscape salinization
Seawater intrusion (SWI) affects coastal landscapes worldwide. Here we describe the hydrologic pathways through which SWI occurs - over land via storm surge or tidal flooding, under land via groundwater transport, and through watersheds via natural and artificial surface water channels—and how human modifications to those pathways alter patterns of SWI. We present an approach to advance
Authors
Ashley Helton, James Dennedy-Frank, Ryan Emanuel, Scott C Neubauer, Kyra Adams, Marcelo Ardon, Lawrence Band, Kevin A. Befus, Hanne Borstlap, Jamie Duberstein, Adam Gold, Kominoski John, Alex Manda, Holly A. Michael, Stephen Moysey, Allison Myers-Pigg, Justine Annaliese Neville, Gregory E. Noe, Jeeban Panthi, Elnaz Pezeshki, Matthew Sirianni, Ward.Nicolas
Geochemistry and spatial distribution of Neoproterozoic dike swarms from the northwestern tip of the Arabian-Nubian Shield: Implications for crustal extension Geochemistry and spatial distribution of Neoproterozoic dike swarms from the northwestern tip of the Arabian-Nubian Shield: Implications for crustal extension
Ediacaran dike swarms in the Arabian-Nubian Shield (ANS) provide key insights into post-collisional tectonics and magmatism. This study presents new chemical data, two 40Ar/39Ar ages, and spatial distribution analysis for dike swarms in the northernmost ANS exposures in SW Jordan. Hornblende from a lamprophyre sill intruding the Saramuj Conglomerate yielded a plateau age of ∼592 ± 3 Ma
Authors
Hind Ghanem, Abeer Salman, Ryan J. McAleer, Cees W. Passchier, Ghaleb H. Jarrar
Discovery of an intact Quaternary paleosol, Georgia Bight, USA Discovery of an intact Quaternary paleosol, Georgia Bight, USA
A previously buried paleosol was found on the continental shelf during a study of sea floor scour, nucleated by large artificial reef structures such as vessel hulks, barges, train cars, military vehicles, etc., called “scour nuclei”. It is a relic paleo-land surface of sapling-sized tree stumps, root systems, and fossil animal bone exhumed by scour processes active adjacent to the...
Authors
Ervan G. Garrison, Matthew Newton, Benjamin Prueitt, Emily C. Jones, Debra A. Willard
The stratigraphic record of the mid-Piacenzian warm period on the Atlantic Coastal Plain The stratigraphic record of the mid-Piacenzian warm period on the Atlantic Coastal Plain
Anthropogenic climate change is an existential threat to our planet, impacting everything from the delicate balance of ecosystems to the availability of vital resources. Coastal regions, particularly vulnerable to the impacts of climate change due to rising sea levels and changing weather patterns, are experiencing increased erosion, flooding, and habitat loss. Understanding how coastal...
Authors
Harry J. Dowsett, Whittney Spivey
The nonpoint source challenge: Obstacles and opportunities for meeting nutrient reduction goals in the Chesapeake Bay watershed The nonpoint source challenge: Obstacles and opportunities for meeting nutrient reduction goals in the Chesapeake Bay watershed
This document examines the Chesapeake Bay watershed response to nutrient and sediment reduction efforts under the Clean Water Act's total maximum daily load (TMDL) regulation. As the 2025 Chesapeake Bay TMDL deadline approaches, water quality goals remain unmet, primarily because of nonpoint source pollution, the largest remaining source of nutrients and sediment, and the primary...
Authors
Zachary M. Easton, Kurt Stephenson, Brian Benhem, J.K. Bohlke, Anthony R Buda, Amy S. Collick, Lara Fowler, Ellen Gilinsky, Andrew Miller, Gregory E. Noe, Leah Palm-Forster, Leonard Shabman, Tess Wynn-Thompson