Publications
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Arctic Ocean stratification set by sea level and freshwater inputs since the last ice age Arctic Ocean stratification set by sea level and freshwater inputs since the last ice age
Salinity-driven density stratification of the upper Arctic Ocean isolates sea-ice cover and cold, nutrient-poor surface waters from underlying warmer, nutrient-rich waters. Recently, stratification has strengthened in the western Arctic but has weakened in the eastern Arctic; it is unknown if these trends will continue. Here we present foraminifera-bound nitrogen isotopes from Arctic...
Authors
Jesse R. Farmer, Daniel Sigman, Julie Granger, Ona M. Underwood, Francois Frapiat, Thomas M. Cronin, Alfredo Martinez-Garcia, Gerald H. Haug
Miocene neritic benthic foraminiferal community dynamics, Calvert Cliffs, Maryland, USA: Species pool, patterns and processes Miocene neritic benthic foraminiferal community dynamics, Calvert Cliffs, Maryland, USA: Species pool, patterns and processes
The presence/absence and abundance of benthic foraminifera in successive discrete beds (Shattuck “zones”) of the Miocene Calvert and Choptank formations, exposed at the Calvert Cliffs, Maryland, USA, allows for investigation of community dynamics over space and time. The stratigraphic distribution of benthic foraminifera is documented and interpreted in the context of sea-level change...
Authors
Stephen J. Culver, Seth R Sutton, David J. Mallinson, Martin A Buzas, Marci M. Robinson, Harry J. Dowsett
The Chesapeake Bay program modeling system: Overview and recommendations for future development The Chesapeake Bay program modeling system: Overview and recommendations for future development
The Chesapeake Bay is the largest, most productive, and most biologically diverse estuary in the continental United States providing crucial habitat and natural resources for culturally and economically important species. Pressures from human population growth and associated development and agricultural intensification have led to excessive nutrient and sediment inputs entering the Bay...
Authors
Raleigh Hood, Gary W. Shenk, Rachel L Dixon, Sean M. C. Smith, William P. Ball, Jesse Bash, R. Batiuk, Kathy Boomer, Damian C Brady, Carl Cerco, Peter Claggett, Kim de Mutsert, Zachary M. Easton, Andrew J Elmore, Marjorie A. M. Friedrichs, Lora A. Harris, Thomas F. Ihde, Iara Lacher, Li Li, Lewis C. Linker, Andrew Miller, Julia Moriarty, Gregory E. Noe, George Onyullo, Kenneth A Rose, Katherine Skalak, Richard Tian, Tamie L Veith, Lisa A. Wainger, Donald E. Weller, Yinglong J. Zhang
Borehole sampling of surficial sediments in Northern Virginia and Southern Maryland Borehole sampling of surficial sediments in Northern Virginia and Southern Maryland
From 2014 to 2017, the U.S. Geological Survey’s Florence Bascom Geoscience Center (FBGC) entered into an inter-agency agreement with the Federal Highway Administration’s Turner-Fairbank Highway Research Center (TFHRC) to assist in field site selection and auger drilling fieldwork. The TFHRC was developing a device to measure the erosional properties of clay-rich sediments to be used for...
Authors
Peter G. Chirico, Jessica D. DeWitt, Sarah E. Bergstresser
Afghanistan artisanal and small-scale mining sector Afghanistan artisanal and small-scale mining sector
For millennia, extractive activity in Afghanistan (officially the Islamic Republic of Afghanistan, or IRA) has been entirely artisanal or small-scale in scope. Various international governments, organizations, and companies have supported the growth of the sector, and the Government of the Islamic Republic of Afghanistan (GoIRA) views its mineral wealth as vital to the country’s...
Authors
Jessica D. DeWitt, Sindhuja Sunder, Kathleen M Boston
Age and tectonic setting of the Quinebaug-Marlboro belt and implications for the history of Ganderian crustal fragments in southeastern New England, USA Age and tectonic setting of the Quinebaug-Marlboro belt and implications for the history of Ganderian crustal fragments in southeastern New England, USA
Crustal fragments underlain by high-grade rocks represent a challenge to plate reconstructions, and integrated mapping, geochronology, and geochemistry enable the unravelling of the temporal and spatial history of exotic crustal blocks. The Quinebaug-Marlboro belt (QMB) is an enigmatic fragment on the trailing edge of the peri-Gondwanan Ganderian margin of southeastern New England...
Authors
Gregory J. Walsh, John N. Aleinikoff, Robert A. Ayuso, Robert P. Wintsch
Permafrost thaw in northern peatlands: Rapid changes in ecosystem and landscape functions Permafrost thaw in northern peatlands: Rapid changes in ecosystem and landscape functions
Peatlands within the northern permafrost region cover approximately 2 million km2 and are characterized by organic soils that can be several meters thick, and a fine-scale mosaic of permafrost and non-permafrost landforms interspersed by shallow ponds and lakes. Ongoing permafrost thaw is transforming these peatlands, causing abrupt changes to their morphology, hydrology, ecology, and
Authors
David Olefeldt, Liam Hefferman, Miriam C. Jones, A. Britta Sannel, Claire C. Treat, Merritt R. Turetsky
Enhanced terrestrial runoff during Oceanic Anoxic Event 2 on the North Carolina Coastal Plain, USA Enhanced terrestrial runoff during Oceanic Anoxic Event 2 on the North Carolina Coastal Plain, USA
A global increase in the strength of the hydrologic cycle drove an increase in the flux of terrigenous sediments into the ocean during the Cenomanian–Turonian Oceanic Anoxic Event 2 (OAE2) and was an important mechanism driving nutrient enrichment and thus organic carbon burial. This global change is primarily known from isotopic records, but global average data do not tell us anything...
Authors
Christopher M Lowery, Jean Self-Trail, Craig Barrie
Estimating Piacenzian sea surface temperature using an alkenone-calibrated transfer function Estimating Piacenzian sea surface temperature using an alkenone-calibrated transfer function
Stationarity of environmental preferences is a primary assumption required for any paleoenvironmental reconstruction using fossil materials based upon calibration to modern organisms. Confidence in this assumption decreases the further back in time one goes, and the validity of the assumption that species temperature tolerances have not changed over time has been challenged in Pliocene...
Authors
Harry J. Dowsett, Marci M. Robinson, Kevin M. Foley
The liquefaction record of past earthquakes in the Central Virginia Seismic Zone, Eastern United States The liquefaction record of past earthquakes in the Central Virginia Seismic Zone, Eastern United States
Following the 2011 moment magnitude, MM 5.7 Mineral, Virginia, earthquake, we conducted a search for paleoliquefaction features and found 41 sand dikes, sand sills, and soft‐sediment deformation features at 24 sites exposed in cutbanks along several rivers: (1) the South Anna River, where paleoliquefaction features were found in the epicentral area of the Mineral earthquake and farther...
Authors
Martitia P. Tuttle, Kathleen Dyer-Williams, Mark W. Carter, Steven L. Forman, Kathleen Tucker, Zamara Fuentes, Carlos Velez, Laurel Bauer
New interpretations of the ages and origins of the Hawkeye Granite Gneiss and Lyon Mountain Granite Gneiss, Adirondack Mountains, NY: Implications for the nature and timing of Mesoproterozoic plutonism, metamorphism, and deformation New interpretations of the ages and origins of the Hawkeye Granite Gneiss and Lyon Mountain Granite Gneiss, Adirondack Mountains, NY: Implications for the nature and timing of Mesoproterozoic plutonism, metamorphism, and deformation
The Hawkeye Granite Gneiss and Lyon Mountain Granite Gneiss are widespread Mesoproterozoic plutonic rocks that occur in the amphibolite- to granulite-facies Adirondack Highlands of northern New York, USA. The strongly deformed Hawkeye Granite Gneiss, previously dated by zircon multi-grain thermal ionization mass spectrometry (TIMS) U-Pb analyses at about 1100 Ma, was intruded by the...
Authors
John N. Aleinikoff, Gregory J. Walsh, Ryan J. McAleer
Biogeography and ecology of Ostracoda in the U.S. northern Bering, Chukchi, and Beaufort Seas Biogeography and ecology of Ostracoda in the U.S. northern Bering, Chukchi, and Beaufort Seas
Ostracoda (bivalved Crustacea) comprise a significant part of the benthic meiofauna in the Pacific-Arctic region, including more than 50 species, many with identifiable ecological tolerances. These species hold potential as useful indicators of past and future ecosystem changes. In this study, we examined benthic ostracodes from nearly 300 surface sediment samples, >34,000 specimens...
Authors
Laura Gemery, Thomas M. Cronin, Lee W. Cooper, Harry J. Dowsett, Jacqueline M. Grebmeier