Publications
Filter Total Items: 825
Stop 3 – The Petersburg “Granite” redefined: Recognition and implications of Silurian to Devonian rocks in central-eastern Virginia
Introduction Although the Petersburg Granite had long been in practical use as a building stone since the 1830s (Watson, 1906; 1907; 1910; Darton, 1911; Steidtmann, 1945), it was first formally defined as a geologic unit by Anna Jonas on the 1928 geologic map of Virginia. Anna Jonas defined this unit as a Precambrian coarse-grained porphyritic biotite granite that was intruded by finer grained gra
Authors
Mark W. Carter, Ryan J. McAleer, Marcie Occhi, Christopher Holm-Denoma, Jorge A. Vazquez, Brent E. Owens
Stratigraphy and age of a prominent paleosol in a late Pleistocene sedimentary sequence, Mason Neck, Virginia
The High Point paleosol is 2.28-meters-thick aggradational soil developed in fining upward estuarine-alluvial sand and loess. The paleosol is exposed in a few shoreline cliff faces of Mason Neck, Virginia. Although a former A horizon is missing, the E, Bw, Bt, and C horizon sequence seen in the sediments indicates subaerial pedogenesis. Pedogenesis began with initial estuarine-alluvial floodplain
Authors
Helaine W. Markewich, Douglas A. Wysocki, Milan J. Pavich, Joseph P. Smoot, Ronald J. Litwin
The statistical power to detect regional temporal trends in riverine contaminants in the Chesapeake Bay Watershed, USA
Chemical contamination of riverine ecosystems is largely a result of urbanization, industrialization, and agricultural activities occurring on adjacent terrestrial landscapes. Land management activities (e.g., Best Management Practices) are an important tool used to reduce point and non-point sources of pollution. However, the ability to confidently make inferences about the efficacy of land manag
Authors
Tyler Wagner, Paul McLaughlin, Kelly L. Smalling, Sara E. Breitmeyer, Stephanie Gordon, Gregory Noe
The presence of denitrifiers in bacterial communities of urban stormwater best management practices (BMPs)
Stormwater best management practices (BMPs) are engineered structures that attempt to mitigate the impacts of stormwater, which can include nitrogen inputs from the surrounding drainage area. The goal of this study was to assess bacterial community composition in different types of stormwater BMP soils to establish whether a particular BMP type harbors more denitrification potential. Soil sampling
Authors
Natalie Hall, Masoumeh Sikaroodi, Dianna M. Hogan, R. Christian Jones, Patrick Gillevet
Review of ESA SYMP 7: A dynamic perspective on ecosystem restoration–establishing temporal connectivity at the intersection between paleoecology and restoration ecology
Landscape connectivity is vital not only spatially, but also temporally; as ecosystems change, it is important to be aware of past, present, and future variables that may impact ecosystem function and biodiversity. As climate and environments continue to change, choosing appropriate restoration targets is becoming more challenging. By considering the paleoecological and paleoenvironmental record f
Authors
Rachel Reid, Jenny McGuire, Jens-Christiane Svenning, G. Lynn Wingard, David Moreno-Mateos
Calcareous plankton biostratigraphic fidelity and species richness during the last 10 m.y. of the Cretaceous at Blake Plateau, subtropical North Atlantic
Species distributions of well-preserved and diverse assemblages of planktonic foraminifera and calcareous nannofossils spanning the last 10 m.y. of the Cretaceous (middle Campanian through Maastrichtian) are analyzed from samples taken across a 1400 m depth transect at Blake Nose in the western subtropical North Atlantic (Ocean Drilling Program Sites 1049, 1050 and 1052). Age models constructed by
Authors
Brian T. Huber, Nataliya A. Tur, Jean Self-Trail, Kenneth G. MacLeod
The Yorktown Formation: Improved stratigraphy, chronology and paleoclimate interpretations from the U.S. mid-Atlantic Coastal Plain
The Yorktown Formation records paleoclimate conditions along the mid-Atlantic Coastal Plain during the mid-Piacenzian Warm Period (3.264 to 3.025 Ma), a climate interval of the Pliocene in some ways analogous to near future climate projections. To gain insight into potential near future changes, we investigated Yorktown Formation outcrops and cores in southeastern Virginia, refining the stratigrap
Authors
Harry J. Dowsett, Marci M. Robinson, Kevin M. Foley, Timothy D. Herbert
A practical solution: The Anthropocene is a geological event, not a formal epoch
The Anthropocene has yet to be defined in a way that is functional both to the international geological community and to the broader fields of environmental and social sciences. Formally defining the Anthropocene as a chronostratigraphical series and geochronological epoch with a precise global start date would drastically reduce the Anthropocene’s utility across disciplines. Instead, we propose t
Authors
Philip Gibbard, Andrew M Bauer, Matthew Edgeworth, William F Ruddiman, Jacquelyn L. Gill, Merritts. Dorothy J, Stanley C. Finney, Lucy E. Edwards, Michael J.C. Walker, Mark Maslin, Erle C Ellis
Proportions, timing, and re-equilibration progress during the 1959 Summit Eruption of Kīlauea: An example of magma mixing processes operating during OIB petrogenesis
Petrographic and chemical analysis of scoria samples collected during the 1959 Kīlauea summit eruption illustrates the progress of thermal and chemical homogenization of the melts, and the gradual growth and/or re-equilibration of olivine phenocrysts, over the course of the eruption. Glass compositions show that thermal equilibration was largely complete within the span of the eruption, whereas ch
Authors
Rosalind L. Helz
PlioMIP: The Pliocene Model Intercomparison Project
PlioMIP is a network of paleoclimate modelers and geoscientists who, through the study of the mid-Pliocene Warm Period (mPWP ~3.3–3.0 million years ago), seek to understand the sensitivity of the climate system to forcings and examine how well models reproduce past climate change.
Authors
A. M. Haywood, Harry J. Dowsett
Postcards from the field
My research focuses on pre-20th century conditions in the Greater Everglades Ecosystem of south Florida to provide the context for resource managers to set targets for restoration. A primary goal of Everglades restoration is to re-establish more natural delivery of freshwater to the wetlands and estuaries in the region. By analyzing biotic assemblages from sediment cores collected from Florida B
Authors
G. Lynn Wingard
Diagenetic barite-pyrite-wurtzite formation and redox signatures in Triassic mudstone, Brooks Range, northern Alaska
Mineralogical and geochemical studies of interbedded black and gray mudstones in the Triassic part of the Triassic-Jurassic Otuk Formation (northern Alaska) document locally abundant barite and pyrite plus diverse redox signatures. These strata, deposited in an outer shelf setting at paleolatitudes of ~45 to 60°N, show widespread sedimentological evidence for bioturbation. Barite occurs preferenti
Authors
John F. Slack, Ryan J. McAleer, Wayne (Pat) Shanks, Julie A. Dumoulin