Publications

Molecular characterization of sedimentary organic matter (SOM), termed macerals, is a common goal when seeking to understand petroleum generation as well as other geologic processes in deep time. However, unambiguous measurement of discrete macerals is challenging due to the small size of organic particles in sedimentary rocks, the proximity of different organic matter types to one...

Solid bitumen reflectance (BRo in %) is widely used as a thermal maturity proxy in source-rock reservoirs, yet solid bitumen texture and physical attributes may be affected by varying environmental constraints during its formation, e.g., water saturation, mineral catalysis, or salinity. Herein we investigated the development of solid bitumen properties during artificial maturation using...

Estimates of dynamic groundwater volumes supplying baseflow to streams are important for water availability projections during extended periods of drought. The primary goals of this study were to provide dynamic storage volume estimates, inferred from streamflow recession analysis, for baseflow regimes within seven gaged catchments within the Neversink Reservoir Watershed (NRW), a...

Bedrock roadcuts developed with blasting along the New Hampshire State Route 111 bypass in Windham expose the metasedimentary Silurian Berwick Formation and intrusions of multiple phases of foliated to nonfoliated granite to granitic pegmatite of the Devonian New Hampshire Plutonic Suite. Fracture characterization at two roadway rock cuts (roadcuts) included measurement of fractures over...

Study of the accretionary biomineralised hardparts of organisms (sclerochronology) can make a useful contribution to palaeoclimatology. Ontogenetic sequences of isotopic data (δ18O and Δ47 values) from the shells of marine molluscs are a source of information on seasonal sea-surface temperatures that can be used for detailed and rigorous evaluation of the outputs of numerical climate...

This is the second volume in the U.S. Geological Survey (USGS) series of reports on stratigraphy entitled “Stratigraphic Notes,” which consists of short papers that highlight stratigraphic studies, changes in stratigraphic nomenclature, and explanations of stratigraphic names and concepts used on published geologic maps. “Stratigraphic Notes” is a long-term (multiyear), multivolume...

Many mountain belts are built through repeated collision, and in the case of orogenies closely spaced in time, determining when one orogeny ends and another begins can be challenging. The southern Appalachian mountains were formed by three mountain-building events closely spaced in time, including the Taconic (ca. 480–440 Ma), Neoacadian (ca. 375–340 Ma), and Alleghanian (ca. 330–265 Ma)...

Pollen records from the unglaciated southeastern region of North America provide an overview of biogeographic changes associated with vegetational migration northward following the retreat of the Laurentide Ice Sheet. Changing insolation during the Holocene affected forest composition on the Coastal Plain, and rising sea level controlled the distribution of marsh and forested wetlands...

To test the influence of environmental conditions on aromaticity of solid bitumen generated during petroleum generation, four organic-rich (26–36 wt% total organic carbon) oil shale samples collected from the Neoproterozoic–Lower Cambrian restricted marine Salt Range Formation in the upper Indus Basin, Pakistan, were pyrolyzed under hydrous and anhydrous conditions. Experiments used...

Cretaceous sediments are disconformably overlain by Pliocene sediments along the banks of Greens Mill Run, Greenville, North Carolina, located in the central coastal plain. The Cretaceous sediments, composed of glauconitic sand and clay, have previously been informally considered part of the Maastrichtian Peedee Formation. The Pliocene sediments are assigned to the Yorktown Formation and...

The Paleocene-Eocene thermal maximum (PETM; ∼56 Ma) is a hyperthermal event associated with the rapid input of carbon into the ocean-atmosphere system. The oxidation of petrogenic organic carbon (OCpetro) may have released additional carbon dioxide (CO2), thereby prolonging the PETM. However, proxy-based estimates of OCpetro oxidation are unavailable due to the lack of suitable...

Carbon fluxes in tidal brackish marshes play a critical role in determining coastal wetland carbon sequestration and storage, thus affecting carbon crediting of coastal wetland restoration. In this study, a process-driven wetland biogeochemistry model, Wetland Carbon Assessment Tool DeNitrification-DeComposition was applied to nine brackish marsh sites in Mississippi River (MR) Deltaic...