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Pysochron: A Python-based solution for calculating cosmogenic 26Al/10Be isochron burial ages Pysochron: A Python-based solution for calculating cosmogenic 26Al/10Be isochron burial ages

Cosmogenic 26Al/10Be isochron burial dating is a powerful tool for dating sediment burial over the past several million years. By measuring in-situ 26Al and 10Be in a suite of samples from the same depth in a buried deposit, it is possible to quantify the inventory of cosmogenic nuclides produced after burial, date the burial of shallow sediments, identify sediment reworking, and...
Authors
William Elijah Odom

Shifting baselines of coral-reef species composition from the Late Pleistocene to the present in the Florida Keys Shifting baselines of coral-reef species composition from the Late Pleistocene to the present in the Florida Keys

The ongoing global-scale reassembly of modern coral reefs is unprecedented compared with the observed stability of most late Quaternary reef assemblages. One notable exception is the marine isotope stage (MIS) 5e (ca 130–116 thousand years ago [ka]) reefs in the Florida Keys, where the ubiquitous shallow-water coral, Acropora palmata, was near absent. Little is known, however, about...
Authors
Lauren Toth, Anastasios Stathakopoulos, Scarlette Shan-Hwei Hsia, David A. Weinstein

Ecological thresholds and transformations due to climate change: The role of abiotic stress Ecological thresholds and transformations due to climate change: The role of abiotic stress

An ecological threshold is the point at which a comparatively small environmental change triggers an abrupt and disproportionately large ecological response. In the face of accelerating climate change, there is concern that abrupt ecosystem transformations will become more widespread as critical ecological thresholds are crossed. There has been ongoing debate, however, regarding the...
Authors
Michael Osland, John B. Bradford, Lauren Toth, Matthew J. Germino, James Grace, Judith Z. Drexler, Camille L. Stagg, Eric E. Grossman, Karen M. Thorne, Stephanie Romanach, Davina Passeri, Gregory E. Noe, Jessica R. Lacy, Ken Krauss, Kurt P. Kowalski, Glenn R. Guntenspergen, Neil K. Ganju, Nicholas Enwright, Joel A. Carr, Kristin B. Byrd, Kevin Buffington

Geochemical and tectonic evolution of the Ordovician Bronson Hill arc and Silurian and Devonian Connecticut Valley–Gaspé trough: Eastern Vermont and western New Hampshire, USA Geochemical and tectonic evolution of the Ordovician Bronson Hill arc and Silurian and Devonian Connecticut Valley–Gaspé trough: Eastern Vermont and western New Hampshire, USA

We present major and trace element whole-rock geochemistry of 94 samples from the Bronson Hill arc (BHA) and Connecticut Valley–Gaspé trough (CVGT). These data, when combined with recent zircon U-Pb geochronology and a reexamination of existing whole-rock geochemistry, enable a new analysis of the tectonic history of the ancient Laurentian-Ganderian margin in the northern Appalachians of...
Authors
Peter M. Valley, Gregory J. Walsh, Arthur J. Merschat, Ryan J. McAleer

Nanometer-scale relationships between sedimentary organic matter molecular composition, fluorescence, cathodoluminescence, and reflectance: The importance of oxygen content at low thermal maturities Nanometer-scale relationships between sedimentary organic matter molecular composition, fluorescence, cathodoluminescence, and reflectance: The importance of oxygen content at low thermal maturities

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...
Authors
Aaron M. Jubb, Paul C. Hackley, Ryan J. McAleer, Jing Qu

Properties of solid bitumen formed during hydrous, anhydrous, and brine pyrolysis of oil shale: Implications for solid bitumen reflectance in source-rock reservoirs Properties of solid bitumen formed during hydrous, anhydrous, and brine pyrolysis of oil shale: Implications for solid bitumen reflectance in source-rock reservoirs

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...
Authors
Paul C. Hackley, Justin E. Birdwell, Ryan J. McAleer

Stratigraphy, structure, and geomorphology of the central Appalachians across the North Mountain fault zone near Harrisonburg, Virginia, USA Stratigraphy, structure, and geomorphology of the central Appalachians across the North Mountain fault zone near Harrisonburg, Virginia, USA

This field trip focuses on the geology of the central Appalachian Valley and Ridge province near Harrisonburg, Virginia, USA. Recent geologic mapping utilizing 1-m resolution lidar data has revealed new insights into the Paleozoic stratigraphy, structural geology, and Neogene landscape evolution of the region. The detailed mapping reveals the presence of the Big Spring Station Member and...
Authors
Daniel H. Doctor, Alexander Addison Gray, William Elijah Odom

Dynamic baseflow storage estimates and the role of topography, geology and evapotranspiration on streamflow recession characteristics in the Neversink Reservoir Watershed, New York Dynamic baseflow storage estimates and the role of topography, geology and evapotranspiration on streamflow recession characteristics in the Neversink Reservoir Watershed, New York

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...
Authors
Joshua R. Benton, Daniel H. Doctor

Bedrock fracture characterization of the New Hampshire State Route 111 bypass, Windham, New Hampshire Bedrock fracture characterization of the New Hampshire State Route 111 bypass, Windham, New Hampshire

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...
Authors
Gregory J. Walsh, Nicholas Edwin Powell

Molluscan isotope sclerochronology in marine palaeoclimatology: Taxa, technique and timespan issues Molluscan isotope sclerochronology in marine palaeoclimatology: Taxa, technique and timespan issues

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...
Authors
Andrew Johnson, Bernd Schone, Sierra V. Petersen, Niels de Winter, Harry J. Dowsett, Jean-Francois Cudennec, Elizabeth Harper, Ian Winkelstern

The National Park Service Stratotype Inventory The National Park Service Stratotype Inventory

Beginning in 2020, the National Park Service (NPS) began a systematic effort to document the occurrence of stratotypes exposed within, partially within, and near NPS administrative boundaries. The NPS stratotype inventory project represents an important component of a geologic resource inventory, as these designations are vital to our national geologic heritage (“geoheritage”) and...
Authors
Tim C. Henderson, Vince L. Santucci, Justin S. Tweet, Tim Connors, Nancy R. Stamm, Randall C. Orndorff, David R. Soller, Cullen Scheland
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