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Reconstructing the paleoceanographic and redox conditions responsible for variations in uranium content in North American Devonian black shales

The uranium (U) content, and more recently, the ratio between 238U and 235U in black shales are commonly applied as a proxy to determine redox conditions and infer organic-richness. Uranium contents typically display a linear relationship with total organic carbon (TOC) in shales. This relationship is due to the processes and mechanisms responsible for the incorporation of U into the sediment duri
Authors
Michelle L. Abshire, Natascha Riedinger, John M. Clymer, Clint Scott, Silke Severmann, Stephen J. Romaniello, James O. Puckette

New insights into organic matter accumulation from high-resolution geochemical analysis of a black shale: Middle and Upper Devonian Horn River Group, Canada

Organic matter (OM) accumulation in organic matter-rich mudstones, or black shales, is generally recognized to be controlled by combinations of bioproductivity, preservation, and dilution. However, specific triggers of OM deposition in these formations are commonly difficult to identify with geochemical proxies, in part because of feedbacks that cause geochemical proxies for these controls to vary
Authors
Haolin Zhou, Nicholas B. Harris, Tian Dong, Korhan Ayranci, Jilu Feng, Benoit Rivard, Paul C. Hackley, Javin J. Hatcherian

Vitrinite reflectance analysis

Vitrinite is a maceral group (a set of organic matter types with similar properties and appearance) derived from the remains of woody material from vascular plants and is composed of the thermally evolved products of lignin and cellulose. Vitrinite is the dominant component of humic coal and is found as a minor component dispersed into sedimentary rocks, especially mudrocks, the primary source roc
Authors
Paul C. Hackley

Assessment of undiscovered continuous oil resources in the Bakken and Three Forks Formations of the Williston Basin Province, North Dakota and Montana, 2021

Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean resources of 4.3 billion barrels of oil and 4.9 trillion cubic feet of gas (associated) in the Bakken and Three Forks Formations of the Williston Basin Province, North Dakota and Montana.
Authors
Kristen R. Marra, Tracey J. Mercier, Sarah E. Gelman, Christopher J. Schenk, Cheryl A. Woodall, Andrea D. Cicero, Ronald M. Drake, Geoffrey S. Ellis, Thomas M. Finn, Michael H. Gardner, Jane S. Hearon, Benjamin G. Johnson, Jenny H. Lagesse, Phuong A. Le, Heidi M. Leathers-Miller, Kira K. Timm, Scott S. Young

Multimineral petrophysics of thermally immature Eagle Ford Group and Cretaceous mudstones, U.S. Geological Survey Gulf Coast 1 research wellbore in central Texas

Traditional petrophysical methods to evaluate organic richness and mineralogy using gamma-ray and resistivity log responses are not diagnostic in source rocks. We have developed a deterministic, nonproprietary method to quantify formation variability in total organic carbon (TOC) and three key mudrock mineralogical components of nonhydrocarbon-bearing source rock strata of the Eagle Ford Group by
Authors
Lauri A. Burke, Justin E. Birdwell, Stanley T. Paxton

Assessment of undiscovered conventional oil and gas resources of China, 2020

Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean resources of 13.4 billion barrels of oil and 244.4 trillion cubic feet of gas in nine geologic provinces of China.
Authors
Christopher J. Schenk, Tracey J. Mercier, Cheryl A. Woodall, Geoffrey S. Ellis, Thomas M. Finn, Phuong A. Le, Kristen R. Marra, Heidi M. Leathers-Miller, Ronald M. Drake

Alaska natural gas hydrate production testing: Test site selection, characterization and testing operations

This Interagency Agreement supports the U.S. Department of Energy (DOE) and its research partners in understanding, predicting, and testing the recoverability and potential production characteristics of onshore natural gas hydrate in the Greater Prudhoe Bay area on the Alaska North Slope (ANS: Prudhoe Bay, Kuparuk River, and Milne Point areas) or other areas deemed suitable by DOE and USGS for pot
Authors
Timothy Collett

Capacity assessment for Earth Monitoring, Analysis, and Prediction (EarthMAP) and future integrated monitoring and predictive science at the U.S. Geological Survey

Executive SummaryManagers of our Nation’s resources face unprecedented challenges driven by the convergence of increasing, competing societal demands and a changing climate that affects the stability, vulnerability, and predictability of those resources. To help meet these challenges, the scientific community must take advantage of all available technologies, data, and integrative Earth systems mo
Authors
Jennifer L. Keisman, Sky Bristol, David S. Brown, Allison K. Flickinger, Gregory L. Gunther, Peter S. Murdoch, MaryLynn Musgrove, John C. Nelson, Gregory D. Steyer, Kathryn A. Thomas, Ian R. Waite

Oil and gas wastewater components alter streambed microbial community structure and function

The widespread application of directional drilling and hydraulic fracturing technologies expanded oil and gas (OG) development to previously inaccessible resources. A single OG well can generate millions of liters of wastewater, which is a mixture of brine produced from the fractured formations and injected hydraulic fracturing fluids (HFFs). With thousands of wells completed each year, safe manag
Authors
Denise M. Akob, Adam Mumford, Andrea Fraser, Cassandra Rashan Harris, William H. Orem, Matthew S. Varonka, Isabelle M. Cozzarelli

Random forest

This entry defines and discusses the random forest machine learning algorithm. The algorithm is used to predict class or quantities for target variables using values of a set of predictor variables. It uses decision trees that are generated from bootstrap sampling of the training data set to create a "forest". The entry discusses the algorithm steps, the interpretative tools of the resulting mode
Authors
Emil D. Attanasi, Timothy Coburn

Impacts of climate change on groundwater availability and spring flows: Observations from the highly productive Medicine Lake Highlands/Fall River Springs Aquifer System

Medicine Lake Highlands/Fall River Springs Aquifer System, located in northeastern California, is home to some of the largest first-order springs in the United States. This work assesses the likely effects of projected climate change on spring flow. Four anticipated climate futures (GFDL A2, GFDL B1, CCSM4 rcp 8.5, CNRM rcp 8.5) for California, which predict a range of conditions (generally warmin
Authors
Lauren K Mancewicz, L. Davisson, Shawn J Wheelock, Erick R. Burns, Simon R. Poulson, Scott W. Tyler
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