A5042713694- Paleontology and Stratigraphy of Fossils
- Geology and Paleoclimatology Research
- Geochemistry and Geologic Mapping
- Methane Hydrates and Related Phenomena
- Hydrocarbon exploration and reservoir analysis
- Geochemistry and Elemental Analysis
- Geological and Geochemical Analysis
- Geological formations and processes
- Isotope Analysis in Ecology
- Geological Studies and Exploration
- Marine Biology and Ecology Research
- Geological and Geophysical Studies
- Marine and environmental studies
- Ocean Acidification Effects and Responses
- Astro and Planetary Science
- Evolution and Paleontology Studies
- Atmospheric and Environmental Gas Dynamics
- earthquake and tectonic studies
- Oceanographic and Atmospheric Processes
- Archaeology and ancient environmental studies
- Cephalopods and Marine Biology
- Marine and coastal ecosystems
- Radioactive element chemistry and processing
- Geomagnetism and Paleomagnetism Studies
- Pleistocene-Era Hominins and Archaeology
Northwestern University
2015-2024
Korea Polar Research Institute
2020
Planetary Science Institute
1997-2015
University of Minnesota System
2002
Pennsylvania State University
1992-1998
University of Colorado System
1993
University of Colorado Boulder
1985-1993
Organic-carbon-rich strata or black shales, including dark gray to black, laminated, carbonaceous mudrocks characterized by impoverished benthonic faunas, devoid of metazoan life, have long intrigued geol ogists, both because their widespread distribution at certain times in the past and early recognition as potential hydrocarbon source rocks. One major obsessions many workers, mid1900s, was application uniformitarian principles depositional models for shales. Thus, although it recognized...
Research Article| February 01, 2006 Orbital time scale and new C-isotope record for Cenomanian-Turonian boundary stratotype Bradley B. Sageman; Sageman 1Department of Geological Sciences, Northwestern University, Evanston, Illinois 60208, USA Search other works by this author on: GSW Google Scholar Stephen R. Meyers; Meyers 2Department Geology Geophysics, Yale New Haven, Connecticut 06511, Michael A. Arthur 3Department Geosciences, Pennsylvania State University Park, 16802, Author Article...
High-resolution osmium (Os) isotope stratigraphy across the Cenomanian–Turonian Boundary Interval from 6 sections for four transcontinental settings has produced a record of seawater chemistry that demonstrates regional variability as function terrestrial and hydrothermal inputs, revealing impact palaeoenvironmental processes. In every section 187Os/188Os profiles show comparable trend; radiogenic values in lead up to Oceanic Anoxic Event 2 (OAE 2); an abrupt unradiogenic trend at onset OAE...
Integrated geochemical data suggest that black shale deposition in the Devonian Geneseo Formation of western New York was initiated by coincidence siliciclastic starvation and intensification seasonal water column stratification mixing. Once established, however, maintained through efficient recycling biolimiting nutrients which enhanced primary productivity. Recycling efficiency achieved a positive feedback loop oscillating benthic redox conditions N P regeneration from sediments, sustained...
Secular changes in bulk sedimentation have a significant impact on the preservation of climatic signals rhythmically bedded strata.In this study quantitative cyclostratigraphic methodology is developed to use these signal distortions as means reconstruct sedimentation.The method exploits moving-window Fourier technique that we designate ''evolutive harmonic analysis'' (EHA).We calibrate specific set geologic conditions (i.e., sedimentation) using series stratigraphic models and then apply...
An integrated lithologic, paleontologic, and multi-proxy geochemical study of the Middle Devonian Oatka Creek Formation, a black shale in northern Appalachian Basin, indicates that number different factors contributed to organic carbon-rich deposition. Conditions leading this organic-rich sedimentary deposit were ultimately controlled by relative sealevel rise, dominantly eustatic but with possible contributions from local tectonics, which cut off supply carbonate basin. Geochemical proxy...
Research Article| January 01, 2012 Intercalibration of radioisotopic and astrochronologic time scales for the Cenomanian-Turonian boundary interval, Western Interior Basin, USA Stephen R. Meyers; Meyers * 1Department Geoscience, University Wisconsin−Madison, 1215 West Dayton Street, Madison, Wisconsin 53706, *E-mail: smeyers@geology.wisc.edu. Search other works by this author on: GSW Google Scholar Sarah E. Siewert; Siewert Brad S. Singer; Singer Bradley B. Sageman; Sageman 2Department Earth...
An analysis of orbitally influenced climate‐sensitive sedimentation is conducted across a meridional transect the proto‐North Atlantic, to reconstruct behavior carbon cycle and climate during Oceanic Anoxic Event 2 (OAE 2; ∼94 Ma). Midlatitude near equatorial sites spanning deep‐ocean shelf environments are evaluated using new inverse method for identification calibration orbital influence in ancient strata. The results yield consistent independent astrochronologies at each...
Quantification of Milankovitch orbital cyclicity within ancient strata has become a principal tool for refinement the geologic time scale. However, accurate characterization signal in deep paleoclimate records is commonly challenged by inadequate radiometric constraints calibration spatial rhythms to temporal periods. This problem can potentially introduce large errors into derivative timescales. In this study we develop new method identification and cyclostratigraphic records. The (average...
This study revises and improves the chronostratigraphic framework for late Turonian through early Campanian time based on work in Western Interior U.S. introduces new methods to better quantify uncertainties associated with development of such scales. Building unique attributes Basin, which contains abundant volcanic ash beds rhythmic strata interpreted record orbital cycles, we integrate radioisotopic data improved accuracy a recently published astrochronologic Niobrara Formation. New...
Research Article| May 01, 2000 Eutrophication by decoupling of the marine biogeochemical cycles C, N, and P: A mechanism for Late Devonian mass extinction Adam E. Murphy; Murphy 1Department Geological Sciences, Northwestern University, Evanston, Illinois 60208, USA Search other works this author on: GSW Google Scholar Bradley B. Sageman; Sageman David J. Hollander Geology (2000) 28 (5): 427–430. https://doi.org/10.1130/0091-7613(2000)28<427:EBDOTM>2.0.CO;2 Article history received: 12 Oct...
Research Article| August 01, 1996 Estuarine circulation in the Turonian Western Interior seaway of North America Rudy Slingerland; Slingerland 1Department Geosciences, Pennsylvania State University, University Park, 16802 Search for other works by this author on: GSW Google Scholar Lee R. Kump; Kump Michael A. Arthur; Arthur Peter J. Fawcett; Fawcett Bradley B. Sageman; Sageman Eric Barron Author and Article Information Publisher: Geological Society First Online: 01 Jun 2017 Online ISSN:...
Research Article| June 01, 2009 When do black shales tell molybdenum isotope tales? G.W. Gordon; Gordon * 1School of Earth & Space Exploration, Arizona State University, Tempe, 85287-1404, USA *E-mail: Gwyneth.Gordon@asu.edu. Search for other works by this author on: GSW Google Scholar T.W. Lyons; Lyons 2Department Sciences, University California–Riverside, Riverside, California 92521-0423, G.L. Arnold; Arnold J. Roe; Roe 3Department and Environmental Rochester, New York 14627, B.B. Sageman;...
Research Article| November 01, 2008 Eustatic sea-level record for the Cenomanian (Late Cretaceous)—Extension to Western Interior Basin, USA Andrew S. Gale; Gale 11Department of Earth and Environmental Sciences, University Portsmouth, Portsmouth PO1 3QL, UK Search other works by this author on: GSW Google Scholar Silke Voigt; Voigt 22Leibniz Institute Marine 24148 Kiel, Germany Bradley B. Sageman; Sageman 33Department Geological Northwestern University, Evanston, Illinois 60208, William J....