Research Geologist
Geology, Energy & Minerals Science Center
Email:
phackley@usgs.gov
Office Phone:
703-648-6458
Fax:
703-648-6419
ORCID:
0000-0002-5957-2551
Location
John W Powell FB
12201 Sunrise Valley Drive
Reston
, VA
20192-0002
US
Supervisor:
Evan A Bargnesi
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To test if reflectance increases to sedimentary organic matter (vitrinite) caused by broad ion beam (BIB) milling were related to molecular aromatization and condensation, we used Raman and Fourier transform infrared (FTIR) spectroscopies to evaluate potential compositional changes in the same vitrinite locations pre- and post-BIB milling. The same locations also were examined by atomic force microscopy (AFM) to determine topographic changes caused by BIB milling (as expressed by the areal root-mean-square roughness parameter Rq). Samples consisted of four medium volatile bituminous coals. We used a non-aggressive BIB milling approach with conditions of [(5 min, 4 keV, 15°incline, 360° rotation at 25 rpm and 100%...
Categories: Data;
Tags: Bituminous Coal,
Broad Ion Beam,
Coal resources,
Energy Resources,
Geochemistry, All tags...
Ion Milling,
Pennyslvania,
Sedimentary Organic Matter,
Thermal Maturity,
USGS Science Data Catalog (SDC),
Vitrinite reflectance, Fewer tags
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Solid organic matter (OM) in sedimentary rocks produces petroleum and solid bitumen when it undergoes thermal maturation. The solid OM is a 'geomacromolecule', usually representing a mixture of various organisms with distinct biogenic origins, and can have high heterogeneity in composition. Programmed pyrolysis is a common conventional method to reveal bulk geochemical characteristics of the dominant OM while detailed organic petrography is required to reveal information about the biogenic origin of contributing macerals. Despite advantages of programmed pyrolysis, it cannot provide information about the heterogeneity of chemical compositions present in the individual OM types. Therefore, other analytical techniques...
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The refractory nature of zircon to temperature and pressure allows even a single zircon grain to preserve a rich history of magmatic, metamorphic, and hydrothermal processes. Isotopic dating of micro-domains exposed in cross-sections of zircon grains allows us to interrogate this history. Unfortunately, our ability to select the zircon grains in a heavy mineral concentrate that records the most geochronologic information is limited by our inability to predict internal zonation from observations of whole zircon grains. Here we document the use of a petrographic microscope to observe and image the photoluminescence (PL) response of whole zircon grains excited under ultraviolet (UV) light, and the utility of this PL...
Categories: Data;
Tags: Adirondacks, NY,
Beauty Spot, NC,
Geochemistry,
Geochronology,
Sussex County, VA, All tags...
USGS Science Data Catalog (SDC),
Woodbury, CT, Fewer tags
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Geological models for petroleum generation suggest thermal conversion of oil-prone sedimentary organic matter in the presence of water promotes increased liquid saturate yield, whereas absence of water causes formation of an aromatic, cross-linked solid bitumen residue. To test the influence of exchangeable hydrogen from water, organic-rich (22 wt.% total organic carbon, TOC) mudrock samples from the Eocene lacustrine Green River Mahogany zone oil shale were pyrolyzed under hydrous and anhydrous conditions at temperatures between 300 and 370°C for 72 hrs. Petrographic approaches including optical microscopy, reflectance, Raman spectroscopy, and scanning electron and transmission electron microscopy, supplemented...
Categories: Data;
Tags: Anhydrous pyrolysis,
Colorado,
Energy Resources,
Garfield County,
Geochemistry, All tags...
Hydrous pyrolysis,
Organic petrography,
Petroleum generation,
Raman spectroscopy,
Rifle,
Solid bitumen,
Solid bitumen reflectance,
Thermal maturity,
USGS Science Data Catalog (SDC), Fewer tags
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This data release contains reflectance measurements for eight samples submitted to the USGS Organic Petrology Laboratory in Reston. Samples include two artificial rock samples made from cement with organic matter added (samples 001-002), a coal and shale sample (samples 003-004, respectively), and hydrous pyrolysis residues for samples 001-004. The hydrous pyrolysis experiments were conducted at 330°C for 72 hours at the United States Geological Survey's (USGS) Denver Federal Center. Samples were mounted into 1-inch circular briquettes in USGS-Reston according to ASTM D2797 for organic petrographic analysis. Cement plugs (samples 001-002, and pyrolysis residues 005-006) were crushed to approximately 1 mm top-size...
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