Paul C. Hackley, Ph.D.
Paul Hackley is a Research Geologist with the USGS Geology, Energy & Minerals (GEM) Science Center in Reston, VA.
As project chief of the Thermal Indices project I pursue research on thermal maturity, chemical composition and physical state of sedimentary organic matter. The Thermal Indices project is part of the Geology, Energy & Minerals (GEM) Science Center and is funded by the Energy Resources Program (ERP). The Thermal Indices project team develops and applies petrographic methods for the reliable identification of different types of sedimentary organic matter, and measures and interprets the response of organic matter to thermal stress in natural environments and in laboratory-based heating experiments. Improved understanding of the thermal evolution of sedimentary organic matter enables more accurate assessment of petroleum source rock maturation, thereby decreasing uncertainty in the determination of thermal histories, the timing of petroleum generation and the placement of resource assessment spatial boundaries. This leads to the overall goal of improving estimates of undiscovered petroleum resources, which is a central mission of the ERP.
My work focuses on four integrated research task areas which have petrographic approaches to thermal indices as their common denominator: 1) standardization and reproducibility of measurement, 2) utilization of hydrous pyrolysis for (artificial) thermal conversion of sedimentary organic matter, 3) petrographic innovation areas for thermal indices and organic evolution, and 4) petrographic laboratory support.
Thermal indices research is accomplished from the Organic Petrology and Hydrous Pyrolysis laboratories in Reston. The laboratories include facilities for sample preparation, hydrous pyrolysis, optical and fluorescence microscopy, and infrared spectroscopy. The Thermal Indices project team works with external collaborators from global academic, government and industry groups. All thermal indices research efforts reach toward the goal of improving fossil fuel resource assessments by generating new understanding of the processes occurring during thermal evolution of sedimentary organic matter and its conversion to petroleum.
Professional Experience
Unconventional petroleum systems
Conventional oil and gas assessment
Coalbed methane
Coal
Application of organic petrology techniques to fossil fuel resource assessment
Education and Certifications
Ph.D., George Mason University
M.S., George Washington University
B.A., Shippensburg State University
Affiliations and Memberships*
The Society for Organic Petrology (TSOP)
International Committee for Coal and Organic Petrology (ICCP)
American Association of Petroleum Geologists (AAPG)
American Society for Testing and Materials (ASTM)
Geological Society of America (GSA)
Science and Products
Filter Total Items: 44
Data from Nanoscale Molecular Fractionation of Organic Matter within Unconventional Petroleum Source Beds (2019)
Fractionation of petroleum during migration through sedimentary rock matrices has been observed across lengths of meters to kilometers. Selective adsorption of specific chemical moieties at mineral surfaces and/or the phase behavior of petroleum during pressure changes are typically invoked to explain this behavior. Given the current emphasis on unconventional (continuous) resources, there is a ne
USGS Gulf Coast Petroleum Systems and National and Global Oil and Gas Assessment Projects-Louisiana-Mississippi Salt Basins and Western Gulf Provinces, Upper Cretaceous Tuscaloosa Marine Shale Assessment Unit Boundaries and Assessment Input Data Forms
This data release contains the boundaries of assessment units and input data for the assessment of undiscovered gas hydrate resources on the north slope of Alaska. The Assessment Unit is the fundamental unit used in the National Assessment Project for the assessment of undiscovered oil and gas resources. The Assessment Unit is defined within the context of the higher-level Total Petroleum System.
Petroleum geology data from Cenozoic rock samples in the eastern U.S. Gulf Coast collected 2014 to 2016
The U.S. Geological Survey assessed undiscovered petroleum resources in the downdip Paleogene formations of the U.S. Gulf Coast in 2018. During the assessment new data and information were collected to evaluate thermal maturity, source rock character, and unconventional reservoir rock prospectivity for the Cenozoic-aged section in south Louisiana. Samples were analyzed using multiple analytical ap
Mercury injection capillary pressure data in the U.S. Gulf Coast Tuscaloosa Group in Mississippi and Louisiana collected 2015 to 2017
This data release contains mercury injection capillary pressure (MICP), pseudo-wetting saturation, and carbon dioxide (CO2) column height data for subsurface Tuscaloosa Group samples from Mississippi and Louisiana.
High Microscale Variability in Raman Thermal Maturity Estimates from Shale Organic Matter - Data Release
Here the spatial variation in Raman estimates of thermal maturity within individual organic domains from several shale geologic reference materials originating from the Boquillas, Marcellus, Niobrara, and Woodford Formations are assessed from the respective Raman response. We show that for all four shales the thermal maturity parameters extracted from Raman spectra by iterative peak fitting can va
DDT and related compounds in pore water of shallow sediments on the Palos Verdes Shelf, CA
For nearly two and a half decades following World War II, production wastes from the worlds largest manufacturer of technical DDT were discharged into sewers of Los Angeles County. Following treatment, the wastes were released via a submarine outfall system to nearshore coastal waters where a portion accumulated in shallow sediments of the Palos Verdes Shelf (PVS). An investigation of the pore-wat
Petroleum geology data from Mesozoic rock samples in the eastern U.S. Gulf Coast collected 2011 to 2017
This data release contains Rock-Eval pyrolysis, organic petrographic (reflectance), and X-ray diffraction mineralogy data for subsurface Mesozoic rock samples from the eastern onshore Gulf Coast Basin (primarily Mississippi and Louisiana). Samples were analyzed in support of the U.S. Geological Survey (USGS) assessment of undiscovered petroleum resources in the Upper Cretaceous Tuscaloosa marine s
Appendices for Transgressive-regressive cycles in the metalliferous, oil shale-bearing Heath Formation (Upper Mississippian), central Montana
This set of data files are the appendices for paper titled Transgressive-regressive cycles in the metalliferous, oil shale-bearing Heath Formation (Upper Mississippian), central Montana. The dataset consists of 8 appendices, including a histogram of solid bitumen and vitrinite Ro values, gas chromatograms, isotopic data, organic and inorganic geochemical analyses, and x-ray diffraction mineralogy
Filter Total Items: 144
Investigating the effects of broad ion beam milling to sedimentary organic matter: Surface flattening or heat-induced aromatization and condensation?
Previous work has proposed transfer of kinetic heat energy from low-energy broad ion beam (BIB) milling causes thermal alteration of sedimentary organic matter, resulting in increases of organic matter reflectance. Whereas, other studies have suggested the organic matter reflectance increase from BIB milling is due to decreased surface roughness. To test if reflectance increases to sedimentary org
Authors
Paul C. Hackley, Aaron M. Jubb, Brett J. Valentine, Javin J. Hatcherian, Jing-Jiang Yu, William K. Podrazky
Examination of inertinite within immature Eagle Ford Shale at the nanometer-scale using atomic force microscopy-based infrared spectroscopy
The nanoscale molecular composition of sedimentary organic matter is challenging to characterize in situ given the limited tools available that can adequately interrogate its complex chemical structure. This is a particularly relevant issue in source rocks, as kerogen composition will strongly impact its reactivity and so is critical to understanding petroleum generation processes during catagenes
Authors
Aaron M. Jubb, Paul C. Hackley, Justin E. Birdwell, Javin J. Hatcherian, Jing Qu
Photoluminescence imaging of whole zircon grains on a petrographic microscope—An underused aide for geochronologic studies
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 ge
Authors
Ryan J. McAleer, Aaron M. Jubb, Paul C. Hackley, Gregory J. Walsh, Arthur J. Merschat, Sean P. Regan, William C. Burton, Jorge A. Vazquez
Characterization of the unconventional Tuscaloosa marine shale reservoir in southwestern Mississippi, USA: Insights from optical and SEM petrography
This study presents new optical petrography and electron microscopy data, interpreted in the context of previously published petrophysical, geochemical, and mineralogical data, to further characterize the Tuscaloosa marine shale (TMS) as an unconventional reservoir in southwestern Mississippi. The basal high resistivity zone has a higher proportion of Type II sedimentary organic matter than the ov
Authors
Celeste D. Lohr, Brett J. Valentine, Paul C. Hackley, Frank T. Dulong
Nanoscale molecular composition of solid bitumen from the Eagle Ford Group across a natural thermal maturity gradient
Microscopic solid bitumen is a petrographically defined secondary organic matter residue produced during petroleum generation and subsequent oil transformation. The presence of solid bitumen impacts many reservoir properties including porosity, permeability, and hydrocarbon generation and storage, among others. Furthermore, solid bitumen reflectance is an important parameter for assessing the ther
Authors
Aaron M. Jubb, Justin E. Birdwell, Paul C. Hackley, Javin J. Hatcherian, Jing Qu
Sample mounting for organic petrology: No thermal effects from transient exposure to elevated temperatures
For sample mounting, organic petrology laboratories typically use cold-setting epoxy-resin (e.g., 40 °C, used by Oklahoma Geological Survey, OGS) or heat-setting thermoplastic (e.g., 180 °C, used by U.S. Geological Survey, USGS). Previous workers have suggested a systematic huminite/vitrinite reflectance (VRo) increase was associated with the thermoplastic preparation process, relative to epoxy mo
Authors
Paul C. Hackley, Brian J. Cardott
Fluorescence spectroscopy of ancient sedimentary organic matter via confocal laser scanning microscopy (CLSM)
Fluorescence spectroscopy via confocal laser scanning microscopy (CLSM) was used to analyze ancient sedimentary organic matter, including Tasmanites microfossils in Devonian shale and Gloecapsomorpha prisca (G. prisca) in Ordovician kukersite from North American basins. We examined fluorescence emission as a function of excitation laser wavelength, sample orientation, and with respect to location
Authors
Paul C. Hackley, Aaron M. Jubb, Robert Burruss, Amy E Beaven
Oil-source rock correlation studies in the unconventional Upper Cretaceous Tuscaloosa marine shale (TMS) petroleum system, Mississippi and Louisiana, USA
The U.S. Geological Survey assessed undiscovered unconventional hydrocarbon resources reservoired in the Upper Cretaceous Tuscaloosa marine shale (TMS) of southern Mississippi and adjacent Louisiana in 2018. As part of the assessment, oil-source rock correlations were examined in the TMS play area where operators produce light (38–45° API), sweet oil from horizontal, hydraulically-fractured wells
Authors
Paul C. Hackley, Kristin Opferkuch Dennen, Daniel Garza, Celeste Lohr, Brett Valentine, Javin J. Hatcherian, Catherine B. Enomoto, Frank T. Dulong
Evidence of wildfires and elevated atmospheric oxygen at the Frasnian–Famennian boundary in New York (USA): Implications for the Late Devonian mass extinction
The Devonian Period experienced significant fluctuations of atmospheric oxygen (O2) levels (∼25–13%), for which the extent and timing are debated. Also characteristic of the Devonian Period, at the Frasnian–Famennian (F–F) boundary, is one of the “big five” mass extinction events of the Phanerozoic. Fossilized charcoal (inertinite) provides a record of wildfire events, which in turn can provide in
Authors
Zeyang Liu, David Selby, Paul C. Hackley, Jeffrey Over
Applications of correlative light and electron microscopy (CLEM) to organic matter in the North American shale petroleum systems
Scanning electron microscopy (SEM) has revolutionized our understanding of shale petroleum systems through microstructural characterization of dispersed organic matter (OM). However, due to the low atomic weight of carbon, all OM appears black in SEM (BSE image) regardless of differences in thermal maturity or OM type (kerogen types or solid bitumen). Traditional petrographic identification of OM
Authors
Brett J. Valentine, Paul C. Hackley
A chemo-mechanical snapshot of in-situ conversion of kerogen to petroleum
Organic matter (OM) from various biogenic origins converts to solid bitumen in-situ when it undergoes thermal maturation. It is well documented that during this process, the ratios of both hydrogen and oxygen to carbon will decrease, resulting in an increase in OM aromaticity and molecular chemo-mechanical homogeneity. Although there have been extensive efforts to reveal molecular alteration occur
Authors
Arash Abarghani, Mehdi Ostadhassan, Paul C. Hackley, Andrew E. Pomerantz, Siamak Nejati
Evidence of cosmic impact at Abu Hureyra, Syria at the Younger Dryas Onset (~12.8 ka): High-temperature melting at >2200 °C
At Abu Hureyra (AH), Syria, the 12,800-year-old Younger Dryas boundary layer (YDB) contains peak abundances in meltglass, nanodiamonds, microspherules, and charcoal. AH meltglass comprises 1.6 wt.% of bulk sediment, and crossed polarizers indicate that the meltglass is isotropic. High YDB concentrations of iridium, platinum, nickel, and cobalt suggest mixing of melted local sediment with small qua
Authors
Andrew M.T. Moore, James P. Kennett, Douglas J. Kennett, William M. Napier, Ted E. Bunch, James C. Weaver, Malcolm A. LeCompte, Victor Adedji, Paul C. Hackley, Jacob B. Lowenstern, Gunther K. Kletetschka, Brendan J. Culleton, Robert E. Hermes, James H. Wittke, Joshua J. Razink, Michael Gaultois, Allen West
Science and Products
Filter Total Items: 44
Data from Nanoscale Molecular Fractionation of Organic Matter within Unconventional Petroleum Source Beds (2019)
Fractionation of petroleum during migration through sedimentary rock matrices has been observed across lengths of meters to kilometers. Selective adsorption of specific chemical moieties at mineral surfaces and/or the phase behavior of petroleum during pressure changes are typically invoked to explain this behavior. Given the current emphasis on unconventional (continuous) resources, there is a ne
USGS Gulf Coast Petroleum Systems and National and Global Oil and Gas Assessment Projects-Louisiana-Mississippi Salt Basins and Western Gulf Provinces, Upper Cretaceous Tuscaloosa Marine Shale Assessment Unit Boundaries and Assessment Input Data Forms
This data release contains the boundaries of assessment units and input data for the assessment of undiscovered gas hydrate resources on the north slope of Alaska. The Assessment Unit is the fundamental unit used in the National Assessment Project for the assessment of undiscovered oil and gas resources. The Assessment Unit is defined within the context of the higher-level Total Petroleum System.
Petroleum geology data from Cenozoic rock samples in the eastern U.S. Gulf Coast collected 2014 to 2016
The U.S. Geological Survey assessed undiscovered petroleum resources in the downdip Paleogene formations of the U.S. Gulf Coast in 2018. During the assessment new data and information were collected to evaluate thermal maturity, source rock character, and unconventional reservoir rock prospectivity for the Cenozoic-aged section in south Louisiana. Samples were analyzed using multiple analytical ap
Mercury injection capillary pressure data in the U.S. Gulf Coast Tuscaloosa Group in Mississippi and Louisiana collected 2015 to 2017
This data release contains mercury injection capillary pressure (MICP), pseudo-wetting saturation, and carbon dioxide (CO2) column height data for subsurface Tuscaloosa Group samples from Mississippi and Louisiana.
High Microscale Variability in Raman Thermal Maturity Estimates from Shale Organic Matter - Data Release
Here the spatial variation in Raman estimates of thermal maturity within individual organic domains from several shale geologic reference materials originating from the Boquillas, Marcellus, Niobrara, and Woodford Formations are assessed from the respective Raman response. We show that for all four shales the thermal maturity parameters extracted from Raman spectra by iterative peak fitting can va
DDT and related compounds in pore water of shallow sediments on the Palos Verdes Shelf, CA
For nearly two and a half decades following World War II, production wastes from the worlds largest manufacturer of technical DDT were discharged into sewers of Los Angeles County. Following treatment, the wastes were released via a submarine outfall system to nearshore coastal waters where a portion accumulated in shallow sediments of the Palos Verdes Shelf (PVS). An investigation of the pore-wat
Petroleum geology data from Mesozoic rock samples in the eastern U.S. Gulf Coast collected 2011 to 2017
This data release contains Rock-Eval pyrolysis, organic petrographic (reflectance), and X-ray diffraction mineralogy data for subsurface Mesozoic rock samples from the eastern onshore Gulf Coast Basin (primarily Mississippi and Louisiana). Samples were analyzed in support of the U.S. Geological Survey (USGS) assessment of undiscovered petroleum resources in the Upper Cretaceous Tuscaloosa marine s
Appendices for Transgressive-regressive cycles in the metalliferous, oil shale-bearing Heath Formation (Upper Mississippian), central Montana
This set of data files are the appendices for paper titled Transgressive-regressive cycles in the metalliferous, oil shale-bearing Heath Formation (Upper Mississippian), central Montana. The dataset consists of 8 appendices, including a histogram of solid bitumen and vitrinite Ro values, gas chromatograms, isotopic data, organic and inorganic geochemical analyses, and x-ray diffraction mineralogy
Filter Total Items: 144
Investigating the effects of broad ion beam milling to sedimentary organic matter: Surface flattening or heat-induced aromatization and condensation?
Previous work has proposed transfer of kinetic heat energy from low-energy broad ion beam (BIB) milling causes thermal alteration of sedimentary organic matter, resulting in increases of organic matter reflectance. Whereas, other studies have suggested the organic matter reflectance increase from BIB milling is due to decreased surface roughness. To test if reflectance increases to sedimentary org
Authors
Paul C. Hackley, Aaron M. Jubb, Brett J. Valentine, Javin J. Hatcherian, Jing-Jiang Yu, William K. Podrazky
Examination of inertinite within immature Eagle Ford Shale at the nanometer-scale using atomic force microscopy-based infrared spectroscopy
The nanoscale molecular composition of sedimentary organic matter is challenging to characterize in situ given the limited tools available that can adequately interrogate its complex chemical structure. This is a particularly relevant issue in source rocks, as kerogen composition will strongly impact its reactivity and so is critical to understanding petroleum generation processes during catagenes
Authors
Aaron M. Jubb, Paul C. Hackley, Justin E. Birdwell, Javin J. Hatcherian, Jing Qu
Photoluminescence imaging of whole zircon grains on a petrographic microscope—An underused aide for geochronologic studies
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 ge
Authors
Ryan J. McAleer, Aaron M. Jubb, Paul C. Hackley, Gregory J. Walsh, Arthur J. Merschat, Sean P. Regan, William C. Burton, Jorge A. Vazquez
Characterization of the unconventional Tuscaloosa marine shale reservoir in southwestern Mississippi, USA: Insights from optical and SEM petrography
This study presents new optical petrography and electron microscopy data, interpreted in the context of previously published petrophysical, geochemical, and mineralogical data, to further characterize the Tuscaloosa marine shale (TMS) as an unconventional reservoir in southwestern Mississippi. The basal high resistivity zone has a higher proportion of Type II sedimentary organic matter than the ov
Authors
Celeste D. Lohr, Brett J. Valentine, Paul C. Hackley, Frank T. Dulong
Nanoscale molecular composition of solid bitumen from the Eagle Ford Group across a natural thermal maturity gradient
Microscopic solid bitumen is a petrographically defined secondary organic matter residue produced during petroleum generation and subsequent oil transformation. The presence of solid bitumen impacts many reservoir properties including porosity, permeability, and hydrocarbon generation and storage, among others. Furthermore, solid bitumen reflectance is an important parameter for assessing the ther
Authors
Aaron M. Jubb, Justin E. Birdwell, Paul C. Hackley, Javin J. Hatcherian, Jing Qu
Sample mounting for organic petrology: No thermal effects from transient exposure to elevated temperatures
For sample mounting, organic petrology laboratories typically use cold-setting epoxy-resin (e.g., 40 °C, used by Oklahoma Geological Survey, OGS) or heat-setting thermoplastic (e.g., 180 °C, used by U.S. Geological Survey, USGS). Previous workers have suggested a systematic huminite/vitrinite reflectance (VRo) increase was associated with the thermoplastic preparation process, relative to epoxy mo
Authors
Paul C. Hackley, Brian J. Cardott
Fluorescence spectroscopy of ancient sedimentary organic matter via confocal laser scanning microscopy (CLSM)
Fluorescence spectroscopy via confocal laser scanning microscopy (CLSM) was used to analyze ancient sedimentary organic matter, including Tasmanites microfossils in Devonian shale and Gloecapsomorpha prisca (G. prisca) in Ordovician kukersite from North American basins. We examined fluorescence emission as a function of excitation laser wavelength, sample orientation, and with respect to location
Authors
Paul C. Hackley, Aaron M. Jubb, Robert Burruss, Amy E Beaven
Oil-source rock correlation studies in the unconventional Upper Cretaceous Tuscaloosa marine shale (TMS) petroleum system, Mississippi and Louisiana, USA
The U.S. Geological Survey assessed undiscovered unconventional hydrocarbon resources reservoired in the Upper Cretaceous Tuscaloosa marine shale (TMS) of southern Mississippi and adjacent Louisiana in 2018. As part of the assessment, oil-source rock correlations were examined in the TMS play area where operators produce light (38–45° API), sweet oil from horizontal, hydraulically-fractured wells
Authors
Paul C. Hackley, Kristin Opferkuch Dennen, Daniel Garza, Celeste Lohr, Brett Valentine, Javin J. Hatcherian, Catherine B. Enomoto, Frank T. Dulong
Evidence of wildfires and elevated atmospheric oxygen at the Frasnian–Famennian boundary in New York (USA): Implications for the Late Devonian mass extinction
The Devonian Period experienced significant fluctuations of atmospheric oxygen (O2) levels (∼25–13%), for which the extent and timing are debated. Also characteristic of the Devonian Period, at the Frasnian–Famennian (F–F) boundary, is one of the “big five” mass extinction events of the Phanerozoic. Fossilized charcoal (inertinite) provides a record of wildfire events, which in turn can provide in
Authors
Zeyang Liu, David Selby, Paul C. Hackley, Jeffrey Over
Applications of correlative light and electron microscopy (CLEM) to organic matter in the North American shale petroleum systems
Scanning electron microscopy (SEM) has revolutionized our understanding of shale petroleum systems through microstructural characterization of dispersed organic matter (OM). However, due to the low atomic weight of carbon, all OM appears black in SEM (BSE image) regardless of differences in thermal maturity or OM type (kerogen types or solid bitumen). Traditional petrographic identification of OM
Authors
Brett J. Valentine, Paul C. Hackley
A chemo-mechanical snapshot of in-situ conversion of kerogen to petroleum
Organic matter (OM) from various biogenic origins converts to solid bitumen in-situ when it undergoes thermal maturation. It is well documented that during this process, the ratios of both hydrogen and oxygen to carbon will decrease, resulting in an increase in OM aromaticity and molecular chemo-mechanical homogeneity. Although there have been extensive efforts to reveal molecular alteration occur
Authors
Arash Abarghani, Mehdi Ostadhassan, Paul C. Hackley, Andrew E. Pomerantz, Siamak Nejati
Evidence of cosmic impact at Abu Hureyra, Syria at the Younger Dryas Onset (~12.8 ka): High-temperature melting at >2200 °C
At Abu Hureyra (AH), Syria, the 12,800-year-old Younger Dryas boundary layer (YDB) contains peak abundances in meltglass, nanodiamonds, microspherules, and charcoal. AH meltglass comprises 1.6 wt.% of bulk sediment, and crossed polarizers indicate that the meltglass is isotropic. High YDB concentrations of iridium, platinum, nickel, and cobalt suggest mixing of melted local sediment with small qua
Authors
Andrew M.T. Moore, James P. Kennett, Douglas J. Kennett, William M. Napier, Ted E. Bunch, James C. Weaver, Malcolm A. LeCompte, Victor Adedji, Paul C. Hackley, Jacob B. Lowenstern, Gunther K. Kletetschka, Brendan J. Culleton, Robert E. Hermes, James H. Wittke, Joshua J. Razink, Michael Gaultois, Allen West
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government