Petrographic Thermal Indices Research Active
A petrographic thermal index is typically an organic matter indicator in sedimentary rocks that allows for estimations of burial temperature. Petrographic thermal indices include the commonly used proxy vitrinite reflectance as well as other approaches such as solid bitumen reflectance, fluorescence, micro-Raman, and micro-Fourier transform infrared (FTIR) spectroscopies. Measurements from these approaches can be used to estimate the thermal maturity of organic matter, which in turn can lead to improved predictions of undiscovered hydrocarbon resource volumes, petroleum system properties, and calibration of burial history models.
These various petrographic thermal indices differ in their responses to temperature stress and are sometimes limited in their application to certain rock types. Correlations among thermal indices have also historically been poorly documented or misapplied. Thus, additional investigations of the physical and chemical evolution of sedimentary and organic matter during burial and heating are required to better develop and refine petrographic thermal indices. This work improves the assessment of Undiscovered Oil and Gas Resources in the United States, which is a central mission of the Energy Resources Program. Improved understanding of petrographic thermal indices can also be used in organic petrology investigations, which include environmental studies that investigate paleoclimate conditions and anthropogenic contaminant research.
Research Geologist | Paul C. Hackley | phackley@usgs.gov | 703-648-6458 |
Physical Science Technician | Javin J. Hatcherian | jhatcherian@usgs.gov | 703-648-6455 |
Research Geologist | Celeste D. Lohr | clohr@usgs.gov | 703-648-6438 |
Research Geologist | Ryan J. McAleer | rmcaleer@usgs.gov | 703-648-6052 |
Physical Scientist | Jennifer L. Nedzweckas | jlrivera@usgs.gov | 703-648-6449 |
Research Geologist | Margaret M. Sanders | msanders@usgs.gov | 703-648-6427 |
Research Scientist | Clinton Scott | clintonscott@usgs.gov | 703-648-6329 |
Physical Scientist | Rebecca A. Smith | rsmith@usgs.gov | 703-648-6433 |
Physical Scientist | Brett J. Valentine | bvalentine@usgs.gov | 703-648-6480 |
Listed below are other science projects or tasks associated with this project.
Vitrinite Reflectance Service
Thermal Indices Innovation
Standardization of Petrographic Thermal Indices
Hydrous Pyrolysis and Kerogen Conversion
Listed below are data products associated with this project.
Screening geochemistry, gas chromatography, and solid bitumen reflectance data in the Bakken petroleum system, Williston Basin, USA
Thirty-two organic-rich samples from the lower and upper shale members of the Devonian–Mississippian Bakken Formation were collected from eight cores across the Williston Basin, USA, at depths (~7,575–11,330 ft) representing immature through post peak oil/early condensate thermal maturity conditions. Reflectance results were correlated to programmed temperature pyrolysis parameters [hydrogen index
Data from Cretaceous formations of the Babouri-Figuil Sedimentary Basin, northern Cameroon
SEM-CL investigation of sedimentary organic matter samples
Evaluation of pore-like features in sedimentary organic matter
Portable Raman spectroscopic analysis of bulk crushed rock
Textural occurrence and organic porosity of solid bitumen in shales
TOC, Reflectance and Raman Data from Eocene Green River Mahogany Zone
Reflectance and confocal laser scanning fluorescence spectroscopy of bituminite in Kimmeridge Clay
Atomic Force Microscopy-based Infrared Spectroscopy Data within Immature Eagle Ford Shale at the Nanometer-scale
Investigating the effects of broad ion beam milling to sedimentary organic matter
Reflectance, Raman band separation and Mean multivariant curve resolution (MCR) in organic matter in Boquillas Shale
Bitumen Reflectance Data from the Tattoo Well in the Horn River Basin, Sample E200205
Listed below are publications associated with this project.
Scanning electron microscopic evaluation of broad ion beam milling effects to sedimentary organic matter: Sputter-induced artifacts or naturally occurring porosity?
Interlaboratory study: Testing reproducibility of solid biofuels component identification using reflected light microscopy
Reply to Comment by M.D. Lewan
Mapping ancient sedimentary organic matter molecular structure at nanoscales using optical photothermal infrared spectroscopy
Relating systematic compositional variability to the textural occurrence of solid bitumen in shales
Maturation study of vitrinite in carbonaceous shales and coals: Insights from hydrous pyrolysis
Evaluating aromatization of solid bitumen generated in the presence and absence of water: Implications for solid bitumen reflectance as a thermal proxy
The effect of diagenesis and acetolysis on the preservation of morphology and ultrastructural features of pollen
Finalization of the Confocal Laser Scanning Microscopy (CLSM) working group
Identification of thermal maturity-relevant organic matter in Shale Working Group Report 2021
Molecular mechanisms of solid bitumen and vitrinite reflectance suppression explored using hydrous pyrolysis of artificial source rock
Characterization of bituminite in Kimmeridge Clay by confocal laser scanning and atomic force microscopy
Listed below are online interactive applications associated with this project.
Photomicrograph Atlas
A database of images related to the characterization of fossil fuel resources in the United States and the world.
Listed below are partners who collaborate on work performed within this project.
- Overview
A petrographic thermal index is typically an organic matter indicator in sedimentary rocks that allows for estimations of burial temperature. Petrographic thermal indices include the commonly used proxy vitrinite reflectance as well as other approaches such as solid bitumen reflectance, fluorescence, micro-Raman, and micro-Fourier transform infrared (FTIR) spectroscopies. Measurements from these approaches can be used to estimate the thermal maturity of organic matter, which in turn can lead to improved predictions of undiscovered hydrocarbon resource volumes, petroleum system properties, and calibration of burial history models.
These various petrographic thermal indices differ in their responses to temperature stress and are sometimes limited in their application to certain rock types. Correlations among thermal indices have also historically been poorly documented or misapplied. Thus, additional investigations of the physical and chemical evolution of sedimentary and organic matter during burial and heating are required to better develop and refine petrographic thermal indices. This work improves the assessment of Undiscovered Oil and Gas Resources in the United States, which is a central mission of the Energy Resources Program. Improved understanding of petrographic thermal indices can also be used in organic petrology investigations, which include environmental studies that investigate paleoclimate conditions and anthropogenic contaminant research.
Petrographic Thermal Indices Research Project Staff Research Geologist Paul C. Hackley phackley@usgs.gov 703-648-6458 Physical Science Technician Javin J. Hatcherian jhatcherian@usgs.gov 703-648-6455 Research Geologist Celeste D. Lohr clohr@usgs.gov 703-648-6438 Research Geologist Ryan J. McAleer rmcaleer@usgs.gov 703-648-6052 Physical Scientist Jennifer L. Nedzweckas jlrivera@usgs.gov 703-648-6449 Research Geologist Margaret M. Sanders msanders@usgs.gov 703-648-6427 Research Scientist Clinton Scott clintonscott@usgs.gov 703-648-6329 Physical Scientist Rebecca A. Smith rsmith@usgs.gov 703-648-6433 Physical Scientist Brett J. Valentine bvalentine@usgs.gov 703-648-6480 - Science
Listed below are other science projects or tasks associated with this project.
Vitrinite Reflectance Service
Vitrinite is a maceral group that is derived from the remains of woody material from vascular plants and is composed of the thermally evolved products of lignin and cellulose. A maceral group is a set of organic matter types with similar properties and appearance. Vitrinite reflectance measures the percentage of incident light that is reflected from the surface of vitrinite as calibrated to a...Thermal Indices Innovation
Thermal indices innovation focuses on the utilization of correlative microscopy and spectroscopy techniques for innovative approaches to advance the understanding of thermal indices development. These techniques include correlative light and electron microscopy (CLEM), confocal laser scanning microscopy (CLSM), and atomic force microscopy and infrared microscopy (AFM-IR), among others. Use of...Standardization of Petrographic Thermal Indices
Advent of the shale revolution since about 2005 caused increased demand for reliable petrographic measurements of thermal maturity in shale via vitrinite reflectance, which has long been considered the gold standard approach. The first standardized methodology for vitrinite reflectance measurement in shale became available in 2011. Subsequent interlaboratory studies demonstrated that significant...Hydrous Pyrolysis and Kerogen Conversion
Hydrous pyrolysis (HP) experimentation is a laboratory method used to thermally mature organic-rich sedimentary rocks. It simulates petroleum generation in the closest available analogue to that of a natural system. Artificial maturation of sedimentary organic matter (SOM) to petroleum allows for the examination of its molecular chemistry to address the issue of anomalous reflection measurement... - Data
Listed below are data products associated with this project.
Filter Total Items: 16Screening geochemistry, gas chromatography, and solid bitumen reflectance data in the Bakken petroleum system, Williston Basin, USA
Thirty-two organic-rich samples from the lower and upper shale members of the Devonian–Mississippian Bakken Formation were collected from eight cores across the Williston Basin, USA, at depths (~7,575–11,330 ft) representing immature through post peak oil/early condensate thermal maturity conditions. Reflectance results were correlated to programmed temperature pyrolysis parameters [hydrogen index
Data from Cretaceous formations of the Babouri-Figuil Sedimentary Basin, northern Cameroon
This study contains TOC and programmed pyrolysis data, as well as vitrinite reflectance collected from 12 samples taken from the Babouri-Figuil Sedimentary basin in northern Cameroon.SEM-CL investigation of sedimentary organic matter samples
High-resolution scanning electron microscopy (SEM) visualization of sedimentary organic matter (SOM) is widely utilized in the geosciences for evaluation of microscale rock properties relevant to depositional environment, diagenesis, and the processes of fluid generation, transport, and storage. However, despite thousands of studies which have incorporated SEM approaches, the inability of SEM to dEvaluation of pore-like features in sedimentary organic matter
Research examining organic-matter hosted porosity has significantly increased during the last ten years due to greater focus on understanding hydrocarbon migration and storage in source-rock reservoirs, and technological advances in scanning electron microscopy (SEM) capabilities. The examination of nanometer-scale organic-matter hosted porosity by SEM requires the preparation of exceptionally flaPortable Raman spectroscopic analysis of bulk crushed rock
This study presents a simplified method and empirical relationships for determining organic matter thermal maturity using a portable Raman system equipped with a 785 nm laser, for analysis of crushed, whole-rock samples. Several sets of rocks comprised of shale and coal samples with various mineralogical composition, thermal maturity, total organic carbon (TOC), and age were used to test the methoTextural occurrence and organic porosity of solid bitumen in shales
This study presents Raman spectroscopic data paired with scanning electron microscopy (SEM) to assess solid bitumen composition and porosity development as a function of solid bitumen texture and association with minerals. A series of hydrous pyrolysis experiments (1-103 days, 300-370°C) using a low maturity (0.25% solid bitumen reflectance, BRo), high total organic carbon [(TOC), 14.0 wt. %] NewTOC, Reflectance and Raman Data from Eocene Green River Mahogany Zone
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. percent total organic carbon, TOC) mudrock sampleReflectance and confocal laser scanning fluorescence spectroscopy of bituminite in Kimmeridge Clay
This work investigates the characterization of bituminite (amorphous sedimentary organic matter) in Kimmeridge Clay source rock via confocal laser canning microscopy (CLSM) and atomic force microscopy (AFM). As part of an International Committee for Coal and Organic Petrology working group, an immature (0.42% vitrinite reflectance), organic-rich (44.1 wt.% total organic carbon content) sample of KAtomic Force Microscopy-based Infrared Spectroscopy Data within Immature Eagle Ford Shale at the Nanometer-scale
The nanoscale molecular composition of kerogen is a challenging parameter to characterize given the chemical and structural complexity exhibited by this important biopolymer. However, kerogen composition will strongly impact its reactivity and so is a critical parameter to understand petroleum generation processes during kerogen catagenesis. The recent advent of tip-enhanced analytical methods, suInvestigating the effects of broad ion beam milling to sedimentary organic matter
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 micrReflectance, Raman band separation and Mean multivariant curve resolution (MCR) in organic matter in Boquillas Shale
The molecular composition of petroliferous organic matter and its composition evolution throughout thermal advance are key to understanding and insight into petroleum generation. This information is critical for comprehending hydrocarbon resources in unconventional reservoirs, as source rock organic matter is highly dispersed, in contact with the surrounding mineral matrix, and may be present as mBitumen Reflectance Data from the Tattoo Well in the Horn River Basin, Sample E200205
Bitumen reflectance data from a sample collected from the vertical EOG TATTOO D129 A28-F/094-O-10 ("Tattoo") well in the Horn River Basin, as part of the collection of a high-resolution geochemical data set. - Publications
Listed below are publications associated with this project.
Filter Total Items: 23Scanning electron microscopic evaluation of broad ion beam milling effects to sedimentary organic matter: Sputter-induced artifacts or naturally occurring porosity?
Research examining organic-matter hosted porosity has significantly increased during the last decade due to greater focus on understanding hydrocarbon migration and storage in source-rock reservoirs, and technological advances in scanning electron microscopy (SEM) capabilities. The examination of nanometer-scale organic-matter hosted porosity by SEM requires the preparation of exceptionally flat gAuthorsBrett J. Valentine, Paul C. HackleyInterlaboratory study: Testing reproducibility of solid biofuels component identification using reflected light microscopy
Considering global market trends and concerns about climate change and sustainability, increased biomass use for energy is expected to continue. As more diverse materials are being utilized to manufacture solid biomass fuels, it is critical to implement quality assessment methods to analyze these fuels thoroughly. One such method is reflected light microscopy (RLM), which has the potential to compAuthorsAgnieszka Drobniak, Maria Mastalerz, Zbigniew Jelonek, Iwona Jelonek, Tushar Adsul, Neža Malenšek Andolšek, Omid Haeri Ardakani, Tara Congo, Batbold Demberelsuren, Bryon S. Donohoe, Ashley Douds, Deolinda Flores, Ranjin Ganzorig, Santanu Ghosh, Andrew Gize, Paula Alexandra Goncalves, Paul C. Hackley, Javin J. Hatcherian, James C. Hower, Stavros Kalaitzidis, Sławomir Kędzior, Wayne Knowles, Jolanta Kus, Kacper Lis, Grzegorz Lis, Bei Liu, Qingyong Luo, Meili Du, Divya Mishra, Magdalena Misz-Kennan, Theophile Mugerwa, Jennifer Nedzweckas, Jennifer M. K. O'Keefe, Jackie Park, Richard Pearson, Henrik I. Petersen, Julito Reyes, Joana Ribeiro, Genaro de la Rosa-Rodriguez, Piotr Sosnowski, Brett J. Valentine, Atul Kumar Varma, Małgorzata Wojtaszek-Kalaitzidi, Zhanjie Xu, Alexander Zdravkov, Konrad ZiemianinReply to Comment by M.D. Lewan
No abstract available.AuthorsK.E. Peters, Paul C. Hackley, A.E. PomerantzMapping ancient sedimentary organic matter molecular structure at nanoscales using optical photothermal infrared spectroscopy
Elucidating the molecular structure of sedimentary organic matter (SOM) is key to understanding petroleum generation processes, as well as ancient sedimentary environments. SOM structure is primarily controlled by biogenic source material (e.g., marine vs. terrigenous), depositional conditions, and subsurface thermal history. Additional factors, e.g., strain, may also impact the molecular structurAuthorsAaron M. Jubb, Martha (Rebecca) Stokes, Ryan J. McAleer, Paul C. Hackley, Eoghan Dillion, Jing QuRelating systematic compositional variability to the textural occurrence of solid bitumen in shales
This study presents Raman spectroscopic data paired with scanning electron microscopy (SEM) images to assess solid bitumen composition as a function of solid bitumen texture and association with minerals. A series of hydrous pyrolysis experiments (1–103 days, 300–370 °C) using a low maturity (0.25% solid bitumen reflectance, BRo), high total organic carbon [(TOC), 14.0 wt%] New Albany Shale sampleAuthorsMartha (Rebecca) Stokes, Brett J. Valentine, Aaron M. Jubb, Paul C. HackleyMaturation study of vitrinite in carbonaceous shales and coals: Insights from hydrous pyrolysis
The presence of vitrinite in sedimentary rocks of post-Silurian age allows its reflectance to be used to estimate the thermal maturation of organic matter in petroleum systems. Increasing reflectance of vitrinite, which is primarily driven by aromaticity, depends primarily on the time and temperature attributes of its evolutionary pathway. This study evaluated carbonaceous shales proximal to coalAuthorsDivya K. Mishra, Paul C. Hackley, Aaron M. Jubb, Margaret M. Sanders, Shailesh Agrawal, Atul K. VarmaEvaluating aromatization of solid bitumen generated in the presence and absence of water: Implications for solid bitumen reflectance as a thermal proxy
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 hydrogen from water, organic-rich (22 wt% total organic carbon, TOC) mudrock samples from the Eocene lacAuthorsPaul C. Hackley, Aaron M. Jubb, Patrick L. Smith, Ryan J. McAleer, Brett J. Valentine, Javin J. Hatcherian, Palma J. Botterell, Justin E. BirdwellThe effect of diagenesis and acetolysis on the preservation of morphology and ultrastructural features of pollen
Pollen morphology on its own and in conjunction with other characteristics has elucidated the origin and evolution of various plant groups. Previous studies of fossil pollen rarely discuss the effects of diagenesis and sample preparation on pollen characteristics, i.e., variability in staining, pollen morphology, and pollen wall ultrastructural characteristics. This paper examines the effect of acAuthorsMichael Zavada, Paul C. HackleyFinalization of the Confocal Laser Scanning Microscopy (CLSM) working group
A working group in Commission II to investigate applications of confocal laser scanning microscopy (CLSM) for organic petrology investigations has finalized with publication of the manuscript “Characterization of bituminite in Kimmeridge Clay by confocal laser scanning and atomic force microscopy” in the International Journal of Coal Geology. The manuscript is available via Open Access from https:AuthorsPaul C. Hackley, Jolanta KusIdentification of thermal maturity-relevant organic matter in Shale Working Group Report 2021
The Identification of Thermal Maturity-Relevant Organic Matter in Shale Working Group of the ICCP was established in 2008 to provide guidelines for identifying and measuring the reflectance of the population of dispersed organic matter that is relevant to thermal maturity determination. Information products published by the working group include ASTM D7708 Standard Test Method for Microscopical DeAuthorsPaul C. Hackley, Javin J. Hatcherian, Jennifer L. Rivera, Margaret M. Sanders, Brett J. ValentineMolecular mechanisms of solid bitumen and vitrinite reflectance suppression explored using hydrous pyrolysis of artificial source rock
The most commonly used parameter for thermal maturity calibration in basin modelling is mean random vitrinite reflectance (Ro). However, Ro suppression has been noted in samples containing a high proportion of liptinite macerals. This phenomenon has been demonstrated empirically using hydrous pyrolysis of artificial source rock containing various proportions of thermally immature Wyodak-Anderson cAuthorsMargaret M. Sanders, Aaron M. Jubb, Paul C. Hackley, Kenneth E. PetersCharacterization of bituminite in Kimmeridge Clay by confocal laser scanning and atomic force microscopy
This work investigates bituminite (amorphous sedimentary organic matter) in Upper Jurassic Kimmeridge Clay source rock via confocal laser scanning microscopy (CLSM) and atomic force microscopy (AFM). These petrographic tools were used to provide better understanding of the nature of bituminite, which has been historically difficult to identify and differentiate from similar organic matter types inAuthorsPaul C. Hackley, Jolanta Kus, João Graciano Mendonça Filho, Andrew D. Czaja, Angeles G. Borrego, Dragana Životić, Brett J. Valentine, Javin J. Hatcherian - Web Tools
Listed below are online interactive applications associated with this project.
Photomicrograph Atlas
A database of images related to the characterization of fossil fuel resources in the United States and the world.
- Partners
Listed below are partners who collaborate on work performed within this project.