Home / Charcoal & Coal Petrology / Coal Petrology

Douglas Allchin (1997): James Hutton and Coal. PDF file, Cadernos IG/UNICAMP, 7: 167-183.

American Association of Petroleum Geologists

The Australian Coal Industry´s Research Program (ACARP): Underground Coal. Go to: Rank of coal seam.

X. Bao et al. (2023): Quantifying climate conditions for the formation of coals and evaporites. Free access, National Science Review.
"... We show that coal records were associated with an average temperature of 25°C and precipitation of 1300 mm ^yr-1 before 250 Ma. Afterwards, coal records appeared with temperatures between 0°C and 21°C and precipitation of 900 mm ^yr-1
[...] Evaporite records were associated with average temperature of 27°C and precipitation of 800 mm ^yr-1 ..."

J.R.W. Benicio et al. (2019): Recurrent palaeo-wildfires in a Cisuralian coal seam: A palaeobotanical view on highinertinite coals from the Lower Permian of the Parana´ Basin, Brazil. Open access, PLoS ONE, 14: e0213854.

C.K. Boyce et al. (2010): X-ray photoelectron emission spectromicroscopic analysis of arborescent lycopsid cell wall composition and Carboniferous coal ball preservation. In PDF, International Journal of Coal Geology, 83: 146–153.

Canadian Society for Coal Science and Organic Petrology (CSCSOP). Their aim is to encourage and promote the practice, research and development of coal science in Canada and abroad through the practice of coal petrography and geochemistry.

! C.B. Cecil et al, (1985): Paleoclimate controls on late Paleozoic sedimentation and peat formation in the central Appalachian Basin (USA). In PDF, International Journal of Coal Geology, 5: 195-230.
See also here.
Note fig. 9: Interpreted depositional settings of the Upper Freeport coal bed and associated rocks.

M.E. Chrpa et al. (2023): A marine origin of coal balls in the Midland and Illinois basins, USA. Open access, Communications Earth & Environment, 4.
"... Despite their importance to paleobotany, the salinity of coal-ball peat remains controversial. Pennsylvanian coal balls from the Midland and Illinois basins contain echinoderms and early high-magnesium calcite cement
[...] Coal balls likely formed in the marine-freshwater mixing zone ..."

! The Coal Association of Canada: Introduction to Coal.
The link is to a version archived by the Internet Archive´s Wayback Machine.

! John C. Crelling, Coal Research Center and Department of Geology, Southern Illinois University, Carbondale: Petrographic Atlas of Coal and Carbon Compounds. The main purpose of this atlas is to show what coals, cokes, chars, carbons, graphites, and other natural and man-made carbonaceous materials look like under the optical microscope. All photomicrographs were taken in reflected white light with and without the use of a polarizer, an analyzer, and a retarder plate. In some cases the photomicrographs were taken in fluorescent light using ultra-violet illumination. Go to:
Coal Macerals Tutorial.
Snapshot provided by the Internet Archive´s Wayback Machine.

! S. Dai et al. (2020): Recognition of peat depositional environments in coal: A review. Free access, International Journal of Coal Geology, 219.
! See especially fig. 5: Overview of the progression of plant and fungal tissues and burned material from the peat surface through peatification and coalification to produce the major maceral groups.
Fig. 6A: Coprolitic macrinite in a chamber in wood (now fusinite); the coprolites were charred along with the wood.
Note also fig. 10D: Fusinite in a Cretaceous coal.
Fig. 11C: Degraded inertinite in coal. Fusinite- and semifusinite-like reflectances indicating the charring of degraded material of woody origin.

! S. Dai et al. (2021): Modes of occurrence of elements in coal: A critical evaluation. Free access, Earth-Science Reviews, 222.

I. Degani-Schmidt et al. (2015): Charcoalified logs as evidence of hypautochthonous/autochthonous wildfire events in a peat-forming environment from the Permian of southern Paraná Basin (Brazil). Abstract, International Journal of Coal Geology, 146: 55–67. See also here (in PDF).

! C.F.K. Diessel (2010): The stratigraphic distribution of inertinite. In PDF, International Journal of Coal Geology, 81: 251–268. See also here (abstract).

! W.A. DiMichelle, National Museum of Natural History, Smithsonian Institution, and T.L. Phillips, University of Illinois: The Response of Hierarchially Structured Ecosystems to Long-Term Climatic Change: A Case Study using Tropical Peat Swamps of Pennsylvanian Age. From:
NATIONAL ACADEMY PRESS, National Research Council, Washington, D.C.,1995: Effects of Past Global Change on Life.

Director Referate: Kohle. In German.

! Claus F.K. Diessel (2010): The stratigraphic distribution of inertinite. Abstract, International Journal of Coal Geology, 81: 251-268.

! W.A. DiMichele and T.L. Phillips 1994): Paleobotanical and paleoecological constraints on models of peat formation in the Late Carboniferous of Euramerica. In PDF, Palaeogeography, Palaeoclimatology, Palaeoecology, 106: 39-90.
See also here.

Â.C.S. dos Santos et al. (2022): Record of Brachyoxylon patagonicum, a Cheirolepidiaceae wood preserved by gelification in the aptian Maceió Formation, Sergipe–Alagoas Basin, NE Brazil. In PDF, Journal of South American Earth Sciences.
See also here.
"... The presence of fungal remains within the wood tissue, and the absence of signs of plant defense against fungal decay suggest saprophytic fungus–wood interactions that likely occurred during a stage of aerobic exposure before burial.

Earth Science Australia (by Paul Michna where no other author is indicated): Coal. See also:
Coal: all you really wanted to know. The concept of coal rank.
The link is to a version archived by the Internet Archive´s Wayback Machine.

! The Food and Agriculture Organization (FAO), the United Nations: Industrial charcoal making: Chapter 2. Wood carbonisation and the products it yields.
"... Carbonisation is a particular form of that process in chemical technology called pyrolysis that is the breakdown of complex substances into simpler ones by heating. ..."
! Worth checking out: 2.5 The stages in charcoal formation.

Larissa Gammidge, Department of Geology, University of Newcastle, Australia: Coal: an introduction. Scroll down to: "Concept of Coal Rank". The rank of a coal refers to the degree of coalification endured by the organic matter. See also: ! Atlas of coal macerals.
These expired links are available through the Internet Archive´s Wayback Machine.

GeoDZ (Lexikon Geografie, Lexikon Geologie, Lexikon Geodäsie, Topologie & Geowissenschaften, in German):
Inkohlung.
Inkohlungsgrad.
These links are now available through the Internet Archive´s Wayback Machine.

Coal Geology Division, Geological Society of America: Links to Other Coal Geology Webpages.

Geology.com (published by Hobart King). News and information about geology and earth science. Go to:
Coal Through a Microscope.

B. Gieren (2006): Die Landpflanzenevolution im Phanerozoikum aus petrographischer und geochemischer Sicht. PDF file, in German. Thesis, Georg-August-Universität, Gõttingen.

David Glick, The Society for Organic Petrology (TSOP): References on Organic Petrology.

S.F. Greb et al. (2006): Evolution and Importance of Wetlands in Earth History. PDF file, In: DiMichele, W.A., and Greb, S., eds., Wetlands Through Time: Geological Society of America, Special Publication, 399: 1-40.
Rhacophyton and Archaeopteris in a Devonian wetland as well as Pennsylvanian, Permian, Triassic and Cretaceous wetland plant reconstructions.
Note figure 1: Evolution of wetland types in the Silurian and Devonian.
See also here.
Still available through the Internet Archive´s Wayback Machine.

S.F. Greb et al. (2006): Coal and the environment. In PDF, AGI Environmental Awareness Series, 10, Alexandria, Virginia, USA, American Geological Institute, 68 pp.

The Greening Earth Society (byDesign and PowervisioN): About Coal, Coal Mining, and Fossil Fuel. An anntotated link directory.

H. Hagdorn and K.-P. Kelber (2015): 19. Kohle, Alaun und Vitriol - Historische Rohstoffgewinnung. - p. 417-426, PDF file, in German.
! Mining history of "Lettenkohle" (Ladinian, Triassic) from southern Germany.
In: Hagdorn, H., Schoch, R. & Schweigert, G. (eds.): Der Lettenkeuper - Ein Fenster in die Zeit vor den Dinosauriern. Palaeodiversity, Special Issue (Staatliches Museum für Naturkunde Stuttgart).
! Navigate from here for other downloads (back issues of Palaeodiversity 2015, scroll down to "Special Issue: Der Lettenkeuper ...").

William W. Hambleton: Petrographic Study of Southeastern Kansas Coals. Go to: Petrography of the Mineral, Croweburg, and Bevier Coals, Description of Components. Plates available in PDF.

! Adrian Hutton et al. (1994): Chemical and Petrographic Classification of Kerogen/Macerals. Abstract, Energy Fuels, 1994, 8:1478–1488.

! V. Hudspith et al. (2012): Evaluating the extent to which wildfire history can be interpreted from inertinite distribution in coal pillars: An example from the Late Permian, Kuznetsk Basin, Russia. In PDF, International Journal of Coal Geology, 89: 3–25.

IEA Coal Research, London: The purpose of this site is to provide information about analysis of coal technology, supply and use.
The link is to a version archived by the Internet Archive´s Wayback Machine.

llinois Department of Natural Resources, Illinois State Geological Survey, Champaign: Coal Section. Go to: Older and Out of Print Coal Publications. About Coal Resources, Coal Quality, Preparation and Utilization, Coal Economics, Environmental Aspects of Coal Mining and Utilization, etc. Most links are PDF files and can be either downloaded or viewed directly.
These expired links are now available through the Internet Archive´s Wayback Machine.

! Indiana Geological Survey, Bloomington, IN: Atlas of Coal Macerals. This Atlas of Coal Macerals presents the current classifications of the International Committee for Coal and Organic Petrology (ICCP) together with examples of coal macerals. Photomicrographs of macerals were taken on polished sections under a reflected light microscope (with oil objective) in white or fluorescent light. Excellent!

International Committee for Coal and Organic Petrology (ICCOP). The ICCP members are engaged in many different branches, fundamental and applied, of coal and organic petrology.

! International Committee for Coal and Organic Petrology (ICCP), 1998: The new vitrinite classification. PDF file, (ICCP System 1994), reprinted from Fuel 77, p. 349-358. See also here (Download website Indiana Geological Survey).

! International Committee for Coal and Organic Petrology (ICCP), 2001: The new inertinite classification. PDF file, (ICCP System 1994), reprinted from Fuel 80, p. 459-471. See also here (Download website Indiana Geological Survey).

International Humic Substances Society:
The motto of IHSS is "To Advance the Knowledge, Research and Application of Humic Substances".
For scientists with interest in humic substances in the coal, soil, and water sciences, and to provide opportunities for them to exchange ideas, skills, and viewpoints.
See also here (Wikipedia).

International Journal of Coal Geology (Elsevier).
The International Journal of Coal Geology deals with fundamental and applied aspects of the geology, petrology, geochemistry and mineralogy of coal, oil/gas source rocks, and shales.
The scope of the journal encompasses basic research, computational and laboratory studies, technology development, and field studies.

E.C. Jeffrey (1917): Petrified Coals and Their Bearing on the Problem of the Origin of Coals. PDF file, Proceedings of the National Academy of Sciences of the United States of America, 3: 206–211.00

! G. Jovanovski et al. (2023): Chemistry and geology of coal: nature, composition, coking, gasification, liquefaction, production of chemicals, formation, peatification, coalification, coal types, and ranks. In PDF, ChemTexts, 9.
See also here.
Note figure 6: An overview of the progression of plant and fungal tissues and burned material from peat.
Table 4: US coal rank system showing the parameters used to define ranks.

! T. Kasielke (2019): Steinkohle–Gestein des Jahres 2018: Entstehung und Eigenschaften der Ruhrkohle. PDF file, in German. Jahrb. Bochumer Bot. Ver., 10: 233–245.

K.-P. Kelber (2015): 5. Die Makroflora des Lettenkeupers . PDF file, in German; p. 51-100, in: Hagdorn, H., Schoch, R. & Schweigert, G. (eds.): Der Lettenkeuper - Ein Fenster in die Zeit vor den Dinosauriern. Palaeodiversity, Special Issue (Staatliches Museum für Naturkunde Stuttgart).
See also here.

! K.L. Kennedy et al. (2013): Lower Devonian coaly shales of northern New Brunswick, Canada: plant accumulations in the early stages of Terrestrial colonization. In PDF, Journal of Sedimentary Research, 83: 1202–1215. See also here.

Kentucky Geological Survey, University of Kentucky:
! Heat, time, pressure, and coalification.

Kentucky Coal Association: Coal Education.

Kentucky Educational Television (KET): COAL: Ancient Gift Serving Modern Man American Coal Foundation. Go to: Types of Coal, and Coal Terms Glossary.

Kentucky Geological Survey:
Coal Information. These web pages provide a simple guide about coal formation, mining, resources, and more, e.g. "What is coal?", How is coal formed?", "Kinds and types of coal: a summary", "Important properties and uses of coal", "Identification of Coal Components".
These expired links are now available through the Internet Archive´s Wayback Machine.

! Ann G. Kim (2010): 1.1. The Formation of Coal. PDF file, in: Coal and Peat Fires: A Global Perspective. Edited by Glenn B. Stracher, Anupma Prakash and Ellina V. Sokol (Elsevier).

O.C. Kopp and L.A. Harris (1988): Are alternative coalification paths possible for terrestrial coal? Abstract, Geology, 16: 844-847.

J. Kus et al. (2020): Coal petrological and xylotomical characterization of Miocene lignites and in-situ fossil tree stumps and trunks from Lusatia region, Germany: Palaeoenvironment and taphonomy assessment. Abstract, International Journal of Coal Geology. See also here (in PDF).
Note figure 2: In-situ preserved stumps encountered in the 2nd Miocene Seam Horizon of Lower Lusatia.

Michelle Lamberson, Department of Earth and Ocean Sciences, University of British Columbia, Vancouver: The Society for Organic Petrology (TSOP). The Society for Organic Petrology (TSOP; pronounced "Tee'-sop") was established to consolidate and foster the organizational activities of scientists and engineers involved with coal petrology, kerogen petrology, organic geochemistry and related disciplines. Visit the WWW links related to TSOP activities.

B. Liu et al. (2022): Evidence for the repeated occurrence of wildfires in an upper Pliocene lignite deposit from Yunnan, SW China. In PDF, International Journal of Coal Geology, 250.
See also here.
"... Different types of wildfire occurred in this paleomire with a predominance of low-temperature surface fires, as indicated by mean inertinite reflectance (Ro) values ranging from 1% to 2% in most samples. High-temperature fires are less recorded ..."

! B. Liu et al. (2022): SEM petrography of dispersed organic matter in black shales: A review. In PDF, Earth-Science Reviews, 224.
See also here.

Jian Liu and Anne Graham, Reference Department, IU Libraries (in collaboration with Lois Heiser, Geology Library, IU Libraries and Indiana Geological Survey, IU: Our Hoosier State Beneath Us: Coal. An easy to understand introduction with black and white illustrations.

! L. Marynowski et al. (2014): Molecular composition of fossil charcoal and relationship with incomplete combustion of wood. Abstract, Organic Geochemistry, 77: 22–31. See also here (in PDF).

L. Marynowski et al. (2011): Effects of weathering on organic matter Part II: Fossil wood weathering and implications for organic geochemical and petrographic studies. Abstract, Organic Geochemistry, 42: 1076-1088.

! L.C. McParland et al. (2010): Is vitrification in charcoal a result of high temperature burning of wood? Abstract, Journal of Archaeological Science, 37: 2679–2687. See also here (in PDF).

Melbourne Earth Sciences, Australia: Coal Resources. Lecture notes, in PDF.
Now recovered from the Internet Archive´s Wayback Machine.

O.M. Moroeng et al. (2018): Characterization of coal using electron spin resonance: implications for the formation of inertinite macerals in the Witbank Coalfield, South Africa. Free access, Int. J. Coal Sci. Technol., 5: 385–398.

! Palaeobotanical Research Group, Münster, Westfälische Wilhelms University, Münster, Germany. History of Palaeozoic Forests, COAL SWAMP FORESTS. Link list page with picture rankings. Several dioramas of coal swamp forests. The links give the most direct connections to illustrations available on the web.
Still available through the Internet Archive´s Wayback Machine.

Palaeobotanical Research Group, Münster, Westfälische Wilhelms University, Münster, Germany. History of Palaeozoic Forests, COAL. Link list page with picture rankings. The links give some information on coal and the analysis of its microscopic constituents.

Coal and Organic Petrology Laboratories, Pennsylvania State University: Coal and Organic Petrology Laboratories. Provides references about the optical and other physical properties of coals, inorganics, chemistry and molecular structure of coals, coal preparation, coal description and classification etc. Worth to visit: Links.
Snapshots provided by the Internet Archive´s Wayback Machine.

H.I. Petersen et al. (2013): Deposition, floral composition and sequence stratigraphy of uppermost Triassic (Rhaetian) coastal coals, southern Sweden. In PDF, International Journal of Coal Geology, 116–117: 117–134. See also here (abstract).

! T.L. Phillips et al. (1985): Stratigraphic and interregional changes in Pennsylvanian coal-swamp vegetation: environmental inferences. In PDF, International Journal of Coal Geology, 5: 43-109.
See also here.

Rosemary Prevec, Geology Department Rhodes University, South Africa (website by Science in Africa): The power of plants: how ancient forests drive SA´s economy. About Glossopteris forests and coal. This expired link is available through the Internet Archive´s Wayback Machine.

! G.J. Retallack et al. (1996): Global coal gap between Permian-Triassic extinction and Middle Triassic recovery of peat-forming plants. In PDF, Abstract, Geological Society of America, Bulletin, 108: 195–207.
See also here and there.
"... It is a curious fact that no coal seam of Early Triassic has yet been discovered, and those of Middle Triassic age are rare and thin. ..."
"... we favor explanations involving extinction of peat-forming plants at the Permian-Triassic boundary, followed by a hiatus of some 10 m.y. until newly evolved peat-forming plants developed tolerance to the acidic dysaerobic conditions of wetlands. ..."

D. Riedel (2009): Kohle ist nicht gleich Kohle. PDF file, in German.

E. Salmon et al. (2009): Early maturation processes in coal. Part 1: Pyrolysis mass balance and structural evolution of coalified wood from the Morwell Brown Coal seam. PDF file, Organic Geochemistry, 40: 500-509.

The Science and Mathematics Teaching Center, University of Wyoming: Coal. Go to: Coalification.
These expired links are now available through the Internet Archive´s Wayback Machine.

! C.R. Scotese et al. (2021): Phanerozoic paleotemperatures: The earth's changing climate during the last 540 million years. In PDF, Earth-Science Reviews, 215. See also here.
"... This study provides a comprehensive and quantitative estimate of how global temperatures have changed during the last 540 million years. It combines paleotemperature measurements determined from oxygen isotopes with broader insights obtained from the changing distribution of lithologic indicators of climate, such as coals, evaporites, calcretes, reefs, and bauxite deposits. ..."

! A.C. Scott (2002): Coal petrology and the origin of coal macerals: a way ahead? In PDF, International Journal of Coal Geology, 50: 119-134.

! A.C. Scott (1998): The legacy of Charles Lyell: advances in our knowledge of coal and coal-bearing strata. In PDF, Geological Society, London, Special Publications, 143: 243-260. See also here.

Stanley P. Schweinfurth, U.S. Geological Survey: Coal - A Complex Natural Resource. An overview of of factors affecting coal quality and use in the United States. With a contribution on coal quality and public health by Robert B. Finkelman. Best page to navigate would be from the site map site.

S. Sen et al. (2016): Discussion on the concepts in paleoenvironmental reconstruction from coal macerals and petrographic indices. In PDF, Marine and Petroleum Geology, 73. See also here (abstract).

S. Sen (2016): Review on coal petrographic indices and models and their applicability in paleoenvironmental interpretation. Abstract, Geosciences Journal. See also here.

P.K. Singh and A.S Naik (2015): Coal microscopy as a tool to understand the beneficiation problems of Indian Gondwana coals. In PDF, e-Journal of Science & Technology (e-JST).

B. Slater (2011): Fossil focus: Coal swamps. n PDF, Palaeontology Online. See also here.

The Society for Organic Petrology (TSOP). TSOP was established to consolidate and foster the organizational activities of scientists and engineers involved with coal petrology, kerogen petrology, organic geochemistry and related disciplines. This site is hosted by the Department of Earth and Ocean Sciences, University of British Columbia, Vancouver. Worth checking out: University Research Groups. See also:
TSOP Newsletters as PDF files.

Michael Spann, School of Electronic, Electrical and Computer Engineering, University of Birmingham:
Coal.
Lecture notes, Powerpoint presentation.

Spektrum.de Spektrum Akademischer Verlag:
Lexikon der Chemie, Macerale.
Lexikon der Geowissenschaften, Maceral (in German).

D.C. Steart et al. (2007): The Cobham Lignite Bed: the palaeobotany of two petrographically contrasting lignites from either side of the Paleocene-Eocene carbon isotope excursion. PDF file, Acta Palaeobotanica 47: 109-125.
This expired link is available through the Internet Archive´s Wayback Machine.

Cathy D. Stewart, Steelynx, Michigan Library Consortium: Coal and Coking on the Internet. Coal and Coking at Some US Non-Profit Organizations.

! I. Suárez-Ruiz et al. (2012): Organic Petrology: An Overview. PDF file, in: A.I. Al-Juboury(ed.): Petrology - New Perspectives and Applications.

! I. Suárez-Ruiz et al. (2012): Review and update of the applications of organic petrology: Part 1, geological applications. In PDF, International Journal of Coal Geology, 99: 54-112.

! I. Suárez-Ruiz and J. Crelling (eds, 2008): Applied Coal Petrology (Elsevier), and here (Amazon). Worth checking out: Table of contents.
See also here.
! Then click the 3. link named "Untitled" (in PDF).
See especially: "2.2.1 Organic Petrography: Macerals and Microlithotypes", starting on PDF page 27.

! Sykorova, I. et al. (2005): Classification of huminite. PDF file, (ICCP System 1994) reprinted from International Journal of Coal Geology 62, p. 85-106. See also here (Download website Indiana Geological Survey).

Toyo Takakuwa, Sumitomo Coal Mining Co, Tokyo: Coal Links Worldwide.

! G.R. Upchurch Jr. (1995): Dispersed angiosperm cuticles: Their history, preparation, and application to the rise of angiosperms in Cretaceous and Paleocene coals, southern western interior of North America. In PDF, International Journal of Coal Geology, 28: 161-227. See also here.

! U.S. Geological Survey: GEO-DATA Explorer (GEODE). The site lets you zoom in on maps and add layers showing different data sets. The site's international collections emphasize the distribution of natural resources such as oil, coal, and natural gas.

S. Villalba Breva et al. (2012): Peat-forming plants in the Maastrichtian coals of the Eastern Pyrenees. In PDF, Geologica Acta, 10.

S. Wang et al. (2021): Coal petrology of the Yimin Formation (Albian) in the Hailar Basin, NE China: Paleoenvironments and wildfires during peat formation. In PDF, Cretaceous Research, 124.
See also here.

A.T. Wheeler (2016): Palaeoenvironmental and palaeoclimatic reconstruction of the Witbank coal deposits (Karoo Basin South Africa). In PDF, Thesis, University of Pretoria.

! Wikipedia, the free encyclopedia: Coal, and
Maceral. See also here (in German).
Also worth checking out: Inkohlung.

Wikipedia, the free encyclopedia:
Category:Coal.
Jet (gemstone).
Kategorie:Kohle (in German).
Gagat (in German).

! J.P. Wilson et al. (2017): Dynamic Carboniferous tropical forests: new views of plant function and potential for physiological forcing of climate. In PDF, New Phytologist, 215: 1333–1353. See also here.
! Figure 2 shows the fungal evolution and abundance of coal basin sediments over the Phanerozoic.

The World Coal Institute (WCI), London. The WCI is a global industry association comprising the major international coal producers and stakeholders. Go to: What is coal? See also Coal Statistics.

! Politechnika Wroclawska, Wroclaw, Poland: Coal. Lecture notes, in PDF.

The Science and Mathematics Teaching Center, University of Wyoming: Wyoming Coal Website.

L. Xiao et al. (2023): Maceral and Organic Geochemical Characteristics of the No. 6 Coal Seam from the Haerwusu Surface Mine, Inner Mongolia, China. Open access, Geologica Acta, 18.12, 1-11.

Z. Zamani et al. (2023): Coal petrology, sedimentology and depositional environment of the Parvadeh coals in the Upper Triassic, Tabas Block of Central-East Iran. Free access, International Journal of Coal Science & Technology, 10.

A. Zdravkov et al. (2019): Organic petrological and geochemical properties of jet from the middle Triassic Mogila Formation, West Bulgaria. Open access, Geologica Carpathica, 70: 62–74.