"Chariots of Fire" to "Fire on Earth": Stream-of-consciousness from the Olympics to fossil charcoal/fire studies through poet William Blake

Until the gymnastics and swimming got underway, I hadn’t been watching much of this year’s summer Olympics. However, on the day after the opening ceremonies, I started my quadrennial games viewing odyssey with Chariots of Fire, the 1981 movie highlighting the athletic and faith journeys of two British runners, Harold Abrahams and Eric Liddell, to the 1924 Olympics. The movie story line begins and ends with the 1978 memorial service for Abrahams. The sequence at the end (https://www.youtube.com/watch?v=3vxlX5wyEQs) includes the hymn, “And did those feet in ancient time”, the unofficial hymn of England. (Some feel it should be the national anthem although there are dissenters: http://blogs.spectator.co.uk/2016/01/theres-nothing-patriotic-about-william-blakes-jerusalem/) The hymn has been included in other movies, such as Calendar Girls (sung in Women’s Institute meetings) and Four Weddings and a Funeral (sung during first wedding).

The lyrics for the hymn are from a poem by William Blake, written ~1804 (music* by Sir Hubert Parry). The movie title, Chariots of Fire, is from a phrase in the poem (at the end of the third poem stanza; in middle of second hymn verse), alluding to the Old Testament Bible description of the prophet Elijah being taken to heaven in a fiery chariot pulled by flaming horses. Other events and locations in the four-stanza poem, however, are not the standard Bible references of Reformation-to-early 20^th-century Protestant hymns.  The first line queries if Jesus walked in England, possibly during his pre-ministry years, while the last lines of the second stanza ask “And was Jerusalem builded here, Among these dark Satanic mills”.

There are different interpretations of what Blake meant by “dark Satanic mills". Was he referring to the Albion Flour Mills, “first major factory in London” built in the early days of the Industrial Revolution, destroyed by fire in 1791, but not torn down for almost 20 years? The factory mill, when operational, threatened to ruin the livelihood of small local millers. Or was he referring metaphorically to establishment churches or major universities? Whatever Blake’s intention, images of soot-belching factories of the Industrial Revolution initially pop into one’s head.

One instance using the Industrial Revolution metaphor is found in Fire on Earth: An Introduction by Andrew Scott, David Bowman, William Bond, Stephen Pyne, and Martine Alexander (Wiley Blackwell, 2014; http://www.wiley.com/WileyCDA/WileyTitle/productCd-111995357X.html). The author of Chapter 12 writes, discussing the ‘Pyric Transition’ when civilization transitioned from biomass to fossil fuel usage:

     “For fire history, ‘industrialization’ is shorthand for that shift in fuel from surface biomass to fossil biomass, with all that means for how humanity applies and withholds fire on the land. Usefully, the general culture agrees, since popular imagination has long identified the Industrial Revolution with William Blake’s ‘dark satanic’ mills’ belching soot from combusted coals” (p. 231).

The book covers the history of “fire on earth” and the scientific methods of studying it. The authors include a geologist (Scott whose work, plus those of his colleagues and students, I have written about previously, http://carbonacea.blogspot.com/2014/10/paleo-wildfires-and-extinctions-at-gsa.html, http://carbonacea.blogspot.com/2014/10/wildfire-and-extinction-ii-gsa-2014.html), a botanist, ecologist, historian, and forester. All the authors’ research has involved aspects of fire science, how fire has affected landscape, ecosystems, and civilization, and the geologic and anthropological records preserving that information. I have not read the book from front to back, but have read or skimmed through sections that have particular interest to me.

Sixteen chapters are divided into four major parts: I) Fire in the Earth System; II) Biology of Fire; III) Anthropogenic Fire; IV) The Science and Art of Wildland Fire Behavior Management. The book’s Preface explains that each author spoke “in his own disciplinary tongue”, so the style of descriptive language may vary among chapters written by scientists versus historians. Following an introduction to what is fire and methods of studying fire (ancient and modern events), the historical flow of the book is from deep geologic time when plants (the fuel) first appeared on land (late Silurian/early Devonian, ~400 million years ago) to the present day. Some of the sections on fire in the geological record seem too short for my interest in that aspect, but the authors point out that the 390-page text is meant as an introduction to a topic that spans several disciplines. The references for each part, however, are comprehensive, and a companion website includes the figures and tables from the book, teaching material, and links to relevant websites, videos, podcasts.

This book is an excellent example of the value of interdisciplinary research in earth processes. As Scott writes in the online book description, fire is "an integral part of the study of geology, biology, human history, physics, and global chemistry".  In fact, this approach is very "Big History". Big History “examines long time frames using a multidisciplinary approach based on combining numerous disciplines from science and the humanities.”

I found particularly interesting, possibly from being an undergraduate history major before switching fields to earth science for grad school, the historical development of human interaction with fire, based on both historic documents and anthropological and geologic research into the last couple million years since the appearance of earliest human species. Man (using “man” and “his” as inclusive genderless terms) began his fire management relationship as a fire sustainer before he learned how to start or make a fire. The Chapter 11 author points out that man is the only creature that can control fire, and used it for cooking, warmth, land clearing, warfare. Eventually sustainable fresh wood/plant fuels for combustion could not keep up with demand, and, in the Pyric Transition during Industrialization, fossil plant-derived fuels (coal, petroleum, natural gas) became the primarily combustion sources (p. 231, 232).

Prometheus bringing fire to mankind (D'Aulaires' Book of Greek Myths, 1962)

 Fire is a natural process; we utilize it as a resource and tool, but also attempt to manage it as a natural disaster. Man has different relationships with various earth materials and processes, including what we call disasters because of their human disruption. For example, volcanoes, earthquakes, cyclones/hurricanes/tornados: we cannot control those, but try to lessen damage and injury through building codes or just getting out of the way. At the other end of the spectrum, various rock and fuel resources we exploit for civilization's benefit, and currently or retroactively try to ameliorate pollution and damage from extractive processes. Between these endpoints, fire, like surface water, we use and try to beneficially manage, but we cannot totally control.

The management of wildfires includes modern study of both physics and chemistry of burning plus methods to extinguish fires. The results of this research also benefit those trying to interpret the scale and intensity of fire events recorded in the rock record. Andrew Scott, his students and colleagues, particularly Claire Belcher and her own students, have made an important leap in interdisciplinary research in using modern fire science experimental techniques to interpret the fire record in the deep geologic past (hundreds of millions of years). Fusinite (the fossil charcoal 'maceral' in coal) and related combustion particulates in coals and sedimentary rocks are indicators of ancient wildfire. But, a better understanding of temperature and type of deep-time fire events and what the source material was (for example, plant or exposed/eroded coal deposit) has come from experiments testing the types of combustion products produced by various materials (https://sites.google.com/site/palaeofirelab/home; Fire Phenomena and the Earth System: An Interdisciplinary Guide to Fire Science).

This interdisciplinary approach to the analysis of geologic and prehistoric fire events, combining modern fire science, and geologic and anthropological charcoal/fire studies, is innovative. Fire on Earth, brings together related topics and useful avenues of research that could be easily missed otherwise if their results were published in specialty topic journals (not just physical versus social science journals but among narrowly specialized science/technology publications). Fire on Earth, similarly to how David Christian has described Big History in general, “help(s)” the reader “across the divide between the two cultures—from the sciences to the humanities” in the discussion of a millions-year-old natural process that has shaped civilization.

*I was recently surprised to find, regrettably at a funeral, that there is another hymn to the same tune but with different words: “O day of peace that dimly shines”. It was the closing anthem for the deceased, an English immigrant to the US, because the tune identifies so strongly with England.

**More on Big History:

http://www.nytimes.com/2014/09/07/magazine/so-bill-gates-has-this-idea-for-a-history-class.html?_r=0 (background, Bill Gates’ support, pros and cons)

https://www.bighistoryproject.com/home (Gates’ funded high school Big History project)

Particulate organic matter as paleocurrent indicators: dispersed fossil wood in Pennsylvania Bluestone

The tag line for this blog describes that posts are about geologic carbon, excluding carbonate and aqueous dissolved organic matter, focusing on sedimentary and metamorphic organic matter (OM=organic matter) and products from fossil fuel resources. I come at this topic from the organic petrology or microscopy methods I use to investigate geologic problems of level of diagenesis/ very-low-grade metamorphism or what assemblages of particulate organic matter can convey about depositional environment or climate. Many applications of or advancements in organic petrology are related to fossil fuel exploration or utilization, but there are other non-fossil-fuel applications of sedimentary OM data in the geologic sciences. However, in my experience and opinion, those are not commonly used, either because organic petrology is not part of the usual geology curriculum, therefore, not well known, or because light microscopy is not "high tech".

One occurrence of sedimentary OM greets me frequently while I am walking the dog. I live in an old neighborhood of lawns, large trees, and pachysandra (my personal trace plant for old neighborhoods); most of the homes were built around 1900. Although numerous sidewalks are now cement, many remain the original large slabs of Pennsylvania Bluestone, some with fossil wood fragments exposed on cut or slabbed surfaces. Pennsylvania Bluestone is a Middle to Upper Devonian feldspathic sandstone of the Catskill delta or Catskill/Pocono clastic wedge, outcropping now in southern New York, northeastern Pennsylvania, and northern New Jersey. It is the "molasse" of the Acadian orogeny, whose thermal and deformational peak in the northern Appalachians to the east (Maine, New Hampshire, Massachusetts, Connecticut) occurred in the Lower Devonian.

Bluestone in disrepair but shows typical sidewalk slab size and thickness. Twenty-pound (9 kg) puppy for scale.

Bluestone derives its name "from a deep-blue-colored sandstone first found in Ulster County, NY" (http://www.endlessmountainstone.com/bluestone/). In Pennsylvania, the focus of the bluestone industry is in Susquehanna County bordering New York state. Other colors include tans, various grays, and lilac/purple. The Endless Mountain Stone Company website (in 2002, Endless Mountain was the "largest  'bluestone' producer in Northeastern Pennsylvania, FCOFG field guide, p. 85*) also describes the quarrying, cutting or slabbing operations that produce stone for sidewalks, paving, building and facing stone. The environment of deposition of quarried stone includes offshore bars, beaches, and tidal interchannels.

Ripple marks (interference ripples?) on bluestone sidewalk slabs.

Ripple marks, in different location than above, on wet sidewalk in street lights at night.

Although the Pennsylvania Bluestone Association states that the stone is "clear of most organic residues", megascopic particulate fossil wood is occasionally visible. A stratigraphic section of one quarry in the 2002 Field Conference of Pennsylvania Geologists guidebook (Figure 79, p. 86) to the bluestone region, marks locations of "carbonized plant fossils" and "plant-bearing ss".

Patio bluestone showing range of color, some ripple marks, and, in slab in foreground, dispersed fossil wood fragments.

Old bluestone sidewalk slab; fossil wood weathered out leaving casts.

Fossil wood in both rippled and non-rippled bed surfaces in recently-quarried bluestone (in re-laid sidewalk using old original slabs and smaller new slabs to replace broken material). Fragments on non-rippled surface (lower left) show a general consistent orientation.

In the photo above, fossil wood, on the non-rippled bedding surface, is generally aligned due to the ancient water flow direction that deposited the layer and acts as a paleocurrent indicator. Such indicators include any elongated particles including graptolites and other fossils, and sedimentary structures such as ripples, crossbedding, and flute casts. However, alignment of linear objects, such as the wood fragments, can only narrow paleocurrent flow direction to two directions 180 degrees apart. Asymmetrical ripples and flute casts are examples of structures that can define a single direction. Below is an example of paleocurrent direction analysis, showing bidirectional results, from measuring orientation of wood fragments in a Devonian shale of the Appalachian/Catskill basin (in Potter and others, 1979, Devonian Paleocurrents in the Appalachian Basin).

Three more examples of oriented fossil wood in Pennsylvania Bluestone. Blue color in bottom two photos due primarily due to time of day, just prior to sunset.

(from Potter and others, 1979, Devonian Paleocurrents in the Appalachian Basin)

Above is the cumulative paleocurrent direction analysis of Appalachian Devonian sediments, including those of the Catskill/Pocono wedge, showing general western flow and deposition due to unroofing/erosion of the lower Devonian Acadian orogenic thermal/deformational axis to the east. Fossil wood fragments (=particulate land plant organic matter), such as that seen in the bluestone, were an important contributor to this data set.

BTW, at the time this post was written, the blog background was an extreme close-up of wood fragments in bluestone (below).

*Catskill delta field guides:

    Facies and Sedimentary Environments of the Catskill System Tract in Central Pennsylvania, Pittsburgh Association of Petroleum Geologists, 2009 http://www.papgrocks.org/PAPGGuidebook_Spring09.pdf

    From Tunkhannock to Starrucca: Bluestone, Glacial Lakes, and Great Bridges in the “Endless Mountains” of Northeastern Pennsylvania, Field Conference of Pennsylvania Geologists, 2009.

http://fcopg.org/wp-content/uploads/2014/06/67th2002.pdf

Graptolite reflectance and correlation with other diagenetic and very-low-grade metamorphic indicators

The correlation chart and references in this post have been updated as of November 28, 2020. In the chart, the mean maximum reflectance correlation of Malinconico has been changed and is based now on her (my) data from the prehnite-pumpellyite metamorphic terrane of northern Maine, USA, rather than a compilation with other published mean maximum graptolite reflectance published data. The mean random and mean maximum graptolite reflectance correlations of Luo et al. (2020) and the mean random equation of Bertrand and Malo (2012) have been added. Inclusion of Kübler Indices and associated metapelitic (anchizone, etc) zones have been removed (see text below).

My first independent organic petrology research project, in the late 1980's-early 1990's, was a graptolite reflectance study of the low- to very-low-grade metamorphic region of the northern US Appalachians in northern Maine. The goals were to 1) test the applicability of the technique, used in other anchizone regions, to these prehnite-pumpellyite grade rocks, and 2) outline in more detail the regional patterns or trends in metamorphism.

Silurian monograptid graptolites from Lawler Ridge, several miles north of Millinocket, Maine. Mean maximum reflectance 10.6% + 1.0 (n=20).

Graptolites are extinct colonial marine invertebrates of the Phylum Hemichordata with a geologic age range from Cambrian to Carboniferous. They derive their name from the pencil-mark appearance of preserved periderm on shales (Graptolithus= rock writing). Since the mid-1970's, the reflectance of graptolites, in a similar fashion to vitrinite reflectance, has been used to determine the diagenetic level or organic maturity of rocks that, either due to a marine environment of deposition (EOD) or age older than the flourishing of land plants (pre-Silurian), lack vitrinite derived from woody plant matter. Graptolite reflectance has been applied to both petroleum source rock evaluation and analysis of patterns of anchizone/subgreenschist metamorphism, the level of metamorphism between sedimentary rocks and greenschist facies metamorphic rocks where some diagenetic indicators may no longer be applicable and where big micas and flashy garnets, staurolites etc have not yet appeared. (In one talk in ~1992, I did compare the anchizone to the Neutral Zone of Star Trek, which separates Romulan space from Federation space: the anchizone is the area where neither those looking for liquid hydrocarbons nor those studying traditional metamorphic petrology care to go.)

However, the urge to correlate graptolite reflectance values to the well-known or more standard vitrinite-reflectance scale has been problematic for a number of reasons. Firstly, since vitrinite and graptolites are hardly ever found in the same rock, due again to age of rock or EOD, correlation has been made through intermediaries, such as solid bitumen/scolecodont/chitinozoan reflectance, conodont alteration indices (CAI), and Rock-Eval pyrolysis Tmax, that are found in or that can be applied to both vitrinite-bearing and graptolite-bearing rocks. However, a drawback particularly of using intermediaries such as CAI and subgreenschist mineral facies is the wide qualitative range of the categories within those indicators. 

Secondly, the percent graptolite reflectance has been reported in different forms: 

1) mean maximum reflectance: on each of numerous specimens in a single polished whole-rock sample, under polarized light (polarizer in light path), the microscopic stage is rotated to the orientation of the maximum reflectance of the highly anisotropic graptolite exoskeleton and then the reflectance is recorded; a mean and standard deviation is calculated from all the maximum reflectances for that sample; 

2) maximum-maximum or true maximum reflectance which is just the single highest maximum reflectance value of all specimens measured on a sample; no standard deviation; 

3) mean random reflectance, polarized light: the instantaneous measured value with no stage rotation is collected on numerous specimens in a sample, mean and standard deviation calculated; the range of reflectances collected can be quite variable depending on degree of anisotropy, and standard deviation can be large;

4) mean random reflectance, in non-polarized light. The reflectance of the non-polarized surface is theoretically an average of the anisotropic range of that specimen’s surface reflectivity. With a large enough number of measurements, the mean random reflectances in both polarized and non-polarized light should be equal, but the standard deviation in polarized light will be larger. 

Besides correlation to thermal maturation indices commonly used in sedimentary rocks and oil-gas exploration (CAI, vitrinite reflectance/coal rank), since graptolite reflectance has been used in zeolite/prehnite-pumpellyite subgreenschist terranes, proper correlation with related terminology such as diagenesis, anchizone/epizone, very-low-grade/low-grade metamorphism is also an issue. Discussions on the limits of the anchizone based on illite crystallinity and relationship to mineral facies and coal rank (bituminous/anthracite) have been ongoing for decades. In 2007, the International Union of Geological Sciences (IUGS) published a correlation classification for very-low to low-grade metamorphic rocks (Árkai and others, 2007), with vitrinite reflectance, diagenetic to low-grade metamorphic zones, subgreenschist mineral facies, and boundaries for metapelitic zones (diagenetic zone, anchizone, epizone) based on the illite crystallinity Kübler Index (KI). Lower and upper KI limits of the anchizone were 0.42-0.25˚ delta 2theta, respectively. Many of the boundaries were gradational or covered a range of values, but it appeared, to me, that there was international consensus. 

So, in 2016, partly for a couple papers still (and even now in 2020) in draft form and partly in response to a petroleum industry colleague asking how well constrained the vitrinite/graptolite correlations are, I made a huge spread sheet with the IUGS 2007 very-low-metamorphic indicators chart, CAI, and vitrinite-graptolite reflectance correlations from numerous collected graptolite reflectance papers (most source references following). From that, I posted in this blog entry, a correlation chart of metamorphic grade, mineral facies, KI with metapelitic zone, coal rank with vitrinite reflectance, and CAI, plus the mean random graptolite reflectance of Bertrand (1990) and Petersen et al. (2013), and mean maximum graptolite reflectance that was a consensus compilation of my own data from northern Maine and several publications that reported mean maximum graptolite reflectance data.

However, since my 2016 chart, there has been an increasing interest in graptolite reflectance and publication of important papers, particularly from China and Denmark. The surge in interest is due to large unconventional petroleum discoveries in Lower Paleozoic black shales. I am also finally getting around to finalizing my graptolite reflectance study in the prehnite-pumpellyite region of northern Maine. Coincidently, however, there has been changes in standardization used for illite crystallinity studies that has changed the KI limits of the anchizone (Warr and Ferreiro Mählmann, 2015) plus continuing discussion on the variability of the boundaries of the anchizone relative to mineral facies and to coal ranks in different regions (Ferreiro Mählmann and Frey, 2012; Warr and Cox, 2016).

It should be pointed out that the anchizone is defined specifically by illite crystallinity: Kisch wrote in 1990 (p. 42), “The main argument against such re-definitions […in terms of the metamorphic grade in associated materials…] is that the notion of the anchizone is intractably bound to phyllosilicate mineralogy in clastic sedimentary rocks, and particularly defined in terms of illite ‘crystallinity’…Such re-definition of the anchizone in terms other than illite ‘crystallinity’ should therefore be rejected.” In the Alps, there is a range of vitrinite reflectance values associated with the lower and upper boundaries of the anchizone depending on geothermal gradient or heating rate indicating that there are material differences in the chemical and mechanical kinetics of the transformation of clay crystallinity and the physiochemical structure of vitrinite. In addition, the influence of pressure varies between clay and organic matter. Warr and Cox (2016) also reported that in the famous zeolite to prehnite-pumpellyite facies metamorphic region of New Zealand, the epizone, previously interpreted to be equivalent to chlorite-grade greenschist metamorphism, should now include pumpellyite-actinolite facies, formerly in the anchizone.

Therefore, my new 2020 table below, does not include any reference to Kübler Index and related metapelitic zones, despite my fondness for the term “anchizone”. I so far have only found one researcher that reports KI and associated graptolite reflectance (Rantitsch 1995, 1997). Most graptolite reflectance practitioners are working in gas exploration, rather than very-low-grade metamorphic terrane studies, and the co-existing indicators in my area of northern Maine are CAI and zeolite/prehnite-pumpellyite mineral facies. 

The new table BELOW has FIVE correlative relationships of graptolite reflectance: three from studies reporting random reflectance, but that use different intermediaries to relate graptolite to vitrinite reflectance and are from different geological provinces, and two correlations of graptolite mean maximum reflectance.

TABLE (click on it to enlarge): Correlation of metamorphic grade, mineral facies, coal rank, vitrinite reflectance from the IUGS Subcommission on the Systematics of Metamorphic Rocks (Árkai et al., 2007); general boundaries of zeolite facies to vitrinite reflectance (Kisch, 1981); CAI (conodont alteration index) to vitrinite reflectance (Repetski et al., 2008); mean random graptolite reflectance, non-polarized light, from equation based on natural and heat-treated graptolites plus previously published sources (Luo et al., 2020); mean random graptolite reflectance, non-polarized light (to vitrinite reflectance through chitinozoan reflectance: Bertrand, 1990); mean random graptolite reflectance, non-polarized light (to vitrinite reflectance combining results in Bertand, 1990, 1993: Bertrand and Malo, 2012); mean random graptolite reflectance, non-polarized light (to vitrinite reflectance through RockEval pyrolysis Tmax: Petersen et al., 2013); mean maximum graptolite reflectance equation based on natural and heat-treated graptolites plus previously published sources (Luo et al., 2020); mean maximum graptolite reflectance to CAI (Bradley et al., 2000)  and metamorphic facies (Richter and Roy, 1976) of northern Maine, USA (Malinconico, 1992, 1993, unpublished data).

Another useful correlation chart is that of Hartkopf-Fröder (2015; their Figure 26). They comprehensively include not just coal rank, reflectance of vitrinite and graptolites and CAI, but other zooclasts, coloration of spores/pollen and other microfossils, and hydrocarbon generation zones. They did not include mineral metamorphic facies, which were important for my work. Three graptolite reflectance scales are in their chart: Petersen and others (2013) and two by Bertrand and colleagues (1990, 2012); I included those in my chart. Their bibliography includes graptolite reflectance citations (such as several by Bertrand) that are not listed below. Another bibliographic list (Microsoft Word document) of “Zooclast Reflectance” citations is on the website of The Society for Organic Petrology (TSOP) (https://www.tsop.org/references.html). Luo et al. (2020) have a useful graph (Figure 13) for visualization that plots several graptolite-vitrinite reflectance correlations against each other. 

These tables do not solve the graptolite/vitrinite reflectance correlation problem. They do, however, show state of the current publicly available knowledge.

Selected GRAPTOLITE REFLECTANCE 

and diagenetic to very-low-metamorphic indicator references 

including those examined for construction of the correlation table.

(Citations specifically mentioned or used in the table are in bold.) 

Árkai, P., Sassi, F., Desmons, J., 2007, Very low- to low-grade metamorphic rocks (Chapter 2.5), in Fettes, D., and Desmons, J., eds., Metamorphic Rocks: A Classification and Glossary of Terms (Recommendations of the International Union of Geological Sciences Subcommission on the Systematics of Metamorphic Rocks): Cambridge, UK, Cambridge University Press, p. 36-42.

Bertrand, R., 1990, Correlations among the reflectances of vitrinite, chitinozoans, graptolites, and scolecodonts: Organic Geochemistry, v. 15, no. 6, p. 565-574.

Bertrand, R., 1993, Standardization of solid bitumen reflectance to vitrinite in some Paleozoic sequences of Canada, in F. Goodarzi and R.W. Macqueen, eds., Geochemistry and petrology of bitumen with respect to hydrocarbon generation and mineralization: Energy Sources, v. 15, p. 269-287.

Bertrand, R., and Heroux, Y., 1987, Chitinozoan, graptolite and scolecodont reflectance as an alternative to vitrinite and pyrobitumen reflectance in Ordovician and Silurian strata, Anticosti Island, Quebec, Canada, American Association of Petroleum Geologists Bulletin, v. 71, p. 951-957.

Bertrand, R., and Malo M., 2012, Dispersed organic matter reflectance and thermal maturation in four hydrocarbon exploration wells in the Hudson Bay Basin: regional implications: Geological Survey of Canada, Open File 7066, 52 p. http://publications.gc.ca/collections/collection_2012/rncan-nrcan/M183-2-7066-eng.pdf 

Bradley, D. C., Tucker, R. D., Lux, D.; Harris, A. G., and McGregor, D. C., 2000, Migration of the Acadian orogen and foreland basin across the northern Appalachians of Maine and adjacent areas: U.S. Geological Survey Professional Paper 1624, 49 p. 

Bustin, R., M., Link, D., and Goodarzi, F., 1989, Optical properties and chemistry of graptolite periderm following laboratory simulated maturation: Organic Geochemistry, v. 14, p. 355-364.

Cao, C., Sang, Q., Fang, Y., 2000, The study of graptolite reflectance as the indicator of source-rock maturation in Ordovician and Silurian of Tarim basin, Ordos, Jiangsu areas: v. 39, issue 1, Acta palaeontologica sinica, p. 151-156. (In Chinese; English abstract and figure captions)

Cardott, B. J., and Kidwai, M. A., 1991, Graptolite reflectance as a potential thermal-maturation indicator, in K. S. Johnson, ed., Late Cambrian-Ordovician geology of the southern Midcontinent, 1989 symposium: Oklahoma Geological Survey Circular 92, p. 203-209.

Clausen, C.-D. and Teichmüller, M., 1982, Die Bedeutung der Graptolithenfragmente im Paläozoikum von Soest-Erwitte für Stratigraphie und Inkohlung: Fortschritte in der Geologie von Rheinland und Westfalen, v. 30, p. 145-167.

Cole, G. A., 1994, Graptolite-chitinozoan reflectance and its relationship to other geochemical maturity indicators in the Silurian Qusaiba shale, Saudi Arabia: Energy & Fuels., v. 8, p. 1443-1459.

Ferreiro Mählmann, R., Frey, M., 2012, Standardisation, calibration and correlation of the Kübler-index and the vitrinite/bituminite reflectance: an inter-laboratory and field related study: Swiss Journal of Geosciences, v. 105: 153-170.

Gentzis, T., T. de Freitas, F. Goodarzi, M. Melchin, and A. Lenz, 1996, Thermal maturity of lower Paleozoic sedimentary successions in Arctic Canada: AAPG Bulletin, v. 80, p. 1065-1084.

Goodarzi, F., 1984, Organic petrology of graptolite fragments from Turkey: Marine and Petroleum Geology, v. 1, p. 202-210.

Goodarzi, F., 1985, Dispersion of optical properties of graptolite epiderms in increase maturity in early Paleozoic organic sediment: Fuel, v. 64, p. 1735-1740.

Goodarzi, F., 1990, Graptolite reflectance and thermal maturity of Lower Paleozoic rocks, in V. F. Nuccio and C. E. Barker, eds., Applications of thermal maturity studies to energy exploration: SEPM, Rocky Mountain Section, p. 19-22.

Goodarzi, F., Gentzis, T., Harrison, C., and Thorsteinsson, R., 1992, The significance of graptolite reflectance in regional thermal maturity studies, Queen Elizabeth islands, Arctic Canada: Organic Geochemistry, v. 18, no. 3., p. 347-357.

Goodarzi, F., and Norford, B. S., 1985, Graptolites as indicators of the temperature histories of rocks: International Journal of Coal Geology, v. 11, p. 127-141.

Goodarzi, F., and Norford, B. S., 1989, Variation of graptolite reflectance with depth of burial: International Journal of Coal Geology, v. 11, p. 127-141.

Hartkopf-Fröder, C., Königshof, P., Littke, R., Schwarzbauer, J., 2015, Optical thermal maturity parameters and organic geochemical alteration at low grade diagenesis to anchimetamorphism: A Review: International Journal of Coal Geology, v. 150-151, p. 74-119.

Kemp, A. E. S., Oliver, G. H. I. and Baldwin, J. R., 1985, Low-grade metamorphism and accretion tectonic: Southern Uplands terrain, Scotland: Mineralogical Magazine, v. 49, p. 335-344.

Kisch, H.J., 1981, Coal rank and illite crystallinity associated with the zeolite facies of Southland and the pumpellyite-bearing facies of Otago, southern New Zealand: New Zealand Journal of geology and Geophysics, v. 24, p. 349-360.

Kisch, H.J., 1990, Calibration of the anchizone: a cricial comparison of illite 'crystallinity' scale used for definition: Journal of Metamorphic Geology, v. , p. 31-46.

Kurylowicz, L. E., Ozimic, S., McKirdy, D. M., Kantsler, A. J. and Cook, A. C., 1976, Reservoir and source rock potential of the Larapinta Group, Amadeus Basin, Central Australia: Australian Petroleum Exploration Association Journal, v. 16, p. 44-65.

Luo, Q., Goodarzi, F., Zhong, N., Wang, Y., Qiu, N., Skovsted, C. B., Suchy, V., Schovsbo, N. H., Morga, R., Xu, Y., Hao, J., Liu, A., Wu, J., Cao, W., Min, X., Wu, J., 2020, Graptolites as fossil geo-thermometers and source material of hydrocarbons: An overview of four decades of progress: Earth-Science Reviews, v. 200, Article 103000. doi:10.1016/j.earscirev.2019.103000 

Luo, Q., Hao, J., Skovsted, C.B., Luo, P., Khan, I., Wu, J., Zhong, N., 2017. The organic petrology of graptolites and maturity assessment of the Wufeng–Longmaxi Formations from Chongqing, China: insights from reflectance cross-plot analysis: International Journal of Coal Geology, v. 183, p. 161–173. 

Luo, Q., Hao, J., Skovsted, C.B., Xu, Y., Liu, Y., Wu, J., Zhang, S., Wang, W., 2018. Optical characteristics of graptolite-bearing sediments and its implication for thermal maturity assessment: International Journal of Coal Geology, v. 195, p. 386–401. 

Luo, Q., Zhong, N., Dai, N., Zhang, W., 2016. Graptolite-derived organic matter in the Wufeng–Longmaxi Formations (Upper Ordovician–lower Silurian) of southeastern Chongqing, China: implications for gas shale evaluation: International Journal of Coal Geology, v. 153, p. 87–98. 

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How BIG is BIG? (Data out of context and spinning the message: US Atlantic OCS and other oil reserve estimates in the news)

Two weeks ago, the US Department of Interior announced that the US Atlantic Outer Continental Shelf (OCS) was removed from the 2017-2022 offshore lease sale (http://www.cnn.com/2016/03/15/politics/obama-drilling-atlantic-coast/index.html;

http://washpost.bloomberg.com/Story?docId=1376-O42VSQ6JTSEX01-2P7U5E8RTS87GP3EKFMV10Q903). The January 2015 Draft Proposed Program for the OCS 2017-2022 lease sale originally included parts of the Mid-Atlantic and South Atlantic planning areas from Virginia south to Georgia; the portion of the Mid-Atlantic planning area offshore of Delaware and Maryland, and the North Atlantic planning area (offshore New Jersey north to Maine) were not in the Draft Proposal (see Figure 1). On March 15, 2016, however, the Proposed Program (http://www.boem.gov/2017-2022-Proposed-Program-Decision/) was published and now excludes the entire US Atlantic OCS. This decision was welcomed by environmental groups, various members of the US Congress from Atlantic coastal states (http://www.menendez.senate.gov/news-and-events/press/east-coast-senators-introduce-bill-to-prevent-atlantic-offshore-drilling-say-killthedrill), NASA and the US Navy (https://www.washingtonpost.com/news/energy-environment/wp/2016/03/14/the-governments-atlantic-drilling-plan-takes-friendly-fire-from-the-pentagon/), and some coastal communities. However, industry (http://www.oilandgasinvestor.com/feds-nix-atlantic-five-year-offshore-lease-plan-842361), plus governors of southern states who were hoping offshore fossil fuel production would bring income to the states, were disappointed, to say the least. (It is important to note, that although there is federal revenue sharing from offshore lease royalties to some Gulf Coast states, there is no revenue sharing plan in place for Atlantic states.)

 

Figure 1: Draft proposed Atlantic OCS planning area (from http://www.pressofatlanticcity.com/news/breaking/offshore-drilling-meegting-today-in-atlantic-city/article_49dbb8ee-c992-11e4-a1db-670b91b0f8ed.html)

The news articles above mention the 2011 assessed mean amount of potential fossil fuel resources for the entire Atlantic OCS, which includes the North, Mid- and South Atlantic planning areas: 3.3 billion barrels of oil (Bbo) and 31.3 trillion cubic feet (Tcfg) of natural gas (http://www.boem.gov/uploadedFiles/2011_National_Assessment_Factsheet.pdf). The revised 2014 assessment adjusts those mean numbers upwards to 4.72 Bbo and 37.51 Tcfg. These numbers are for the "Undiscovered Technically Recoverable"* resources on the Atlantic continental shelf within the US Exclusive Economic Zone (EEZ) that extends 200 miles from the US coastline. The lease blocks, however, would start no closer than 50 miles offshore (contrary to Senator Menendez' tweeted anti-drilling but Photoshopped picture of an oil rig within sight of beachgoers**). The assessments are based on wells drilled, mostly dry or uneconomic, and seismic data collected before the early 1990’s moratorium on Atlantic OCS oil and gas resource development, and on study of "analogs" which are known hydrocarbon plays in similar geologic settings in other parts of the world. The assessment, besides reporting the mean estimated amount, also provides other probabilities of occurrence: for the entire Atlantic OCS, there is a 5% chance (2014 revised assessment) of 9.23 Bbo and 67.7 Tcfg, but a large (95%) chance there is only 1.32 Bbo and 11.8 Tcfg.

But is this estimated resource amount BIG? Is loss of access to the Atlantic OCS a major blow to the Nation's energy independence and security, as some articles suggest? Although industry and industry media outlets would understand the relevance of the assessed numbers in relation to oil reserves around the world, the general public does not. A BILLION sounds immense, so readers may think we are missing out on a large national resource by blocking development. Without context, that is, without comparisons to other data, the numbers may be misleading. From the map below (Figure 2), however, one can see that Atlantic mean assessed amounts are minor compared to the Gulf of Mexico, and less than offshore California where there is proven production. According to an article in Eos, March 17, 2016,

“The removal of that lease sale would lower the projection of future U.S. oil production by about 0.1% and would lower the U.S. natural gas production projection by 0.06%, according to the Interior Department’s Bureau of Ocean Energy Management (BOEM). ‘Thus, the energy security of the United States will remain strong without offshore leasing in the Atlantic during the 2017–2022 program,’ BOEM states in the new OCS proposal.”

 Figure 2: Figure 5-6 from http://www.boem.gov/2017-2022-DPP/ (p. 101 of pdf): Assessment of UTRR of the OCS, 2011 (Atlantic OCS Updated 2014)

Another example of numbers out of context is also related to oil reserves. In the early-2000’s, whether or not to open the Alaska National Wildlife Refuge (ANWR) 1002 Area to drilling was a contentious and controversial topic. Many against drilling said there was only several months of oil there, based on data in a US Geological Survey (USGS) report (https://www.nwf.org/News-and-Magazines/National-Wildlife/Animals/Archives/2010/Arctic-Refuge-Turns-Fifty.aspx). WHAT? This argument was used as a reason not to drill. The USGS 1998 petroleum assessment of the 1002 Area (http://pubs.usgs.gov/fs/fs-0028-01/fs-0028-01.pdf) states that the mean Technically Recoverable oil in the 1002 Area (not including Native Lands or offshore waters) is 7.7 Bbo.  According to the Congressional Record-Senate (April 18, 2002, p. 5027), Senator John Corzine (D-NJ) said ". . . Based on estimates from the U.S. Geological Survey, it is likely to have little more than 6 months' worth of capacity relative to 1 year of U.S. demand. The oil wouldn't even begin to be available for at least 10 years. And it wouldn't reach peak production for 20 years."

Corzine's statement does include the phase "relative to 1 year of U. S. demand" which is key to understanding what is meant by "6 months' worth of capacity". In 2002, US crude oil consumption was 19.761 million barrels of oil PER DAY. If you divide that daily consumption (million barrels per day) into the mean recoverable 1998 estimate for the entire 1002 area (7.7Bbo, undeformed plus smaller geologically deformed region), you get the equivalent of 388 days or, using 1 month=30 days, 12.9 months, of US oil usage. Using instead the 95%-probability estimate of 3.4 Bbo (in just the undeformed part of 1002), the result is 170 days or 5.7 months of US oil consumption. But, could the 1002 Area, if ever in production, produce 20 million barrels a day? Could it be the Nation’s sole source of petroleum? NO. The estimated 1002 Area peak production daily rate ranges from 600,000 - 1.9 million barrels/day from multiple wells over a total 50-60 year life of the field (http://dog.dnr.alaska.gov/Publications/Documents/OtherReports/Oil_Gas_in_ANWR_Review_2003-02.pdf, p.6; http://www.eia.gov/pub/oil_gas/petroleum/analysis_publications/arctic_national_wildlife_refuge/pdf/anwr101.pdf). For comparison, current daily production from the world's largest conventional oil field, Saudi Arabia's megagiant Ghawar field, is ~5 million barrels/day. For the 1002 Area, saying there is only 6 months of oil, without detailing how that number was calculated, without saying that it is supposed to be some sort of useful analogy, is deceptive.

Although here in the USA, we are in the height of "spin" season with the coming Presidential election, sound bites or media reports with partial information or numbers out of context happen at any time in any field, not just the earth sciences. A piece of data or information, no matter how accurate can, without revelation of how it was derived or if isolated from larger trends or data sets, lead to an incorrect assumption on the part of the listener or reader. This can occur by design, to twist or “spin” a meaning, or inadvertently, but for greatest transparency, educated discussion and informed decision making, complete data and background derivations must be available.

* Technically Recoverable means we have the drilling and production technology to access and produce the resource. Sometimes assessment estimates are given as "Economically Recoverable" which means what can be produced with a profit at a particular market price of oil/gas: if the price is too low, as we have seen in the last year, production of some resources, such as unconventional shale gas and shale oil, may not be cost effective.

** (http://twitter.com/SenatorMenendez/status/560157585274572800/photo/1;

oil rig original photo: http://www.shutterstock.com/s/offshore+rig/search.html?page=3&thumb_size=mosaic&inline=214057231)

KEYWORDS AND TERMS: "Atlantic Outer Continental Shelf", OCS, "offshore lease sale"