The Origin of Coal
by Stuart E. Nevins, M.S. (aka Steve Austin)
Accumulated, compacted and altered plants form a sedimentary
rock called coal. It is not only a resource of great economic importance, but a
rock of intense fascination to the student of earth history. Although coal forms
less than one percent of the sedimentary rock record, it is of foremost
importance to the Bible-believing geologist. Here is where he finds one of his
strongest geological arguments for the reality of the great Noachian Flood.
Two theories have been proposed to explain the formation of
coal. The popular theory held by many uninformitarian geologists is that the
plants which compose the coal were accumulated in large freshwater swamps or
peat bogs during many thousands of years. This first theory which supposes
growth-in-place of vegetable material is called the autochthonous theory.
The second theory suggests that coal strata accumulated from
plants which had been rapidly transported and deposited under flood conditions.
This second theory which claims transportation of vegetable debris is called the
Fossils In Coal
The types of fossil plants found in coal do not clearly
support the growth in place theory (autochthonous). The fossil lycopod trees
(e.g., Lepidodendron and Sigillaria) and giant ferns
(especially Psaronius) common in Pennsylvanian coals may have had
some ecological tolerance to swampy conditions, yet other Pennsylvanian coal
plants (e.g., the conifer Cordaites, the giant scouring rush
Calamites, the various extinct seed ferns) by their basic construction must
have preferred well-drained soils, not swamps. The anatomy of coal plants is
considered by most investigators to indicate tropical or subtropical climate, a
conclusion which can be used to argue against growth in place (autochthonous)
theory, for modern swamps are most extensive and have the deepest accumulation
of peat in the higher-latitude cooler climates. Because of the increased
evaporative power of the sun, modern tropical and subtropical regions have the
most meager peats.
It is not uncommon to find marine fossils such as fish,
moluscs, and brachiopods in coal. Coal balls, which are rounded masses of matted
and exceptionally well preserved plant and animal fossils (including marine
creatures)1 are found within coal strata and associated with coal
strata. The small marine tubeworm Spirorbis is commonly attached to
plants in Carboniferous coals of Europe and North America.2 Since
there is little anatomical evidence suggesting that coal plants were adapted to
marine swamps, the occurrence of marine animals with nonmarine plants suggests
mixing during transport, thus favoring the water transport (allochthonous)
Among the most fascinating types of fossils associated with
coal seams are upright tree trunks which often penetrate tens of feet
perpendicular to stratification. These upright trees are frequently encountered
in strata associated with coal, and on rare occasions are found in the coal. In
each case the sediments must have amassed in a short time to cover the tree
before it could rot and fall down.
One's first impression may be that these upright trees are in
their original growth position, but several lines of evidence indicate
otherwise. Some of the trees penetrate the strata diagonally, while others are
found upside down. Sometimes an upright tree appears to be rooted in
growth position in a stratum which is entirely penetrated by a second upright
tree. The hollow trunks are commonly filled with sediment unlike the immediately
surrounding rocks. Logic applied to the previous examples demonstrates
transportation of the trunks.
The most important fossil relating to the controversy over
the formation of coal is Stigmaria, a fossil root or rhizome.
Stigmaria is frequently found in strata below coal seams and is commonly
associated with upright trees. Stigmaria studied nearly 140 years ago by
Charles Lyell and J.W. Dawson in the Carboniferous coal sequence of Nova Scotia
was considered to provide unambiguous proof of growth-in-place. Many modern
geologists still insist that Stigmaria represents an in situ root
in the soil below the coal swamp. The Nova Scotia coal sequence was recently
restudied by N.A. Rupke3, who found four types of sedimentary
evidence for the water transport (allochthonous) origin of Stigmaria. The
fossil is usually fragmental and is rarely attached to a trunk, it shows a
preferred orientation of its long axis due to current action, it is filled with
sediment unlike the immediately surrounding rock, and it is often found on
multiple horizons in beds which are entirely penetrated by upright trees.
Rupke's research brings serious doubt upon the popular growth in place
(autochthonous) interpretation of other Stigmaria-bearing strata.
Coal commonly occurs in a sequence of sedimentary strata
called a cyclothem. An idealized Pennsylvanian cyclothem
may have strata deposited in the following ascending order: sandstone, shale,
limestone, underclay, coal, shale, limestone, shale. A typical cyclothem
will normally be missing one or more of the component strata. In any one
locality cyclothems commonly repeat tens of times with each cycle of
deposition accumulated on a previous one. There are fifty successive cycles in
Illinois and over a hundred in West Virginia.
Although the coal bed forming a portion of the typical
cyclothem is usually quite thin (commonly an inch to a few tens of feet
thick), the lateral extent of coal is often incredible. Modern stratigraphic
research4 has correlated the Broken Arrow coal (Oklahoma), Croweburg
coal (Missouri), Whitebrest coal (Iowa), Colchester No. 2 coal (Illinois), Coal
IIIa (Indiana), Schultztown coal (W. Kentucky), Princess No. 6 coal (E.
Kentucky), and Lower Kittanning coal (Ohio and Pennsylvania). These form a
single, vast seam of coal exceeding one hundred thousand square miles in area in
the central and eastern United States. No modern swamp has an area remotely
approaching the great Pennsylvanian coals.
If the growth in place (autochthonous) model for coal
formation is correct, a very unusual set of circumstances must have prevailed.
An entire region, often encompassing many tens of thousands of square miles,
would have to be raised simultaneously relative to sea level to permit swamp
accumulation, and then lowered to permit the ocean to flood the area. If the
coal forest was raised too far above sea level, the swamp and its antiseptic
water necessary for the accumulation of peat would have been drained. If during
the peat accumulation time the sea invaded the swamp, the marine conditions
would have killed the plants, and other sediment instead of peat would have been
deposited. According to the popular model, the formation of a thick bed of coal,
then, would indicate the maintenance of an incredible balance over many
thousands of years between the rate of peat accumulation and the rise of sea
level. Such a situation seems most improbable, especially when the cyclothem
is known to recur a hundred times or more in a vertical section. Could such
cycles be better explained by accumulation during successive advances and
retreats of flood waters?
One of the most talked about portions of the cyclothem
is the underclay. The nonbedded, plastic layer of clay often underlies the coal
stratum and is considered by many geologists to be a fossil soil on which the
swamp existed. The presence of underclay, especially when it possesses
Stigmaria, is often claimed to be prima facie evidence for the growth
in place (autochthonous) origin of coal-forming plants.
Modern research, however, has cast some doubt on the fossil
soil interpretation of underclays. No soil profile similar to modern soils is
evident in underclays. Some of the minerals found in the underclay are not the
type which would be expected in a soil. Instead underclays commonly show graded
bedding (coarser grained material at the base) and evidence of clay
flocculation. These are simple sedimentary features which would form in any
water accumulated layer.
Many coal seams do not rest on underclays and little evidence
of soil exists. In some cases coal strata rest on granite, schist, limestone,
conglomerate or other rock unsuitable for soil. Underclay without a coal bed
above is common as well as underclay resting on top of coal. The absence of
recognizable soils below beds of coal shows the improbability of any type of
luxuriant vegetation growing in place and argues for transportation of the
Texture of Coal
Investigation of the microscopic texture and structure of
peat and coal contributes to the understanding of the origin of coal. A. D.
Cohen5 initiated a comparative structural study between modern
growing in place (autochthonous) mangrove peats and a rare modern water
transport (allochthonous) beach peat from southern Florida. Most growing in
place (autochthonous) peats had plant fragments showing random orientation with
a dominant matrix of finer material, while the water transport (allochthonous)
peat showed current orientation of elongated axes of plant fragments generally
parallel to the beach surface with a characteristic lack of the finer matrix.
The poorly sorted plant debris in the growing in place (autochthonous) peats had
a massive structure due to the intertwining mass of roots, while the water
transport (allochthonous) peat had characteristic microlamination due to the
absence of intergrown roots.
Following this study Cohen remarked: "A peculiar enigma which
developed from study of the water transport (allochthonous) peat was that
vertical microtome sections of this material looked more like thin sections of
Carboniferous coal than any of the growing in place (autochthonous) samples
studied."6 Cohen noted that the characteristics of his water
transport (allochthonous) peat (orientation of elongated fragments, sorted
granular texture with general lack of finer matrix, microlamination with lack of
matted root structure) are also general characteristics of
Boulders in Coal
One of the most striking inorganic features of coal is the
presence of boulders. These have been noted in coal beds all over the world for
more than one hundred years. P.H. Price7 conducted a study of
boulders in the Sewell Coal of West Virginia. The average weight of 40 boulders
collected was 12 pounds with the largest weighing 161 pounds. Many of the
boulders were igneous and metamorphic rocks unlike any rock outcrops
in West Virginia. Price suggested that the boulders may have been entwined
in the roots of trees and transported from a distant area. Thus, the occurrence
of boulders in coal favors the water transport (allochthonous) model.
The nature of the process of metamorphosis of peat to form
coal has been disputed for many years. One theory suggests that time is
the major factor in coalification. The theory, however, has become unpopular
because it has been recognized that there is no systematic increase in the
metamorphic rank of coal with increasing age. There are some blatant
contradictions: lignites representing low metamorphic rank occur in some of the
oldest coal-bearing strata while anthracites representing the highest
metamorphic rank occur in some of the youngest strata.
A second theory supposes pressure to be the major
factor in coal metamorphosis. The theory is refuted by numerous geological
examples where metamorphic rank does not increase in highly deformed and folded
strata. Furthermore, laboratory experiments demonstrate that increase of
pressure can actually retard the chemical alteration of peat to coal.
A third theory (by far the most popular) suggests the
temperature is the important factor in coal metamorphosis. Geological
examples (igneous intrusions into coal seams and underground mine fires)
demonstrate that elevated temperature can cause coalification. Laboratory
experiments have also been quite successful. One experiment8 produced
a substance like anthracite in a few minutes by using a rapid heating process
with much of the heat being generated by the cellulosic material being altered.
Thus, the metamorphosis of coal does not require millions of years of applied
pressure and heat, but can be produced by quick heating.
We see that many positive evidences have appeared which
strongly support the water tramsport (allochthonous) model and the accumulation
of many of the coal layers during the Noachian Flood. Upright fossil trees
within coal seams suggest rapid accumulation of the vegetable debris. Marine
animals and terrestrial (not swamp-dwelling) plants in coal imply
transportation. The microstructure of many coal strata shows particle
orientation, sorted texture, and microlamination indicating transportation (not
growth-in-place) of plant material. Boulders present in coal demonstrate
transportation processes. The absence of a soil below many coal strata argues
for the drifting of coal-forming plants. Coal appears to form a regular and
typical portion of the cyclothem being as clearly water-laid as the other
rocks. Experiments in the alteration of vegetable material show that coal
resembling anthracite does not require millions of years to form, but can be
produced rapidly by a short heating process.
1 S.H. Mamay and E.L. Yochelson, "Occurrence and
Significance of Marine Animal Remains in American Coal Balls," U.S. Geological
Survey Professional Paper 354-1, 1962, pp. 193- 224.
2 H.G. Coffin, "A Paleoecological Misinterpretation," Creation
Research Society Quarterly, 1968, vol. 5, pp. 85-87.
3 N.A. Rupke, "Sedimentary Evidence for the Allochthonous Origin of
Stigmaria, Carboniferous, Nova Scotia," Geological Society of America
Bulletin, 1969, vol. 80, pp. 2109-2114.
4 C.R. Wright, "Environmental Mapping of the Beds of the Liverpool
Cyclothem in the Illinois Basin and Equivalent Strata in the Northern
MidContinent Region," unpublished Ph.D. thesis, 1965, Univ. of Illinois; R.M.
Kosanke, "Palynological Studies of the Coals of the Princess Reserve District in
Northeastern Kentucky," U.S. Geol. Survey Prof. Paper 839, 1973, 20 p.
5 A.D. Cohen, "An Allochthonous Peat Deposit from Southern Florida,"
Geological Society of America Bulletin, 1970, vol. 81, pp. 2477-2482.
6 Ibid., p. 2480.
7 P.H. Price, "Erratic Boulders in Sewell Coal of West Virginia,"
Journal of Geology, 1932, vol. 40, pp. 62-73.
8 G.R. Hill, Chemical Technology, May 1972, p. 296.
* Professor Geology and Archaeology Christian Heritage
College El Cajon, California.