How Does Wood Petrify
Wood must first be covered with such agents as volcanic ash, volcanic
lava flow, volcanic mud-flows, sediments in lakes and swamps or
material washed in by violent floods - by any means which would
exclude oxygen and thus prevent decay. A number of mineral
substances (such as calcite, pyrite, marcasite) can cause petrification,
but by far the most common is silica. Solutions of silica dissolved in
ground water infiltrate the buried wood and through a complex
chemical process are precipitated and left in the individual plant cells.
Here the silica may take a variety of forms; it may be agate, jasper,
chalcedony or opal. The beautiful and varied colors of petrified wood
are caused by the presence of other minerals that enter the wood in
solution with the silica. Iron oxide stains the wood orange, rust, red or
yellow. Manganese oxide produces blues, blacks or purple.
Mineralized fossil bone
Fossil bone can be mineralized in several ways. Permineralized fossils have their
original pore space infilled with minerals. Permineralization is commonly confused with
petrification, in which the original material of an organism is replaced with minerals,
and the pore space is infilled with minerals. In other words, petrification is a combination
of permineralization and replacement.
By far, permineralization is the most common type of preservation for most fossil bone,
and even when petrification has occurred, there is almost invariably evidence that
permineralization occurred first (otherwise, there would be no preservation of the original
cavities in the bone!). So, if you are wondering what petrified bone looks like, imagine
the bone material being replaced by other minerals, sometimes preserving the fine
structure of the bone, sometimes not, and the open pore spaces infilled as seen here. I
plan to eventually present some truly petrified bone eventually.
In either case, the boundary between the original, open pore space and the replaced
material is quite obvious, because of variations in the shape and orientation of the crystals
infilling the pores. In the case of the Haversian canals of bone, this is usually indicated by
concentric growth of crystals from the inner surface of the canal towards the interior,
often with clear radially-arranged crystals and/or layers of different minerals at early
infilling versus later stages.
For more information on bone fossilization processes, including illustrations, see Reid
(1996) and Hubert et al. (1996).
‘Instant’ Petrified Wood
‘Instant petrified wood’ — so ran the heading to the announcement in Popular
Science, October 1992 [1]. It’s also the reality of research conducted at the
Advanced Ceramic Labs at the University of Washington in Seattle (USA).
Researchers have also made wood-ceramic composites that are 20–120% harder
than regular wood, but still look like wood. Surprisingly simple, the proces
involves soaking wood in a solution containing silicon and aluminium
compounds. The solution fills the pores in the wood, which is then oven-cured at
44C (112F). According to the lab’s research director, Daniel Dobbs, such
experiments have impregnated the wood to depths of about 5 millimetres (0.2
inches). Furthermore, deeper penetration under pressure and curing at higher
temperature have yielded a rock-hard wood-ceramic composite that has
approached petrified wood.
Patent 'Recipe' for Petrification
However, priority for the discovery of a 'recipe' for petrification of wood must go
to Hamilton Hicks of Greenwich, Connecticut (USA), who on September 16, 1986
was issued with US Patent Number 4,612,050. [2] According to Hicks, his
chemical 'cocktail' of sodium silicate (commonly known as 'water glass'), natural
spring or volcanic mineral water having a high content of calcium, magnesium,
manganese and other metal salts, and citric or malic acid is capable of rapidly
petrifying wood. But in case you want to try this 'recipe,' you need to know that
for artificial petrification to occur there is some special technique for mixing
these components in the correct proportions to get an 'incipient' gel condition.
Hicks wrote:
'When applied to wood, the solution penetrates the wood. The mineral
water and sodium silicate are relatively proportioned so the solution is a
liquid of stable viscosity and is acidified to the incipient jelling [gelling]
condition to a degree causing jelling [gelling] after penetrating the wood,
but not prior thereto. That is to say, the solution can be stored and
shipped, but after application to the wood, jells [gels] in the wood. When
its content is high enough, the penetrated wood acquires the
characteristics of petrified wood. The wood can no longer be made to
burn even when exposed to moisture or high humidity, for a prolonged
period of time. The apparent petrification is obtained quickly by drying
the wood. [3]
The patent indicates that the amount of acid in the solution appears to have a
critical effect on the production of the gel phase within the cell structure of the
wood, although evaporation also plays its part. Wood thoroughly impregnated,
even if necessary by repeated applications or submersions of the wood in the
solution, after drying evidently has all the characteristics of petrified wood,
including its appearance.
Both Hicks and the researchers at the University of Washington lab have
suggested potential uses for such 'instant' petrified woods:
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Fireproofing wooden structures such as houses and horse stables (the
horses wouldn't be tempted to chew on the wood either!).
Longer-wearing floors and furniture.
Greater strength wood for structural uses.
Insect, decay and salt water 'proofing' wood in buildings, etc.
Rapid Natural Petrification
The chemical components used to artificially petrify wood can be found in natural
settings around volcanoes and within sedimentary strata. Is it possible then that
natural petrification can occur rapidly by these processes? Indeed! Sigleo [4]
reported silica deposition rates into blocks of wood in alkaline springs at
Yellowstone National Park (USA) of between 0.1 and 4.0 mm/yr.
From Australia come some startling reports. Writing in The Australian Lapidary
Magazine, Pigott [5] recounts his experiences in southwestern Queensland:
'. . . from Mrs McMurray [of Blackall], I heard a story that rocked me and
seemed to explode many ideas about the age of petrified wood. Mrs
McMurray has a piece of wood turned to stone which has clear axe
marks on it. She says the tree this piece came from grew on a farm her
father had at Euthella, out of Roma, and was chopped down by him
about 70 years ago. It was partly buried until it was dug up again,
petrified. Mac McMurray capped this story by saying a townsman had a
piece of petrified fence post with the drilled holes for wire with a piece of
the wire attached.
'Petrified wood thousands of years old? I wonder is it so?'
Several months later Pearce[6] added further to these amazing stories of woods
rapidly petrified in the ground of 'outback' Queensland:
'. . . Piggott writes of petrified wood showing axe marks and also of a
petrified fence post.
'This sort of thing is, of course, quite common. The Hughenden district, N.
Q. [North Queensland], has . . . Parkensonia trees washed over near a
station [ranch] homestead and covered with silt by a flood in 1918
[which] had the silt washed off by a flood in 1950. Portions of the trunk
had turned to stone of an attractive colour. However, much of the trunks
and all the limbs had totally disappeared.
'On Zara Station [Ranch], 30 miles [about 48 kilometres] from
Hughenden, I was renewing a fence. Where it was dipped into a hollow
the bottom of the old posts had gone through black soil into shale. The
Gidgee wood was still perfect in the black soil. It then cut off as straight
as if sawn, and the few inches of post in the shale was pure stone. Every
axe mark was perfect and the colour still the same as the day the post
was cut . . . .
'I understand that down in the sandhill country below Boulia [southwestern Queensland], where fences are often completely covered by
shifting sand, it's a common thing for the sand to shift off after a number
of years, leaving stone posts standing erect.'
From the other side of the world comes a report of the chapel of Santa Maria of
Health (Santa Maria de Salute), built in 1630 in Venice, Italy, to celebrate the end
of The Plague. Because Venice is built on watersaturated clay and sand, the
chapel was constructed on 180,000 wooden pilings to reinforce the foundations.
Even though the chapel is a massive stone block structure, it has remained firm
since its construction. How have the wooden pilings lasted over 360 years? They
have petrified! The chapel now rests on 'stone' pilings![7]
Experimental Verification
Of course, none of these reports should come as a surprise, since the processes of
petrification of wood have been known for years, plus the fact that the process
can occur, and has occurred, rapidly. For example Scurfield and Segnit [8] had
reported that the petrification of wood can be considered to take place in five
stages:
1. Entry of silica in solution or as a colloid into the wood.
2. Penetration of silica into the cell walls of the wood's structure.
3. Progressive dissolving of the cell walls which are at the same time
replaced by silica so that the wood's dimensional stability is maintained.
4. Silica deposition within the voids within the cellular wall framework
structure.
5. Final hardening (lithification) by Drying out.
Furthermore Oehler [9] had previously shown that the silica minerals quartz and
chalcedony critically important in the petrification of wood, can be made, rapidly
in the laboratory from silica gel. At 300°C (572°F) and 3 kilobars (about 3,000
atmospheres) pressure only 25 hours was required to crystallize quartz, whereas
at only 165°C (329°F) and 3 kilobars pressure the same degree of crystallization
occurred in 170 hours (about seven days).
Similarly, Drum [10] had partially silicified small branches by placing them in
concentrated solutions of sodium metasilicate for up to 24 hours, while Leo and
Barghoorn [11] had immersed fresh wood alternately in water and saturated ethyl
silicate solutions until the open spaces in the wood were filled with mineral
material, all within several months to a year. Likewise, as early as 1950 Merrill
and Spencer [12] had shown that the sorption of silica by wood fibres from
solutions of sodium metasilicate, sodium silicate and activated silica sols (a
homogeneous suspension in water) at only 25°C (77°F) was as much as 12.5
moles of silica per gram within 24 hours--the equivalent of partial
silicification/petrification. As Sigleo concluded,
'These observations indicate that silica nucleation and deposition can
occur directly and rapidly on exposed cellulose [wood] surfaces. [13]
Conclusions
The evidence, both from scientists' laboratories and God's natural laboratory,
shows that under the right chemical conditions wood can be rapidly petrified by
silicification, even at normal temperatures and pressures. The process of
petrification of wood is now so well known and understood that scientists can
rapidly make petrified wood in their laboratories at will.
Unfortunately, most people still think, and are led to believe, that fossilized wood
buried in rock strata must have taken thousands, if not millions, of years to
petrify. Clearly, such thinking is erroneous, since it has been repeatedly
demonstrated that petrification of wood can, and does, occur rapidly. Thus the
timeframe for the formation of the petrified wood within the geological record is
totally compatible with the biblical time-scale of a recent creation and a
subsequent devastating global Flood.
References
1. Phil McCafferty, 'Instant petrified wood?', Popular Science, October 1992, pp.
56-57.
2 Hamilton Hicks, 'Mineralized sodium silicate solutions for artificial
petrification of wood', United States Patent Number 4,612,050, September
16,1986, pp. 1-3. As cited by: Steven Austin, CatastroRef--'Catastrophe Reference
Database: Catastrophes in Earth History, Geologic Evidence, Speculation and
Theory', Institute for Creation Research, San Diego. Entry no. 267.
3. Hicks, Ref 2.
4. A.C. Sigleo, 'Organic geochemistry of silicified wood, Petrified Forest National
Park, Arizona', Geochimica et Cosmochimica Acta, Vol. 42, 1978, pp. 1397-1405.
5. Roy Piggott, The Australian Lapidary Magazine, January 1970, p. 9.
6. R.C. Pearce, 'Petnfied wood', The Australian Lapidary Magazine, June 1970, p.
33.
7. Segment on 'Burke's Backyard', Channel 9 TV, Sydney, June 1995.
8. G. Scurfield and E.R. Segnit, 'Petnfication of wood by silica minerals',
Sedimentary Geology, Vol. 39, 1984, pp. 149- 167.
9. John H. Oehler, 'Hydrothermal crystallization of silica gel', Geological Society
of America Bulletin, Vol. 87, August 1976, pp. 1143-1152.
10. R.W Drum, 'Silicification of Betula woody tissue in vitro', Science, Vol. 161,
1968, pp 175-176.
11. R.E Leo, and E.S. Barghoorn, 'Silicification of wood', Harvard University
Botanical Museum Leaflets, No. 25, 1976, pp. 1-47.
12. R.C. Mernll and R.W. Spencer, 'Sorption of sodium silicates and silicate sols
by cellulose fibers', Industrial Engineering Chemistry, Vol. 42, 1950, pp. 744-747.
13. Sigleo, Ref 4, p. 1404.
Trees to
Stone
Imagine a large basin area with numerous rivers and streams flowing through
lowland. A lush landscape with coniferous trees up to nine feet in diameter and
towering almost two hundred feet tall surrounds you. Ferns, cycads and giant
horsetails grow abundantly along the waterway, providing food and shelter for
many insects, reptiles, amphibians, and other creatures.
During the Triassic Period (200 - 250 million years ago) the Colorado Plateau
area of northeastern Arizona was located near the equator and on the
southwestern edge of the landmass known as "Pangea". (Eventually this supercontinent separated to create our present continents.) This tropical location
resulted in a climate and environment very different from today. Fossil
evidence of this ancient land lies in the sediments called the Chinle Formation
that is now exposed in Petrified Forest National Park.
Araucarioxylon Arizonicum
Over time, trees died or perhaps were knocked
over by floodwaters or wind. Rivers carried the
trees into the lowlands, breaking off branches,
bark, and small roots along the way. Some trees
were deposited on the flood plain adjacent to the
rivers and others were buried in the stream
channels. Most of the trees decomposed and
disappeared. But a few trees were petrified,
becoming the beautiful fossilized logs we see
today. Most of the fossilized logs are from a tree
called Araucarioxylon arizonicum. Two others,
Woodworthia and Schilderia, occur in small
quantities in the northern part of the park. All 3
species are now extinct.
Petrification:
Some logs were buried by sediment before they could decompose while
volcanoes to the west spewed tons of ash into the atmosphere. Winds carried
ash into the area where it was incorporated into the deepening layers of
sediment. Ground water dissolved silica from the volcanic ash and carried it
through the logs. This solution filled, or replaced cell walls, crystallizing as the
mineral quartz. The process was often so exact that replacement left a fossil
that shows every detail of the logs’ original surfaces and, occasionally, the
internal cell structures. Iron rich minerals combined with quartz during the
petrification process, creating the brilliant rainbow of colors.
Uplift and Erosion:
Over time, this area has endured many changes. About 60 million years ago,
after the Chinle Formation was deeply buried by younger strata, the region was
uplifted as part of the massive Colorado Plateau. As time passed, many rivers
and storms eroded the land, removing the layers of rock until, again, the Chinle
Formation was exposed. Now fossilized logs lie strewn across the clay hills and
are exposed in cliff faces. Most logs are broken into segments. Humans did not
cut the logs. Because the sections are still in order, we know that the logs
fractured after they were buried and the petrification process was complete.
Since petrified logs are composed of quartz, they are hard and brittle and break
easily when subjected to stress. Earthquakes or the gradual lifting of the
Colorado Plateau may have produced such stress.
Petrified wood is found in every state and in many countries, so why was this
place made a national park? It was originally established to protect some of the
largest and most beautifully preserved concentrations of petrified wood in the
world. We now know, however, that few places in the world have a fossil
record of the Triassic Period that is so diverse and complete. These things make
your park special.
Next here is a website that can be accessed by having the students go to this site to
perform some lesson or information search based on what is appropriate for your class
room. http://www.cbv.ns.ca/townlinks/fossil/definitions/definitions.html
Excerpt
How Fossils are Formed
Excerpt from Introduction to Fossil Collecting
(C) 1994-2000, Glen Kuban, E-mail: gkpaleo@yahoo.com
Part of Kuban's K-Paleo Place home page
When an animal or plant dies, it usually is soon eaten by scavengers or decomposed by
bacteria. However, in some cases a flood, mudslide, sandstorm, or other event quickly
buries a creature, or it may become entombed in ice, tar, or tree resin. When such an
event happens, an organism is largely protected from decay, and may remain buried for
millions of years. Through geologic time, and interactions with mineral seepage,
pressure, and other factors, the organism or material around it may change in various
ways. The changes may involve distortions, infillings, color changes, and the partial or
complete conversion to rock (discussed below). Eventually, the specimen may be
exposed again (this time as a fossil) through erosion or other factors, including human
excavators.
In general, the hard parts of an organism such as teeth, bones, shells, and wood, are more
likely to be preserved than soft parts, since hard parts are more resistant to scavenging
and decay. Fortunately, well-preserved specimens including soft parts are sometimes
found, and missing parts often can be deduced with fair confidence by studying the
structures of the existing parts, and by comparisons with similar species living today.
The process by which dead organisms or their parts are transformed into fossils is called
fossilization. The study of the factors and conditions that affect the fossilization process
is called taphonomy. One of the most common changes fossils undergo through time is
the partial or complete conversion to rock. This process (which can happen in various
ways), is called petrifaction or petrification. You have probably heard the term
"petrified," meaning "turned to stone." Certain types of petrification are given special
names. If only the open spaces or soft parts of an organism are filled with minerals (such
as silica or calcite), leaving the solid parts intact, the process is called permineralization.
If an organism's bones, shell, or other hard parts are dissolved and replaced with other
minerals, the process is called replace- ment. Sometimes the original shell or skeleton
will remain, but undergo a change in crystal structure called recrystallization. If the entire
organism dissolves away, leaving a hollow cavity, the cavity is referred to as a natural
mold. If a natural mold is filled with minerals, the infilling is called a natural cast, or if
you like fancy words, a pseudomorph. Often molds and casts occur together. Sometimes
the area inside the shell of a mollusk (such as a clam) will fill with sediment, after which
the shell dissolves away. This internal mold is sometimes called a steinkern, which is
German for "stone kernel."
In some cases an organism's remains may be preserved through freezing (also called
refrigeration), or through drying (desiccation), as sometimes happens with droppings of
cave animals. Some fossil plants and insects are compressed into thin carbon films,
sometimes called carbonizations, or distillations. Other fossils comprise only the outward
impression of an organism or its parts, such as an impression of tree bark. If the
impression or trace that records the living movements or functions of an ancient organism
(as in the case of animal burrows, trails and trackways), the fossil is called a trace fossil
or ichnite. Trace fossils (as distinguished from "body fossils") also include eggs, tooth
marks, stomach contents, and coprolites (fossil excrement), and any other product or
trace made while an ancient organism was still alive.
Petrifaction
Another common mode of preservation of plants is petrifaction, which is the
crystallization of minerals inside cells. One of the best-known forms of petrifaction is
silicification, a process in which silica-rich fluids enter the plant's cells and crystallize,
making the cells appear to have turned to stone (petrified). Famous examples of
silicification may be found in the petrified forests of the western United States (see
Petrified Forest National Park). Petrifaction may also occur in animals when minerals
such as calcite, silica, or iron fill the pores and cavities of fossil shells or bones.
Recrystallization
Many animal shells are composed of the mineral aragonite, a form of calcium carbonate
that breaks down over millions of years to form the more stable mineral calcite. This
method of preservation, called recrystallization, destroys the microscopic details of the
shell but does not change the overall shape. Snail shells and bivalve shells from the
Jurassic Period (205 million to 138 million years before present) and later are still
composed principally of aragonite. Most older shells that have been preserved have
recrystallized to calcite.
How are Fossils Created?
It's an exciting feeling to see a fossil in a museum. But how are these fossils formed?
What are the different ways that a fossil can be saved for us to see? Well, to answer
this, there are four major ways in which a fossil can be preserved. They are:
petrification, molds, impressions, amber and sedimentary fossils. Below, find a
description of each:
Petrification
Petrification occurs when a living object is slowly turned to stone of a huge number
of years. Petrification is sometimes called "permineralization" because it is brought
about mainly by minerals. Minerals seep through the organic matter is an object,
filling it completely. Then the organic matter rots away, but a mineral version of the
fossil is left. This process usually works best in the fossilization of trees. Some of the
most famous petrified trees are in California, and contain huge rings that describe
ancient eras.
Molds
Molds are literally molds of an animal. Sometimes animals became trapped in mud,
dirt or clay. Then their bodies deteriorated, leaving behind their shape and size in the
ground. When the hole created by this is discovered, it is known as a mold. A mold
can be created in two ways. An organism can deteriorate and leave a hole showing
details of its body. Or a hollow object, such as a shell, can become filled with matter.
When the object deteriorates, the matter filling it is left behind as a mold.
Impressions
Have you ever seen a dinosaur's footprint? These are formed when mud, clay or silt
containing an imprint made by an animal turns to stone. This is an example of an
impression, or the impression that an animal leaves in soft matter. These fossils are
useful in determining weight and structure of ancient animals. Sometimes, even
toenails and pores can be seen!
Amber
Some fossils are preserved in amber. Amber is a sap-like substance from trees. It is
sap that has dried over hundreds of years. Because tree sap is so sticky, it is
possible for bugs and even small animals to be trapped within it. In time, the sap
hardens to amber and a perfect specimen of the creature is preserved. Amber fossils
are plentiful, and are sometimes worn as necklaces and bracelets today!
Sedimentary Fossils
The sea bed contains perhaps the most fossils on the earth. This is because the soft
ground under the sea is made of sedimentary rock, or rock that is composed of
layers of land. When sea creatures die, they drift to the bottom of the ocean and are
covered with a layer of sand. In time, a volcano or mudslide, etc.,may cover the
surface under which they are buried. In this way, a new layer is added, and the fossil
is preserved in layers of time. Therefore, fossils made in this way are sometimes
referred to as "sedimentary fossils." While there are many of these fossils, they are
often very hard to get to. Often, they are dug from ground that was once
underwater. In fact, fossils in sedimentary layers are useful in indicating when land
was above and below ground.
Restated and activity follows