Petrified wood has been preserved for millions of years by the process of petrification. This process turns the wood into quartz crystal, which is very brittle and shatters. Even though petrified wood is fragile, it is also harder than steel. The process of petrification starts with three raw ingredients: wood, water and mud. Petrification of the wood found in the Petrified Forest began during the Triassic Period when the primitive conifers fell to the ground and into the waterways, entering into their journey through time. The logs were swept and tumbled downstream with sediment and other debris. The streams traveled through a plain of lakes and swamps where the wood, sediment and debris were deposited along the way. Four hundred feet of sediment was deposited in the plain by the rivers that originated from the Mogollon Highland volcanic mountain range. That layer of sediment is known today as the Chinle Formation. As the logs were deposited in the plain they were buried with mud and debris, beginning the petrification process. The mud that covered the logs contained volcanic ash, a key ingredient in the petrification process. When the volcanic ash began to decompose it released chemicals into the water and mud. As the water seeped into the wood the chemicals from the volcanic ash reacted to the wood and formed into quartz crystals. As the crystals grew over time, the wood became encased in the crystals which, over millions of years, turned the wood into stone. http://www.desertusa.com/mag00/jan/papr/rock.html

How long wood takes to petrify depends on the conditions. First, the wood needs to be sealed away from oxygen so that it petrifies at all, rather than decays; petrification can only take place under anoxic conditions where the organisms which contribute to decay can't live. However, if that condition is met it turns into a "how long is a piece of string" question. Considerations are: How much water is in the environment? (Soaking wet contributes to faster petrification/permineralization.) What is the pH? (Acidic or low pH can contribute to faster petrification/permineralization, whereas high pH tends to simply degrade the plant material.) What minerals are in the environment? (Different minerals migrate at different speeds, and the solubility of the mineral counts.) What kind of plant was it, and how vascularized? (The rule of thumb is, the more vascularized the plant is, and the more open the grain, the more quickly minerals can move into it.) What is the local temperature? (Cold temperatures tend to slow down mineralization, warmer temperatures speed it.) However, all other things being equal, the fastest petrification can happen when the wood is in relatively warm conditions, soaked in groundwater saturated with calcium carbonate -- under those conditions it can petrify in only a few centuries. If it petrifies with non-soluble silicate minerals, however, then full petrification may take hundreds of thousands of years to well over a million years. Silicate petrification can only happen faster than that under very hot and very acidic conditions, which are fairly rare. But as you see, the answer of "how long does it take" can vary widely. jalex137 brings up a remarkable case of petrification happening in a few years, documented on a page at the University of Alaska. However, I cannot find any supporting evidence for that page at all, even under park information or in any of the standard journals indexed online, and I would have expected the standard geophys. databases to take notice of it. It is interesting, but I would want to know more about it before that time scale can be accepted as accurate. Be aware, too, that petrification isn't a yes/no kind of thing; partially mineralized and permineralized wood exists at all stages of petrification and permineralization, where organic matter is still present.

"How long does it take?" is not the same question as "How long ago?". Recent experiments support the hypothesis that it can take place relatively rapidly, over a few years to a couple of centuries depending on the thickness of the wood involved, and the particular conditions. And scientific common sense tells us it has to, otherwise the wood would simply decay. ... The University of Alaska documents a known case of petrification in 5 years, calling into question their own assumption that it "usually" takes over 100,000 years: How Does Wood Become Petrified? Usually, it takes over 100,000 years for it to be completely turned into stone, but in the Seward Peninsula it only took a few years! The astonishing rapid permineralization of forests in Kenai Fjords National Park has once again proven that "Alaska is the Land of Extremes". The phenomenon of rapid permineralization occurring was only a theoretical premise until the 1964 earthquake. The largest earthquake in the Northern Hemisphere of 9.2 on the Richter scale caused 70m (230ft) tsunamis that inundated the coastal areas with seawater at depths of 3m to 15m (11.8ft to 59ft). The long submersion, up to 5 years in seawater, caused the trees to replace the water in their tissues with seawater that contained silica and other minerals. Organic tissue, like wood, contains pores and spaces. The seawater fills the pores of the organic tissues and moves through the cellular spaces. During this process, the saturated water evaporates and the excess minerals are deposited on the cells and tissues. This process creates many layers of silica that replaces the organic tissue and turns a once viable tree to stone. http://www.alaska.edu/opa/eInfo/index.xml?StoryID=19

I expect we could petrify a small piece of wood in a laboratory in hours or days if we picked an ideal specimen and near-perfect conditions to do it. We could also devise a mechanism which replaces only a few micrograms of organic material at a time once a year and extrapolate a billion years to completely petrify a 1,000g specimen. It seems obvious to me that there will be a wide range of possible time spans. Those who cite spans longer than a dozens or hundreds of years are clearly not basing that on first-hand observation or experiment but rather on extrapolation based on observations and assumptions. Sources quoting millions of years do so based on a model which allows some quantity of water with some concentration of minerals to "percolate" through a specimen replacing some percentage of organic material with mineral material. The quantity of water, concentration of mineral and efficiency of the replacement process are assumed based on measurements and the time to complete petrification is extrapolated based on these numbers. We can't really prove those values are typical, but scientists base all of these kinds of studies on assumptions since we can not observe the historical processes. If the measurements and assumptions are valid, the numbers they give are right - but we can only demonstrate that the assumptions are consistent with a variety of observations, we can never "prove" they are right.

It depends on how scared it is...

lynnenorth said : Feb, 14 2006 at 08:39 AM I defy you to petrify any piece of wood large enough to visible in "hours"....and yes, we make assumptions, based on reasons. I , renield says: actually it does not take too long really for wood to petrify.. it can from what is know take wood and many other things .. atleast about up to a year or a little over.. i have done an experiment with a piece of wood i had it in a jar of water for about probely 2 months now, and it is beggining to get as hard as a rock and it is darker than what it was when i first started.. and now it has lost its capacity to float, it just sinks down to the bottom. allo f the stratta we see on the earth with its many difrent layers was formed in noah's flood 4,400 yrs ago. the earth is opnly 6,000 yrs old ya know..it is quite common knowledge.. and everyone knows eveolution is a hoax.. and it is a religion. a very foolish stupid thing to believe in. but anyway i was just adding this to say what i have done.. renfields35@aol.com

Depending on the conditions it can easily occur in under 100 years. http://www.icr.org/article/1145/ Don't trust all the answers people give you, especially if they contain the words "millions of years"