Coalified Oak Stump Found
http://www.creationism.org/articles/OakStumpUkraine.htm
©2007   by Yuri Petetsky
An interesting finding was discovered in the very heart of Ukraine, in the Cherkasy region, near the city of Kaniv (100 km southeast from Kiev), the last retreat of the famous Ukrainian poet Taras Shevchenko.
In 1967 during the construction of a foundation pit for Kanivska hydroelectric power station an oak stump was found in alluvial sand at the depth of 22m (65 feet).

This area is quite flat, as the most of the Ukrainian territory, with the exception of the Crimean peninsula and Carpathians in the west.  So, there is not much of volcanic activity and the temperature at this depth is low.

View from the steep right bank, the tomb of Taras Shevchenko, upstream Dnipro, the reservoir and power station at the background.

The explanation above says: "As any other wood under similar conditions it was subjected to processes of natural carbonization and acquired its dark color. The scientific value of this exhibit is in its location at this considerable depth, disproving the belief that the depth of the river alluvium testifies for long geological age of the alluvium itself. The point is that this oak was felled with an axe, what can be well observed from the surface of the cut.  Therefore the geological age of the stump is determined by the time of appearance of metal axes in our area, which happened not longer than 3 thousand years ago.  Thus the geological age of the stump is technogenic."

So it did not take millions of years for this stump to be buried at 22m (65') depth and for carbonization to occur.