kivistuvad

Kivistuvad is a Finnish term that translates to "petrifying" or "turning to stone." It generally refers to the process of fossilization, where organic material is gradually replaced by minerals, resulting in a stone-like replica of the original organism. This process typically occurs over geological timescales, often in the presence of water rich in dissolved minerals like silica or calcium carbonate.

The conditions necessary for kivistuvad are specific. Rapid burial of the organic remains is crucial to protect them from decomposition by scavengers and bacteria. This burial also helps to create an environment where mineral-rich water can percolate through the sediments surrounding the remains. Over time, the original organic material, such as bone, wood, or shell, dissolves and is simultaneously replaced by precipitated minerals.

The resulting fossil retains the shape and often the fine details of the original organism, but is composed entirely of mineral matter. Kivistunud wood, for example, can exhibit intricate patterns of growth rings and cellular structures, even though it is now essentially rock. This natural process is fundamental to the study of paleontology, providing invaluable insights into the history of life on Earth. The term can also be used more metaphorically to describe something that has become rigid or unchanging.