What is relative dating of rocks and fossils 100 dating along
If this hole is later filled with other minerals, it is a cast.
An endocast, or internal mold, is formed when sediments or minerals fill the internal cavity of an organism, such as the inside of a bivalve or snail or the hollow of a skull. If the chemistry is right, the organism (or fragment of organism) can act as a nucleus for the precipitation of minerals such as siderite, resulting in a nodule forming around it.
Some fossils are biochemical and are called chemofossils or biosignatures.
Permineralization is a process of fossilization that occurs when an organism is buried.
to dinosaurs and trees, many meters long and weighing many tons.
Paleontology is the study of fossils: their age, method of formation, and evolutionary significance.
A shell is said to be recrystallized when the original skeletal compounds are still present but in a different crystal form, as from aragonite to calcite.
Compression fossils, such as those of fossil ferns, are the result of chemical reduction of the complex organic molecules composing the organism's tissues.
If this happens rapidly before significant decay to the organic tissue, very fine three-dimensional morphological detail can be preserved.
Nodules from the Carboniferous Mazon Creek fossil beds of Illinois, USA, are among the best documented examples of such mineralization.
This process can occur in very small spaces, such as within the cell wall of a plant cell.