Trilobites, dinosaurs, mammoths, ancient man and, yes, even excrement—all of these have all been unearthed in fossilized states, giving us insights into what life was like in the distant past.
Fossils, in a nutshell, are preserved remnants, impressions or traces of organisms from prehistoric times. Most of what we know about life before and during the Stone Age is directly related to the discovery of such remains.
But what exactly are fossils? And how did they get here?
The process called “fossilization” requires just the right conditions to actually preserve organisms for over thousands of years in states that allow us identify and record them. It can occur in a number of ways.
In some cases, natural sediments may have instantly covered a dead organism, creating a natural cast that preserves the animal in its complete state. Over time, the surrounding sediments harden, serving as a mold, even long after the organism’s organic matter has decomposed completely.
Just like in the movie “Jurassic Park”, prehistoric insects were sometimes fossilized in sticky tree sap. This gooey substance sealed and preserved them in their original state. As time passed, the sap hardened into a resin called amber .
Petrified wood is another form of fossil. Prehistoric trees underwent a process wherein sand, silica or pyroclastic materials (such as volcanic ash) penetrated their cellular structure. This process renders wood fiber into an almost rock-hard state, while preserving its basic form and characteristics.
Prehistoric dinosaur or animal footprints also became fossilized. Sometimes an imprint made in mud would be covered by volcanic ash or other mud with a finer consistency. Eventually, the top layer wears off or is removed, revealing the imprints left in the original mud, which has become a hardened mineral after thousands of years.
Coprolites—essentially fossilized dung—are also crucial to our understanding of prehistoric times. They serve as windows on the past, containing sediments and resins that tell us what ancient animals and our cave dwelling ancestors had for dinner (or if they ate each other).
The discovery of fossils has spawned several branches of science, including Paleontology, Paleobotany, Paleobiology and Paleoecology. It is as if Mother Earth had planted natural time capsules for us to dig up and learn from when we were ready to understand more of her wondrous ways.
Alfablue, February 2013