How do fossils form?
Fossils aren't limited to dinosaur bones or ancient plants; they can also include footprints, trails, or even dung, known as coprolite.
Hyderabad: When an animal or plant dies, its remains usually decompose completely. However, under the right conditions, such as rapid burial, fossilisation can occur. Fossils aren’t limited to dinosaur bones or ancient plants; they can also include footprints, trails, or even dung, known as coprolite.
Here’s how fossilisation works: When an animal dies and its body sinks to the ocean floor, the soft tissues decay, leaving only the skeleton. This skeleton becomes buried by sediment, like mud or sand, falling from above. The sea floor is particularly conducive to fossilisation, explaining why many fossils are marine in origin. Land animals can also be swept out to sea and buried in a similar manner.
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As more sediment accumulates, the skeleton gets buried deeper. Over time, increasing pressure turns the sediment into solid rock. Deeply buried and encased in stone, the skeleton eventually dissolves due to groundwater, leaving behind a cavity that retains the shape of the original skeleton. This cavity is called a natural mold.
Mineral-rich water then fills the mold, depositing minerals that form a cast of the cavity. This cast mirrors the shape of the original skeleton but lacks its internal structures.
Millions of years later, geological processes like mountain building and earthquakes bring the rock containing the fossil to the Earth’s surface. Erosion from wind and rain gradually exposes the fossil, ready to be discovered.
Buried secrets
The word fossil comes from the Latin word fossils, which literally means ‘dug up’ and from the word fodder, which means ‘to dig’
Fossils can be very large or very small. Micro fossils are only visible with a microscope. Bacteria and pollen are micro fossils
Macro fossils can be several meters long and weigh several tons. Macro fossils can be petrified trees or dinosaur bones
Preserved remains become fossils if they reach an age of about 10,000 years
The fossilized teeth of woolly mammoths are some of our most “recent” fossils
