Login

how fossils are formed? how we can determine the age of fossil ?

Fossils may be defined as the remains of the organisms which have been preserved in the form of molds or cast in rocks etc. since prehistoric ages. When a plant or an animal dies, their remains falls on the ground. Over a period of time their body gets covered by sediments brought by rivers, winds etc. These sediments keeps on getting accumulated for over hundreds of years and when that land gets eroded, the fossils can be seen clearly. Thus, the process of accumulation of dead remains of plants and animals for over hundreds of years results in the formation of fossils.

 The age of the fossils can be determined by the following way:

1) Radiometric dating

In this method, the age of the fossil can be determined by tracing the radioactive elements present in the rocks and examining it chemically.

2) Relative dating

The fossils are found in the sedimentary rocks in the form of layers accumulated over large span of time. So, using this fact, the geologist find the age of fossils in the way that the fossil found at the bottom of those layers are found to be older than that found above those.

  • 122
View Full Answer

WHEN ORGANISMS DIES , THEIR BODIES WILL DECOMPOSE & BE LOST .. BUT SOMETIMES THE BODY OR AT LEAST SOME PARTS OF THE BODY MAY BE IN THE ENVIRONMENT THAT DOES NOT LET IT DECOMPOSE COMPLETELY .... 

FOR EXAMPLE , A DEAD INSECT GET CAUGHT IN HOT MUD. IT WILL NOT DECOMPOSE COMPLETELY. THE MUD EVENTUALLY HARDEN & RETAIN THE IMPRESSION OF THE BODY PART OF THE INSECT . IN THIS WAY THE FOSSIL OF INSECT FORM...

THE AGE OF FOSSIL CAN BE DETERMINED BY 2 METHODS . THESE ARE :-

(1) RELATIVE METHOD - IN THIS METHOD THE FOSSIL WHICH ARE IN UPPER LAYER ARE MORE RECENT THAN THOSE WHICH ARE IN DEEPER INSIDE THE EARTH..

(2) CARBON DATING METHOD :- EVERY LIVING ORGANISM HAS CARBON-14 ATOMS WHICH ARE RADIOACTIVE .WHEN A LIVING ORGANISM DIES & FORM FOSSIL , ITS CARBON-14 RADIOACTIVITY GOES ON DECREASING . IN THIS METHOD , THE CARBON-14 RADIOACTIVITY OF THE FOSSIL ARE COMPARED WITH CARBON-14 RADIOACTIVITY OF THE PRESENT LIVING ORGANISMS.....

  • 63

 Fossils may be defined as the remains of the organisms which have been preserved in the form of molds or cast in rocks etc. since prehistoric ages.

When a plant or an animals dies, their remains falls on the ground. Over a period of time their body gets covered by sediments brought by rivers, winds etc. These sediments keeps on getting accumulated for over hundred of years and when that land gets eroded, the fossils can be seen clearly. Thus, the process of accumulation of dead remains of plants and animals for over hundreds of years results in the formation of fossils.

T here are two components to this estimation of age of fossils.

Relative- If we dig into the earth and start finding fossils, it is reasonable to suppose that the fossils we find closer to the surface are more recent than the fossils we find in deeper layers.

Dating fossils- detecting the ratios of different isotopes of the same element in the fossil material

  • 9
What are you looking for?