Importance of fossils and Suitable conditions for fossils formation
Suitable conditions for the formation of fossils
The organism’s body must be buried immediately after death in a medium that preserves it from decomposition, The organism must have a hard skeleton, A suitable medium must be found in which the mineral material replaces the organic material of the living organism.
The importance of the fossils
The fossils help in studying the life evolution which is known by the fossil record, The fossils exist in the rocks of the different areas. and the fossil record indicates the extinction and the evolution of the organisms.
Studying the fossil record showed that life started first in the sea, then established on the land. The organisms always developed from simple to complicated as:
|The archaeopteryx fossil is considered a link between the reptiles and the birds.|
The fish were the first vertebrates that appeared, followed by the amphibians, then the reptiles, and finally the birds and the mammals appeared together.
The invertebrates (such as the coral and the mollusks with the shells) appeared before the vertebrates.
The algae appeared before the mosses and the ferns. The angiosperms appeared before the gymnosperms.
The fossils help in the age determination of the sedimentary rocks, and you know that the index fossils indicate the age of the sedimentary rocks because the age of the rocks is the same age of the fossils existed in them.
|The fossils help in the age determination of the sedimentary rocks.|
The index fossils are the fossils of the organisms that had lived for a short period of time in the past and had a wide geographic distribution, then became extinct.
The fossils help in petroleum exploration. You know that geologists take samples from the rocks of the exploratory wells when they search for petroleum.
|The fossils help in petroleum exploration.|
These samples are studied under the microscope, and if they contain microfossils like the foraminifera and the radiolaria, They will point to the age of the rocks that existed in the exploratory wells, and the suitable conditions for the petroleum formation.
The fossils help in figuring out the paleoenvironment. The fossils give an idea about the environment in which they lived during the old geologic ages, and also they indicate the climate of these ages.
The coral fossils indicate that the environment where they live was clear warm shallow seas, The ferns fossils indicate that the environment where they lived was a hot and rainy tropical environment.
The nummulites fossils are found in the limestone rocks of Gebel El-Mokattam and indicate that this area was a seafloor more than 35 million years ago.