Geology Current Affairs - 2020
Scientists have claimed that they have discovered oldest fossils on Earth in rocks from Quebec, Canada.
Carbon dating techniques suggest that these rocks are at least 3.8 billion years old and might even be 4.3 billion years old.
- The fossils are tiny and consist of tubes and filaments up to half a millimetre in length and around half the width of a human hair.
- The fossils are thought to be the remains of bacteria that lived on iron and dwelt around hydrothermal vent systems i.e. mineral rich hot springs on the seafloor.
- They’re made of haematite, a type of iron oxide (known as rust). Some of the filaments are branched, some resemble loose coils and others appear to be joined to knobs of haematite.
- These structures were found to contain graphite as well as the minerals apatite and carbonate which are basically associated with biological matter.
- Iron—oxide granules was also found and in other sections of the rocks, structures such as carbonate rosettes were discovered which might have formed as biological matter broke down.
- The rocks in which the fossils were found are metamorphic i.e. they have experienced high temperatures and pressures since they were formed.
- The size and arrangement of the haematite structures indicates that these microbes were breathing oxygen at a time when oxygen is thought to have been scarce.
- This discovery supports the idea that life emerged from hot, seafloor vents shortly after planet Earth formed.
- Thus, provides strong evidence that the first life on Earth and formed around nutrient-rich hydrothermal vents at the bottom of the ocean.
- It is one of leading theories to show signs of how life spawned on Earth, as opposed to other theories such as panspermia, which suggests that life was deposited by asteroid or other rocky body that crashed into Earth.