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THE PRECAMBRIAN ERA



The Precambrian sub-divided into:

          The Archean Era (about 3960-2500 Mya)

          The Proterozoic Era (about 2500-540 Mya)


ACTIVITIES IN THE ARCHEAN ERA
Extensive Orogenesis

The prokaryotes, bacteria and blue-green algae emerged

Formation of Greenstone belts and banded iron ores
         
          Shallow seas appeared.


ACTIVITIES IN THE PROTEROZOIC ERA
Eukaryotic cells and multicellular lives emerged
The Earth experienced warm and moist conditions

The Earth experienced Dry and Cold climate

Soft-bodied marine invertebrates (Earliest known fossils) e.g. Annelids, Sponges, Sea anemones emerged


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