Fossil microorganisms in the Archaean

Ancient Archaean and Proterozoic rocks are model objects for the investigation of rocks comprising astromaterials. Three types of fossil microorganisms found in Archaean rocks of Karelia are determined: 1. forms found in situ, in other words microorganisms of the same-age as the rock matrix, that is valid Archaean fossils, 2. endolithic fossil microorganisms, that is to say forms inhabited early formed rocks, and 3. younger than Archaean-Proterozoic mineralised microorganisms, that is later contamination. The structures belong (from our point of view) to the first type, or genuine Archaean forms were mainly under our examination. Practical investigation of ancient microorganisms from Greenstone-Belt of Northern Karelia turns to be very perspective. It shows that even in such ancient period as the Archaean an ancient diverse world existed. Moreover probably such relatively highly organised forms as cyanobacteria and perhaps eukaryotic forms existed in Archaean world.