New data on the structure and composition of stromatolite buildups (Northern Anabar Region)

Abstract

Lamination, a characteristic feature of stromatolites, is related to thin alternation of mineral and organogenic layers. The present paper is devoted to structures of Lower Riphean stromatolites in the Fomich River area (northern Anabar Uplift) that were described for the first time and studied with an electron microscope. Two Colonnella forms with different microstructures were examined. It has been established that a banded texture is observed if an organogenic layer is mainly composed of tightclusters of filiform (theread like) particles. However, a clotted texture is recorded if the layer is represented by isolated coccomorphic (rounded) particles. The chemical composition of these tiny structures, which can accumulate several elements, is discussed and analyzed. In the past, the organogenic layer represented a biofilm that comprised a complex-function cyanobacterial community.