Characteristics of Palaeoproterozoic stromatolites in China

In China, Palaeoproterozoic stromatolites are best represented by taxa from the Hutuo Group of the Wutai Mountains and the Changchengian Group of the Yanshan Range, which all belong to Palaeoproterozoic rocks with a time range from ∼2500 to 1600 Ma. From the present data, Palaeoproterozoic stromatolite assemblages are mainly characterized by the following features. 1. (1) The Palaeoproterozoic stromatolite succession contains many special elements such as forms of Pilbaria, Externia, Kussoidella, Confunda, Discorsia, Vertexa, Tibia, Dongyeella, Jiananella, Shugongsiella, Yaochicunia, Zhongtiaoshania, which so far have not been found in Meso- and Neoproterozoic rocks. 2. (2) The assemblages of the Palaeoproterozoic stromatolites cannot be compared wich those of the Meso- and Neoproterozoic stromatolites in representative elements. 3. (3) The microstructures of the Palaeoproterozoic stromatolites are dominated by banded and streaky types, but grumelous type, which is found frequently in Meso- to Neoproterozoic rocks, has been found only occasionally. 4. (4) The stromatolite-building microorganisms of the Palaeoproterozoic stromatolites are dominated by quite thin filaments (