Abstract Spheroidal microfossils mainly 20 to 100 μm in diameter and exhibiting granular surface textures have been recovered from Early Precambrian rocks by applying a new method of water separation in combination with thin chemical preparation. In contrast to the Acritarcha, these microfossils are characterized by a relatively low specific weight (close to one) and considerable fragility due to impregnation by mineral matter. They occur in Archean sediments of Hindustan, in rocks of the Baltic and Aldan Shields with ages of 3.0 to 3.5 billion ($ 10^{9} $) years, and in Proterozoic deposits in many regions of Euro-Asia. They commonly occur in great number in Precambrian sediments of West Africa. Australia and North America. These forms are here regarded asMenneria Lopuchin and are considered to be bluegreen algae.Menneria resembles alga-like forms reported by Engel, Nagy and their co-workers from the Onverwacht Series and microfossils reported by Schopf and Barghoorn from the Fig Tree Series, both of the Swaziland System of southern Africa. In addition to spheroidalmicrofossils, ribbon-like and filiform microstructures are here reported from Archean deposits. The biogenic structures here described from the Early Precambrian of Euro-Asia are considered to have been photosynthetic and planktonic. Their progressive evolution, intensive production of organic matter, and biogeochemical role in concentration of rare elements is discussed.


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    Titel :

    Structures of biogenic origin from Early Precambrian rocks of Euro-Asia


    Beteiligte:

    Erschienen in:

    Erscheinungsdatum :

    1975




    Medientyp :

    Aufsatz (Zeitschrift)


    Format :

    Print


    Sprache :

    Englisch



    Klassifikation :

    Lokalklassifikation TIB:    535/3908/4290
    BKL:    44.71 Verkehrsmedizin



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