Origin of Silicate Spherules and Geochemistry of Re and Platinum-Group Elements Within Microfossil-Bearing Archean Chert from the 3.4 Ga Strelley Pool Formation, Western Australia.

Silicate spherules have been identified from the ca. 3.4 Ga-old Strelley Pool Formation (SPF) in the Pilbara Craton, Western Australia.

Distinguishing cellular from abiotic spheroidal microstructures in the ca. 3.4 Ga Strelley Pool Formation.

The morphogenesis of most carbonaceous microstructures that resemble microfossils in Archean (4-2.5 Ga old) rocks remains debated. The associated carbonaceous matter may even-in some cases-derive from abiotic organic molecules.

Early Archean planktonic mode of life: Implications from fluid dynamics of lenticular microfossils.

Lenticular, and commonly flanged, microfossils in 3.0-3.4 Ga sedimentary deposits in Western Australia and South Africa are unusually large (20-80 μm across), robust, and widespread in space and time.

Major and minor elemental compositions of streambed biofilms and its implications of riverine biogeochemical cycles.

Chemical compositions of streambed biofilms from a major river of central Japan (the Kushida River) were obtained, with data of associated sediments (fine-grained fractions < 63 μm) and dissolved components of waters, in order to provide preliminary information about biogeochemical significance of streambed biofilms. During the sampling period (July 31st to August 3rd, 2013), dissolved components of the river waters were influenced by the dam reservoir. Concentrations of NO, silica (as Si), SO, PO and Ca decreased across the dam, whereas Fe and Mn increased across the dam, and then decreased downstream rapidly.

Speciation of Paleoarchean Life Demonstrated by Analysis of the Morphological Variation of Lenticular Microfossils from the Pilbara Craton, Australia.

The ca 3.4 Ga Strelley Pool Formation (SPF) of the Pilbara Craton, Australia, represents a Paleoarchean sedimentary succession preserving well-described and morphologically diverse biosignatures such as stromatolites and cellularly preserved microfossils. The SPF microfossil assemblage identified from three greenstone belts includes relatively large (20-80 μm in width), acid-resistant, organic-walled lenticular microfossils, which can be extracted using a palynological technique.

Investigation of the Geochemical Preservation of ca. 3.0 Ga Permineralized and Encapsulated Microfossils by Nanoscale Secondary Ion Mass Spectrometry.

Observations of Archean organic-walled microfossils suggest that their fossilization took place through both encapsulation and permineralization. In this study, we investigated microfossils from the ca. 3.

The Raman-Derived Carbonization Continuum: A Tool to Select the Best Preserved Molecular Structures in Archean Kerogens.

Unlabelled: The search for indisputable traces of life in Archean cherts is of prime importance. However, their great age and metamorphic history pose constraints on the study of molecular biomarkers. We propose a quantitative criterion to document the thermal maturity of organic matter in rocks in general, and Archean rocks in particular.

Biogenicity of morphologically diverse carbonaceous microstructures from the ca. 3400 Ma Strelley pool formation, in the Pilbara Craton, Western Australia.

Morphologically diverse structures that may constitute organic microfossils are reported from three remote and widely separated localities assigned to the ca. 3400 Ma Strelley Pool Formation in the Pilbara Craton, Western Australia. These localities include the Panorama, Warralong, and Goldsworthy greenstone belts.

Diversity in the Archean biosphere: new insights from NanoSIMS.

The origin of organic microstructures in the approximately 3 Ga Farrel Quartzite is controversial due to their relatively poor state of preservation, the Archean age of the cherts in which they occur, and the unusual spindle-like morphology of some of the forms. To provide more insight into the significance of these microstructures, nano-scale secondary ion mass spectrometry (NanoSIMS) maps of carbon, nitrogen, sulfur, silicon, and oxygen were obtained for spheroidal and spindle-shaped constituents of the Farrel Quartzite assemblage. Results suggest that the structures are all bona fide approximately 3 Ga microfossils.

Three-dimensional morphological and textural complexity of Archean putative microfossils from the Northeastern Pilbara Craton: indications of biogenicity of large (>15 microm) spheroidal and spindle-like structures.

We recently reported a diverse assemblage of carbonaceous structures (thread-like, film-like, spheroidal, and spindle-like) from chert in the ca. 3.0 Ga Farrel Quartzite of the Gorge Creek Group in the Pilbara Craton, Western Australia.