Abiotic, Graphitic Microstructures in Micaceous Metaquartzite about 3760 Million Years Old from Southwestern Greenland: Implications for Early Precambrian Microfossils

AUTOR(ES)

Nagy, Bartholomew

RESUMO

An Early Precambrian micaceous metaquartzite subjected to low to moderate metamorphism in the Isua area of Southwestern Greenland was derived from the erosion of preexisting rocks which were probably sialic in composition. This metaquartzite may have been formed before the emergence of life. It contains globular particles of graphite arranged in narrow veins or along foliation or bedding planes. This rock contains no organic compounds besides traces of methane and no biologically significant elements associated with the graphite microstructures. Reaction of primitive methane with ferric oxides appears to have oxidized the methane to the vein graphite and reduced the ferric oxides to ferrous-ferric oxide (magnetite). The graphitic microstructures are likely to be abiotic in origin, although a biological origin is not impossible. Somewhat younger microstructures found in other locations on earth have often been described as microfossils; this origin should be reexamined on the basis of the above mentioned conclusions.

Documentos Relacionados

• OCCURRENCE OF BIOGENIC STERANES AND PENTACYCLIC TRITERPANES IN AN EOCENE SHALE (52 MILLION YEARS) AND IN AN EARLY PRECAMBRIAN SHALE (2.7 BILLION YEARS): A PRELIMINARY REPORT*
• Pellet microfossils: Possible evidence for metazoan life in Early Proterozoic time
• Microfossils in micrites from Serra da Bodoquena (MS), Brazil: taxonomy and paleoenvironmental implications
• Evidence that most human Alu sequences were inserted in a process that ceased about 30 million years ago.
• The Thule episode epidemiological follow up after the crash of a B-52 bomber in Greenland: registry linkage, mortality, hospital admissions.