The Warrawoona Group is a
geological unit
A stratigraphic unit is a volume of rock of identifiable origin and relative age range that is defined by the distinctive and dominant, easily mapped and recognizable petrographic, lithologic or paleontologic features (facies) that characterize ...
in
Western Australia
Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...
containing putative fossils of
cyanobacteria cells. Dated 3.465 Ga, these
microstructures, found in
Archean
The Archean Eon ( , also spelled Archaean or Archæan) is the second of four geologic eons of Earth's history, representing the time from . The Archean was preceded by the Hadean Eon and followed by the Proterozoic.
The Earth during the Arc ...
chert
Chert () is a hard, fine-grained sedimentary rock composed of microcrystalline or cryptocrystalline quartz, the mineral form of silicon dioxide (SiO2). Chert is characteristically of biological origin, but may also occur inorganically as a ...
, are considered to be the oldest known geological record of life on Earth.
Description
The fossils in this group were discovered by
Arthur Hugh Hickman in 1983 in
Warrawoona, , a region on the
Pilbara craton
The Pilbara Craton is an old and stable part of the continental lithosphere located in the Pilbara region of Western Australia.
The Pilbara Craton is one of only two pristine Archaean 3.6–2.7 Ga (billion years ago) crusts identified on the ...
in the northern part of
Pilbara province.
Whether or not the fossils are authentic was disputed in the past, as
abiotic
In biology and ecology, abiotic components or abiotic factors are non-living chemical and physical parts of the environment that affect living organisms and the functioning of ecosystems. Abiotic factors and the phenomena associated with them under ...
processes could not be ruled out. Currently the fossils are thought to be of biological origin, however there is no conclusive evidence of fossilized organisms in the formation, and whether the lines in the rock are fossilized
stromatolite
Stromatolites () or stromatoliths () are layered sedimentary formations ( microbialite) that are created mainly by photosynthetic microorganisms such as cyanobacteria, sulfate-reducing bacteria, and Pseudomonadota (formerly proteobacteria). T ...
s.
The rocks also include
felsic volcanic rocks.
See also
*
North Pole, WA for similar issues
*
Origin of life
In biology, abiogenesis (from a- 'not' + Greek bios 'life' + genesis 'origin') or the origin of life is the natural process by which life has arisen from non-living matter, such as simple organic compounds. The prevailing scientific hypothes ...
*
Timetable of the Precambrian
*
Geology of Australia
The geology of Australia includes virtually all known rock types, spanning a geological time period of over 3.8 billion years, including some of the oldest rocks on earth. Australia is a continent situated on the Indo-Australian Plate.
Compon ...
*
Fig Tree Formation
References
Further reading
*
* {{cite book, last1=Condie, first1=K. C. , date=1981, title= Archean Greenstone Belts, publisher=Elsevier Scientific Publishing Company, location=New York City, volume=3, isbn= 0-444-41854-7
External links
Geological Society of Australia
Geologic groups of Oceania
Geologic formations of Australia
Geology of Western Australia
Archean
Precambrian Australia
Pilbara
Origin of life