Precambrian Period (4.500 Bya – 0.542 Bya)
The Precambrian time period covered both the Hadean and Archean Eon’s.
The first stage of the Precambrian period was in the Hadean Eon, when planet Earth formed and the sun became its source of heat. The formation of the moon also occurred, then the formation of planet Earth’s magnetic field began.
It is during the Archean Eon that Craton’s formed on planet Earth through tectonic plate movement, terrestrial bombardment and volcanic activity. Continents and Super-continents are formed and deformed through the activity of Craton’s.
A Craton is a large block of crustal rock that forms part of the Earth’s crust. They are considered to have been stable and subjected to very little geological changes over a long period of time. However, Craton’s do undergo a series of events, which include the growth stage, drifting, formation and deformation of both oceanic and continental crusts.
4.600 – 4.500 Bya
Our Solar System was created as the Sun developed eight known planets and other hypothetical entities. The planets were gradually built up by the cosmic dust, which revolved around our young sun in a flat disk of gas and dust. The known planets of our solar system all formed within 100 million years of each other, from the gas and debris that our sun had accumulated. Note: Bya = Billion years ago.
Today our Solar System includes four terrestrial planets such as Mercury (4.503 Bya), Venus (4.600 Bya), Earth (4.543 Bya) and Mars (4.600 Bya). There are also two gas giants, Jupiter (4.503 Bya) and Saturn (4.503 Bya), plus two ice giants, Uranus (4.503 Bya) and Neptune (4.503 Bya). It is also thought that our Solar System has at least five dwarf planets, an asteroid belt, numerous comets, and a large number of icy bodies, which lie beyond the orbit of Neptune.
4.500 – 3.800 Bya
Jupiter, (it is thought), was originally no bigger than our own planet Earth and was about four times further away from the sun than its current position. However, the Sun’s gravitation pulled the four outer planets closer until they stabilized themselves.
It is thought that Jupiter’s migration took around 700,000 years to reach its present day orbital position around our Sun. The migration probably started about 2 to 3 million years after Jupiter began its life as asteroid, far from the sun.
Saturn, Uranus and Neptune, the other three outer planets, (it was also thought), were created about the same time as Jupiter, about 4.503 Bya and were also about four times further away from the sun than they are today. Saturn, Uranus and Neptune would have had similar orbital journeys to that of Jupiter.
Jupiter’s journey resulted in an inward spiral-shaped movement into the solar system, with an orbit around the Sun that resulted in an increasingly narrowing path.
Jupiter was and still is a Trojan asteroid magnet. Trojan asteroids are a large group of asteroids that share Jupiter’s orbit around the sun. Today there are about 50 percent more Trojan asteroids in front of Jupiter than behind it.
Jupiter, Saturn, Uranus and Neptune became the vacuum cleaners and refuse blowers of our Solar System as they took their 700,000 year migrational journey. They interfered with the settling space debris of our Solar System, which resulted in the Late Heavy Bombardment (LHB). Their gravitational push and pull effect also had a disturbing, if not destructive affect on the inner planets, Mercury, Venus, Earth and Mars.
It should also be noted that the “Nice” model of Solar System development claims that the outer planets developed close to the Sun and moved outwards over the same period of time. The formation of our Solar System and planet Earth is ambiguous, so let us stick with the accepted versions for now.
4.400 – 4.270 Bya
The Yilgarn Craton, (the bulk of present day Western Australia), was formed and contains zircon crystals in the crust of the Jack Hills portion of the Narryer Gneiss. They have been estimated to date back to about 4.400 billion years ago, (its area is greater than 650,000 km2 / 250,966 mi2), is rich in minerals and iron ore.
4.388 – 3.750 Bya
The Nuvvuagittuq Greenstone Belt (NGB), (now located on the eastern shore of Hudson Bay, 40 km southeast of Inukjuak, Quebec), was created due to a sequence of metamorphosed mafic to ultramafic volcanic events. The associated sedimentary rocks forming the greenstone belt are considered to be some of the oldest rocks on Earth. However, due to confliction with aging techniques, the true ages are still unresolved.
Metamorphic Mafic Rocks (e.g. mafic schists and gneisses, amphibolites) are derived from mafic igneous rocks, mainly basalts and andesites and of lesser importance, gabbros.
Metamorphic relates to rock that has undergone transformation by heat, pressure, or other natural agencies, such as the folding of strata or the nearby intrusion of igneous rocks, ie: “metamorphic gneisses”
Mafic is used to describe a silicate mineral or igneous rock that is rich in magnesium and iron, and is thus a portmanteau of magnesium and ferric. Mafic rocks also have an association with volcanic activity.
Ultramafic Rock, are igneous rock, with a very low silica content and rich in minerals such as hypersthene, augite, and olivine. These rocks are also known as ultrabasic rocks. Examples include: peridotite, kimberlite, lamprophyre, lamproite, dunite, and komatiite. Volcanic ultramafic rocks are rare outside of the Archaean eon.
4.300 – 2.570 Bya
The Superior Craton is now situated in Canada, covering Quebec, Ontario, S.E. Manitoba and northern Minnesota in the USA. It is the biggest Craton formed during the Precambrian and Archean period. The Superior Craton, (about 1,572,000 km2 / 606,953 mi2 in size), formed about
4.300 billion years ago and underwent geological changes until about 2.570 Bya.
4.100 – 3.800 Bya
The Late Heavy Bombardment (LHB) occurred approximately between 4.1 to 3.8 billion years ago (Bya). The Late Heavy Bombardment (LHB) brought the Hadean Eon to an end and continued into the first Eoarchean Era of the Archean Eon.
The Late Heavy Bombardment (LHB) caused the lunar cataclysm, which made significant changes to the Moon’s surface environment. Collisions of asteroids, comets and foreign objects not only affected our Moon; they also affected the early terrestrial planets in our inner Solar System, including Mercury, Venus, Earth, and Mars.
It is believe that water originated from the bombardment of the icy constructed comets during this time. Hence it is also thought that they could have sparked the DNA chemical building blocks for life. But all this is just conjecture at this point of time.
Archean (Archaean) Eon (4.000 – 2.500 Bya)
The start of the Archean Eon is only defined by the isotopic age of the earliest rocks and it is divided into four Era’s:
Eoarchean Era (4.000 – 3.600 Bya)
Paleoarchean Era (3.600 – 3.200 Bya)
Mesoarchean Era (3.200 – 2.800 Bya)
Neoarchean Era (2.800 – 2.500 Bya)
The Archean Eon began about 4 billion years ago (Bya) with the formation of Earth’s crust and extended to the start of the Proterozoic Eon 2.5 billion years ago (Bya).
The atmosphere of the early Archean Eon would have been putrid, toxic and anoxic. The Earth’s crust was still forming and volcanic activity was rampant. Volcanic gas permeated the atmosphere that would have contained carbon dioxide (CO2) and some water vapour (H2O). It is thought that photodissociation took place as photons reacted on certain molecules, but the amount of free oxygen (O2) emitted was very small in the beginning of the Archean Eon.
The Eoarchean (Eoarchaean) Era (4.000 – 3.600 Bya)
In this first stage of the Archean Eon, which spans 400 million years, it is thought that planet earth formed a solid crust with lava flowing on the surface. But due to the Late Heavy Bombardment (LHB) mayhem would have taken place. Impacts would have caused dust and debris to be flung into the atmosphere. Larger objects would have fractured and penetrated the Earth’s crust, whilst spewing lava everywhere.
4.031 – 3.580 Bya
The Acasta Gneiss was created and metamorphosed as Tonalite gneiss in the Slave Craton, which is now in the Northwest Territories of Canada.
4.030 – 2.580 Bya
The Slave Craton is now part of the North Western Canadian Shield, in the Northwest and Nunavut Territories of Canada. The Slave Craton, (covers about 300,000 km2 / 120,000 mi2), includes the 4.031 billion year old Acasta Gneiss, which has some of one of the oldest dated rocks on Earth. It is dominated by greenstones, turbidite sequences created about 2.730 – 2.630 Bya and plutonic rock formation about 2.720 – 2.580 Bya. Older gneiss and granitoid rocks underlie large parts of the Slave Craton.
The Slave Craton is divided into a West-Central Basement Complex, the Central Slave Basement Complex, and an eastern province, named the Hackett River Terrane or the Eastern Slave Province. These two domains of east and west are separated by a 2.700 billion year old suture, which is defined by two isotopic boundaries running north to south over the Slave Craton.
3.900 – 2.500 Bya
It is thought that Chemoautotrophs developed during this period of time. However, no fossils have ever been found for this period of time, nobody knows what the first organism were really like. People only surmise.
Chemoautotrophs are organisms that derive energy for their life functions from inorganic chemicals. They feed on chemicals that are good electron donors, such as hydrogen sulfide, sulfur, or iron. Chemoautotrophs are able to “fix” carbon by taking atoms of carbon, from inorganic compounds, such as carbon dioxide (CO2), and use them to make organic compounds such as sugars, proteins, and lipids.
Most chemoautotrophs are extremophiles, bacteria or archaea that live in hostile environments, (such as deep sea vents of volcano’s), and are the primary producers in such ecosystems.
3.800 Bya
A dramatic second phase of planetary migration occurred between the outer planets about 3.800 billion years ago. This was triggered when the orbits of Jupiter and Saturn became briefly locked together. Saturn took exactly twice
as long as Jupiter to complete an orbital circuit around the sun. Not only was there a destabilizing effect
on Jupiter and Saturn, Uranus and Neptune were also affected as well.
This instability was corrected as Jupiter migrated inward, whilst Saturn, Uranus and Neptune migrated outward. After a few million years these outer planets settled into stable orbital positions, very close to those we see today.
The Late Heavy Bombardment (LHB) came to end about 3.8 Bya.
3.800 – 3.700 Bya
The Isua Greenstone Belt, (now in South Western Greenland), is
considered to be an Archean apatite greenstone belt. It is thought that the belt is aged between 3.7 and 3.8 billion years old. The belt contains variably metamorphosed mafic volcanic and sedimentary rocks. Its origin and association with graphite is a potential used as a biomarker.
The Nuvvuagittuq Greenstone Belt, (now in northern Quebec, Canada), is thought to be 3.750 billion years old. The Nuvvuagittuq Greenstone Belt contains 3 major components:
(1) Cummingtonites, (metamorphic amphiboles), which forms most of the belt.
(2) Mafic and ultramafic sills that intrude the amphibolites.
(3) Banded iron formations in sedimentary rock that formed in sea water.
The formation of these rocks in the Earth’s crust indicated fast flowing steams and rivers, plus extreme tidal activity in the forming oceans. This more than likely was caused by volcanic and tectonic plate activity, both affecting the Earth’s crust.
The Moon was also closer to Earth and undergoing its own volcanic activity. The Moon would have had a massive impact on Earth’s early forming oceans causing extremely high tidal activity. Hurricane-force winds would have been prevalent on planet Earth.
Earth was still experiencing very hostile conditions, hence bacterial activity in an anoxic environment cannot be proven at this time.
3.630 – 2.800 Bya
Vaalbara – the unproven supercontinent. It is thought that Proto-continents started to form due to movement of the Earth’s crust. It has been postulated that the earliest known supercontinent was Vaalbara, which formed about 3.636 billion years ago. They surmise that Vaalbara consisted of the Kaapvaal Craton, (now in eastern South Africa), and the Pilbara Craton, (now in north-western, Western Australia). E. S. Cheney named Vaalbara in 1996.
Hence the Pilbara and Kaapvaal cratons are thought to have some of the oldest rocks in the world and they contain well-preserved Archaean microfossils. Athough the existence of Vaalbara is thought to be possibly between 3.630 and 2.800 Bya; it can’t be unequivocally proven.
Paleoarchean (Palaeoarchaean) Era (3.600 – 3.200 Bya)
This is this second stage of the Archean Eon, which spans 400 million years. This era is defined chronometrically and is not referenced to a specific level of rock formation.
3.600 – 3.500 Bya
Early Life?
They say that undisputed evidence of the early life on Earth seems to date from at least 3.5 billion years ago. So! Did the split between bacteria and archaea occur during this time period? I don’t think so!
Planet Earth was in a state of flux, life requires stable conditions. Life can exist in extreme, but constant conditions. However, tectonic plate movement, volcanism, a toxic atmosphere, tsunami’s, hurricane force winds and soil erosion are not conducive for life formations.
3.600 – 3.300 Bya
The Narryer Gneiss Terrane of Western Australia is composed of a
tectonically interleaved and polydeformed mixtures of granite, mafic intrusions and metasedimentary rocks in excess of 3.3 billion years old.
However, some parts of the Narryer Gneiss
Terrane have been estimated to be in excess of 3.6 billion years old. These rocks have experienced multiple
metamorphic events over time, resulting in amphibolite or granulite rock
conditions.
3.600 – 2.500 Bya
The Dharwar or Karnataka Craton, (now in South India), is part of the Indian Shield. The bedrock in this region
formed between 3.600 and 2.500 Bya.
The Dharwar Craton lies roughly between Chennai, Goa, Hyderabad, and Mangalore in the Karnataka and Andhra Pradesh states. It has been a relatively stable geologic terrain for the past billion years.
3.500 – 3.200 Bya
The Singhbhum Craton is now part of the supracrustal provinces in eastern India. It originally started to form about 3.510 Bya, but under went two magmatic episodes between 3.470 to 3.440 Bya and 3.365 to 3.285 Bya.
3.500 – 3.200 Bya
The Pilbara area, northern Western Australia, has shown evidence of four large meteorite impacts between 3.5 and 3.2 billion years ago.
Although microbial mat fossils such as Stromatolites were found in 3.48 billion year old sandstone in Western Australia, bacterial activity during this time cannot be proven. Why? Old sand granules can be compacted to form new rock.
Stromatolites are layered bio-chemical accretionary structures formed in shallow water by the trapping, binding and cementation of sedimentary grains by biofilms (microbial mats) of microorganisms, especially cyanobacteria.
3.500 – 3.200 Bya
The Kaapvaal Craton, including the Barberton Greenstone Belt, (now
in South Africa), underwent two tectonic episodes of terrane accretion about 3.5 and 3.2 Bya.
The Barberton Greenstone Belt, also known as the Makhonjwa Mountains formed about 3.500 to 3.200 billion years ago. It is situated on the eastern edge of Kaapvaal Craton of the Swaziland–Barberton areas of South Africa. It is known for its gold mineralisation and for its komatiites.
Komatiites are an unusual type of ultramafic volcanic rock.
Ultramafic Rock is an igneous rock with very low silica content and is rich in minerals such as hypersthene, augite, and olivine.
3.500 – 2.600 Bya
The Mauranipur and Babina Greenstone Belts in India formed between 3.5 to 2.6 billion years ago due to volcanic activity.
3.460 – 3.300 Bya
The Zimbabwe Craton is now in an area located in Southern Africa and is thought to have been formed 3.460 to 3.300 billion years ago and was
part of the ancient continent of Western Gondwana.
The Zimbabwe Craton apparently formed from the suture of two smaller blocks, the Tokwe Segment to the south and the much smaller Rhodesdale Segment, (Rhodesdale gneiss), to the north. These rocky segments have been dated to be around 3.460 billon years old. The Tokwe and Rhodesdale Segments probably stabilized about 3.300 billion years ago.
3.300 – 3.200 Bya
The Bastar Craton, (now in India), is composed of Archaean nuclei of tonalite–trondhjemite–granodiorite gneisses, enveloped by older granite–greenstone belt with banded iron formation (BIF). The Sonakhan Group of Bastar Craton of the
central Indian shield is comprised of volcanic sedimentary rocks.
Mesoarchean (Mesoarchaean) Era (3.200 – 2.800 Bya)
This is this third stage of the Archean Eon, which spans 400 million years. The era is defined chronometrically and is not referenced to a specific level in a rock section on planet Earth.
The Sun’s luminosity during the Mesoarchean Era was thought to be about 70% of its current value. This may have cancelled out any influence of a greenhouse effect that may have been operating. Planet Earth is thought to have had a continual warm surface during this period of time.
Earth’s atmosphere was still greatly affected by volcanic activity. Ammonia, methane, carbon dioxide, nitrogen and neon, seems to be present in this early atmosphere. It is thought that the carbon dioxide (CO2) levels were decreasing. However, more water vapour (H2O), nitrogen (N) and additional hydrogen (H), was entering the atmosphere due to volcanic out gassing. The amount of free oxygen (O2) emitted was still small, but increasing.
Volcanic and tectonic plate activity was still greatly affecting the flow of steams and rivers. The moon was still closer to Earth, but slowly moving away and cooling down. The gravitational pull of the Moon would still cause extremely high tidal activity on the forming oceans. The winds would still be of hurricane force.
It is also thought that Photosynthetic organisms started to appear between 3.2 and 2.4 billion years ago and they began to enrich the atmosphere with oxygen. However, there are different opinions about this. At this point of time, planet Earth’s environment would still be too hostile for life.
3.200 Bya
The Kaapvaal Craton, Zimbabwe Craton, and Limpopo Belt,
(now in southern Africa), are made from Archaean type terranes and contain crust material from at least 3.200 billion years ago. They are underlain by a thick, (250 km / 160 mile), layer of buoyant mantle from which garnets and diamonds are being produced.
3.100 – 2.500 Bya
The
Baltic Shield (or Fennoscandian Shield) is a segment of the Earth’s crust belonging to the East European Craton and was formed by tectonic plate activity between 2.500 and 3.100 billion years ago.
The Baltic Shield represents a large part of Fennoscandia, (now north western Russia and the northern Baltic Sea). It is composed mostly of Archean and Proterozoic gneisses and greenstone. However, the scouring by the ancient glaciers and the acidity of the soil has destroyed all the palaentologically interesting materials, such as fossils.
3.100 – 2.083 Bya
Ur – the smallest supercontinent.
The landmass known as Ur, (a proposed supercontinent, but smaller than present day Australia), formed about 3.100 Bya. However, Vaalbara, (a previously considered proto supercontinent), was still in existence. Was tectonic plate upheaval taking its toll? Maybe Ur was beginning to form as Vaalbara was breaking up. This is also open to conjecture. Maybe Ur merged with Vaalbara. Anyway, the two Cratons of India, the Western and Singhbhum Cratons, were thought to be apart of Ur.
3.000 – 2.600 Bya
The Saharan Metacraton is a description of the continental crust in
the north-central part of Africa. It
contains the oldest rocks in Egypt, which are about 2.700 billion years
old. Where as rocks in southern Libya
and eastern Chad have been dated between 2.900 and 2.600 billion years
old. The original Craton from which this formed could have been 3.000 billion years old.
3.000 – 1.850 Bya
The Tanzania Craton is an old and stable part of the continental
lithosphere in central Tanzania. Some
of the rocks are over 3 billion years old.
The Tanzania Craton forms the highest part of the East African
Plateau. The rocks in this area were intruded by granites and under went Migmatization in different events that date
back to 2.900, 2.700, 2.400 and 1.850 Bya.
2.980 – 2.880 Bya
The Rio Maria Crust, (now of Southeastern Amazonian Craton, Brazil), formed 2.980 to 2.880 billion years ago due to the dating of the zircons found there.
2.900 Bya
The Pongola Glaciation occurred around 2.900 billon years ago. It is currently the oldest known glaciation in the planet’s geologic history.
2.900 – 2.700 Bya
It is thought that huge pulses, due to tectonic plate movement, started the formation of island arcs and oceanic plateaus planet wide from 2.900 to 2.700 billion years ago.
2.880 – 2.860 Bya
The Rio Maria Granite-Greenstone Terrane, (now in the Amazonian Craton of Brazil), has a formation of Sanukitoid rocks due to a shear event around 2.870 billion years ago. The Rio Maria Granodiorite has yielded zircon of up to 2.880 billion years old. The granites from Rio Maria terrane are aged around this time period.
Sanukitoids are a variety of high-Magnesium (Mg) granitoid andesite found in convergent margin settings.
Granitoid or granitic rock is a variety of coarse grained, plutonic rock — granite or similar which is composed predominantly of feldspar and quartz mica.
Andesite is an extrusive rock intermediate in composition between rhyolite and basalt. Andesite lava is of moderate viscosity and forms thick lava flows and domes.
2.845 – 2.803 Bya
The supercontinent Vaalbara finally broke up between 2.803 and 2.845 Bya.
2.803 Bya
The landmass Ur also broke up at this point of time. Maybe Ur and Vaalbara collided and broke up together?
Neoarchean (Neoarchaean) Era (2.800 – 2.500 Bya)
This is this fourth and final stage of the Archean Eon, which spans 300 million years. The era is defined chronometrically and is not referenced to a specific level in a rock section on planet Earth.
The Moon by now is having a greater influence on planet Earth.
As the Moon orbits around planet Earth it stabilizes the wobbling of Earth on its axis of rotation, which now oscillates between 22.1 and 24.5 degrees. Because Earth is tilted on its axis, the formation of the four seasons makes planet Earth more conducive to the formation of life. But oxygen was still limited to small quantities in the atmosphere.
The Earth’s Crust was thickening and dusty on the surface. Minerals and matter would permeate the surface of Earth’s crust through tectonic plate movement and volcanic activity and in time formed soil and buried Paleosol after certain events.
Also! The scarcity of records for tectonic activity and intrinsic channel changes, hamper the interpretation of stratigraphic events at this time.
Paleosol, (fossil soils), is the matter buried within sedimentary and volcanic deposits.
Ephemeral ponds and alluvial sequences could have been the sources of the deposited Paleosol organic matter. However, the Paleosols soils that formed during this period have no relationship in their chemical and physical characteristics to the present day climate or vegetation.
2.720 – 2.655 Bya
The Superior Craton, (now in Canada and USA), (it is thought), was going through various geological developments between the western and the eastern part of the Craton. The western part of the Superior Craton appears to have had five major orogenic belt developments such as:
The Northern Superior Orogeny 2.720 Bya, the Uchian Orogeny 2.720 – 2.700 Bya, the Central Superior Orogeny 2.700 Bya, the Shebandowanian Orogeny 2.690 Bya and the Minnesotan Orogeny 2.680 Bya.
The eastern part of the Superior Craton appears to have had two major terrane collisions. The first major collision was when the Rivière terrane from the east collided with the Hudson Bay terrane located at the west side 2.700 Bya. A collision with the Uchian orogeny concurrently happened at the south and the west regions.
The second major collision concerns the NE Superior Craton and implies that active anorogenic magmatism took place during the accretion of the Southern Superior Craton, perhaps between 2.690 and 2.655 Bya.
2.720 – 2.100 Bya
Kenorland (a supercontinent) was formed about 2.720 billion years ago as a result of a series of accretion events due to tectonic nucleation. The tectonic plate movement, (it has been thought), brought the Kaapvaal, Karelian, Pilbara, and Superior Cratons closer together. These Cratons and other island arcs seemed to have coalesced into one large landmass and formed Kenorland.
It appears that Kenorland suffered from extreme volcanism. Between 2.480 and 2.450 Bya, protracted tectonic magma plume rifting occurred and this contributed to the glacial events between 2.450 and 2.220 Bya. It is thought that Kenorland finally broke up about 2.100 Bya, about 400 million years into Paleoproterozoic Era.
Next we enter the Proterozoic Eon between 2.500 to 0.541 Bya, which was the era of continental shield formation and oxygen build up events.
So! What Really Happened in the Archean Eon?
The people who formulated their premise on the Archean Eon based their ideas on the works of others who preceded them. From time immemorial, people have questioned the origins of the universe and life itself.
From the 1800’s people started to chemically analyse the atmosphere and material things, questioned life and the biblical understandings of their time.
Darwin’s book “On the Origin of Species” in 1859, encourage people to challenge biblical reasoning and many people sort to explore their own ideas and concepts about their existence. In 1927 it was thought that an expanding universe could be traced back in time to an originating single point. This became the theory of the “Primeval Atom”. In 1929 it was concluded that galaxies were drifting apart.
The people who chose to reject the biblical understanding formulated the “Big Bang” theory. The “Big Bang” was based on assumptions and conjecture. It is a flawed theory. However, people wanted things to fit into their own reasoning. From the “Big Bang” came the postulating of the formation of the universe and our solar system. Then came the formation of planet Earth and the beginnings of life.
Now the postulating has entered the Archean Eon and the time of reckoning has come. Isotopic testing of rock is flawed due to contamination of material in the “Parent Daughter” relationship of the isotope (half-life) decay of elements. It may well work under specially controlled laboratory conditions, but it fails in fieldwork.
The originality of the material is not known, nor observable in its original state or source. Testing of the same rock using various types of isotopic testing, gives great variations in the dating. In many cases people have averaged different results to fudge the required results to suite their understanding.
None of the data that I have presented in this thesis can really be proven.
It isn’t really about lying. It is just about unfounded assumptions and conjecture. What I have presented is fundamentally, the imagination of others.
What are your thoughts about the Archean Era?
It seems to be a good story, but slightly perverted.