OLDEST ROCKS AND FOSSILS, STROMATOLITES AND BANDED IRON

ÄLTESTE GESTEINE UND FOSSILIEN, STROMATOLITHEN UND BÄNDEREISENERZ

Es wurde schon viel darüber diskutiert, welches Gestein das älteste ist und worin sich möglicherweise erste Lebensspuren befinden (von links oben nach rechts unten): Nuvvuagittuq- Grünstein aus Kanada, evt. mit Lebensspuren, Acasta-Gneiss aus Kanada oder Isua-Grünstein von Grönland (Lebensspuren?). Auf jeden Fall findet das Ganze an der Grenze vom Archaikum zum Hadaikum statt also vor plus/minus 4 Milliarden Jahren... Ich habe ein Statement eingeholt von Kristen Coleman (Science Mall, USA).

     

The discussion about the oldest rock of the world, containing perhaps biogenic structures does not end (left above to right below): Nuvvuagittuq Greenstone, possibly with traces of life, Acasta Gneis or Isua Greenstone (traces of life?). It happens at the border between Archean and Hadean (ca 4 billions)... I bought Acasta Gneis from Thomas Kapitany, Australia, Nuvvuagittuq Greenstone and Isua Greenstone from Science Mall/USA. So I asked Kristen Coleman (Science Mall) to give me a statement:

“Conflict arises on the method of dating, accuracy, and exact location collected. When we recommend an age date it is with the confidence in saying that "the general average" microprobed or sampled.

Nuvvuagittug is about 4.3 with a minimum age of 3.8 Ga. The Nuvvuagittuq Greenstone Belt consists of recorded isotopic compositions that can only be produced in the Hadean (i.e. older than 4 billion years ago) and the complete isotopic study of all the lithologies included in the Nuvvuagittuq Greenstone Belt suggests that it was formed NEARLY 4.4 billion years ago. It IS the oldest without question and is only surpassed by just a little by the Jack Hills Zircons. (Below a picture of the Nuvvuagittuq Greenstone Belt in Québec/Canada.)

Isua is about 3.8 Ga.
Acasta Gneiss is 3.5-4 Ga.

Then there is Akilia sediments which include banded iron beds. Akilia rocks do show evidence of life at 3.85 Ga. This is the earliest time life would have had an opportunity to "organize" itself in a very tight zone, as before 3.9 Ga the Earth would have been very inhospitable. It is a little different from Isua
as it is from a different location.

North Pole stromatolite, probably one of the oldest examples of preserved fossil stromatolites in the geological record are about 3.5 Ga, found in Western Australia. Some stromatolites from South Africa are also in the same range (some people don't know that), such as the Fig Tree chert stromatolite at about 3.2 Ga.Gunflint chert stromatolite is 1.9 Ga. Apex Chert is 3.45 Ga. Barberton Greenstone and similar belts is about 3.5 - 3.8 Ga.

The oldest material on Earth is the Jack Hills zircons, with an average date of 4.4 Ga (below, with a piece of oldest stromatolites from Strelley Pool, Western Australia, ca 3.5 billions).

The problem lies in whether the reported date represents the age that the rock itself formed or the residue of an isotopic signature of older material that melted to form the rock.

Being that the youngest age of Nuvvuagittuq is 3.8 Ga and the probable cutoff for life to have existed is at 3.9 Ga, it is entirely possible that Nuvvuagittuq contains some ultra-primitive biogenic marker. This is just my opinion but I would not rule it out. It is like finding any other ancient fossil, you don't find the fossil until you separate it from the rock. Heat, pressure and tectonic forces could have utterly destroyed any evidence that it once did exist.

We don't know for sure yet, so it is an open-ended debate.”

ELEMENTARY POWER FORMS THE EARTH... Artist's impression of a Hadean Eon landscape, ca 4.5 billions of years ago... (Credit: Tim Bertelink via Wikipedia) - URKRÄFTE FORMEN DIE ERDE... Künstlerische Impression der "Landschaft" vor ca. 4,5 Milliarden Jahren, dem Hadaikum.

ZIRKONE ERZÄHLEN VOM HADAIKUM - 4,4 MILLIARDEN
ZIRCONS TELLS US OF THE HADEAN - 4.4 BILLIONS

Zircons are the oldest known materials on our planet. They offer a window in time back as far as 4.4 billion years ago, the Hadean, when the planet was a mere 160 million years old. Because zircon crystals are exceptionally resistant to chemical changes, they have become the gold standard for determining the age of ancient rocks. - The picture left below shows a stone (ca 2.5x2.5 cm) of my collection - it has "only" 3,5 billions, but the tiny zircons in it existed 4.4 billions of years ago. Above the location of Jack Hills/Western Australia, right below a false-color microscope image of a 4-billion-year-old zircon. (Image credit: John Valley)

Die Jack Hills sind eine Hügelkette in Westaustralien. In ihnen wurden die weltweit bisher ältesten Zirkone gefunden. Diese etwa 4,4 Milliarden Jahre alten Minerale ermöglichten bahnbrechende Forschungen zu den Umweltbedingungen des Hadaikums. - Das Bild links unten zeigt einen Stein (ca. 2,5x2,5 cm) aus meiner Sammlung - er ist "nur" 3,5 Milliarden Jahre alt, aber die winzigen Zirkone darin existierten bereits vo 4,4 Milliarden Jahren. Oben der Fundort Jack Hills, rechts unten das Falschfarben-Mikroskopfoto eines Zirkons.

Bill Erickson (Studied Geosciences at The University of Arizona) on facebook: During the Archean and until the Neoproterozoic, Australia and western Laurentia were contiguous (Nuna and Rodinia). It's interesting that the oldest zircons (4.4 Ga) are from the Jack Hills in western Australia and the oldest whole rocks are from the Acasta Gneiss of the Slave craton in northwestern Canada (4.03 Ga). Perhaps these regions of Laurentia and Australia, which were conjoined during most of the Precambrian, was the earliest continental crust that formed on the surface of the Earth.

Jack-Hills-Zirkone aus Australien befinden sich in dem Gestein oben (4,4 Mrd.). Darunter ein kleines Stück mit den ältesten bisher bekannten Stromatolithen: Strelley Pool, ebenfalls Australien (3,5 Mrd.). - Das Bild unten zeigt ebenfalls eine Scheibe (8x5 cm) eines Strelley-Pool-Stromatolithen aus Australien - and the location.

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STROMATOLITES - PROVIDERS OF OXYGEN
AND REAL ARTWORKS OF NATURE...

STROMATOLITHEN - SAUERSTOFFLIEFERANTEN
UND WAHRE KUNSTWERKE DER NATUR...

An diesen Stromatolithen aus den östlichen Anden südlich der bolivianischen Stadt Cochabamba ist der feinlagige Aufbau deutlich zu erkennen. Alter: Maastrichtium, Kreide, etwa 70 Millionen Jahre alt. Foto: Creative Commons.

These stromatolites from the eastern Andes, south of the Bolivian town Cochabamba, show very clearly the straticulated structure. Age: Upper Cretaceous, ca 70 millions ago.

These 1.9 billion year old (stromatolite) organisms made the atmosphere breathable for life. Stromatolites are the fossil remains of Early Proterozoic layered bacteria domes. Location: Tree River, Port Epworth, Nunavut, northern Canada.

 
Image may contain: tree, sky, outdoor and nature
Maria Angelica Muniz Frosi to The Proterozoic and Archean Eon , Deep Time geology

Banded iron at Fortescue Falls, Dales Gorge, Karijini National Park, Hamersley Range, Western Australia
between 2 and 2.2 billion years old

 

 

 

 

BANDED IRON FORMATIONS AND
THE GREAT OXYGENATION EVENT

The Banded Iron Formations (BIF) are abundant around the time of the Great Oxygenation Event (GOE), ca 2,400 million years ago, and become less common after 1,800 mya with evidence pointing to intermittent low levels of free atmospheric oxygen. The conventional hypothesis is that the banded iron layers were formed in sea water as the result of oxygen released by photosynthetic cyanobacteria. Picture: Banded iron at Fortescue Falls, Dales Gorge, Karijini National Park, Hamersley Range, Western Australia,
between 2 and 2.2 billion years old.

It has 2.6 billions and comes from Western Australia: a slice of "Banded Iron", 13 cm wide, indicating oxygen at that time. (Troppenz collection)

Sie ist 2,6 Milliarden Jahre alt und stammt aus West-Australien: eine Scheibe "Bändereisenerz", 13 cm breit, ein Indikator für existierenden Sauerstoff bereits zu dieser Zeit. (Sammlung Troppenz)

EVEN PROCARYOTES ARE SUSPECTED
TO PRODUCE MULTICELLULAR LIFE...

SELBST PROKARYOTEN SIND VERDÄCHTIG,
MEHRZELLIGES LEBEN HERVORZUBRINGEN...

Nothing is "not possible" - that's what I learned during my Precambrian studies. Even prokaryotes without nucleus are suspected of potentially producing complex multicellular life. If that was true, there is nothing left to inhibit the Precambrian biota. We could even speculate that there might have been animate worlds even before the Franceville biota from Gabon, which are yet to be discovered or which have literally vanished "without a trace" as a result of geological processes in the course of billions of years. Prokaryotes may not have a nucleus, but their DNA lies freely in the cytoplasm, the basic substance of the cell.

Apart from that, these cells are also capable of connecting and exchanging information. We know this for example from myxobacteria (photo on p. 43), which predominantly live on the soil on decaying organic material and move actively by gliding. They form swarms of thousands of communicating cells and are kept together by means of messenger substances (intercellular signals). Myxobacteria are currently in a transition phase from unicellular to multicellular organisms! The association of a great number of cells presumably facilitates nutrition, as the concentration of digestive enzymes is then increased.

It is fantastic: When nutrients become scarce, the cells surge towards each other and about 100,000 bacteria form a fruiting body with a size of only 1/10 mm. In this fruiting body, cells turn into spores - but the majority is used to nourish the group and help it survive... Myxospores are especially well protected against dehydration and show only little metabolic activity. They can remain in this stage and wait patiently until the supply of nutrients improves - by change of location or with the help of hosts or wind. These microorganisms' way of living is similar to that of eukaryotic slime moulds, and thus an example of convergent development. (My book "The New Precambrian")
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Selbst Prokaryoten ohne Zellkern werden verdächtigt, möglicherweise mehrzelliges komplexes Leben hervorbringen zu können. Dann stünde den präkambrischen Faunen wirklich nichts mehr im Wege, und es dürfte auch spekuliert werden, dass es bereits vor der Franceville-Fauna aus Gabun Lebewelten gegeben haben könnte, die entweder noch nicht entdeckt wurden oder durch geologische Vorgänge über Jahrmilliarden im wahrsten Sinne des Wortes "spurlos" verschwunden sind. Prokaryoten haben zwar keinen Zellkern, jedoch befindet sich ihre DNA frei im Zytoplasma, der Grundsubstanz der Zelle.

Außerdem: auch diese Zellen sind in der Lage, sich zu verbinden und Informationen auszutauschen. Bekannt ist das u. a. von Myxobakterien (Foto gegenüberliegende Seite), die vornehmlich am Boden auf verrottendem organischen Material leben, sich durch ein Gleitsystem aktiv bewegen können, Schwärme aus tausenden von Zellen bilden und sich durch Botenstoffe (interzelluläre Signale) verständigen und zusammenhalten. Sie befinden sich derzeit im Übergang von einzelliger zu mehrzelliger Lebensweise! Vermutlich erleichtert der Zusammenschluss vieler Zellen die Ernährung, weil auf diese Weise die Konzentration der Verdauungsenzyme erhöht wird.

Es ist phantastisch: Wenn die Nahrung knapp wird, strömen die Zellen zusammen und bilden aus etwa 100.000 Bakterien einen nur 1/10 mm "großen" Fruchtkörper, in dem sich die Zellen zu Sporen wandeln - ein Großteil wird jedoch zum Überleben der Gruppe als Nährstoff verwendet.... Die Myxosporen sind besonders gut vor Austrocknung geschützt und haben nur einen ganz geringen Stoffwechsel. Im Dauerstadium können sie so bequem abwarten, bis sich die Nahrungsverhältnisse verbessern - durch Ortswechsel mit Hilfe von Wirten oder Wind. Die Lebensweise dieser Mikroorganismen ähnelt der von eukaryotischen Schleimpilzen, ist also ein Beispiel für konvergente Entwicklung. (Mein Buch "Wohin die Spuren führen")