[meteorite-list] AD - Nuvvuagittuq specimens, oldest terrestrial rock (4.28Ga), and oldest evidence of life on Earth (BIF : 3.8Ga)

From: Fabien Kuntz <wwmeteorites_at_meteoritecentral.com>
Date: Tue, 17 May 2011 00:32:59 +0100 (BST)
Message-ID: <128672.72360.qm_at_web29616.mail.ird.yahoo.com>

Hello,

after some request from meteorite friends, I offer here a new selection of
specimens from Nuvvuagittuq. This time the complete suite of 5 rocks. The
oldests terrestrial rocks on Earth (primitive/hadean crust relics), and smples
of Banded Iron Formations, the oldest evidence of life on Earth...


The samples have been obtained directly from the team published the study in
Science (26 Sept. 2008 : http://www.sciencemag.org/content/321/5897/1828), they
will be sended with signed letter and the field data I recieved with the
samples.

The Nuvvuagittuq greenstone belt is an Eoarchean/Hadean succession preserved
along the eastern coast of Hudson Bay in the Northeastern Superior Province,
Quebec, Canada. It is essentially composed of three major lithological units:

1) Mafic cummingtonite-amphibolite, known as the ?faux-amphibolite?. Oldest
known (terrestrial!) rock on Earth (146Sm-142Nd isochron with an age of 4280
+53/?81 million years) :



http://www.wwmeteorites.com/NuvvuagittuqFA.html


2) Ultramafic and mafic sills that intrude the fauxamphibolite, represented here
by both garnet-rich and Fe-rich amphibolites lithologies (147Sm-143Nd isochron
with a slope corresponding to an age of 4023 ? 110 Ma), probably the second
oldest terrestrial rock on Earth (older than Acatsta gneiss) :



http://www.wwmeteorites.com/NuvvuagittuqAmphibolites.html


 3) Chemical sedimentary rocks comprising a banded iron formation (BIF) and a
silica-formation, represent the oldest evidence of biological activity on Earth
( ~3.8Ga). Formed in sea water as the result of oxygen released by
photosynthetic cyanobacteria (bluegreen algae), combining with dissolved iron in
Earth's oceans to form insoluble iron oxides, which precipitated out, forming a
thin layer on the substrate :



http://www.wwmeteorites.com/NuvvuagittuqBIF.html


Fabien

 Fabien Kuntz
M?t?orites (ventes, expertise, conf?rences)
Animation scientifique et technique
WWMETEORITES (Siret : 511 850 612 00017)
www.wwmeteorites.com
Received on Mon 16 May 2011 07:32:59 PM PDT