Massive #hematite later brecciated by quartz veining, From the Soudan ironstone, Ely greenstone belt, Vermilion district of northern Minnesota.
These ironstones are sandwiched between pillow basalts of approximately 2.7 billion years old.
Today, molybdenum is one of the most common trace elements in the ocean due to oxidative weathering of #Molybdenite. But in the Archean the oceans were reducing, and molybdenum was scarce.
Other nitrogenases evolved to use other transition elements, but Mo-nitrogenase was first, and best.
Molybdenite enables the Earth's biosphere!
#MinCup25 #NitrogenFixation #Nitrogenase #Archean #GreatOxidationEvent
#Molybdenite is the primary host for the element molybdenum in the Earth's crust.
Molybdenum is part of the most effective biological molecule for nitrogen fixation (Mo-nitrogenase), which converts atmospheric N2 to a bio-available form.
The grey sphere is Mo; this complex molecule likely evolved more than 3.2 billion years ago.
#MInCup25 #NitrogenFixation #Nitrogenase #Archean
A well illustrated talk by Dr. Ali Polat (University of Windsor, Ontario), the 2024 Geological Associate of Canada Robinson lecturer. He gave persuasive evidence for compressive tectonics throughout the Archean.
Figure is of refolded isoclinal folds in the Archean (2.8 Ga) Storø Greenstone belt, southern West Greenland.
#McGillUniversity #GAC #UWindsor #Ontario #Canada #Greenland #Archean #Geology #Tectonics
Plain light thin section (~ 4 cm wide)
Pale pink garnets (inclusion-rich cores and inclusion-free rims) surrounded by mostly biotite.
From the Nuvvuagittuq formation near #Inukjuak Canada.
Coupled Sm-Nd isotopes suggest that the original rock (the protolith) may be as old as 4.3 billion years. This sample has been pervasively metamorphosed at least four times since then.
The oldest Scandinavian bedrock was "born" in Greenland according to a new geological study from the University of Copenhagen. The study helps us understand the origin of continents and why Earth is possibly the only planet in our solar system with life.
Geoscientists have uncovered a missing link in the enigmatic story of how the continents developed—a revised origin story that doesn’t require the start of plate tectonics or any external factor to explain their formation. Instead, the findings recently published in Nature Communications, rely solel
Summary. The EarthScope Transpotable Array (TA) deployment provides dense array coverage throughout the continental United States and with it, the opportunity f
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Bill Minarik
💧🌏 Greg Cocks
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